Battery under load
I've been looking for an answer to a specific question, on past discussions on other forums and I also have an open topic on another forum but it always gets into the weeds of what batteries and what ...
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Just to follow up I ran a test yesterday to see how long these batteries would hold up. Once again, relying on a $9 voltmeter connected to the main 12v lugs in the electrical compartment. However that meter matches my handheld voltmeter.
I disconnected it from 120v, let it rest for 30 min. At that point was still reading 12.8. Instead of running the furnace fan I turned on all the lights till I read 7.1 amps at the battery. That brought the voltage down to 12.3. In 45 minutes it dropped to 12.2. After an hour and 20 min. dropped to 12.1. It settled there for the next 3 hours when it dropped to 12.0.
The plan was to let it dip to 11.9 before terminating and seeing what the rebound voltage was but it was 9:30 and 6 hours in so I decided to quit, still reading 12.0. Waited 30 minutes and the voltage had rebounded to 12.3.
So I plugged it back in and went to bed. I now have some evidence of how long they will last and also what to expect in terms of voltage drop under load.
Thanks everyone for your input.
I disconnected it from 120v, let it rest for 30 min. At that point was still reading 12.8. Instead of running the furnace fan I turned on all the lights till I read 7.1 amps at the battery. That brought the voltage down to 12.3. In 45 minutes it dropped to 12.2. After an hour and 20 min. dropped to 12.1. It settled there for the next 3 hours when it dropped to 12.0.
The plan was to let it dip to 11.9 before terminating and seeing what the rebound voltage was but it was 9:30 and 6 hours in so I decided to quit, still reading 12.0. Waited 30 minutes and the voltage had rebounded to 12.3.
So I plugged it back in and went to bed. I now have some evidence of how long they will last and also what to expect in terms of voltage drop under load.
Thanks everyone for your input.
