battery question - optimate

[Mike Sands]

If I leave my battery on 'tender' with my optimate for say a week in cold weather, when I come to start the bike it won't turn it fast enough. This is despite the optimate having gone through its proper green light sequence.
However, if I jump start it, then go for a ride then leave it for say 4 or 5 hours (not on charge), it will still start no problem. So the engine is now cold, but the battery still has enough oomph to churn it over at a very healthy speed.

What I don't understand is why my Optimate is somehow failing to keep it in the state it was put away in.
Mike

 

[zimtuff]

If I leave my battery on 'tender' with my optimate for say a week in cold weather, when I come to start the bike it won't turn it fast enough. This is despite the optimate having gone through its proper green light sequence.
However, if I jump start it, then go for a ride then leave it for say 4 or 5 hours (not on charge), it will still start no problem. So the engine is now cold, but the battery still has enough oomph to churn it over at a very healthy speed.

What I don't understand is why my Optimate is somehow failing to keep it in the state it was put away in.
Mike

The engine is still warmish after 4-5 hours.I would get the battery tested under load.

 

[owl]

Sounds like the battery is knackered to me, Mike.

 

[budman]

..I got news for ya..it's not the battery..it's not the tender...it's the bike...it's called......anomaly.....some have it..some don't..sad to say, mine and yours does..

 

[Mike Sands]

Sounds like the battery is knackered to me, Mike.

Yeah probably but if the engine's alternator is capable of rcharging the battery so it churns it really quickly even after several hours of cooling down, why can't the optimate do the same?
Mike

 

[owl]

Don't know the answer to that one, Mike, but last December my car was doing the self same thing. No start in the morning - just a click. An hour on the battery charger and it was good for starting all day. Until next morning again. New battery sorted it.

 

[zimtuff]

Yeah probably but if the engine's alternator is capable of rcharging the battery so it churns it really quickly even after several hours of cooling down, why can't the optimate do the same?
Mike

Your engine/gearbox is 40-50kgs of metal with 4 litres of warm oil and about the same in coolant. It wont cool down for at least 10 hours or more ,so the engine is still "loose" and spins easy.
Not only that,but the batteries chemical reaction speeds up with heat,and as the battery is more or less above the engine,it is also kept warm by heat from the slowly cooling engine.

I went down the shop in my diesel landcruiser for the milk and paper yesterday and the engine was 20c at 6am when cold,when I got back 10 mins later it was on about 50c.
At 10am I went out again and it was on 36c,so it was still 16c hotter than the cold start after 4hrs.

 

[Mike Sands]

OK - so I am going to try starting it 24 hours after a good run (without plugging in the optimate). then I will do another run and leave it a week plugged into the optimate. That should remove the warm engine variable
Mike

 

[zimtuff]

OK - so I am going to try starting it 24 hours after a good run (without plugging in the optimate). then I will do another run and leave it a week plugged into the optimate. That should remove the warm engine variable
Mike

You said 4-5 hrs before,it will not be warm after 24 hrs and you already know its not starting with the battery tender plugged in.
The only way to prove/disprove the engine warmth theory is to keep the bike warm overnight with a plug in blanket or some other way of keeping in the engine warm.
Another thing affecting the battery is that the bikes alternator is probably pushing a lot more amps than the tender.

IMO you would save a lot of time and effort by just getting the battery tested under load.

 

[Willtill]

Stick a multimeter on your battery, set it for DC volts. Disconnect your coils and then turn over the engine. If you drop under 9.6 volts, you may have a bad battery.