Battery charging advice please.

[TeaPig]

Interesting. Aside from your own experience do you have any other evidence that modern trickle chargers cause this? I ask because my (personal) experience has been the exact opposite that batteries kept on conditioners degrade slower.

Yeah, I agree. Battery charging is an exact and well understood science which the more sophisticated modern chargers are designed to take into account, including the ability to maintain a fully charged lead acid battery for extended periods without damage or loss of capacity. It is possible to knacker a battery by leaving it hooked up to a cheap charger for too long but that's a different story.

 

[grimo]

No manufacturer will tell you how long the extended period is, all I know to be true is that it will reduce over time the battery capacity.

The batteries fitted to bikes and cars are really not designed to be kept on a float charge, they are there to provide large amounts of current over short periods of time to start the engine. They also supply a smooth DC supply to the vehicle and boost demand from what the alternator can supply.

Batteries designed to be on float charge are more suited for alarms and other protective devices that require dc supplies to operate relays like on circuit breakers where a full battery is essential and even these batteries require change because they fail over time.

I am of course only giving my recommendations and you are all free to decided for yourselves. These smart chargers do a better job of charging batteries because the charge cycle is monitored and they will fully charge your battery.

The current draw on a bike with no alarm is going to be very small, Milli amps.
If a fully charged 14Ah battery supplied a current of 10ma per hour then it should last for around 8 weeks before it requires charging.

Regards,

 

[Mr K]

Had my 54 plate R1200GS from new.
Optimate is hooked up, direct on battery whenever the bike is not in use for longer than a couple of weeks.

56,000+ miles and still on OE battery.

Make of that what you will.

 

[TeaPig]

No manufacturer will tell you how long the extended period is, all I know to be true is that it will reduce over time the battery capacity.


I am of course only giving my recommendations and you are all free to decided for yourselves.

It's always interesting when we get contradictory advice in these threads so after a bit of reading in order to get to the bottom of the problem, it's unsurprising to find that there is truth in both camps. The bottom line, as far as I can see, is that a lead acid starter battery can be constantly float charged without detriment provided the charger can very accurately control the charging voltage. This is I assume what the likes of optimate etc. are designed to do.

Unfortunately, some unsophisticated trickle chargers without constant voltage control, if connected for long periods, will either undercharge the battery leading to sulphation, or overcharge leading to drying out of the cells. Both the latter will reduce the charge capacity of the battery and shorten the service life

Doing nothing (leaving the battery unattended for weeks) is worse still.

 

[Grey Beard]

I

The alternative to the BMW charger, which plugs into the special socket below the seat is the Optimate 4, BUT it is not yet available. I am told the BMW socket/CAN-BUS compatible Optimate 4 will be available from about spring 2011. (The current Optimate 4 is NOT CANN-BUS compatible as far as I understand).

Grey Beard

Update

I saw an Optimate 4 in a German BMW Dealer this morning, which was labelled as BMW CAN-BUS compatible, so it looks like this is now available. The dealer wanted €70 for the charger and you would need the BMW socket to charge direct - probably another €10, so not a lot cheaper than a genuine new BMW Charger on eBay at €85 plus postage.

But the Optimate 4 presumably has more flexibility in charge capability.

Grey Beard

 

[peter-k]

It is not compatible with the Can-Bus, even if the manufacturer prints this marketing BS a 1000 times on the packaging. It has to be compatible with the electronic control unit (ZFE), and it is.

 

[ianp5uk]

It depends what they mean by "compatible". Optimate told me the Optimate 4 would not damage the controller but it would not hold the socket open so it has to be attached direct to the battery by some means.

 

[Greg Masters]

Keeping a battery on a constant float charge will decrease its capacity to hold charge i.e from 14Ah to say 10Ah and so on as time progresses. you will find that it won't be able to start your bike after a few times but the smart charger will tell you its good.

My GS is now 2 years old I do not have an alarm fitted and I do not charge it with a charger, it also isn't ridden as much as i like to, I have covered 4800miles with no problems.

My bike spends every spare minute hooked up to an Optimate. The original battery was still well capable of starting the bike after 9½ years.

Can't see why 24/7 connection should be a problem.

I understand that you can disconnect the battery OK if you want to bring it into a warm house over the winter.

The battery would be better kept in a cold location on a Optimate.

Greg

 

[Steptoe]

. You just have to reset the on board computer clock and you loose the service interval record - per a local BMW dealer.

Grey Beard

You do not lose the service record The same as you don't lose the mileage.

 

[Grey Beard]

You do not lose the service record The same as you don't lose the mileage.

OK, I haven't tried that, but this is what the BMW dealer told me and he seemed to know what he was talking about. Even owned 17 (various aged) bikes himself.

Grey Beard.