Duff battery but 12+volts

[billdn]

A battery I've had on trickle charge for a while, battery make is Motobat has a charge of 12.7/12.9volts but when fitted to the bike won't even turn over starter but another one which is fitted, albeit newer is showing 12.5volts but starts bike fine - I'm confused!
Has the prolonged trickle charge on the old battery - maybe a year on charge done something to the power of the battery but not the voltage?. I've heard Motobatt batteries can just die but why the charge in it?

[TrickyMicky]

The voltage is only the 'pressure', it does not reflect the amount (amps) of electricity in the battery. Fair chance that the plates are pretty well sulphated. Have used one of these 'battery conditioners ' in the past and suffered exactly the same fate as yourself. A normal lead acid battery thrives on being discharged very slowly and then re-charged slowly, the to-and-fro effect keeps the plates quire clean.  If there's anybody on here who's as ancient as me they might recall when your elderly aunt had a radio that ran on an accumulator which was just a lead acid cell. The radio used to discharge it very slowly, and when it was flat the man used to come round and swap it for a fully charged one. They lasted for donkeys years.

[robvangulik]

When measuring the Motobatt while (attempting to) start, you'll probably see the volts disappearing before your eyes, which is a clear indication it's life is over.

[Johnwebley]

I had that happen to a Motobatt.

Since then I  just charge, and then disconnect.

In storage, just leave it, and trickle charge every couple of months

Sent from my SM-A750FN using Tapatalk

[K2-K6]

You could take it through a few discharge and recharge cycles to see if it responds in any way.

Just connect a side light type bulb to it and leave it to flatten over a 24 hr period,  then charge again.

[McCabe-Thiele (Ted)]

The voltage is only the 'pressure', it does not reflect the amount (amps) of electricity in the battery. Fair chance that the plates are pretty well sulphated. Have used one of these 'battery conditioners ' in the past and suffered exactly the same fate as yourself. A normal lead acid battery thrives on being discharged very slowly and then re-charged slowly, the to-and-fro effect keeps the plates quire clean.  If there's anybody on here who's as ancient as me they might recall when your elderly aunt had a radio that ran on an accumulator which was just a lead acid cell. The radio used to discharge it very slowly, and when it was flat the man used to come round and swap it for a fully charged one. They lasted for donkeys years.

Not wishing to disagree with your experience this in my view/experience on sulphination causes.

I use a C-Tek smart charger on our Merc the first Lead Acid unbranded battery lasted 12 years - it was left on charge 24/7 for 5 to 6 months every winter. The current AGM technology battery is in its 6th year it gets the same treatment. My understanding of the Suphination process is that the main culprit is the battery not being sufficiently fully charged on a reguar basis - this leads to a deterioation of the lead plates over time.

When I worked at MB Derby new cars in the showroom often needed battery replacement as they had stood for a few months without being sufficiently charged. MB warranty would not cover the cost of such failures on new cars. It has been my experience that vehicles used frequently that cover decent daily mileages often last much longer than low mileage vehicles as they are more regularly at close to full charge. Battery suppliers escape a lot of claims as they often have a minimum voltage requirement for a claim to succeed  - 12.1 volts?. In reality only a dead short / single cell failure is generally covered.

[K2-K6]

"I use a C-Tek smart charger on our Merc the first Lead Acid unbranded battery lasted 12 years - it was left on charge 24/7 for 5 to 6 months every winter. "

Thought that kit had voltage monitoring as part of strategy.  Does it "watch" voltage decay while not charging to then bring in light input once it gets to a pre determined base level, in effect mimicking a vehicle in use with something like cyclical recognition?

Maybe I'm crediting the device with than more logic than it possesses, seems to be the claim for "smart" description.  I know some are particularly effective and can go toward recovery cycle by pulsing up to about 18 volts to attempt a defibrillator for batteries mode to kick a compromised one into life again.

[SumpMagnet]

Mind you...I had just had to do a horrid repar on my Hornet while getting it up and running to sell. Battery read a solid 12V....charged it...fully charged....in the bike, and click...clickclickclickclickclickclickclickclickclickclick ... no vroom.

What had happened was the battery post on the +ve terminal had broken. Vibration, manufacturing fault...whatever....don't know.

It's a pig to get enough heat in to solder without melting the plastic....but in the end, I managed to drill a hole into the terminal, and solder a fat piece of wire into the hole filling it with solder...then soldered the terminal on top, using the wire as a 'bridge' to get the solder to purchase on both sides. Back on the bike....and it fired first press.

The battery was healthy enough, there were plenty of volts when I checked on the meter....but the poor contact between the plates and the terminal meant the volts dropped as soon as any current draw happened, and there wasn't enough power to do more than energise the solenoid over and over. All becuase of a poor connection

[3scs]

Best way to check condition of battery is while under load turn lights on kill switch to off crank it for about 10 seconds if voltage reads 9.6v or above battery is good below 9.6 it’s scrap

[billdn]

Thank you all, yet another life lesson on battery care. So glad can ask what to some might seem obvious questions!