Battery discharge while in use

[PeterJones]

Did most of the diagnostic stuff (thanks for all the help) and generally things seemed to be ok so I did what I should have done early - bought a new battery and all is ok!

Cheers, Peter

 

[PTmowerMech]

I have a maintenance free battery and its reasonably new (maybe 2 years old). That being said could it be the battery even though it charges overnight without any issues?
Cheers, Peter

I've had a few batteries like that in this past month. They would take a charge. But let them sit for any hour or so, and they wouldn't have enough left in them to crank the engine.

 

[Telesis]

Peter, I would strongly suggest doing the simple charging system test with the new battery, if that's one of the things you didn't do prior, before declaring victory. Key off, measure batt voltage, engine running at regular operating speed, measure batt voltage. Measurement 1 = approx 12.5. Measurement 2 = 13-15. If meas 2 is LESS than meas 1, you still have a problem and soon enough, you'll be right back where you started! Please ignore this if you've already verified proper charging operation!

 

[StarTech]

And he needs to doing the second test with the electric PTO engaged.

 

[PeterJones]

Thanks, I see the point and will do...

Cheers, Peter

 

[PeterJones]

12.9v after overnight charge.
13.8v engine running. PTO off
12.5v engine running PTO on
12.8v after 2 hours mowing
12.5v after overnight stay in workshop not on charge. Started ok.

If my 12.8v (after mowing) reading was correct there looks to be an overnight discharge. I will let it sit over the weekend to see it discharges below 12.5v

Again, thanks for the follow up...

Cheers Peter

 

[Scrubcadet10]

how long after mowing did you take the 4th reading? I may be wrong, but i think if you check a battery after it's been charging it will show a high voltage but it may not be the actual sitting battery voltage...

 

[Telesis]

The good news Peter is your charging system looks to be working fine. Don't get too worried about a few tenths of a volt. Scrubcadet is right. The voltage will drop back down to 12.6 (in a perfect world with a new battery) over a bit of time when charging is stopped. Problems with batteries, bad connections, bad charging systems etc manifest themselves with voltage problems of a few volts, not tenths of volts, so you are good to go!