A2B Metro (2008) BMS quit, A batt going!

[Roberta Lynn]

I need to find someone, or shop, in the San Francisco/Santa Cruz area to fix and/or replace the BMS and maybe the battery. If someone has a schematic of the early Metro that would be helpful. I don't even know where the BMS is...in the pack or the "switch module"?
Please email me with any guidance [email protected]

 

[Ann M.]

@Roberta Lynn, you're in luck! The US home office for A2B is in San Francisco . You can reach them on the weareA2B.com contact page or via email, [email protected]. Got to spend some time with Kyle Langdon of A2B at Interbike this year; he and several others of the staff are very familiar with the older Metros.

What makes you think that the battery BMS is shot? If this is the original battery the voltage might look ok, but it's not going to be outputting adequate amps, so it makes the bike either dead or the motor sounds 'grindy'. This would need a replacement battery which A2B has. If not the internal battery they will have the alternate rear rack battery.

Depending upon what is actually happening (you haven't given us any details) it could be a different issue relating to the motor & controller. There are 2 different versions of the controller/motor setup. Very early ones had the controller in the motor and latter models had a subsidiary unit near the cranks. Look for a serial number, probably on the underside of the bottom bracket which will help them identify which version you have.

 

[Roberta Lynn]

I suspect the A BMS, wherever it is, because when I top up the charges after a week's idleness, the B pack charges for about 30 mins (kwhs consumed by the BMS) as usual, but starting about 2 months ago the A pack takes no charge in that instance. Since then the A pack range has declined noticeably (25-30 %) compared to the B. The bike is the early Metro but the hub motor was replaced (fried MOSFET) about 3 or 4 years ago. As all the symptoms are confined to the A pack I don't think the motor/controller is involved.
I've actually dropped by the SF storefront but didn't get any meaningful information.

 

[Ann M.]

The folks at the storefront probably aren't the technical people like Kyle Langdon, the company president. If your A battery is 8 years old you will need to replace the whole battery; it's not the BMS, it's just a worn out battery.