Battery question

[911hillclimber]

This is about the battery in my 1989 Yamaha motorcycle.

It is 12V, 2.5Ah with "AMG technology" made by Motorbatt.
The MTB 4BB battery is a very general purpose unit.

I have neglected this battery as it stood on the garage shelf disconnected for months but put it on charge today.
Volts before charging was a lowly 8.6V (dead?), the charger when connected showed no current flow.

After about 4 hours on charge the volts are 12.6V.

I think this battery is done for; any comments please?

[misteralz]

Depends on what sort of charger it's been on. Four hours doesn't feel like long enough to revivify it. I've had great results with my CTEK, but only after a couple of days, and never with a battery that dead initially.

[911hillclimber]

Thanks for the reply.
The charger is an old one I've had for decades so super simple and old tech, but it has charges last week my Boxster battery etc.

This morning the battery is showing 12.8V so a drop of 0.6v ish over night.

If no charge current is flowing then I presume the battery is not charging but the voltage has gone from 8.5v to 12.6 after 4 hours.

Will pop it into the bike and see if it starts, new one is about £30, so prob the best option in the end.

[misteralz]

Dropping half a volt overnight is your answer, I think, and 30£ is nothing for peace of mind.

[911hillclimber]

Yes, new one on it's way, £26.
I think one on my 911 has dropped too!