12 Volt Battery Generator

52,571

543

61

Posted

Introduction: 12 Volt Battery Generator

Inexpensive 12 volt back-up battery generator that is not hard to make. It will power what counts if the power goes out! Note:

You must have a working knowledge of electricity and electrical circuits to do this project otherwise you could really hurt yourself.

I've powered space heaters, refrigerators, televisions, fans, washing machines, lights. You name it and this will most likely power it including small ac units. The small mini fridge seen here has been running for 25 hours now with plenty of battery power remaining to run more stuff. You can take this to your remote cabin and be completely off grid. See my other instuctables for the foldable lightweight solar panels that compliment this generator nicely!

Supplies:

1. 60 ft of 3-1/2 in by 1-3/4 in board.

2. Box of wood screws 1-1/2 inches long

3. 1500 watt power inverter (pure sine wave inverter recommended)

4. Solar charge controller

5. Battery meter (I have two on this)

6. Toggle switch

7. DC power outlet

8. Two hinges

9. Two clasps

10 Four battery cables

11. Plenty of wiring and a handful of alligator clamps big enough to clamp to batteries. Also other wire connectors and electrical tape. Amounts will vary depending on how you set it all up.

12. Four heavy duty castor wheels

13. Drill with up to a half inch drill bit. You'll probably want some smaller ones to.

14 Door knob drill kit (2 inch) for the round battery meter. Yours may be a different size?

Step 1: Wood Needed

1. You'll need 60 feet of cheap wood that is 3-1/2 in by 1-3/4 in.

2. Cut 9 pieces 26 inches long

3. Cut 7 pieces 17-1/2 inches long

4. Cut 22 pieces 12 inches long

5. Cut 4 pieces 16 inches long

6. Cut 2 pieces 15 inches long

7. Extra pieces of any kind of wood like (2x4) to brace the batteries inside the box.

Step 2: Constructing the Box

Hopefully this picture explains how the box goes together (at least the end result)

1. Start with building the four sides.

a. connect seven 12 inch boards (no space in between) with a 26 inch top and bottom piece. Center the 26 inch boards which should leave roughly 3/4 of an inch on both ends. Repeat this step again. Use the screws but pre-drill all your holes first.

b. connect 4, 12 inch boards with the 16 inch top and bottom pieces. Repeat this again. Again make sure the top and bottom pieces are centered which will leave you with roughly 3/4 inches on both ends. Remember to pre-drill all your holes first.

c. Connect all four sides now.

2. Use all seven of the 17-1/2 inch boards and screw them in the bottom of the box. Space them out so they go from end to end with no left over space.

3. Use the remaining 5, 26 inch pieces to build the top. Lay them flat with no space in between the boards and screw the two 15 inch pieces down opposite direction on top of the boards.

4. Hinge the top to the box.

5. attach clasps to the front to lock the lid down.

6. Flip the box over and screw the castor wheels to the bottom of the box.

Box is done. (Tires were a later addition).

Step 3: Connect the Power Inverter

1. Chose the exact location where you want your inverter to be and leave enough room to drill holes for the positive and negative cables behind the inverter.

2. Drill two holes behind the inverter using the 1/2 inch drill bit.

3. screw the inverter to the top, connect the cables to the inverter and run the cables down through the two holes.

4. Once batteries are in the box you can connect the cables to the batteries.

Step 4: Connecting the Solar Charge Controller

1. Choose the exact placement of your charge controller and again screw it down and drill holes behind it to run the wires down through the top. When the batteries are in the box, you can connect the battery wires from the charge controller to the batteries.

Step 5: Adding the Battery Meter and Toggle Switch

1. Again, find a good convenient spot to attach the toggle switch, some place close to where the battery meter will be. Drill a small hole next to where the toggle switch will be to run the wires down through.

2. Attach your battery meter where you want and then connect it to the toggle switch and battery. You have to have a basic knowledge of electrical to accomplish this. Mine is set up so that I have to switch on the battery meter to see the battery level. I can turn it off or leave it on.

3. If you use a round battery meter like I have on mine, you'll need to drill a hole with the 2 inch door knob drill bit like I did in order to seat it down nicely in the wood. Looks really cool to do it.

Step 6: Adding the LED Light

This is completely up to you what you use but I recycled some fish tank led lights and an old ipod case to create this light. It's taped to an old GPS suction cup holder with directional capability. It's really bright!

Step 7: Adding the Batteries

I used two MK 74 AH Wheelchair batteries. Found a heck of a deal on Craigs List. Just make sure you use 12 volt deep cycle batteries. There's room for one more in there I think but for now this will do. Connect them in parallel. Attach all your gadgets to the batteries via alligator clamps or how ever you do it.

Brace the batteries in place with extra wood so they don't slide around when you move the box.

I use the homemade solar panels and extension cord you see to charge the generator when I can but I also have a 12 volt battery charger that I use when the sun doesn't shine. The panels I have here equal roughly 100+ watts of charging power on a sunny day. I get about 5-6 amps out of the panels.

I hope you like this instructable. Let me know what you think.

Step 8:

Share

Recommendations

  • Epilog Challenge 9

    Epilog Challenge 9
  • First Time Author Contest 2018

    First Time Author Contest 2018
  • Sew Warm Contest 2018

    Sew Warm Contest 2018
user

We have a be nice policy.
Please be positive and constructive.

Tips

Questions

59 Comments

VMAX Solar batteries are great for this, they are sealed and do not release harmful gasses. Check out my similar instructable here which goes into more detail regarding how to select an inverter and batteries:

https://www.instructables.com/id/How-to-Build-a-Battery-Backup-Generator/

Thanks for the comments and link to your instructable! It's been a few years since I posted mine and I have since upgraded a little. I have included a few pictures of my new battery back-up/solar generator. Hope you like it. It features 6 deep cycle MK wheelchair batteries at 76 amps each in parallel . The box is vented in the rear and the lid allows for ventilation as well, although there is very little gassing that occurs with MK batteries. I have attached a 2000 watt pure sine wave inverter to the rear that powers most everything I'd need incase of a power outage. I've had this for a couple years now and have only used it to see what it'll do, never for a power outage. It is wired for a small solar panel/array in the 12 amp range which I intend to increase someday but for now that would simply keep the batteries topped off. My wiring job is not pretty but it works.

battery backup.jpgBattery backup 2.jpgBattery backup 3.jpgBattery backup 4.jpg

http://www.linetech-tr.com/---

all the ingredients

hello, The idea is great, however the way you carried it out needs a lot of improvement...1 put the batteries in separate battery boxes. 2 you need an internal sealed fan to blow in fresh air and additional vent holes to remove any gases generated from charging. This is a safety issue as the gas is explosive. 3 The wiring harness needs much improvement. 4 Never Ever charge large batteries like the ones you are using indoors sealed or not.....Walter Hynson

I take it you have never worked on large battery powered machines Walter Hynson, I have worked on battery powered cherry pickers along with many other battery powered machines and none of them tell you to take them outdoors to charge them the amount of gas output from sealed lead acid batteries is almost nothing there is a little from standard lead acid batteries if you charge them fast but as long as you follow the makers specifications for charging then you will have little problems with the gas if you tried it in a small sealed cupboard then if you tried lighting a match next to the floor then you may have a problem.

In all my years (38) of working with battery powered machines I have never heard of any problem with charging them indoors unless some one tries over charging them then it is their own fault.

regards Poppy Ann.

oops, "lighting a match next to the floor then you may have a problem". Hydrogen goes up, Poppy - you knew that.

Shame about your body going south, mine's headed that way as well. Not holding my breath for Obama health care.

Large enough alternator can be used as a stick or TIG welder with a few modifications. Repaired lots of SS stanchions and rigging 'in the wild'.

Am thinking back to when I was in submarines - do they qualify as "indoors"?

Med can get cold but doesn't have tropical storms! Red Sea was difficult to navigate celestially because haze obscured the horizon and it was before GPS. Had Walker sat nav in Med but kinda useless - took HOURS to compute and sometimes would only get one fix per day AND was a serious drain on battery.

My boat (long story) was confiscated by Cypriot government and sold at "auction" when I came back to the states for a bit. $150,000 boat flogged for $2,500 and I was PNG. Sigh

Hi again,

don't know what I was thinking about re gas but I blame it on my brain slowing down with age(62 now) I was lucky with gps when i started out cruising I fitted a nice 10" plotter on the boat it was only black and white as I could not afford a colour one at the time at the moment it has a 10" colour one along with a 15" combination plotter and radar which is connected up to my autopilot if I had had a self tending head sail I could sail without doing anything once the sails were set but even the way I had it all I had to do was get ready to tack when the plotter bleeped and as the auto pilot turned the boat I just released the head sail when it started flapping and pulled it in on the other side as tight as I could then once the boat was all the way through just a slight trim and I was set until the next tack I can set the plotter to sail within set lines so I knew I could just lay back and let it sail itself when I had a long way to go which was great as I was single handing for most of my time out there, its a pity I came back but it is too late to do anything about it now, all I can do is think of the good times I had which were 10 years on board.

regards Poppy Ann.

I liked it. As an experienced seaman I can tell you, you need not concern yourself too much using this indoors (as long as it's a fresh, well ventilated area. Those are sealed gel batteries as well, so, they are very safe, can be used in any position. They should have a valve for hidrogen/acid discharge, which if it ever happens, it should be minimal. Yes, orderly routing the cables looks better, but who am I to criticize. Safety first, always. Fuse your connections. When you see things like this: http://www.ercshowcase.com/wp-content/uploads/2013/02/cables.jpg you know it took a long time and effort to make it so.

Glad you liked it. Thanks for the expertise

I liked it. As an experienced seaman I can tell you, you need not concern yourself too much using this indoors (as long as it's a fresh, well ventilated area. Those are sealed gel batteries as well, so, they are very safe, can be used in any position. They should have a valve for hidrogen/acid discharge, which if it ever happens, it should be minimal. Yes, orderly routing the cables looks better, but who am I to criticize. Safety first, always. Fuse your connections. When you see things like this: http://www.ercshowcase.com/wp-content/uploads/2013/02/cables.jpg you know it took a long time and effort to make it so.