Here is a little write up on a portable power box I just built. I had most of the parts laying around from past projects. I used a 1000w Xantrex power inverter. A plastic marine battery box from Walmart. A 105 amp hour marine deep cycle battery from Walmart. I had the power inverter and wiring already so I am only about $80 into the project.

I wanted something portable that I could take camping with me or wherever that would provide power to small appliances such as radios, cell phones, lights, power tools, etc.

I have been looking at small generators but there were a few things that kept me from getting one. One was the size. Unless I wanted to drop major coin on a Honda, I would have lost a lot of portability with a generator. Two was cost. Something as reliable as a battery and power inverter would have cost ~$1000. Three was noise. I drive out to the middle of BFE so I can get away from it and relax. The last thing I want to hear is the sound of a generator humming away. And I would also have to have gas on hand to keep it going.

A portable power box just seemed like a much better idea for me as far as the points I stated above go. It is virtually silent. I can keep it in my Jeep and run it. It is small. And it was way more cost effective for me. I was also contemplating hardwiring it into the the Jeep but that pretty much kills its portability.

As far as building it. It was pretty straight forward. I mounted the inverter on the side of the box with four bolts. The battery fit snug inside the box and box also came included with a little divider so I won't slide around in there.

I had an opportunity to test it this weekend while out camping. I ran a small radio off it for pretty much 3 days straight. I also charged my phone with it for a while and ran some area lights off it momentarily. It doesn't look like it really discharged that much. It started at 12.5 volts when I left and is now at 12.3 volts.

Eventually I want to rig up a solar charger to it to keep it somewhat recharged during the day. I also want to mount a little voltmeter in it so I can monitor voltage more easily.

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huh, now why didn't I think of that one, it's perfect

How about wiring it up to some sort of trickle charger to replenish the battery while you move from campsite to campsite?

There are a few threads online about making these and they've always interested me. When I travel I pack along a portable jumpstarter that has some 12V outlets on it. I also have an inverter that I hook up to it. Something like you've made isn't much bigger and will last a lot longer. Check out expedition portal for some more ideas regarding the 12v plugs and volt meter. There is also a guy that has a dual battery setup in his vehicle and his portable pack thing is the second battery. He hooks it up in the system (second battery is in the back cargo area) and it charges and can be used. When he wants he switches it off and unplugs the second battery and it's good to go.

ive been thinking about building one of these, got a few batteries laying around, a nice 250w inverter and a solar panel, cant decide if i should build it into my truck or build a box.

that could be recharged easily from a vehicle with a pair of jumper cables.....

That is one of those things that make this site what it is. A solution to a problem that is better than what I had come up with previously.

Would the inverter fit in the battery box, on the divider? Or would heat be an issue?

I built one similar but made out of plywood. Housed 2 yellow tops, with the inverter mounted on top, and a hole in the side to run the wiring from the solar panels. It was a heavy bitch though and I usually just left it in the bed of the rig.

I've been thinking of using the existing 7 way trailer wiring plug to recharge the batteries while we drive since it has a switched 12 volt pin. Just gotta find the motivation.

There are a few threads online about making these and they've always interested me. When I travel I pack along a portable jumpstarter that has some 12V outlets on it. I also have an inverter that I hook up to it. Something like you've made isn't much bigger and will last a lot longer. Check out expedition portal for some more ideas regarding the 12v plugs and volt meter. There is also a guy that has a dual battery setup in his vehicle and his portable pack thing is the second battery. He hooks it up in the system (second battery is in the back cargo area) and it charges and can be used. When he wants he switches it off and unplugs the second battery and it's good to go.

Thats where I got the idea. I was actually looking for something similar online and came across that post. I eventually would like to do something similar where I could plug it in and it would recharge while I was driving.

That is one of those things that make this site what it is. A solution to a problem that is better than what I had come up with previously.

Would the inverter fit in the battery box, on the divider? Or would heat be an issue?

I really wanted the inverter to fit in the box due to several reasons. One being it would make the package a lot more weather resistant. Another is that the wires would be hidden, and you wouldn't have to worry about something slamming into the inverter and possible damaging it. Heat would possibly be an issue with this though.

I didn't want to have to order a box online though and came across that one at Walmart for $8 so I compromised.

I built one similar but made out of plywood. Housed 2 yellow tops, with the inverter mounted on top, and a hole in the side to run the wiring from the solar panels. It was a heavy bitch though and I usually just left it in the bed of the rig.

I've been thinking of using the existing 7 way trailer wiring plug to recharge the batteries while we drive since it has a switched 12 volt pin. Just gotta find the motivation.

A friend of mine has a winch and a battery mounted on his trailer and thats what he has setup. It is wired into one of the pins of the plug and recharges as he drives.

I was thinking of taking something like a Rubbermaid Action Packer box and using two batteries but quickly realized that it would be one heavy sombitch and it would be a lot bigger package than I wanted. It would be nice to have the extra power but I think for my needs one battery will be sufficient.

Very cool dude, I have enough stuff to build that in my garage right now. What a cool little project. How much have you guys used these yet? I ask because I wonder how fast they drain down on different loads.

Regards,
Abrams

Sweet. I see you're also a Ham...would work great for portable power for Field day.

I have thought of building a similar unit...and maybe just a cheapo $10 auto voltmeter dial gauge to monitor voltage.

Sweet. I see you're also a Ham...would work great for portable power for Field day.

I have thought of building a similar unit...and maybe just a cheapo $10 auto voltmeter dial gauge to monitor voltage.

I went to a field day a few months back in ABQ and saw a few of these type of rigs there. They seemed to work ok :)

i'm just wondering why not hard-mount this in your vehicle?

SLA batteries at 25-55 lbs are not exactly "portable".

for a portable pack, must use nimh or lithium ion, like this: http://www.batteryspace.com/nimhbeltbagpowerpack12v5ah60whhumpfastsmartcharger .aspx

i purchased nimh batteries from this company several years ago (for an electric bike build) and was happy with the price and quality i received.

Very cool.............like the idea for those nice long camping weekends. Where did you get that box from?

kevin, you can get the battery boxes from WalMart or Tractor supply

I've got an old battery in my garage that I'm going to charge up and then hook a load up to it to see how long it will last. I REALLY like this idea, I just want to see how long the battery will last as though it was powering an elec. fridge or something that runs 24 hours/day.

I'm assuming that for this purpose, a deep cycle battery would be the best option as opposed to a standard car/truck battery right?

And would there be any problem with using the battery in this setup, draining it on a long weekend and then putting on a trickle charger for 8010 hrs when you got back home?

And would there be any problem with using the battery in this setup, draining it on a long weekend and then putting on a trickle charger for 8010 hrs when you got back home?

8010 is a lot of hours! 8-10 might be better. :)

When you are using any battery, every time you discharge it, you shorten its life. It's just an unavoidable fact of using a battery. But the deeper you discharge it, the quicker your shorten its life. I've seen charts for it, and some of the higher-end batteries come with specs like how many times you can discharge/recharge before failure, and what minimum voltage you shouldn't discharge below. All batteries might have that info, but I don't know. Of course deep-cycle batteries handle discharging better. Someone else can chime in if they know more detail, but basically you want a battery big enough that you're not discharging it below a certain level before recharging. It will last longer that way.

8010 is a lot of hours! 8-10 might be better. :)



What? Do you expect me to actually proofread what I post here?? :flipoff2:
The - button was my intended target, not the 0. ;)
(You probably had that figured out right?)

The battery I have in my garage is not going to cause me any sleepless nights if I cook it by discharging it too often, or too deeply, so it will play the guinea pig role.
I actually meant to throw it on the charger this afternoon but forgot, guess I'll do it in the morning...
I will post in this thread with my results. I'm not sure if that batt. is even any good, but I will post that up as well. :D

I had a similar setup for the winch on my trailer. Charged through the connector from the truck. I've a complete box like this, including dual battery charging electronics from National Luna a couple of years ago and liked it.
This is the way my second battery will be mounted in my truck. I just add some HD connectors, like the WARN winch connectors, to connect it while in the truck and use the connectors to fit my homemade jumpercables so I can use it as an easy jumpstart device. I'll also fit some fused 12v power plugs to run accessoiries off the system.

Just a suggestion, run a wire from the earth connector on the case to a steel rod and shove the rod into the ground when in use. That prevents YOU from being the easiest path to ground in case the inverter F's up.

Just found a link to the National Luna box:

http://www.nationalluna.com/PPPack.htm

I've got an old battery in my garage that I'm going to charge up and then hook a load up to it to see how long it will last. I REALLY like this idea, I just want to see how long the battery will last as though it was powering an elec. fridge or something that runs 24 hours/day.

I'm assuming that for this purpose, a deep cycle battery would be the best option as opposed to a standard car/truck battery right?

And would there be any problem with using the battery in this setup, draining it on a long weekend and then putting on a trickle charger for 8010 hrs when you got back home?

I took it out camping for 3 days the other weekend. We used it to power a stereo and also used to charge my cell phone. Although these aren't heavy loads the battery didn't discharge at all (left at 12.54v and came back at 12.47v) and the radio was on most of the trip.

Again, the main thing I built this for was to power small things like a radio, cell phone, maybe an area light. It sucks going through 8 D batteries on a radio every 3 hours. And with this I can use it for numerous other things and even self jump with it.

My inverter has a low voltage shutoff for the battery and I think shuts off at around 10v so I don't worry about it discharging too bad.

And for those saying how its not portable. I wanted to be able to move it from car to car easily because I don't always take my Jeep camping. I also wanted to be able to take it out and move to different areas of a campsite or whatever.

I bought the middle powered deep cycle battery from Walmart (EverStart brand). This one has 105 amp hours. The largest one wouldn't fit in that particular battery box.

I am also currently looking for a better box to use. The one from Walmart works pretty well and was cheap but the lid doesn't stay on very well and I would like a swing up type handle like on smaller coolers instead of the two small ones on the sides.

But for now it works great and is SIMPLE. I like to work under the KISS method. When you start adding too much shit it starts to have a lot of fail points. This thing is just simple. A battery wired to an inverter. The only thing that can really go wrong is a fuse blowing or the inverter frying. Or the battery fumes igniting and killing everything within a 10 mile radius. :laughing:

I have to ask why did you fuse the negative?

And a cheapo volt-meter from o'reillys would be perfect, Just mount it on the side of the box where you have some dead space. Should only take 15 minutes with a hole-saw and about 2' of 18ga. wire with a 5A fuse.

As far as the box goes, I've seen similar ones with cloth straps for handles and the lids also had a solid "click" shut. Had to work at it to pry the top off but it was water-tight. I believe they're sold mostly for marine usage?

If I was to do it, I'd find a box that was designed for 2 batteries that the inverter would fit inside, then put a couple of outlets in a bell box with a weatherproof in-use cover so you could still run your radio (it's a weatherproof one, right?) when it's raining and you don't have to worry about the inverter's fans sucking in dust and water all the time. Then again it probably rains a lot more here than there and we don't let the rain stop us from camping.

I'm doing this for my pontoon boat, so I can operate a TV, blender, DVD etc. I thought of doing this for camping also (4wheeling) but thought a smaller one would work better just for lack of space. So I'm going to use a "watercraft" marine deep cycle battery (about the size of a motorcycle battery) I will use a solar charger to keep it charged.