Max Charging Current for SLA Batteries: Avoiding Damage

[cookiebar]

What is the max current for a rapid sealed lead acid battery charger?

Most recommend 0.1C up to 1C where C = Ah rating. I have a max 30-32A regulated 13.8VDC power supply and the battery is 12V, 170Ah. Would charging the battery at the max 32A damage the battery?

 

[willib]

I don't think that the battery will draw the full 32A , in fact i am sure it wont..unless it is past , way past , its prime..
13.8-12 =1.8V
1.8/(internal resistance of battery) approx(.3 ohms) =6 amps..
it should work fine, as it is...
note :: it may draw more or less depending on the actual internal resistance and the amount of charge it allready has ..

 

[cookiebar]

The power supply is current limited but I'm worried abt whether the 32A will cause damage to the battery(if fully drained)?

 

[willib]

does your power supply have an ammeter built in ?

 

[cookiebar]

No but I can easily install 1

 

[willib]

what i mean is, if you were to measure the current , you wouldn't be damageing your Ammeter..?
If not ,then try it with the ammeter installed and see what current the battery is drawing..

 

[cookiebar]

so what is the max allowable current for charging? I can measure the current with a clamp ammeter.

 

[willib]

if you were to measure 6 A when when the battery is connected , you could leave it on for 28 hours ..
170/6 = 28 approx..
as you said at the beginning , 0.1c = 17A , but that is pretty high ...

 

[GENIERE]

... I can measure the current with a clamp ammeter.

DC?


...

 

[GENIERE]

The few times I charged my motorcycle battery with a charger designed for an auto battery, I put the charger in series with the headlamp. Of course the charge time is much longer.

 

[willib]

DC?


...

I was wondering about that myself..
but I'm sure cookiebar knows how to measure current..

 

[Averagesupernova]

I don't know why they wouldn't exist and I can't say I have actually seen one but using a hall sensor you should be able to measure DC amps with a clamp on meter. I have seen sensors that permanently go in-line for current measurement. They are a square donut type of thing that the wire goes through loosely. I can't see why this couldn't be adapted to a clamp on sort of thing. My two cents...

 

[GENIERE]

They are a square donut type of thing that the wire goes through loosely...

Yeah, that seems to jog my memory.