I have the following:

Lead acid battery

Specs: 12V, 7.2 Ah

Model: Portalac PXL12072

Description: Kind of old, so maybe sulfated, but I won't know until I try to charge it.

Lead acid battery charger

Output specs: 10 Amps max., 14.4 VDC, 144 W max.

Model: Denryo BP-1210A

Description: New. "3-stage high tech battery charger"

The charger manual also contains a table that lists other chargers Denryo makes and their recommended batteries. My charger seems to be for batteries between 12V/30Ah (minimum capacity) ~ 12V/100Ah (maximum capacity). However, at 7.2 Ah, its capacity is below the recommended minimum capacity.

My question

Is there a safety risk to use a 7.2 Ah battery with a charger of minimum recommended capacity 30 Ah?

Similar questions

Charging lead-acid batteries?

This question states,

The charge current for small lead-acid batteries should be set between 10% and 30% of the rated capacity (30% of a 2Ah battery would be 600mA).

In my case, 30% of 7.2 Ah is 2.16 A. My charger outputs 10 A max., i.e. 0~10 A. But I don't know how smart the charger is to adjust its output.

What can happen if I try to charge lead acid battery outside charger's capacity range?

This is like my question, but it is unanswered.


Connect it and use a multimeter to see the voltage and then also check the current - if it is below 5A and behaves nicely then I would assume it is doing fine.

If it hammers the battery at 10A and does not do any charge control then you need another charger.

If you don’t have a meter to check what is going on, either get one or stop playing.

  • \$\begingroup\$ Ok. I will start the charge and check voltage and current. I didn't know if it was ok to connect the two for even a minute. But if a short time is safe, I will go ahead and connect them and measure what happens. \$\endgroup\$ – user4396936 Jun 7 '20 at 12:29

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