Dead A2B Alva Technical Help Needed

[uberlieb]

Hi:

I have two Alva+ from A2B that are both "dead". The batteries are at zero when I check the voltage with a meter. At one point recently they were working but sat for awhile and are now dead. Any hints?

When they were working and I sent them to a local shop for repair the bike would "start" meaning when the key fob was touched to the display it would come on, but when I attempted to accelerate they would just cut out. This happened on both bikes and both batteries as I recall. Any hint what might cause this?

If it is battery and / or BMS that are faulty does anyone know how to convince the bike to start with just a proper voltage applied to the magnetic terminals? I think there is some kind of sense wire in there that needs to be triggered for the bike to "start" but I'm not sure.

Thanks in advance!

 

[amberwolf]

Dying batteries would cause what you saw.

You can probably just replace the cells in the batteries with new ones to fix them, but if not you may be able to bypass the battery electronics and build your own replacement packs.

There have been a number of A2B Metro and other models that these have been done with, if you look around the forum for the A2B threads.

Your old thread that you never came back to for us to continue helping you is also there, but it doesn't look like you got very far in testing.

 

[uberlieb]

LOL (at myself)! I forgot I wrote that thread. I was even reading it over and forgot that I wrote it. Old age i guess....

So a year later I am having the same problems basically.

The Metro seems to be different as it doesn't have that electronic keyfob thing. But I will look into those threads too.

I am going to take apart the battery today and make sure all sets of cells are charged up, then try the bike again.

 

[uberlieb]

so I got a little further on this:

The battery had cells below 2v internally (cell pairs actually). I manually charged them up, 1 bank at a time (5 banks of 2s) to get them high enough for the stock charger to take over. The stock charger then did charge them up all the way. Now the bike will "start" (display comes on) but most of the time will not "run". I found when the headlight comes on the bike will run, but most of the time it does not and the bike won't go. Once I made it all the way around the block but 9 times out of 10 it just won't go. I made a youtube video here:

https://www.youtube.com/watch?v=IuFmKnby_D8&t=10s

Perhaps there is some kind of voltage converter in the bike that takes the 40v or so down to 12v or so that powers the headlight and other electronics that is not coming on. I don't know. Any ideas?

 

[fechter]

If it works sometimes, that would point to a loose connection somewhere. Maybe try unplugging and reconnecting all the connectors. Inspect the contacts when they are apart. I've had the socket end spread apart and lose tension. They can be squeezed back with a needlenose pliers.

 

[uberlieb]

Thanks for the reply.

The magnetic connector from the bike to the battery is one of my top suspects. It just doesn't seem to make a really good connection. 2 wires in the connector are power but i think the other two might be a digital signal. I will also try to get at the controller of the bike and see if there is a loose connection but it is not very accessible on that bike (or I have not figured out how to get to it)