DIY solar system with NiFe (nickle Iron) batteries - Survivalist Forum
Survivalist Forum

Advertise Here

Go Back   Survivalist Forum > >
Articles Classifieds Donations Gallery Groups Links Store Survival Files


Notices

Advertise Here
Similar Threads
Thread Thread Starter Forum Replies Last Post
Batteries for Solar after SHTF ryan112ryan Disaster Preparedness General Discussion 31 12-27-2015 03:31 PM
Do these figures look right? Solar Batteries budgetprepp-n Disaster Preparedness General Discussion 2 04-22-2015 02:40 PM
nickel-iron batteries rayray1 Disaster Preparedness General Discussion 22 12-21-2014 11:37 AM
Concern about frozen batteries for solar-electric system MyPrepperLife Farming, Gardening & Homesteading 10 09-11-2013 07:07 AM
Small Batteries 101 Crash Course (not Solar Batteries) Emerald Eyes General Discussion 8 09-21-2012 03:06 PM
Iron Dome missile defence system BOBtheBUTCHER Military Weapons Forum 3 03-15-2012 06:27 PM
Solar charger for AAA batteries? prepper21 Disaster Preparedness General Discussion 27 07-27-2011 04:58 PM
Solar batteries Swampwood DIY - Do It Yourself 12 04-02-2011 03:28 PM
Stockpiling Solar and Batteries nadja Disaster Preparedness General Discussion 18 08-27-2010 05:06 PM
Solar charger for AA batteries kev Urban Survival 19 03-22-2009 09:36 AM

Reply
 
Thread Tools Display Modes
Old 12-23-2012, 12:01 AM
NoTea4U NoTea4U is offline
Hiker
 
Join Date: Nov 2012
Posts: 600
Thanks: 614
Thanked 1,330 Times in 414 Posts
Default DIY solar system with NiFe (nickle Iron) batteries



Advertise Here

This will be a lot of information, so I'm going to title each post. I think it's important for people to know the full process I went through, so you know what you're in for if you decide to build a similar system.

The system I created was for dry-docking a 30' RV. It included NiFe and lead acid batteries (3 banks total), solar panels, and a custom built charge controller. I'll detail it all here in order.

Why I chose NiFe batteries for my main bank (instead of Lead Acid)

I have to admit, I was hooked on NiFe batteries when I learned their strengths and weaknesses. I purchased these for my solar system knowing I'd build the rest to match the cells. Starting with that decision turned out to be of huge benefit, for I reached hurdles at every step of deployment. Had I known of those hurdles in advance, I would have been scared away from NiFe, and I would not have the system I have today. This thread will detail all I learned starting with the batteries. It's a lot of information, but it will be all in one place. I believe anyone considering a DIY solar backup system will benefit greatly from this thread.

My escapade began with an article detailing Thomas Edison's batteries. Though over 100 years of age, his cells were still operating and in use by one of the museums! Reading about NiFe was a dream. Lead-acid is a great choice for some people, but it wasn't for me. I wanted batteries that could stand considerable abuse, and which I could count on even if I didn't baby them. NiFe batteries fit the bill. Let's look at both benefits and drawbacks.

Benefits that sold me on NiFe batteries
  1. Not damaged by freezing, even if they are fully discharged
  2. Not damaged by repeated full discharge (this enables me to buy less capacity, since I don't have 1/2 the battery capacity unavailable as with lead-acid)
  3. Not damaged by an over-voltage charge (all you have to do in extreme situations is top up the water)
  4. Not damaged by excessive charging (again, just top off the water)
  5. The internal structural components are steel, so they are very durable
  6. Can accept a very fast C/5 charge (compared to a C/20 for lead-acid)
  7. With reconditioning, a 50 year service life is common
  8. Well maintained, 20 year serviceable life between reconditioning periods
  9. Poorly maintained, 7-8 year serviceable life between reconditioning periods
  10. Reconditioning requires only distilled water and pot ash. Lithium, if available, increases efficiency.
  11. The purchaser mixes the electrolyte. Alter the composition to optimize the cells for any temperature.
  12. When NiFe batteries are used for low current applications, they significantly outperform the wattage they are rated for.
  13. NiFe can be directly charged from solar panels, so I don't need a charge controller. This is huge for me because I saw a charge controller as a weakness. The fewer and simpler the parts, the less likely I am to have my solar system fail me. Think economic risk here... if essential parts fail and can't be replaced, you have no power.

Detrimental aspects of NiFe batteries
  1. Price - NiFe cost about a dollar per watt of storage capacity at the time I purchased. This is much more than lead-acid.
  2. NiFe is not as energy dense, so they require more space.
  3. NiFe cannot provide as much current on-demand as lead acid. They can't, for example, provide for the huge current draw of a vehicle's starter motor. They do however, perform very well at a draw of up to one third of their rated capacity. A 4200 watt pack can supply up to 1400 watts per hour. That's roughly a 100 Amp draw.

Myths about NiFe
  1. They discharge rapidly. I have tested my batteries and they hold a charge for about 15 months. So they do lose a bit of power in storage, but not a lot. If I'm relying on my solar array, I'm using it daily. This makes the power loss inconsequential. For optimal longevity, I should charge them at least once per year.
  2. Creating a backup solar system on NiFe is hard. I can't count the number of times I was told this. The only thing that made it difficult was disinformation. After I weeded through that, it was exceptionally easy.

Choosing a supplier
If you want to buy new NiFe cells you can buy from China or from India. New NiFe cells are not produced elsewhere in the world, period. Now before you say 'Chinese crap' let me tell you that China produces the NiFe batteries used by almost all military establishments around the globe. The Chinese electric rail system runs on these batteries, as do the backups for many remote cell towers, pumping stations, and other essential services.

There is a US remanufacturer of NiFe batteries in Montana. They do not build new cells, but rather clean existing cells and ship them with new electrolyte. I didn't want used cells at their price, which was 60% higher than Chinese suppliers I reviewed. Reconditioned cells should have the same lifespan as new, so if you want to buy US cells period, remanufactured it is.

The supplier I chose was New Taihang Power Company. They work closely with Changhong and apparently the batteries are virtually identical. New Taihang will not sell small quantities, while Changhong does. When I reached out to the New Taihang factory to buy a small number of additional cells, they recommended Changhong, and so they are the focus here. Changhong has considerably better documentation that New Taihang.

Completing the purchase
I reached my supplier through Alibaba. First, I confirmed that the supplier was bonded and had a high reputation. Then I obtained my quote, sealed the deal, and sent a bank draft to the institution. That part freaked me out a lot, but the bank information was very clearly for the right place. I did some looking into Chinese bank accounts and found out that one cannot open a fraudulent account in the name of the Chinese government under penalty of death. Talk about a wow moment there. Anyway, I sent off the money, and one week later had confirmation the batteries would move to production.

The representative I worked with was exceptional. She sent me regular updates on the status of my order. It was delayed because the Chinese government ordered a HUGE supply of cells from Changhong and New Taihang factory was helping to fill the order. I was presented with the choice to wait an extra 3 weeks or to cancel for a refund. I waited of course, and the cells were in the container after that delay.

It took several weeks for the shipment to arrive in Canada. Prior to the arrival, I was asked for the contact information of my receiver, which I did not have. I've never ordered anything from China direct. I asked my rep if they had worked with any Canadian receivers before, and she recommended one. All customs clearing papers were emailed to me in advance, and the order cleared customs without a hitch. It went into storage at the brokers. I went to the customs office 3 days later and cleared the batteries, then showed up and paid the $150 storage and transfer fees. Storage adds up fast, so don't leave your shipment too long!

Transporting the batteries
It was a 5 hour trip to the port so I could bring my batteries home. They could not be couriered like most case goods, because they are considered hazardous due to the potash in the container.

I was a might shocked when I saw the batteries. They were created in a wooden box, and exceptionally well packaged. They came complete with a bag of dry potash, a bag of lithium, safety goggles, a rubber apron, gloves, a hygrometer... everything needed to make them serviceable. The cables to connect all the cells were also included... along with spares.

Because all goods were dry, I was able to simply load them into a car. 11 batteries totaled about 500 pounds. I needed 10 cells for the battery bank and figured on one extra for emergency replacement. Having seen the durability of these cells first hand, I don't think I'll ever need the replacement. They are rock solid, but as previously mentioned, they are built for military and other intense industrial use.

Building the electrolyte
The electrolyte is nothing but distilled water and potash. You have to put the water in a large jug, to which you add the potash. The water will heat up as the potash dissolves and chemical bonding occurs. VERY IMPORTANT... you cannot add water to the potash. To do so would cause an intense chemical reaction, building a base of extreme concentration strong enough to dissolve flesh on contact. Add potash to the water and you are rather safe. Wear all protective gear.

Lithium hydroxide is included to help increase battery performance. It only adds 5-8% capacity, so it's far from essential, but they include it and you want to add it.

The concentration of the potash and water determines the temperature the battery is best suited to. Plan for winter instead of summer. In the winter, your battery's capacity and efficiency are more important because you have less sun energy for charging. By my calculations, it is better to have less capacity in the summer when you don't need your batteries as much as you do in winter months.

The electrolyte cannot be stored for extended periods outside of the batteries. I tried and ended up with a batch that looked like vomit after sitting a few months. Not sure what happened, but I assume it reacted with my plastic storage container. Maybe it would store in other circumstances, I am not sure. It stores fine dry.

Filling the cells was a simple matter of pouring into a funnel they supplied, and watching until I reached the full line. The casings allow enough light through to see the electrolyte level. I filled all cells to a small bit beyond the full mark.

Charging the cells
Unlike lead-acid cells, the batteries are stone cold dead when the electrolyte is first added. I connected a Mastech variable voltage DC supply to charge the batteries. I set the power supply for 50 Amps variable voltage, and watched closely as the cells charged. It took 14 hours for the cells to fully charge. They bubbled through charging and for 2 days afterwards. The bubbles are explosive offgassing, so you have to do the charging outside. I did it in a garage.

A note about my Mastech DC supply... don't buy the aftermarket leads. Although they are supposed to be rated for 50 Amp 30 Volts, there's no way! I tried and the leads got quite hot at 21 Volts 14 Amps... so hot in fact that I was afraid they'd melt off their plastic shell. I carved an end off a set of jumper cables and used them for leads instead. Worked perfectly and accepted the full 50 Amps. I'm very happy with the Mastech charger. They do sell direct to savvy end users for a 45% discount, so don't waste coin buying a Mastech charger from an intermediary. The model I bought was an HY3050EX. It draws about 14 Amps @ 110 V when charging at the max rate for a 4200 watt battery bank.

That's the end of the basic battery section of the post. I will have to find my formulas for optimal electrolyte strength at different temperatures. I'll post that when it's located. I have a couple manuals I can post too. The next posts will detail choosing the right solar panels, building the charge controller, and testing results.
Quick reply to this message
Old 12-23-2012, 12:15 AM
ComancheSniper's Avatar
ComancheSniper ComancheSniper is offline
See you in my Scope
 
Join Date: Nov 2009
Location: SE Arizona, USA
Posts: 2,618
Thanks: 934
Thanked 5,764 Times in 1,498 Posts
Default

I am starting to get hooked! What was the total cost of your batteries?
Quick reply to this message
The Following User Says Thank You to ComancheSniper For This Useful Post:
Old 12-23-2012, 12:31 AM
Survival Helper's Avatar
Survival Helper Survival Helper is offline
VIP Member
 
Join Date: Oct 2007
Location: Indiana
Posts: 2,509
Thanks: 2,428
Thanked 2,155 Times in 971 Posts
Awards Showcase
Outstanding Helpful Post Outstanding Gear Review 
Total Awards: 2
Default

Great post again, glad I got to see this one as well!!
__________________
HELP KEEP THIS FORUM GOING https://www.survivalistboards.com/payments.php
Quick reply to this message
Sponsored Links
Advertisement
 
Old 12-23-2012, 12:54 AM
NoTea4U NoTea4U is offline
Hiker
 
Join Date: Nov 2012
Posts: 600
Thanks: 614
Thanked 1,330 Times in 414 Posts
Default

Choosing the right solar panels

I have what are technically considered 12 Volt solar panels. Mine are rated at 135 watts, though the factory now produces 140 watt panels in their place.

Okay, so my goal was to direct wire my panels to my battery bank for charging. This would eliminate the need for a charge controller, thus simplifying my system and making it more foolproof. It was my intent to build a solar system that wouldn't contain any weak spots that weren't essential. I was able to achieve this, as you will see when you read about my controller.

Okay, so in order to buy the right solar panels, I needed to ensure the output voltage of the panels directly matched the charge requirements for the battery bank. Most solar panels used on houses today are not 12 Volt panels. They produce too high a voltage for direct wiring. You cannot direct wire a 12 Volt panel to a Lead Acid battery, but you can direct wire one to an NiFe battery bank.

The 12 Volt panels have an open circuit voltage of 22.1 Volts and a peak power voltage of 17.7 Volts. The optimal charge voltage for a ten cell NiFe battery bank is between 15.5 and 18 volts depending on the state of the battery, so the panels peak output closely matches what the batteries need.

One can choose any brand of 12 Volt panel of similar specification. There are reasons to consider different panels. The first is dimensions. In my case the Kyocera panels were shaped properly for me to fit one on each side of my roof vent, allowing for about 20" of clearance. This is optimal because the vent would cast a shadow if too close to the panels (which I wouldn't raise because I didn't want them bucking wind while driving). The problem with shadows is that the performance drop of the panels is very significant if even a small portion of the panel is shaded. Nothing you can do about that... accept it and design your layout accordingly.

When looking at your panels, pay close attention to the warrantee. In my case, I had actually selected a different panel before the Kyocera, only to find out that the Kyocera warrantee would cover me if I installed the panels myself, and on an RV. On the other hand, the other manufacturer would only back panels if installed professionally, and on a fixed residential home.

Installation

I chose a flat mount installation because it was simple and less conspicuous. The brackets are simply "L" brackets which enabled me to mount the panel directly to the surface of the RV. I put RV roofing sealant around the screw holes for the brackets, attached the panels, and then put silicone over the brackets and screw holes. To help prevent theft, I filled the drive holes for all mounts after things were secured. I can remove the silicone fill, but anyone wanting to do a clean pull will need extra time. I also marked the sides of the panel frames so they would be hard to resell, in hopes that a potential thief would see the damage (which affects resale but not usage). I never intend to sell the panels, so I didn't mind marring them a bit.

Wiring
Because your cabling is exposed to the elements, it needs to be rated for the job. I used underground conduit which had the wires within. I needed 10 feet and bought 14. After all the curves and bends (the cable doesn't bend sharply), I ended up using all 14 feet. Buy extra cable because you can cut it shorter if you need to. I have yet to figure out how to cut cable longer.

The rules for cable thickness with a 12 Volt supply are very different than with AC. Current drop off is significant even on short runs, so you need ridiculously thick cable. I won't bore you with the details, other than to say I chose the equivalent of 3 gauge cable to connect my 2 panels with my battery bank. Loss @ 14 feet was under 1% with that thick cable, and it could support a 3rd panel if I ever add one. You can verify your cabling needs using this calculator: http://www.solar-wind.co.uk/cable-sizing-DC-cables.html.

The underground conduit you can purchase will have either 3 or 4 wires within. To save money and have optimal cable flexibility, I chose the type with 4 wires. I connected the wires in pairs so I would have two positive and two negative lines within the cable. I connected the positive terminals of the two panels together, and to one pair of the conduit cables. I connected the negative terminals of the two panels together, and to the other pair of conduit cables. I ran those into a junction box within the RV.

Breaker circuit
You can direct-wire your panels to your charger, but you still need some form of electrical breaker in your circuit. Specifically, you need to be able to turn the system on during the daylight hours, and off during night. If you do not, the power in your batteries feeds back to your solar panels and will disperse. My short term solution was to install a 50 Amp DC toggle switch (http://www.wiringproducts.com/conten..._switches.html) so I could connect and disconnect the charging circuit at will. I drilled a hole into the junction box and attached the toggle.

There is a second reason you need to be able to disable charging. When your batteries are full, any additional current you feed in simply breaks down your electrolyte. As such, you will get more power from your batteries, and have less maintenance, if you only charge the cells when they need it.

Wiring the battery bank to the RV
This part was easy but not intuitive. I used my multimeter to determine which wires in the RV carried the positive and negative charge. I had to do this, because the color coding did not seem to make sense. It was wise, for the colors used in DC automotive circuits do not correspond with those used in house wiring. I disconnected the circuit which allows me to use the RV engine battery for emergency power. I connected the positive side of the battery bank to the positive supplemental power line in the RV, and the negative side of the battery bank to the negative supplemental power line. I tested the lighting and breakers. All worked properly.

Result at this stage

Okay, so now we have our solar panels wired to charge our NiFe battery bank, complete with a cut-off circuit. There is a breaker panel, but only one simple toggle within. The battery bank will power the living quarters in the RV. There is no charge controller yet, so there is no way to know what is happening from a charge perspective.

The next post will deal with the custom charge controller... why I built it, what it does that other charge controllers do not do, and how I eliminated the typical failure points which could apply with other charge control technology. I will also cover the limitations and sacrifices which applied due to my charge control solution.
Quick reply to this message
Old 12-23-2012, 01:16 AM
NoTea4U NoTea4U is offline
Hiker
 
Join Date: Nov 2012
Posts: 600
Thanks: 614
Thanked 1,330 Times in 414 Posts
Default

The batteries were just shy of (updated figure) $3000 landed cost. That included 10 cells for the battery bank, one spare cell for repair purposes, shipping from China, customs clearing, brokerage fees, storage, my trip to pick them up from the port, and all the materials needed to make the electrolyte. The Mastech charger was $510 with shipping.

Heading off to bed for the night... you all take care! I will post about the controller tomorrow.

Last edited by NoTea4U; 12-23-2012 at 12:06 PM.. Reason: * Looked back to my original quotes and updated to match
Quick reply to this message
The Following 11 Users Say Thank You to NoTea4U For This Useful Post:
Old 12-23-2012, 01:17 PM
NoTea4U NoTea4U is offline
Hiker
 
Join Date: Nov 2012
Posts: 600
Thanks: 614
Thanked 1,330 Times in 414 Posts
Default

US Manufacturer update: In the interest of accuracy, I need to update information with respect to US battery availability. It seems Zappworks from Montana now produces a battery in the US which is not factory reconditioned. They're still ridiculously expensive, but some do still want a US manufacturered cell, so you need to know one is available. This must have changed since I purchased my batteries. At that time, all Zappworks cells were reconditioned. It may be that they're still using reconditioned plates and not promoting that fact... I read reports saying that today, but cannot confirm.

More about the NiFe cells: In my above review of NiFe batteries, I mentioned (point 12) that NiFe batteries significantly outperform their ratings when the current draw is low. You need to see the statistics on the batteries to fully appreciate this.

The cells I purchased at TN-350. The Changhong equivalent is NF350-S. Assuming a 17.7 Amp sustained drain, the cells reach 1.05V after 20 hours. However, at a 1.72 Amp sustained drain, the charge lasts 240 hours. This translates to a 10 cell bank @ 20 hour discharge providing 4,602 Watt Hours. If the current draw is reduced to 1.72 Amps, the bank supplies 5360 Watt Hours.

One TN-350 cell is rated at 350 Amp hours, so it should provide 420 Watt Hours. Allowing for 12 cells, that's a 4200 Watt Hour bank. However, you can see by the ratings that low draw (such as LED lighting) would provide me 5360 or more Watt Hours of usable power, so in effect I get about 25% more output than the batteries are rated for.

Does a 1.72 Amp draw provide enough energy? The batteries seem to hold 13 V for the bulk of their discharge. A 1.72 Amp draw @ 13 Volts = 22 Watts. That's enough power for my laptop (11 watts) and three lights (just under 9 watts). Alternatively, if the laptop is off I can run 8 lights. I can do that non-stop for 10 days at 24 hours a day with no charge input. Realistically, I would only use about 6 hours of power in the winter and 3 in the summer, so my system is overbuilt for these purposes. Other appliances are conveniences which would be infrequently used, such as a Foodsaver, or appliances which would be used in times of peak energy production, such as the Fantastic fan. My battery chargers consume 20 Watt Hours to fully refill my Lithium Ion battery packs (for flashlights and such). A 1.72 Amp draw for 24 hours = 536 Watt Hours. If I use 6 hours with 6 lights, plus charge my flashlight batteries daily, plus run my laptop for 5 hours a day, I'm at 183 Watt Hours used and 66% of my daily power allotment is still available. So yes, I do believe this is reasonable.

Anyway... I'll detail the charge controller later today. Hope I'm not giving too much information at once. I always figure it's better to have more information than less, because you can weed out what you don't want.

As mentioned, here are the two links for information on NiFe batteries. The links look the same because the URLs don't all show. They do produce two different files.

https://www.google.ca/url?sa=t&rct=j...55534169,d.cGE

https://www.google.ca/url?sa=t&rct=j...55534169,d.cGE
Quick reply to this message
The Following 12 Users Say Thank You to NoTea4U For This Useful Post:
Old 12-23-2012, 02:56 PM
NoTea4U NoTea4U is offline
Hiker
 
Join Date: Nov 2012
Posts: 600
Thanks: 614
Thanked 1,330 Times in 414 Posts
Default

Charge Controller Background

My decision to devise a charge control system came from my electric outboard motor. I couldn't see charging a Lead Acid battery for the boat from anything but the solar panels. I mean, why drain my NiFe cells to charge other batteries, when I already had panels and could keep the NiFe cells at peak fill rates. This matters because one cannot always forecast the weather. By maintaining peak charge in my NiFe cells, I have much more reserve energy for when storms or overcast weeks arrive.

After calling every manufacturer to find a suitable charge controller, I determined that controllers to accommodate multiple battery chemistries do not exist. The only way I would have one is if I created a device to provide the functionality I sought.

The mind-bending process
Deciding to create a charge control system meant that I'd have a redundant second circuit which could handle Lead Acid. Not to let such a device go to waste, I went about wiring two positive lines from the junction box to battery compartment under the hood. I put two deep cycle batteries in there, connected in parallel. I connected one positive cable runs to those batteries, and the other positive run to the RV's deep cycle starting battery. Both cables terminated at the junction box inside the RV.

I shared a common ground between all battery banks, connecting the negative terminal of every battery bank to the frame. All postive runs led to the junction box, where they would be activated through a series of manual switches. I ended up needing 5 on-off-on switches rated for 50 Amps DC. http://www.wiringproducts.com/conten..._switches.html

The first of the switches determines if the solar panels are off (off position), charging the NiFe batteries (left on position), or charging the Lead Acid batteries (right on position). The Lead Acid circuit includes a PCM controller at this point, so that the voltage is adjusted for Lead Acid charging.

So now, at the toggle of the first switch, I have:
on-left - Correct power for charging the NiFe batteries
off - solar panels disabled for night or when batteries are at peak capacity
on-right - Correct power for charging the Lead Acid battery banks

Now I connect an on-off-on switch to the Lead Acid charging cable. This directs the current to either of the two banks, so that only one is charging at a time.

At this point, I have:
on-left - Correct power for charging the NiFe batteries
off - solar panels disabled for night or when batteries are at peak capacity
on-right - Correct power for charging the Lead Acid battery banks which is then directed to the bank I wish via a second toggle

All that remains is to create the appropriate battery connections.

To each of the three battery bank positive leads, I connect an on-off-on switch in a non-traditional manner, to function as both a safety and a means of directing current. The switches current input connection connects to the battery bank positive lead. One on side connects with the charge circuit for that battery and the other connects with the positive terminal for the DC power running through the RV. An auto-reset 40 Amp 12 automotive breaker is attached between each battery output and the RV power system (3 breakers total). These breakers will disable the battery current in the event of a short, and they will also prevent people from pulling more than 500 watts through the RV wiring.

The outcome
I now have a junction box that looks very simple from the outside. It contains a mere 5 switches.
The top switch is labeled Charge NiFe, Off, Charge Lead-Acid
The second switch on the right is labeled Charge Backup bank, Off, Charge Starting Battery
The last three switches are all marked RV power, Off, Charge

Operational Result
  • To charge any battery, I only need to flip the top and secondary (right) switch to choose the battery bank I want to charge, then set that bottom switch to charge mode.
  • To run off a battery bank, I simply flip any bottom switch to the RV power side.
  • The only mistake I can really make is to try to run the RV off two battery banks at once. This could trip a safety breaker because the batteries would attempt to normalize.

Advantages and must-have reasons I did this
  • The voltage of an NiFe charging circuit is too high to run to 12V devices. This circuit prevents the charge current from ever entering any 12V environment.
  • The toggles enable me to charge any battery bank while any other battery bank provides RV power.
  • The PCM controller enables me to correct the voltage for any charging circuits which are not NiFe. I would not need the PCM controller if I was using only NiFe battery chemistry. If it ever fails, I still have a fully functional NiFe system with safeties.

Disadvantages of my configuration
  • I used a PCM controller to charge the lead acid, instead of a MPPT. This results in about 30% of the solar charge being wasted in the lead-acid circuit. However, it is a secondary circuit, and as such I didn't see the need to spend extra. For those who don't know, an MPPT controller converts excess voltage into charging amps, while a PCM controller simply converts that voltage to heat.
  • It would be possible, if one did not know how to run the junction box, for a person to trip the breakers by accidentally enabling multiple battery banks to run the RV. That is a design limitation which I believe would restrict this from becoming a mainstream design.
  • I could have eliminated the extra right-hand toggle if I the first switch was an on-off-on-on switch... perhaps a rotary dial would work. I couldn't find a switch of such a design which could handle sufficient DC current. There are devices which will enable a high current flow when they have switching current flowing through them, but this approach was cheaper and is still easy to operate.
  • I cannot charge a battery bank while using it within the RV. This is a significant limitation in a SHTF scenario where all my lead acid batteries eventually fail. It would provide no disadvantage if I had two NiFe battery banks instead of one.
Quick reply to this message
The Following 10 Users Say Thank You to NoTea4U For This Useful Post:
Old 12-23-2012, 03:16 PM
NoTea4U NoTea4U is offline
Hiker
 
Join Date: Nov 2012
Posts: 600
Thanks: 614
Thanked 1,330 Times in 414 Posts
Default

Measuring current draw
There is one component which I added after, and it was for measuring the rate of charge and the rate of current draw in the RV.

I decided to splice in a measuring device between the solar panel cables and the junction box. It was so easy, and it provided me a means of seeing the input voltage from the panels, output current from the panels, and collective power generated by the panels since sun-up. A version of the device I installed can be seen here: http://www.ebay.ca/itm/130-Amp-12-24...#ht_582wt_1012. The device works very well, but the display can be hard to read if the temperature of the device is below -10C.

I have only one of these devices. It would make sense to have two, for if a second were placed between the RV positive power circuit and the battery banks, one could see how much current the RV is using throughout the day. As mentioned, i have only one of these so I have to move mine around to measure, and now that I know my typical current draw, and have determined my system to be overbuilt, I don't feel I really need the second. It would still provide useful information though; by comparing the charge and usage figures, one would know how their power status changed on any given day.
Quick reply to this message
Old 12-25-2012, 07:00 PM
John4018 John4018 is offline
Junior Member
 
Join Date: Oct 2012
Location: Alabama
Posts: 245
Thanks: 8
Thanked 691 Times in 145 Posts
Default

Could you post some photo of the setup?
Quick reply to this message
The Following User Says Thank You to John4018 For This Useful Post:
Old 12-26-2012, 09:37 PM
NoTea4U NoTea4U is offline
Hiker
 
Join Date: Nov 2012
Posts: 600
Thanks: 614
Thanked 1,330 Times in 414 Posts
Default

Quote:
Originally Posted by John4018 View Post
Could you post some photo of the setup?
It isn't really conducive to pictures, as the parts are all about the RV. Each pic won't show much. I'll see what I can do though. Should be able to post a few pics for you in about a week.
Quick reply to this message
Old 12-28-2012, 06:58 PM
TANSTAF1's Avatar
TANSTAF1 TANSTAF1 is offline
Survivor
 
Join Date: Aug 2009
Location: Born in ME,in exile in MA
Posts: 2,742
Thanks: 922
Thanked 2,001 Times in 1,093 Posts
Default

For anyone not wanting to deal with China, the following is a link to a US reseller who says theirs are new (made in China).

First though a comment on Alibaba. I have only used them once and it was a deal thru PayPal and paying by American Express. Alibaba and American Express came through with flying colors, but PayPal not so much even after having been provided ample evidence that the product was a fake 32GB microSDHC card.

Anyway here's the link:

http://www.beutilityfree.com/Electric/Ni-Fe
Quick reply to this message
Old 12-29-2012, 10:40 AM
velacreations velacreations is offline
Hunter
 
Join Date: Dec 2010
Posts: 1,305
Thanks: 697
Thanked 871 Times in 456 Posts
Default

do you have a link to your supplier in China?

Also, how did you size your battery bank? You say you are using the 350 ah cells. I know with lead acid, you figure your usage for a day, then multiply by the max amount of cloudy days, then multiply by at least 2 (4-5 is better) to avoid deep discharge. Is the process similar with Ni-Fe?
Quick reply to this message
The Following User Says Thank You to velacreations For This Useful Post:
Old 12-29-2012, 01:53 PM
charliemeyer007's Avatar
charliemeyer007 charliemeyer007 is offline
reluctant sinner
 
Join Date: Jan 2011
Location: Rent Free in your head
Posts: 15,397
Thanks: 34
Thanked 28,236 Times in 9,971 Posts
Default

NoTea4U one of the best DIY threads yet.

In case anyone thinks they might want to make some Edison cells, score your nickels now as soon they will have no nickel in them. Cells need to be sealed as Lithium Hydroxide will precipitate Carbon Dioxide out of the air i.e. a scrubber.


Somewhere in my collection I have a small glass vile with the Edison Battery Company logo cast in. I think it held oil for the terminals. Found along an old telegraph line many years ago.


added http://en.wikipedia.org/wiki/Nickel_(United_States_coin)
Quick reply to this message
The Following 3 Users Say Thank You to charliemeyer007 For This Useful Post:
Old 12-29-2012, 01:56 PM
velacreations velacreations is offline
Hunter
 
Join Date: Dec 2010
Posts: 1,305
Thanks: 697
Thanked 871 Times in 456 Posts
Default

I have seen some homemade Ni-Fe cells online, you really want powdered Ni, and actually, it is not straight Ni, I think it is Ni oxide or something like that.
Quick reply to this message
Old 12-29-2012, 06:44 PM
NoTea4U NoTea4U is offline
Hiker
 
Join Date: Nov 2012
Posts: 600
Thanks: 614
Thanked 1,330 Times in 414 Posts
Default

Quote:
Originally Posted by velacreations View Post
do you have a link to your supplier in China?

Also, how did you size your battery bank? You say you are using the 350 ah cells. I know with lead acid, you figure your usage for a day, then multiply by the max amount of cloudy days, then multiply by at least 2 (4-5 is better) to avoid deep discharge. Is the process similar with Ni-Fe?
You can safely deep discharge NiFe cells, so the process is somewhat different. A common sizing approach is to determine your usage for a day, multiply for 1.1 to allow for losses within the wiring, and multiply by the number of days you want to be able to maintain power. That would be sufficient provided your solar panels were not undersized. You can extend your battery life if you only drain your cells to 25%. If you're charging regularly and won't usually drain your cells in full (as in a solar configuration), don't worry about making an adjustment. But if you will regularly drain the bank, multiply by 1.2 and charge when the bank's nominal voltage reaches 1.09V per cell.

I did not follow the conventional method for sizing my battery bank. I looked primarily at winter needs, a time when charging time and current is quite limited. I assumed an average daily charge during our solar minimum of 80 Watt hours and consumption of 400 Watt hours per day. That left me with a daily deficit of 320 Watt hours. I then purchased a bank capable of supplying that deficit for 10 days, allowing head room of 30% for losses in the 12V system as well as the lower power recovery that occurs with cold batteries. This would limit my reliance on my gas generator... very important.

I faired much better than expected.
  • During the shortest days of our year, I average 100 Watt hours of charge per day instead of 80.
  • I don't transfer large volumes of current, and what I do transfer doesn't move far, so I calculate my typical losses at about 3.5% factoring for my wiring dimensions.
  • I optimized my electrolyte for -10C, which projects to give me about 82% of the battery's capacity at -18C, our typical low point (I have not measured to be sure). I still fair well because the batteries produce about 25% more power than they are rated for, when drained at my typical pace. So even with the modified electrolyte, I still get more than the 350 Ah the cells are rated for.

NiFe batteries soak up a tremendous amount of power when they're low, charging very efficiently. As they top off, the charge rate decreases. This means that a larger battery bank will provide more efficient energy storage than a small one, when charged from an RV generator. In the dead of winter, I can run my generator for 2 hours every 5 days and it replaces the power used in those days. My old genny burns 3/4 of a gallon per hour, so it works out to $7 every 5 days or $42 a month for power. That's during the worst of winter; Input current testing shows my system is solar self-sufficient for 8 months of the year. I have not used the unit in the shoulder months, but the solar output charts for my region suggest I'll consume about $60 of fuel during those two months.

If fuel is not available, I can enjoy typical power consumption for 8 months of each year, and reasonable power in the two shoulder months. I have sufficient charging to support 5 lights for 6 hours every day in the dead of winter, which is not a lot, but enough.
Quick reply to this message
The Following 9 Users Say Thank You to NoTea4U For This Useful Post:
Old 12-29-2012, 07:47 PM
Optimist Optimist is offline
Survivor
 
Join Date: May 2010
Posts: 13,913
Thanks: 48,383
Thanked 19,937 Times in 8,504 Posts
Default

NoTea4U, this has been a very informative thread, and I appreciate your information.
Quick reply to this message
The Following 2 Users Say Thank You to Optimist For This Useful Post:
Old 12-30-2012, 08:59 PM
augoldminer augoldminer is offline
Hunter
 
Join Date: Jun 2011
Location: high desert calif at the edge of the big empty
Posts: 1,499
Thanks: 0
Thanked 1,385 Times in 721 Posts
Default

Did you get a bottle of oil as part of the battery charge kit.
In old Edison Battery Company batteries this oil was to protect against oxygenation and would block the CO2 from reacting with the Lithium Hydroxide.

This oil protects against a number of potential problems with NiFe batteries.

and if these Chinese batteries do not have it i question why not.
Every Edison battery i ever work on had this Oil.

Edison marketed a “Battery Oil" that was nothing more than mineral oil with a coloring in it.
Quick reply to this message
Old 12-31-2012, 12:07 AM
NoTea4U NoTea4U is offline
Hiker
 
Join Date: Nov 2012
Posts: 600
Thanks: 614
Thanked 1,330 Times in 414 Posts
Default

Quote:
Originally Posted by augoldminer View Post
Did you get a bottle of oil as part of the battery charge kit.
In old Edison Battery Company batteries this oil was to protect against oxygenation and would block the CO2 from reacting with the Lithium Hydroxide.

This oil protects against a number of potential problems with NiFe batteries.

and if these Chinese batteries do not have it i question why not.
Every Edison battery i ever work on had this Oil.

Edison marketed a “Battery Oil" that was nothing more than mineral oil with a coloring in it.
Great question!

Mineral oil is useful for the reasons you mention, but only if the batteries will be stationary. If the oil coats the plates, such as would happen when filled batteries bounce around during transport, capacity suffers for some time. The oil does eventually rise to the top, so battery capacity is only temporarily affected. Even so, oil isn't recommended for a mobile solution. I do have oil for if/when my batteries are permanently situated.

Mineral oil does significantly extend electrolyte life, and would be essential in any non-mobile solution.
Quick reply to this message
The Following 4 Users Say Thank You to NoTea4U For This Useful Post:
Old 12-31-2012, 02:27 AM
augoldminer augoldminer is offline
Hunter
 
Join Date: Jun 2011
Location: high desert calif at the edge of the big empty
Posts: 1,499
Thanks: 0
Thanked 1,385 Times in 721 Posts
Default

I have seen the oil in electric mine locomotives.

I ran a Mancha Little Trammer that had 13 kw of NiFe batteries.
http://industrialrail.5u.com/images/...comotive-1.jpg

I know that the cars back in the day used the oil in there batteries
and the old NiFe mine lights also used the oil
+


Quick reply to this message
The Following 3 Users Say Thank You to augoldminer For This Useful Post:
Old 12-31-2012, 07:39 AM
Moose711's Avatar
Moose711 Moose711 is offline
Half assed prepared
 
Join Date: Nov 2008
Location: Anoka Minnesota
Posts: 554
Thanks: 577
Thanked 441 Times in 256 Posts
Default

Thank you for the time you took to educate us on the subject.
Another option to check on for off grid.
Quick reply to this message
The Following User Says Thank You to Moose711 For This Useful Post:
Reply

Bookmarks



Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Survivalist Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Gender
Insurance
Please select your insurance company (Optional)

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 08:23 AM.


Powered by vBulletin®
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimisation provided by DragonByte SEO (Lite) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright © Kevin Felts 2006 - 2015,
Green theme by http://www.themesbydesign.net