Fully charged battery won't turn the starter motor

[Dutch]

Hi all,

Happy New year to you all

My motobat battery is showing 13.8v after being connected to the mains via an optimate but when I try to start the bike up and press the start button it barely turns the starter motor!!

How long do these batteries normally last? I've had it about 4 years now but if it's showing nearly 14.0v surely it should still function.

Is there anything else I should look at, the rectifier maybe? or does the Rectifier only come into play when the bike is running?

Thanks in advance guys
Jeff

[teazer]

What is the voltage as you press the starter button? If it drops a lot, the battery is dead.

You could try to jump start the bike from a spare battery or the car and if it spins over easily, that confirms the battery as the issue. If it's still sluggish, it may be wiring or connectors or the starter solenoid or even the starter motor itself.

[Dutch]

Looks like a new battery then Teazer, just tried it and it drops like a stone from the 13.8v to 4v.

This is my 2nd motobatt are we better with these or is a cell battery better?

Thanks for your help
Regards Jeff

[slosher]

Looks like a new battery then Teazer, just tried it and it drops like a stone from the 13.8v to 4v.

This is my 2nd motobatt are we better with these or is a cell battery better?

Thanks for your help
Regards Jeff

Happy new year Jeff

It's quoted somewhere that Motobatt's need to be kept above 25% of charge or else they will just die on you
Had mine a few years now so i will check mine now you mentioned it mate

Cheers Dave

[Dutch]

Thanks Slosher

Just googled Motobatt batteries and read you should never leave them on charge all the time, only when they drop below 12.2v should you recharge it. When I get home after a ride I always plug it back into the optimate, but maybe this is a mistake as the voltage would probably be near 13.0v I assume after a ride

[stevewharton]

Hi Jeff, had my Motobatt battery on the kettle for over six years now and it's still going strong. When parked in the garage it's always connected to the "Babybatt" charger (as advised by the seller) that I bought with the battery. Not sure whether there's any difference between the way a Babybatt and an Optimate works, but with my battery and charger both designed and made by the same company, perhaps that's why it's lasted a lot longer?
All the best for the new year mate, Steve.

P.S. the Babybatt charger only puts a trickle charge into the battery when needed, otherwise it's on standby and I thought the Optimate did the same?
As for the Yuasa type lead acid batteries, I never had one on the kettle that lasted much more than two years, so it's Motobatt for me 100 per cent.

[oldbiker]

I use the little yellow motobatt charger on the moto-batterys its supposed to cut out when the battery is fully charged and only starts charging again when switched off or removed. So can be left on a while..... On my yamaha xs650 the motobatt seems to last about 5 years and has to work hard to turn the parallel twin over from cold. The one on the gt550 tripple still seems fine after 4+ years.

[raysunners]

Thanks Slosher

Just googled Motobatt batteries and read you should never leave them on charge all the time, only when they drop below 12.2v should you recharge it. When I get home after a ride I always plug it back into the optimate, but maybe this is a mistake as the voltage would probably be near 13.0v I assume after a ride

Hi Jeff, I bought two motobatt batteries one for each bike, both have failed after two years, they where connected to smart chargers when not in use, both back on lead acid batteries now, got over six years from my last lead one

[Dutch]

Thanks Steve & Old Biker

I also thought the Optimate works in the same way Steve, just putting a trickle charge in as and when required and I always connect back up on charge when returning after a run. I actually have a reminder for me when I lock the bike up in the garage to remind me to connect the Optimate because I was once told if a Motobatt runs down you can never recover it so as I say its on charge all the time when the bike is in the garage.

I am really surprised how much voltage it loses when hitting the starter button, the light on the Optimate is green showing the battery is fully charged at 13.8v and when I hit the start button it tries to turn the starter for perhaps 2 sec and when I take a reading after it's dropped to 12.0v a drop of nearly 2v and the green light on the Optimate as now gone out again indicating it needs charging.

Anyway a new Motobatt has been ordered today because this one I think has give up on me

Thanks for your help again
Jeff

[Dutch]

Thanks Slosher

Just googled Motobatt batteries and read you should never leave them on charge all the time, only when they drop below 12.2v should you recharge it. When I get home after a ride I always plug it back into the optimate, but maybe this is a mistake as the voltage would probably be near 13.0v I assume after a ride

Hi Jeff, I bought two motobatt batteries one for each bike, both have failed after two years, they where connected to smart chargers when not in use, both back on lead acid batteries now, got over six years from my last lead one

Thanks Ray

Your message appeared after I posted mine and was considering a lead one and may still get one, they are handy as a spare especially for experimental purposes like today. I could have charged the spare up and proved it was the battery at fault straight away.

Happy New year Ray
And thanks for your input