Battery Charger - Back Current

[David.]

Found this in the BMW Motorrad battery charger instructions, Back current:

"If the charger is connected to the battery but not to the mains, a low current flows back from the battery into the charger. Disconnect the charger from the battery poles if it is not connected to the mains. Otherwise the battery can become completely discharged over months."

This is not something I've previously heard of but may be a reason for some of the problems being experienced with battery chargers being left connected to the bike and the battery going flat. I don't have a BMW charger but think I'll now start disconnecting the charger from the battery when it is not switched on at the mains.

[Casbar]

Only if you leave a charger connected and the charger off. Personally if I'm not maintaining the bike battery, I unplug the lead from the bike.


Saying all this, my battery started to play up yesterday. Bike starts first time, but after running and re-starting it struggles Battery is nearly 3 years old, so will check the cranking and load to see if battery is on its way out.

[David.]

Are batteries covered under the 3 year manufacturer's warranty.

[Casbar]

Are batteries covered under the 3 year manufacturer's warranty.

I phoned the dealer this morning and they told me to book the bike in and they will check it out. No mention of the battery being covered under warranty, but who knows, I'll take it over in the New Year. If you buy a battery off them though, you do get a 2 year warranty, whereas Motorworks etc only provide 1 year even for Exide.

[David.]

I phoned the dealer this morning. No mention of the battery being covered under warranty.

Did the dealer ask which battery charger had been used.

[Casbar]

Did the dealer ask which battery charger had been used.

Lol no considering the battery has been ok for nearly 3 years, think I'm ok

[David.]

If you buy a battery off them though, you do get a 2 year warranty, whereas Motorworks etc. only provide 1 year even for Exide.

The BMW (made by Exide) battery is £130, Select part (bmwsupply.co.uk) whereas, the Motorworks Exide battery is £80, Motorworks BMW Motorcycle Specialists - Shop - Spares and Accessories

This looks the same for £45, AGM12-16 EXIDE MOTORCYCLE BATTERY 12V 16AH 170A 4920 | AGM Batteries | Batteries & Power Electronics | Battery Group

[Casbar]

The BMW (made by Exide) battery is £130, Select part (bmwsupply.co.uk) whereas, the Motorworks Exide battery is £80, Motorworks BMW Motorcycle Specialists - Shop - Spares and Accessories

This looks the same for £45, AGM12-16 EXIDE MOTORCYCLE BATTERY 12V 16AH 170A 4920 | AGM Batteries | Batteries & Power Electronics | Battery Group

Just been quoted £97 by my dealer for the Exide, have checked out the Motorworks Exide as well, but the 12-16 on there and the OEM battery are showing CCA of 200amp but the ones in the link show 170amp. Not sure why as I would have thought the 12-16 Exide is the same CCA, so not sure what that is all about. But it depends on how much you value a 2 year warranty vs a 1 year. Plus if I take the bike to the dealer, I can see if there is anything else wrong. i will be able to negotiate a further discount and they may even replace with good will as the bike is still under warranty - miracles sometimes happen. The dealer looks after a fleet of our bikes and we have bought 3 from them in the last year, so I will be in a favourable negotiating position.

[emlevy]

In the U.S., the battery is covered by the BMW three year warranty.

[David.]

Just been quoted £97 by my dealer for the Exide.

Same as Chester Motorrad, 61218531121|BMW Motorrad AGM Battery 61 21 8531121|Chester Motorrad (chester-motorrad.co.uk)

[Casbar]

In the U.S., the battery is covered by the BMW three year warranty.

Bloody Hell I had better move then - Oh wait!

[David.]

Exide have confirmed that basically BMW asked them to make a bespoke 200 CCA battery. The aftermarket Exide batteries are 170 CCA. It's a stitch-up by BMW to make you buy the OEM battery. Unless you think you can get away with 170 CCA.

(Fortunately, for the Camhead, both OEM and aftermarket Exide batteries are 170 CCA).

[Casbar]

Exide have confirmed that basically BMW asked them to make a bespoke 200 CCA battery. The aftermarket Exide batteries are 170 CCA. It's a stitch-up by BMW to make you buy the OEM battery. Unless you think you can get away with 170 CCA.

(Fortunately, for the Camhead, both OEM and aftermarket Exide batteries are 170 CCA).

Well there is something odd going on - This Exide battery on Motorworks is badged 12-16 but is quoted as 20% more cranking power at CCA200amps


https://www.motorworks.co.uk/vlive/Shop ... rch=SEARCH

[David.]

This Exide battery on Motorworks is badged 12-16 but is quoted as 20% more cranking power at CCA 200A

Motorworks agree with Exide that the CCA is 170A, the descriptive text is misleading.

[Casbar]

Motorworks agree with Exide that the CCA is 170A, the descriptive text is misleading.

That clears that up then  8)