Portable 12 volt power packs - DIY???

Submitted: Sunday, Jun 14, 2009 at 21:49
ThreadID: 69823 Views:20613 Replies:11 FollowUps:9
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Hi All,

Hot on the heels of finishing the successful 9kg gas cylinder/air compressor project, I'm looking into purchasing one of these power packs for use while camping. It might be a viable alternative to modifying the camper, mainly because it's portable.

I've been looking at a Thumper 75 A/H job, but at $700+ it's a bit a rich.

Question is; how difficult would it be to build one?

I've found a 75 A/H SLA (designed for golf buggies, etc) for around $275. Add extra for lighter sockets, plugs, fuses and perhaps a voltmeter, it still comes in cheaper than a 'bought' one.

I've checked a few old threads from this site, but without much luck.

Anyone built one before?

Photos, CCT diagrams??

Any help appreciated!

Cheers, Matt
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Reply By: Member - ross m (WA) - Sunday, Jun 14, 2009 at 22:33

Sunday, Jun 14, 2009 at 22:33
The store bought ones are certainly dear for what you get

For a little over $200 you could get a 100 amp deep cycle battery like a Delkor.
Deep cycles are much the same as golf buggy/fork lift batteries
Make a box for the battery with a snug fit but with ventilation.
You could add a voltmeter and amp meter into the lid also.

ARC make a plastic box with many of these featurs. The early ones has realy cheap and nasty carry handles and the lid never fited properly o mine.
I think they have a new improved model which might be worth a look ,even if just for ideas.
They are usually for sale at superweak auto for $60 approx

The less connections and wiring the more efficient.
AnswerID: 370012

Follow Up By: paulnsw - Monday, Jun 15, 2009 at 07:34

Monday, Jun 15, 2009 at 07:34
Delkor are bottom of the barrel krapper batteries
Delkor are cheap krapper fitted by manufacturers because they are so cheap and nasty. wont find a reputable dealer selling Delkor krapper
FollowupID: 637392

Follow Up By: Member - ross m (WA) - Monday, Jun 15, 2009 at 09:20

Monday, Jun 15, 2009 at 09:20
Lots of owners have Delkor and are quite happy with them.
I bought mine from a reputable dealer , now go find a sand box where the kids will appreciate you.
FollowupID: 637405

Follow Up By: Maîneÿ . . .- Monday, Jun 15, 2009 at 10:50

Monday, Jun 15, 2009 at 10:50
Bugga, so that's why my two Delkor DC's only lasted 6 years

They were really worked to death running a F/F drawing ~10 Amps, plus all the other accessories too.

I replaced them only because I was not 100% positive they would last another three months camped on the beach, where there is absolutely no chance of getting replacements.

One was then used as my CRANKING battery for a further 12 months.

I figured it was justifiable to buy a new DC battery system earlier than required, rather than loose everything in the F/F and then have to pay retail up in the bush for what I would probably consider an 'ordinary' replacement system.
( I also like Ross's "sand box" thought too )

Maîneÿ . . .
FollowupID: 637415

Follow Up By: Member - ross m (WA) - Monday, Jun 15, 2009 at 11:11

Monday, Jun 15, 2009 at 11:11
Mainey,I bought mine from Challenge batteries in ossie park.
The shop said they supply a lot of the prawn trawlers with Delkors.
I couldnt see them putting to sea with batteries that are krap.
FollowupID: 637421

Reply By: Member - Christopher P (NSW) - Sunday, Jun 14, 2009 at 22:37

Sunday, Jun 14, 2009 at 22:37
I bought a deals direct special and changed out the battery after three camping trips, works good, but i would be going for a 200ah agm or sla, or better still, 2v high amp batts and make up from that, that way if one cell dies you can change/replace/ re-organise your batts for longer performance and cheaper price then replacing a 200 ah battery, maybe. i did speak to solaronline guys and he has like 12 6v high amp batts in his combi, so if one goes down he can swap it out with little hassle or re-route his cables.
AnswerID: 370013

Follow Up By: paulnsw - Monday, Jun 15, 2009 at 07:39

Monday, Jun 15, 2009 at 07:39
"maybe" and maybe not!

"solaronline guys and he has like 12 6v high amp batts in his combi" did he fit 750x16 wheels and tyres and high lift springs and air bags?

so its ok to put new batteries with old as well is it?
FollowupID: 637393

Follow Up By: Member - Christopher P (NSW) - Monday, Jun 15, 2009 at 11:19

Monday, Jun 15, 2009 at 11:19
woul;dn't have a clue as i got to speak with the young bloke like all of five minutes. and most of that was asking stuff about solar.
FollowupID: 637422

Reply By: Sand Man (SA) - Monday, Jun 15, 2009 at 07:51

Monday, Jun 15, 2009 at 07:51
But what you get from a "store bought one" is more than a mere portable battery system.

Their are two options I can recommend.

The first is the Thumper, which contains a pack of smaller cells inside the casing.
This enables faster and more complete charging over a standard battery.
The Thumper also comes with an in-car charging kit to maintain the battery pack whilst travelling and in the "jump start" capable models, provides a valuable standby should something happen to your starting battery. An LED voltage meter on the current model provides an instant readout of voltage status at the push of a button and their is a good range of outlet sockets, including Anderson connector, merit style sockets and cigarette socket.

The second option is a Sidewinder "Flyer" which is a battery box with a difference.
The Flyer contains an internal Isolator and is an almost complete replacement for an auxiliary battery. Add a battery and you have a complete solution. This product also has a voltage condition meter and comes with a six metre cable to run back to the primary battery.
I have purchased one of these for my new rig, as I cannot fit an auxiliary battery in the engine bay. The Thumper, via it's own charging kit will connect to the Flyer to provide a similar setup that I currently have in the Jackaroo with the fixed auxiliary battery.

Both products are not "cheap" but they provide more than a basic power pack.
Lesser packs will only give you around 17Ah of power which is only good enough for low voltage requirements.

Both these solutions will give you a complete portable battery system and probably work out to be a similar cost if you purchase a reasonable size AGM battery for the Flyer.

I cannot see the value in a self built or assembled one, but you may save some dollars by purchasing a basic battery bow from Whitworth marine and adding a battery of your own choosing. Make sure the battery is an AGM type if you plan on placing it inside the vehilce while travelling.


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AnswerID: 370030

Follow Up By: Sand Man (SA) - Monday, Jun 15, 2009 at 07:56

Monday, Jun 15, 2009 at 07:56
Geez, I should have used the spell checker before submitting.

Read "there" in place of "their" and "box" in place of "bow".



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FollowupID: 637396

Reply By: Member Brian (Gold Coast) - Monday, Jun 15, 2009 at 08:50

Monday, Jun 15, 2009 at 08:50
Hi Matt,
What do you intend to use your portable power for? I purchased a Projecta jump starter about three years ago..... from memory paid under $200 for it.

Check it out HERE

I have used it to start the Patrol when I had cranking battery issues, and when camping I run four 13 volt flouro lights off it at night. It can be charged from the ciggy lighter in the truck, or from 240V at home. I am very pleased with it and am happy to say so!

Hope this helps.



DISCLAIMER: I am in no way affiliated with Projecta, and if anyone cares to dispute what I have written, don't bother, I ain't interested. It works for me in my rig and NO amount of anyone telling me it can't, or won't or whatever will change that. So save your breath.

AnswerID: 370035

Reply By: Ray - Monday, Jun 15, 2009 at 09:40

Monday, Jun 15, 2009 at 09:40
Hi. I would agree that $700.00 is a bit rich for the Thumper but you say that you want a portable system? First of all where will you be storing the pack when you are on the move, what would you be running off it? a fridge? lights?
If you say that you want it portable I would not go any bigger than a 75 amp.hr. battery.

If you intend to use it for your camper I would use a seven pin female plug so that you can stand the power pack near the draw bar of the camper and plug it in. You would not need to connect all the terminals in the female plug only the supply and return.

On the charge side I would use an Anderson plug as those cigarette lighter plugs are somewhat unreliable. The vehicle side would require adequate fusing and an isolator that only closes when the ignition is on.

I would definitely use an AGM battery or one that is fully sealed but one with a good lifting handle then you probably will not need a battery box at all, although I have made some good strong boxes out of MDF.

It would be important to install some type of cut out so that you do not fully discharge your portable battery overnight. The installation of a voltmeter would be nice to have but not essential. If the believe that you might want to use the battery to start your engine at some time I would have a short set of jumper leads for this purpose.
AnswerID: 370041

Reply By: Maîneÿ . . .- Monday, Jun 15, 2009 at 11:04

Monday, Jun 15, 2009 at 11:04
Buy an AGM as large as possible to fit into one of those black plastic 'battert boxs'Image Could Not Be FoundIt will be at least 100 ah, add a Voltage meter, two way expanded Amp gauge and add an Anderson plug to two thick cables back to the battery terminals to the lid.

Price woud be about $400 maximum, for that you get a larger capacity, quality AGM battery, with all the information shown about Amps going both in or out of the battery and also the battery Voltage.

Maîneÿ . . .
AnswerID: 370046

Follow Up By: Member - Rod N (QLD) - Monday, Jun 15, 2009 at 11:21

Monday, Jun 15, 2009 at 11:21
Put an Anderson on your vehicle to charge it. If you have a charger, put an Anderson on its leads to plug in and charge. You can also add other connectors to the box as required. This idea is similar to my setup. ie it's a portable aux battery.
FollowupID: 637425

Reply By: Mandrake - Monday, Jun 15, 2009 at 12:53

Monday, Jun 15, 2009 at 12:53
I've built two of similar type units - One has 3 X 7ah batteries in it for the bedroom lights in the camper - runs twin 12 LED lights for reading at night.. Lasts about 4 days without too much trouble ..
The other one is now 2 X 26aH batteries in the back of the Jeep in an MDF box
with twin regulators and Anderson plugs to run fridge in car when parked , and solar panels on roof keep it charged when we are driving ...

I also have a regulator and Ammeters in abox attached to the solar "gantry" on the trailer ( see photo below ) The solar panel 80w on top keeps an 85aH battery in the trailer happy ..


AnswerID: 370061

Reply By: RV Powerstream P/L - Monday, Jun 15, 2009 at 17:33

Monday, Jun 15, 2009 at 17:33
I have an American Strong Box that has a baffle plate in it and you can start with a 24 Series battery and if too small move the baffle and go to a bigger battery up to a 31Series that is 110AH.
The best one is 3x4V RV gel Batteries that give 130AH nearly double the thumper capacity.

I also have a Series 3000 Quick Cable Rescue pack sample that allows you to fit your own battery and at the moment it has a 33AH AGM and my son uses it to start diesel machinery in the cold weather.
The downfall of it is it has a 120V charger but we flip the back lid and charge it with a standard charger.
The unit is worth $100 and the battery about $150.

I ask them to do a 240V or universal volt one but they said maybe in a couple of years.
Its not hard to better the Thumper at the price they ask.
AnswerID: 370112

Reply By: Member - Matt H (SA) - Monday, Jun 15, 2009 at 22:08

Monday, Jun 15, 2009 at 22:08
Dear All,

Thanks very much to all for the feedback. This is exactly what I was after. Previously, I have built and successfully used my own dual battery system that functioned perfectly for over 10 years in three different vehicles, and included a successful trip around Oz.

At the moment, I have a Xantrex Powerpack 300 which is a capable unit for what it provides (and includes jump starting a Prado diesel!). All I want to do is expand on the theme and have something larger that will run the Engel for a few days at a time.

Being from a Technician background with the ADF, I have some knowledge of how these systems work, however I wanted to explore other options rather than spend Mega-bucks on a system that for all intents and purposes, is a box with a battery and a few bells and whistles attached.

I fully understand that the commercially available units such as the Thumper are expensive for many reasons. The sale price has to include the company’s R & D costs, tooling, design and intellectual property. The fact that many, if not all, of the designs available are slightly different, means they are all “commercial-in-confidence” type designs and are copyright as such. Hence why I have been unable to find cct diagrams anywhere on the Web so far.

In the main though, most the components incorporated in these designs are available commercially, and it’s merely a matter of designing your own unit based on what is available. Make it as simple as you want it, or as complex as you want it. I am looking at somewhere in between.

To that end, there a few features that I’d incorporate into my design.
• Voltmeter
• Ammeter
• 12 volt outlets (pick your own type – I favour Hella style chrome plated marine ones)
• Fused.
• Recharging facility (in my case, using a 240 volt “staged” battery charger”)
• 12 volt recharging via solar panels or alternator (this will involve a bit more thinking to overcome successfully).

There are other things, including some niceties but you get the picture. Some of you have mentioned a series of smaller batteries in parallel – and I like that! If one of the batteries drops a cell, the offending battery can be easily replaced, but the unit is still usable albeit with a lower A/H capacity in the meantime. Nice!

There is no one solution to my question, rather what works for people out there. That’s why I ask the question. How many variations to the humble mouse trap are there? Lots! We all use what works for us!

AnswerID: 370208

Reply By: bks - Tuesday, Jun 16, 2009 at 11:16

Tuesday, Jun 16, 2009 at 11:16
BCF have a battery box with charger and 12v outlet for about $150. I have one with a 120ah agm battery and it works well. other than the battery doesn't fit in the box but it is a simple matter to remove the lid which contains the charger outlet etc and attach it to the top of the battery.

BCF cattle dog
AnswerID: 370283

Reply By: Mandrake - Tuesday, Jun 16, 2009 at 11:35

Tuesday, Jun 16, 2009 at 11:35
Just thought I'd pop this in just in case - Photo of the panel wiring that runs my camper solar / battery charger ---Image Could Not Be Found\

On the left are 2 cig lighter plugs for Solar Panel input - Reg is the black box at the bottom - on the right are 2 outputs - 1 Ciggy and one Merit ( for fridge) -
below them is a 10 amp overload cutout - push-button type to reset ..

Since this photo the cables to the Solar panels and battery are terminated with Anderson plugs ...


AnswerID: 370290

Follow Up By: Mandrake - Tuesday, Jun 16, 2009 at 11:40

Tuesday, Jun 16, 2009 at 11:40
Hmmmm - seems I don't know what I built - on RHS ciggy lighter is above the
Cutout and the Merit is below !! Also two ammeters in the middle - one shows input from Sloar the other is output via the plugs ...

That is housed in a small plastic box just under the Aluminium Solar Panel carrier on the POD - see photo below ..

Think I gor it right this time ... LOL


FollowupID: 637600

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