Can I charge a jumpstart unit with my charger?

[TheJackal]

I have a LiproPlus 5 charger that does all my battery charging, which says it can charge up to 12v Lead batteries.
I want to use it to charge an old jumpstart battery that has been sat in a garage for a couple of years. Its 12v with 400 Amp output.
So on the charger I have set the charge rate at 3.0 Amps and the volts at 12v. However when I start charging and it does the battery check it says low voltage. If I lower the charging voltage to about 6v it starts charging but after a few seconds it says battery full.

Is it possible use my charger like this or do i need to start it off at a lower amps or voltage to get it going as it is so low already.

I do have a plug in wall charger for it but it is only rated at about 1.25A and i wanted to charge it faster if possible with more Amps.

Any help would be much appreciated.

[TheJackal]

No comments?

[pcool69]

I have had several different chargers that were capable of charging Pb batteries. In every case, you tell the charger the capacity and voltage.

For example, the typical flight box battery is a 7 amp hour 12 volt battery. The setting is .7amps and 12 volt.

I was under the impression that Pb batteries should not (or could not) be fast charged.

[Pinecone]

A lead acid battery that has sat for several years without being charged is probably dead.

The voltage it too low for the charger to safely charge, so it won't. When you set the charger to 6 volt battery, the voltage allows the charger to start working, but the voltage is high enough to make the charge think that the "6 volt" battery is done.

[flynheli]

use a nicad charge setting for a couple of minutes then try pb again.

[TheJackal]

Cheers guys