BBS02 failure

[bentbikeguy]

have ridden this trike about 400 miles over the last 2 years only on paved roads'
Put away last winter here in Washington state until April 15th. Battery was dead so I recharged (48v Shark Pack)
Went for a ride and coasting on a level ground it just died. No display so just Walked it home. Measured battery w/ volt meter = 24v. Battery drained in less than 1/2 mile?
I checked ALL my connections and discovered that before reconnecting the battery wires to motor I had 24v but when I connected both wires it shows 12v.
This leads me to believe the controller is bad? When I put it away last October it was about 75% charged but dead come April.
Waiting on new controller and hopefully will cure issue??

[73Eldo]

I would still be focused on the battery. It sounds like you have had a cell or group of cells that drained much faster than the rest over the winter for some reason. Inside the battery is the BMS module which is battery management. It monitors and controls the charging of each cell group as well as the overall voltage of the pack. 100% charge on the pack is 54.6v which is 13 groups at 4.2v each. It is normal for each group to not be exactly the same so the BMS can monitor and control how much charge gets to each group. 0% is 39v or 3v per group.

During charging the BMS can cut the charge off to the groups that are full but keep it going to the ones that are not. This is called balancing which in most cases only happens when the pack gets close to 100% so if you have a charger that can be set for lower or don't always wait long enough you can end up with the groups at all different voltages which isn't ideal for several reasons. The BMS also monitors the groups during discharge (or non use) so if one group gets down to 3v for any reason it shuts down the whole pack to protect that one group. The rest could be a 3.5v but its still going to shut down the whole pack.

When the BMS shuts down its common for the voltage to drop well below what the actual cut off of 39 in this case. I got a 52v back that the discharge port goes completely dead and the charge port to 24v. Some BMS's do appear to re set themselves if the voltage comes back on its own or when the pack cools (or warms up if it was froze) and others can only be reset by charging.

In your case I would charge the pack to 100% and verify with a seperate volt meter that its 54.6. We want to make sure that there isn't an issue with your charger where maybe its going going to 51 v where it won't even try to balance. Disconnect the charger and let it sit not connected to anything else for a couple hours or even over night and keep checking the voltage. Overnight I would not expect it to drop more than a couple tenths. If it drops by full volts you have some really bad cells and there isn't any point in further testing. It may be repairable by someone who builds or repairs batteries or at least they can harvest the good cells to be re used in some other pack.

If it seems to hold voltage then I would try and slowly and steadily discharge it all the way till it quits again. Either a very easy ride or rig up some other way to load it. Somehow put some drag on the wheel in a stand on the bike or if you have one of those old school halogen work lights that used to get stupid hot wire that to the discharge ports and let that drain it at which point you can more closely monitor the voltage especially when it cuts off and then charge it again.

It sounds like your pack has issues so its never going to be perfect again but maybe a few gentle full cycles it will balance out and still have reasonable range.

[bentbikeguy]

I have recharged the battery and it shows 54volts. Will check tomorrow morning again.
presently taking the side cover off to check the windings just to be sure.

[Dshue]

There is always the possibility of multiple failures. But the initial info about the battery leads me to believe the battery is the culprit.
Try plugging the battery into the motor then unplug it and re measure battery voltage. Also charge the battery when it is disconnected from the motor. If you are charging it while connected you may be reading full charge because of the capacitors in the motor controller.

[bentbikeguy]

I have motor disconnected and then fully charged the battery
24 hours later the voltage dropped .3 volts

[Dshue]

Put a small load on the battery and check the voltage with load connected. Even a light will do. There may be an issue with a connection in the circuit etc where no load voltage reads correct but it won't transmit voltage under load.

[73Eldo]

IF you don't have an easy way to put a small load on it you could try it on the bike with the wheel off the ground or the chain off. With no real load the motor won't draw a ton or have huge surges like it would under normal riding conditions.

[bentbikeguy]

I installed a new controller and still nothing comes on or works.
checked battery voltage again after 1 week (had fully charged and disconnected, checked after 24 hours and still had charge)
battery now shows 26 volts but really basically dead (shorted wires and no spark)
I ordered a 2 new Lipo4 battery pack (one for the trike and one for the bucket of bolts.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[htyiyu]

I've also had a similar situation and I really want a fix so I don't get confused when I continue to have this problem.


drift boss

[victorpatrick]

It's possible that the controller is indeed the cause of the issue you're experiencing with your trike. The drop in voltage from 24v to 12v when connecting both wires suggests a problem with the controller's functionality. Replacing the controller could potentially resolve the problem and allow for proper charging and operation of the battery. tunnel rush