Charging Battery for power tank

mySG_jy · Post by **mySG_jy** » Sat Jan 26, 2008 4:30 pm

I have a power tank that has a 12V 7Ah battery. I am trying to charge it with my charger 12V max 3000mA

Question: Is the charger effective to charge the battery? I have put it on more than 10 hrs but it doesn't seem to move to be effective.

Post by **weixing** » Sat Jan 26, 2008 4:36 pm

Hi,
I thought the power tank come with it's own charger??

Have a nice day.

mySG_jy · Post by **mySG_jy** » Sat Jan 26, 2008 7:10 pm

unfortuately no, I bought a second hand tank, the owner want to keep the charger.

Meng Lee · Post by **Meng Lee** » Sat Jan 26, 2008 8:50 pm

12V 3000mA charger may be too high. By right, any charger with any ampere output will charge any battery, the higher the amperage of the charger, the faster is the charging. But if the charger amperage is too high, the battery will be "fried". According to people i met at Sim Lim Tower, they told me a small amperage charger will take a long time but the battery won't be damaged.

hommel · Post by **hommel** » Sat Jan 26, 2008 10:11 pm

I think yr charger is not so appropriate for your power tank. Yr charging current for is a bit too high. Assuming it is rated at 7Ah, charging current should be recommended at 20% (1400mA). Yr charging voltage even though is rated same as yr battery is insufficient to give a effective full charge, should be upwards of 14v.

mySG_jy · Post by **mySG_jy** » Sun Jan 27, 2008 12:08 am

My charger has 4 voltage range, 6,9,12,15V and providing max Am at 3000mA. So i should move it to 15V? since I can't change the Am

MooEy · Post by **MooEy** » Sun Jan 27, 2008 8:29 am

"By the way, it is not advisable to attempt speeding up
the charging process with this type of charger by
increasing the charging voltage. This can easily result in
overcharging and the conversion of electrolyte into
hydrogen and oxygen gas, building up the internal
pressure — which can cause venting via the safety valve,
and permanent reduction in the battery’s capacity."

anyway, since we are at the topic of battery. let me say this, the 2 main killer of sla/vrla batteries are mainly heat and sulfutaion. heat often occurs due to charging at too high current or voltage. the gel inside the batt ends up being dried up and battery dies.

sulfutation occurs when the battery dips too low a voltage, ie too much is being used. deep cycling in which the battery is fully depleted often causes this. so, dun choose too small a battery for your purpose, these battery hates to be full depleted before getting another charge.

pick at least a 7ah for goto purposes. if u really just wan a small 2ah or so batt, considering wiring a few nihm together. it's far lighter and can be abused in that manner.

another cause of sulfatation is due to not maintain a full charge when storing the batt. always keep the batt charged after use. they don't mind shallow cycling.

should u get another charger with a lower amp? i think just forget abt it. chargers cost almost as much as batteries. get a new batt when the time comes.

~MooEy~

Post by **weixing** » Sun Jan 27, 2008 11:49 am

Hi,

My charger has 4 voltage range, 6,9,12,15V and providing max Am at 3000mA. So i should move it to 15V? since I can't change the Am

Your "charger" is those charger for SLA battery, not those power adapter, right?? If so, then just use the 12V for 12V battery... the "12V" mean for 12V battery, not 12V output. Also, don't change to 15V which is too high and may damage your battery.

Does your charger come with automatic cut-off and full charge indicator?? If yes, you can just leave the charger on without any problem.

Anyway, the "max at 3000mA" mean the charger are able to output 3000mA maximum. It's doesn't mean it'll always output that amount of current.

Have a nice day.

hommel · Post by **hommel** » Sun Jan 27, 2008 12:25 pm

weixing wrote:Hi,
My charger has 4 voltage range, 6,9,12,15V and providing max Am at 3000mA. So i should move it to 15V? since I can't change the Am
Your "charger" is those charger for SLA battery, not those power adapter, right?? If so, then just use the 12V for 12V battery... the "12V" mean for 12V battery, not 12V output. Also, don't change to 15V which is too high and may damage your battery.

Does your charger come with automatic cut-off and full charge indicator?? If yes, you can just leave the charger on without any problem.

Anyway, the "max at 3000mA" mean the charger are able to output 3000mA maximum. It's doesn't mean it'll always output that amount of current.

Have a nice day.

If its a dedicated charger, then 12v means for 12v batt, since this 'charger' does not come with the battery when james purchase, check the output rating on the adapter, most likely is it the output voltage.
The max rating is that the adapter is capable of outputing 3000mA, most unlikely, but its still too high even at eg.2800mA

hommel · Post by **hommel** » Sun Jan 27, 2008 12:35 pm

Oh btw, SLA battery likes to be kept in charge all the while, try not to allow SLA batt to go too low in voltage. Hope you solve your charging problem fast as I think u bought the power pack at about the same time as me and you haven't charge even once yet?