Despair of this bike

pb1001

Just Joined
Aug 19, 2021
2
0
So I have a Ridgeback Arcus with crank motor (Dapu MD250S). I detest this thing but wont bore you with the details.

After a firmware update that fixed the bike dropping from 50% to 0% charge instantly the bike never does more then 19 miles on full charge. Doesnt matter what assistance level I use. I took it to a local ridgeback dealer and they updated the firmware again. They said that should solve the problem, their view was it should do 40 miles easily.

It is no better. The wholesaler/distributer suggested it may be the battery so I spoke to the retailer I purchased it from and they said that a new battery would take 3 months to get!

I decided to buy a replacement battery myself, it is the same voltage, the same physical size both around 400wh (13.6ah). Fully charged it and now when in place on the bike the display lights up breifly but says 0% and the motor wont run. Its as if the bike thinks the battery is flat.

I guess that the battery needs to be paired with the bike or the bike is looking for some sort of code on the BMS and hasnt found it. Or possible there is a 3rd wire beside +ve and -ve that feed some info to the display or controller whch is not on th enew battery. Either way it is no go.

The new battery is showing 41.7v when fully charged the old battery (only covered 500km) shows 40.3v when fully charged

So my questons are if anyone can help.

Is 40.3 v acceptable for a fuly charged battery?
Swapping a battery for a replacement that is f the same spec should it recognise the battery?
Anyone know if there is a reset function I can do on the bike/battery that may synchronise things.

For info Phylion battery 36v
Dapu motor
Sportdrive display/electronics
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,328
6,341
bosch uses a can bus system so the motor controller has to talk to the bms b4 the batt will turn on so i bet that is your problem and why the new one wont work.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,196
8,241
60
West Sx RH
40.3v fully charged means the battery is out of balance or a cell group is bad, a 36v battery should be no lower then 41.4/41.5v if in good order. Only by opening it and checking the 10 cells group voltages will you know, there is no way other wise of knowing unless a smart BMS is used and a pc can read all 10 cell groups.

Once you hit 19 miles or so the low cell group hits lvc early so shuts down the BMS.

The non communication with the generic battery certainly means handshaking is going on and the battery isn't recognised.

If the bike is in warranty then a new battery under warranty is due.
 
Last edited:

pb1001

Just Joined
Aug 19, 2021
2
0
Thanks all. Very quick responses. For info I noticed the walk mode was working (intermittently) so I thought there must be some power there. I then pedalled it back up the slope and suddently the motor cut in (took much longer to cut in than the original battery but once going was OK). There is no percentage display but it looks like the battery is at least working to an extent. I can monitor batery charge by possibly checking voltage or by using the lights built in to the battery and at least se if I get more range.
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,328
6,341
cant you take the bike back under warranty? as waiting 3 months for a new batt is not going to cut it.
 

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