Battery Charging

Hi fellow modelers,
A question with regard to charging up a sealed lead acid battery that came with a recent purchase.
Now the battery that I have is a 6 volt 12.0ah lead acid battery - the charger i have is a 6 volt but only rated up to 10ah, is this still safe to charge up?
Regards 
Phil

normally a charger will have a charging rate on the label...…...something like 500maph...…...meaning 1/2 an amp per hour charge rate and taking 24 hours to charge your battery at 12 amps.

if yours is a charge rate of 10ah.….it is a very fast charge more likely for a motor car or leisure batteries on a caravan or real boat...………..and at that rate, could and probably would do very permanent and irreparable damage to your battery....

check the charge rate as usually listed in milliamps before connecting.it could if an older charger have a sawitch to turn it from normal to "trickle charge" which charges at a rate of 1.0 - 1.5 amps per hour...…..which would be ok but watch for overheating...…...if so discontinue the charge. 


in the worst scenario it could cause a fire.

also always take the battery out of your boat to allow the battery to "breath" and air circulation.

Thankyou, the charger I have is a JP gel cell auto charger for lead acid batteries and it says that the output is 6v/500mA.
Its one that ive used on an old 6v 7ah battery in the past with no probs. Just abit unsure about using it for a 6v 12ah battery

Apple15 wrote:

 it says that the output is 6v/500mA.
Its one that ive used on an old 6v 7ah battery in the past with no probs. Just abit unsure about using it for a 6v 12ah battery

that is perfect then Apple15...…..it would charge your battery in theory from flat to full in 24 hours but I always leave mine on if flat for a couple hours longer. but at 500mA charge rate that is a nice gentle charge that won't hurt your battery. no problems.

Thanks for your help

You will probably find that your JP charger is a "smart" type. It commences to charge at what is often called a "bulk" rate, when a relatively high current is applied. Once the battery is almost fully-charged the charger automatically reverts to a much lower "float" charge-rate, sometimes called a "trickle" charge. At this low current you could leave the thing on charge more or less indefinitely without causing any damage. If your battery hasn't discharged much since the last charge then it may well go straight into float-charge mode.

SLA batteries dislike being left alone for long so it's a good idea to apply a top-up charge once every couple of months, even when you aren't using or planning to use them for a while. Once a SLA battery goes absolutely flat it's usually irrecoverable - although they do make handy weights or doorstops in the workshop!

Do make a note of the different units involved: a charge rate is a current and indicated in A or mA (Amps or Milliamps) whereas the units of AH and mAH are battery capacity in either Amp.Hours or Milliamp.Hours. The essential difference between charging a lead-acid battery and, say, a NiMH or LiPo, is that it is done at a constant voltage, as opposed to a constant current for the latter types.

So now you know!  

Dave M

Having got 6 of the large electric scooter batts in the workshop that are not used at the moment i charge them all up every month after discharging them with a car bulb for around and hour in turn them charge them back up as Dave has said lead acids dont like to become over dishcarged IE going flat and as for door stops they are brill especially to hold down a deck that has just been glued !!!!

Dave