Batteries Tested

[dunnah01]

Our pair of 4 year old grunt lead Acid batteries lost their oomph on our recent French trip so I replaced them with a single AGM. I carted the old batteries around in the moho garage until we got home and then chucked them in the house garage. So about 6 weeks later I decided to put a voltmeter across them - the pesky things still read 13.0v & 12.9v even after standing for 6 weeks. I decided to do a drain test on them by connecting a 5w bulb across the terminals to see how long it would take to drain down to about 12v. Hoping my rough calc on a 110Ah battery they would last a few days each. I was not too upset when it took about 2 hours for each battery to drop to 12v and not recover proving to me that they really are goosed. So the moral is don't use voltage as any guide to how good a battery is

 

[scotjimland]

I have a 20 year old FLA in the shed, removed from a 2003 Honda CRV..

I still use it for 12v testing and also running a 12v inflater for the e-bikes.. just needs a charge every now and again when I remember ..

don't use voltage as any guide to how good a battery is

Absolutely,.
Voltage is only an estimate of the state of charge.. readings depend on whether the battery is being charged, discharged or is at rest..... not the health of the battery

 

[PhilandMena]

You may find this of interest.

LA Batteries Failing on Victron System

Hoping someone can help with my Victron MPPT+Shunt+Protect and Yuasa lead acid leisure battery setup. The batteries started failing at under one year old, and now at one year they are pretty much shot. Apart from two short breaks the van has been UK touring for six months. The stated cycle life...

www.motorhomefun.co.uk

 

[wiff2110]

Our pair of 4 year old grunt lead Acid batteries lost their oomph on our recent French trip so I replaced them with a single AGM. I carted the old batteries around in the moho garage until we got home and then chucked them in the house garage. So about 6 weeks later I decided to put a voltmeter across them - the pesky things still read 13.0v & 12.9v even after standing for 6 weeks. I decided to do a drain test on them by connecting a 5w bulb across the terminals to see how long it would take to drain down to about 12v. Hoping my rough calc on a 110Ah battery they would last a few days each. I was not too upset when it took about 2 hours for each battery to drop to 12v and not recover proving to me that they really are goosed. So the moral is don't use voltage as any guide to how good a battery is

Spot on.