A random question about 12volt batteries.

Da_Big_Jeff

Da_Big_Jeff

Da_Big_Jeff

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I am looking to build a portable power source to power a few electrical items whilst away from mains power. I am having a look into building it around a caravan or Leisure deep cycle battery and mounting it, the relivant output sockets(mostly cigar lighter), an input soket for an external mains charging unit and a simple charge and level indicator into a flight case.

Thing is, it is going to be lugged around a lot between uses so I came to ask about this. Can standard 'wet' batteries handle being sloshed about and being side ways for an evening every now and then, whilst not being used? Sealed, leakproof batteries are probably the safest bet for this purpose, but I am still unsure about the battery being safe on its side or even unside down. Then there are gel filled batteries :confused:.

Any more advice on handling these batteries such as saftey(acid, fire, electricity spring to mind:eek:) and maintaining one is also appreciated.
 
Lead acid release a flammable gas when charging.... Hydrogen or nitrogen I think...

Go for Li-ion cells, safer, lighter, and they don't discharge when you leave them for a week or so like lead acid batteries do...

This pack I've just finished is 11.1v. :)

imgp0978ba2.jpg
 
The size I am looking at is more in the size of a car battery. Going to need to bassically power a laptop and periferals for upto 8 hours a time in one location then packed up and taken home in the car to charge in the garage.

If i were to use the appropriate external power packs for everything it would mean carrying 3 units and wiring them up and still going through atleast 20 longlife a batteries every time.

Something like these:
http://www.batterymegastore.co.uk/cgi-bin/megastore/commerce.cgi?product=Batteries_Caravan!Sealed_Deep_Cycle

So it really means casing it up and using a trolly for it and the rest of the gear.
 
By the sounds of it you will need a 12v battery with around 100Ah then. That pack I made is only good for 5Ah, so you would need lots of them (20, 120 cells in total :eek:), so SLA is probably the only affordable option.

http://www.batteryuniversity.com/ <- Exellent site.

SLA's are fine if you always keep them charged... Just don't leave them for a long time as they discharge on thier own...

I think Gel would be better as they are designed for deep cycles, which is what you would be doing. Bear in mind 100Ah will be heavy. Heavier than a normal car battery for sure.

You may have to get 2, have 1 on charge at home, and the other being used, and alternate them. Good luck, it's not really difficult, just make sure you follow the safety guidelines and you'll be fine. :)

EDIT: What perphirals do you need? Another option would be to buy 4 or 5 extra laptop battery packs, and use them in the laptop instead. You could then power the periphirals off another smaller SLA.
 
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MikeHunt79 said:
Lead acid release a flammable gas when charging.... Hydrogen or nitrogen I think...

Go for Li-ion cells, safer, lighter, and they don't discharge when you leave them for a week or so like lead acid batteries do...
Click to expand...

They most certainly are not safer when they are not inside a pack with the protection circuits. Li-ions are vastly more susceptible to abuse (e.g. shorting or over charging) than lead acid, and generally require far more care in charging and discharging.

A lead acid battery should certainly not self discharge in a week if it's in good condition.

The answer to the OP's question is that a standard "wet" leisure battery is not normally suitable for use in any orientation other than upright. One type of battery that may be suitable for your application are the sealed Odyssey batteries which can be used in any orientation, have deep cycle capability, very high peak current and higher power density than standard flat plate lead acids. Unfortunately, they aren't cheap...
 
^ Yes but when they are used with protection circuits, they are safer. They do not release a flammable gas when charging like lead acid cells do. I know there was a few exploding laptops last year but this was a one-off (I hope). :eek:

Also, a 12v 4.8AH Li-ion pack weighs less than a 12v 1.2AH SLA pack... So it might be worth going to Li-ion route if you use protected cells...

EDIT: 400 charge cycles is pretty good for those odyssey batteries, they are probably the easiest option.
 
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