I am wanting to try and build a tester that tests the capacity of batteries,

I live in Zimbabwe and we have a serious problem with power. In most Areas we have power cuts for 12 Hours a day.

As a result we use inverters and similar battery operated equipment to survive.

Our batteries range from the 2.2Ah 12 volts to on average 250Ah batteries. Voltages are between 12 and 24 volts.

Often un scrupulous supplies insist batteries are faulty when I don't believe they are.

Therefore I am looking for a circuit diagram to build a suitable tester. I have looked on the web and found several diagrams however they appear to be mainly for AA and AAA batteries.

Some direction and assistance will be appreciated

 

You should probably read up on 12v lead acid battery testing.

Larger batteries with liquid and caps can be tested using a hygrometer. Other tests include self disharge rate and charge/load tests.

With some experience you don't need much more than a multimeter and a 12v headlight bulb (and a battery charger!) to get a pretty good idea of a battery's condition.

 

There was a fairly long thread on this forum not log ago advocating carbon pile testing as the state of the art for load-testing lead acid batteries. Less expensive alternatives were discussed. Probably worth reading.

 

There was a fairly long thread on this forum not log ago advocating carbon pile testing as the state of the art for load-testing lead acid batteries. Less expensive alternatives were discussed. Probably worth reading.

A couple of them:

here

and

here

 

If you can find a place to get one of these, it takes the guess work out of it.

Don't need to build a constant current load. It keeps track of the ah.

Just charge the battery, connect a load, and wait until battery discharges to the level you want to measure.