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Ghost Prepper
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33 Posts
Discussion Starter #1
I decided I needed a small solar generator to power low current devices while camping and at the BOL during construction. I was only looking at recharging cell phones, cameras, and occasionally an inflatable air mattress, etc...I looked at possibly purchasing something like the the GZ Yeti 150, but $230-250 seemed a bit much for my small needs. After looking around the house for an hour or two, I came up with the idea of building a small one myself.

My son had recently given me several SAW ammo cans, so I settled on that for the body of the unit, due to it's inherent ruggedness and portability.

I located several 12V 7.5ah Sealed Lead Acid Batteries and wired 2 in parallel for the power source.

A quick look on Amazon and I found a Dual USB+DC Voltmeter+Power Socket+On-Off switch. This covered my needs for DC outputs but I still needed a bit of A/C for the air mattress. After reviewing the specs on the air mattress, I found a 400W inverter would provide what I needed.

For recharging I decided on a small 15W solar panel w/charge controller. I was able to source this from the local auto parts store.

An hour or so of work later and I now have a really functional solar generator that fits my needs for just over $100 in cash.

After this success, I am eager to scale this up to a much larger unit. I recently was able to acquire 4x 12V AGM batteries, which I plan to charge with a 100W solar panel, as a first step. I'll add additional solar panels, but this will get me started.

I know normally you should size your solar and batter bank to your needs, but not knowing what those are yet, this will provide a foundation for our limited electrical needs. I'm open to thoughts and suggestions on the larger build as it is just in the development stages currently.
 

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reluctant sinner
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17,914 Posts
I like it. I would consider isolating each battery with switches. I'm not sure how water proof the ports actually are so I would also consider putting them inside the can. Maybe Velcro the batteries in place.
 

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Ghost Prepper
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33 Posts
Discussion Starter #7
I like it. I would consider isolating each battery with switches. I'm not sure how water proof the ports actually are so I would also consider putting them inside the can. Maybe Velcro the batteries in place.
Underneath the Inverter, there is a 15A fuse to protect the device, with a spare taped to the underside of the lid. This will most likely live in the tool box of my truck, so I'm not as concerned about it being waterproof, especially after cutting the holes in the side of the box for the outlets. I like the velcro idea, that's a good one.
 

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reluctant sinner
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17,914 Posts
Having 2 isolated batteries covers you for accidently leaving something on, running one battery down - you still have a charged one in reserve. Plenty of room in the can for a pack of fuses instead of just one spare.
 

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Ghost Prepper
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33 Posts
Discussion Starter #9
Having 2 isolated batteries covers you for accidently leaving something on, running one battery down - you still have a charged one in reserve. Plenty of room in the can for a pack of fuses instead of just one spare.
Definitely good ideas, and food for thought. I'll see if I can find an easy way of wiring the switches in. Thanks.
 

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Lux in Tenebris
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6,797 Posts
Just ordered switch, gonna duplicate your kit, and add a little charge controller inside can too, this way i can connect solar panel to it and charge a 35ah agm battery i think will fit inside .50cal ammo can....

will post up....
 

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Ghost Prepper
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33 Posts
Discussion Starter #13
Just ordered switch, gonna duplicate your kit, and add a little charge controller inside can too, this way i can connect solar panel to it and charge a 35ah agm battery i think will fit inside .50cal ammo can....

will post up....
Good deal. Hope to see your post.
 

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reluctant sinner
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17,914 Posts
I consider keeping all the connection inside the can by having a vented top plate. With the lid on its almost a faraday cage and water proof to boot.
 

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Something I did that some may consider for a build like this... My work was throwing out several APC back-up power supply units due to dead batteries. I snagged all of them and tossed the batteries.

My small one was this unit...
http://www.techexcess.net/images/products/APC-BE500U-220.jpg

Its powered by a single 12v agm battery in original form. I cut the unit open, added a cooling fan (as the unit isnt designed to run all the time) and cut the factory battery connector off. I then soldered on a set of cheap jumper cables that I cut in half (making 6' leads with large alligator clamps).

For some testing, I hooked it up to an old group 31 truck battery I had in the garage that was several years old. Turned on the small fan and plugged in my 46" lcd tv. Kicked back and started watching a movie with a volt meter on the battery.

After an hour and a half, the unit was only warm to the touch and battery voltage was still holding steady.

Another nice feature of these units is they have a built in charger/maintainer. You could still charge off of a solar panel as well.

I'll have to post a picture when I get home... but typically you can get these for free or dirt cheap when the batteries are dead.

I bought 2 big units (1400 watt each - pure sine wave) for less then $30 each. Try finding a 1000+ watt pure sine inverter for that price... lol All of the APC "Smart" line use pure-sine inverters. Going to be using these as part of my small emergency solar system.

Anyways.. slick build bud.
 

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Registered
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Nice job. I made something similar in a Radio Shack hobby box with a 9 ah battery. It was a tight fit, but I managed to squeeze it in, and by being tight, the battery is secured in place. It provides 2-12 volt outlets, 2-5 volt usb ports, an LCD readout, and an on-off switch. I use a 30 watt fold out solar panel to recharge the system while camping. These type of battery packs are perfect for camping, and emergencies.
 

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Ghost Prepper
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33 Posts
Discussion Starter #18
Something I did that some may consider for a build like this... My work was throwing out several APC back-up power supply units due to dead batteries. I snagged all of them and tossed the batteries.

My small one was this unit...
http://www.techexcess.net/images/products/APC-BE500U-220.jpg

Its powered by a single 12v agm battery in original form. I cut the unit open, added a cooling fan (as the unit isnt designed to run all the time) and cut the factory battery connector off. I then soldered on a set of cheap jumper cables that I cut in half (making 6' leads with large alligator clamps).

For some testing, I hooked it up to an old group 31 truck battery I had in the garage that was several years old. Turned on the small fan and plugged in my 46" lcd tv. Kicked back and started watching a movie with a volt meter on the battery.

After an hour and a half, the unit was only warm to the touch and battery voltage was still holding steady.

Another nice feature of these units is they have a built in charger/maintainer. You could still charge off of a solar panel as well.

I'll have to post a picture when I get home... but typically you can get these for free or dirt cheap when the batteries are dead.

I bought 2 big units (1400 watt each - pure sine wave) for less then $30 each. Try finding a 1000+ watt pure sine inverter for that price... lol All of the APC "Smart" line use pure-sine inverters. Going to be using these as part of my small emergency solar system.

Anyways.. slick build bud.
Cool idea. Some of the larger units won't start straight from a battery, they have to be connected to 110V to power up, but once on, they'll stay on battery as backup.
 

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Good to know. I'll have to do some testing with the bigger units. I haven't messed with them yet as they are 24v and I dont have the extra coin for 4 golf cart batteries yet.

May tie a few old batts together just to see what they do.
 

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Registered
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3,991 Posts
For recharging I decided on a small 15W solar panel w/charge controller. I was able to source this from the local auto parts store.

...

After this success, I am eager to scale this up to a much larger unit. I recently was able to acquire 4x 12V AGM batteries, which I plan to charge with a 100W solar panel, as a first step. I'll add additional solar panels, but this will get me started.
FYI: if the AGM batteries you're looking at are 'car sized', their capacity will probably be around 300 amp hours in total (75 each). For a single 100 watt solar panel, it will take over 50 hours of good sunshine (about 9-10 days, depending on the weather, season, charge controller) to fully recharge them.

For MUCH faster recharging, just use a set of jumper cables connected to a vehicle battery; be sure to start the vehicle immediately after connecting the cables. This is not especially 'healthy' for lead acid batteries, but it will work and won't take a week and a half.
 
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