home made battery pack
Submitted: Friday, Aug 08, 2003 at 14:08
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ExploreOz
I'm really stingy about paying hundreds of dollars for a power pack that's only going to give me 12-24 amp hours to run my Engle. I really don't want to go moving stuff around under the bonnet of the 96 Jackaroo. So! What would be wrong with getting my auto electrician to pop a sealed 90 amp/hour battery into one of those black plastic battery boxes you can buy and hooking up some doovers that are in the proprietry power packs to charge the thing through the cigarette lighter ? That way, I could carry the
home-made battery pack in the back of the truck next to the 40 litre Engel where it won't be vibrated. I'm told the Engel will draw about 2.5 amps and only run half the time so that's ... er ... 2.5 into 90 = 36 times 2 = 72 hours but only let the battery run down to 40% so that's 60% of 72 = 43.2 hours. How long would it then take the cigarette lighter to bring that battery back up to full charge? Would I be better of with a little $300 Scorpion type genny from e-bay or some sort of solar cell arrangement ... and where do yo get solar cells? Thanks for any help ... I'm SO confused! :-(
Reply By: flappan - Friday, Aug 08, 2003 at 14:56
Friday, Aug 08, 2003 at 14:56
If you want to be stingy, then
solar power isn't for you.
Ok, some ideas (no idea if they will actually work though).
Buy a power pack (or 2) from somewhere like Supercheap. They have 2 types, a 600amp hours and a 900 amp hours. How they go running a fridge . . . No idea, I've run 12v lights off them for days, and then started a car, no probs at all.
at about $60 each . . .
The other idea is to buy a cheap Inverter, and run a battery charger off it to charge your battery in a box.
Again, no idea if it would work or be practicle, buy hey, I'll toss up the ideas, someone will tell me whether it'll work or not.
AnswerID:
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Follow Up By: Patrol22 (Queanbeyan - Friday, Aug 08, 2003 at 15:33
Friday, Aug 08, 2003 at 15:33
Flappan - thems are huge batteries at 600 and 900 amp hours - sure they are about 17-14 amp hours and capable of delivering cca 600-900 amps???
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Follow Up By: flappan - Friday, Aug 08, 2003 at 16:00
Friday, Aug 08, 2003 at 16:00
Purely from memory.
and its been know to fail me before.
Quite possibly you are correct. I don't profess to be an expert, as I said, just chucking up ideas
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Follow Up By: Member - John - Friday, Aug 08, 2003 at 20:27
Friday, Aug 08, 2003 at 20:27
Hey Flappan, Been thinking about one of those super cheap jobs just to run a 12v light and a shower for 10 min a day. More importantly, I want a back up should I run the Jackaroo's battery flat. Dont Have a dual battery setup and don't want one. Worried that after a few days in the bush using the light and shower, there might not be enough left to jump start the Jack if I need to.
Am I reading you correctly ? You've Jump started after running lights off the battery for a few days ?
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Follow Up By: flappan - Monday, Aug 11, 2003 at 10:16
Monday, Aug 11, 2003 at 10:16
Yep, quite easily.
In fact, I jump started my vehicle several times, ie 10 times or more before I recharged it, only because I did, rather then I needed to.
They are cheap enough anyway, worth looking at regardless.
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Reply By: Member - Rick - Saturday, Aug 09, 2003 at 00:49
Saturday, Aug 09, 2003 at 00:49
G'day ExploreOz
I have recently thought of doing this method also. But if you use a lead acid battery, for safety's sake you should not keep it in your truck. Why not you ask?
Well, vapour + spark = BANG.
Therefore a sealed gel battery like Opitma would do the trick. But these cost.........to get a battery box + battery + plugs, wire, etc= about $ 400.
So the perspective for a Waeco type pack appears different now, eh?
I finally repacked by rooted Urban for $ 120, and have portability (best feature for my money - I take the battery & light to the required spot, usually
well away [50 foot +] from the vehicle. 12 V light cord is only 20 '). I also get peace of mind + some performance for fridge, heaps for lights, and enough oomph to turn the truck over of the Exide Extreme carks it.
CheersRick (S.A.) - ' It is better to travel hopefully than arrive'
AnswerID:
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Reply By: Deano - Saturday, Aug 09, 2003 at 21:36
Saturday, Aug 09, 2003 at 21:36
Dunno much about the porta paks but recently was treated to a sheep on a spit cooked for 12+ hours and run off of it and the owner hadn't even recharged it. Then, about midnight jumpstarted his mates ute NP.
dealer I recently bought my L300 4by also had one and asked what he thought about them. Reckons he has jumpstarted around 14 vehicles without the thing going flat.
Seems they got the cranking power but as far as amp hours and the math stuff I am lost. Seen them for $139 at repco so just buy two? :)
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Follow Up By: Member - Des - Monday, Aug 11, 2003 at 12:54
Monday, Aug 11, 2003 at 12:54
We got a reconditioned model from Projecta JumpStarter for $80. Has a 17A/hr battery, weighs about 5kg. Not sufficient to run a fridge, but adequate for lights, shower pump, air compressor, etc, and handy insurance against a flat battery. Recharges from cig lighter plug in a few hours. Suits us fine and very happy with it. See Projecta web site.
If you tried to run a fridge from it (say 1.5 or 2 amps/hour) it would run flat overnight and maybe wreck its battery. Having two of them wouldn't solve the problem - you'd be better off getting or making a bigger one. Thanks to all for the tips on that topic.
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Reply By: haze - Sunday, Aug 10, 2003 at 14:41
Sunday, Aug 10, 2003 at 14:41
Quick reply to David N.. The diode now used came from a u/s alternator. it is located on a small panel adjascent to the rear battery.With the dig. voltmeter,main batt. at high idle 14.35v., rear battery 13.9v., with engel running (very old 17l. mod.) 12.25v. So whilst its not charging the daylights out of it, its not losing much either. I do have a far more elaborate setup in the 75 trayback, but it runs freezer, lights, invertor etc. Anywhere from 20a. charge rate (adjustable) using a honda driven 12v. alternator.
cheers haze
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Follow Up By: David N. - Sunday, Aug 10, 2003 at 17:15
Sunday, Aug 10, 2003 at 17:15
haze trust me! (I'm not a used car salesman- or a battery salesman either!!)
You'd be better not using the diode! (I do know what I'm talking about as I was an electrical engineer many moons ago.)
It's always difficult to charge an additional battery properly without an expensive setup, and a diode only makes things worse. The small voltage drop through the diode is bad news and will prevent you getting your battery charged anywhere near max, which is very important both for the long life of the battery and of course how much you'll get out of it before it needs charging again..
A heavy duty relay, (which you can switch manually if you like) however, has virtually no voltage drop and is a much better option if you don't just want a "manual" connection.
I offer this advice purely for your own benefit, as I don't like people getting bum steers from some of the ignorant "experts" out there and I will never make a dollar out of selling you another battery.
Cheers and best wishes.
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Reply By: haze - Sunday, Aug 10, 2003 at 18:02
Sunday, Aug 10, 2003 at 18:02
David, I do trust you, honest (now where have I heard that before!!) By making the initial reply I did was because I reckoned Exploreoz was looking for a fairly elcheapo way out to keep the engel going, which is exactly what Idid for our Disco. And as Isaid, it works, the batt. doesnt go flat, but it is only a "weekend away" arrangement. And I COMPLETELY agree, if you want long term ie.5/6 months away you have to have a far more dedicated setup. Which I do have in my 75s. L/C. Manually switchable solenoid/s for up to three extra batts, 12v. alternator with switchable regulated or constant output (the only way to FULLY charge a battery) driven by a 4hp. honda motor. Amp and volt meters to monitor the goings on AND most important, wiring/ connections (soldered) switches of a capacity to maintain volts and current where you want it. But this dont come cheap, even when you do it yourself
Sometimes a bloke is better off keeping his trap shut!
Thanks anyway David
cheers haze
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