Charging sealed lead acid batteries with a PSU

Thread Starter


Joined May 31, 2013
Hi, I'm new to the forum so I'll introduce myself. My name is Steve and I'm interested in tinkering and making gadgets.

A question I have is, what is the implication/problem of charging a sealed 12v lead acid battery (Alarm panel type) with a 2A 12v PSU?




Joined Sep 9, 2010
The trouble is that to properly charge a SLA you need to top it up to about 13.8V (depends a little on temperature). So if the supply is regulated at 12V, you can't get there.

Now, some supplies will float up to 16V or so if there is little or no load on them. So you might be able to bulk charge at 12V and then trickle at a higher voltage if the supply behaves "just right".
depends if you have a variable psu so that you can have a higher voltage.. or you can make some for use.. there are threads here in AAC that has topics on making variable psu's ..
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Joined May 13, 2013
Check if you have a wall-wart which gives 14 volts or so and use it to charge the battery . Don't forget to use a series resistor so you don't exceed the curren't handling capability of the wall-wart.