Jump Start battery

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stevedg

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#110528 10-Oct-2012 22:29

I picked up a car jump starter battery on special the other day from a local retailer. Seems to be quite good: 900amps peak draw and 19ahr, in a robust case with a led light and led charge indicator. It was advertised as an AGM battery which sounded good as these are supposedly non-spillable, more resistant to vibration and hold their charge better, and twice the price of a standard SLA battery.
When I opened the case to see the battery it was stamped with FM12170B Sealake, and marked as a SLA. I have tried to google for the specs on this battery and no where can I find reference to it being an AGM (although a AGM is a SLA battery).
Does anyone have any idea if this is an AGM battery or is it a case of miss leading advertising? I can’t hear any electrolyte sploshing around inside so it could well be an AGM.
Thanks

Niel

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#703588 19-Oct-2012 16:08

Given the price of them on the internet, I'd guess it is AGM. They are sold for electric scooters. The suffix letter "B" is essentially the terminal variant, Google the number without the B. The specs I've seen are rated up to a 5 min discharge or around 85A, have not seen a max allowed. But for an occasional jump start it does not really matter as you are not going to do hundreds of cycles.

For a jump starter you are much better off with 4x A123 LiFePO4 cells in series, and 3 of those in parallel (12 cells total). Just dangerous to make yourself as each cell is rated 120A for a few seconds. Pb-cells require too much maintenance.

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jeffnz

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#703710 19-Oct-2012 18:39

ADM (absorbed glass mat) is just a lead acid battery but the acid is absorbed into a fibre glass mat so there isn't any liquid as such so non spillable. The SLA (sealed lead acid) is just another name for a battery that is sealed with acid in it. Most car batteries are sealed maint free but in reality they have a baffle system in lid which cools any gas made and returns to liguid state and back to battery but if you tilt over it will eventually spill acid out.

Depends on what you are trying to jump start but 19ah is pretty normal given the average size of jump units. You can buy better grades of the same size that are better at cycling but your's is suffice for jump starting.

Personally I've never seen the point in them as if you are using in a workshop its better to have a couple of lead acid batteries on a trolley.

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stevedg

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#703766 19-Oct-2012 20:36

Thanks all for your replies.

So far I've used the jump starter three times - even 30minutes with the radio on or overnight with a door left open then car won't start (Honda Odyssey V6), so I'm happy with the purchase so far. It's also a good portable 12V source too - eg camping.
The car Battery still tests ok but I wonder. Tested the electrics and there doesn't seem excessive current draw but I'm not a autosparkie.

Steve

jeffnz

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#703771 19-Oct-2012 20:59

get your battery checked it may not be fully charged especially if you are just using a multimeter and it has a surface charge on it.

If its not starting it could be the starter motor but it should start otherwise its a new battery.

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oxnsox

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#703774 19-Oct-2012 21:06

stevedg: Thanks all for your replies.

So far I've used the jump starter three times - even 30minutes with the radio on or overnight with a door left open then car won't start (Honda Odyssey V6), so I'm happy with the purchase so far. It's also a good portable 12V source too - eg camping.
The car Battery still tests ok but I wonder. Tested the electrics and there doesn't seem excessive current draw but I'm not a autosparkie.

Steve

Check what type of battery you have in the Odyssey. If it's a lead calcium type it will need to be charged with the correct charger (if it has been flat) to properly restore it to a full charge state. (A jump start and engine charging won't do this) Might stop it going flat again.

stevedg

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#703800 19-Oct-2012 21:55

The battery is coming up 3 years old so might be getting a bit dated. I got it from th AA 2175, SLA 450CCA. Suspect it might be a Calcium type.
I do charge it when it's flat with a CTEK XS 4003 on the standard setting, think it puts out 14.4V at 4amps. Also has a special mode for cold weather which suggests can be used on AGM batteries which puts out 14.7v at 4amps. Dunno what a Lead Calcium battery requires for a full charge...

jeffnz

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#704012 20-Oct-2012 13:21

thats fine for calcium, given you are having to use jump start and recharge I would think its either the batter getting old or you have a fault in your car as its not normal to do that as I'm sure you are aware. Fix the problem buying a jump start isn't fixing it.

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stevedg

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#704016 20-Oct-2012 13:46

true!