Wondering if anyone can help me diagnose this issue. I have a Amped kit with a 36v Lifepo4. The battery reads normal charge, 34v. When I plug it into the controller and run a load on it, the battery cuts down to zero v. As soon as I unplug the controller the voltage jumps back up to 34v. Could it be a problem with the controller? The BMS on the battery? I do appreciate any input anyone might have.
Bike power cutting out
- Thread starter auto_bike
- Start date
mushymelon
1 kW
A 36 volt battery should be around 45 volts fully charged.
your bms is probably hitting low voltage cutoff.
Disconnect the battery from the bms and retest the voltage.
What battery is it and where did you buy it.
your bms is probably hitting low voltage cutoff.
Disconnect the battery from the bms and retest the voltage.
What battery is it and where did you buy it.
Ditto--your battery is probably completely discharged, and needs recharging. At a guess it's a 12s battery, which would make it about 2.8V/cell right now. If it's a 13s, then its' down to 2.6V/cell, and if 14s, it's only 2.4V/cell.
If it will not recharge, then either your charger has a problem either internally or in the wiring/connectors, or the BMS has either failed or detected a serious problem with the pack and is preventing recharge to protect it.
If it will not recharge, then either your charger has a problem either internally or in the wiring/connectors, or the BMS has either failed or detected a serious problem with the pack and is preventing recharge to protect it.
psychonurse
10 W
Just had a similliar problem with my amped kit going from a 36v to a 48v battery. Needed an upgraded controller.
Except you changed the battery first, and he's still using the same one (AFAICT). it's almost certainly the battery itself that is the issue in this thread, as it is nowhere near fully charged according to the OP.
wesnewell
100 GW
36V lifepo4 battery should read 40-44V fully charged. At only 34V, it's drained. Any attempt to use it and it will sag below 30V under load and either the controller LVC will not allow the controller to work, and/or the bms will shut it off when 1 cell reaches it LVC. Since it drops to 0V, that pretty much assures that the bms is shutting it down as it should. Charge the pack back up and it should work fine unless it has a bad cell/cell group.
dogman dan
1 PW
I suspect a very common problem I've had several times. When the plug between the charger and the battery gets a problem, the charger shows a green light like it's charged. But in fact, it's only disconnected. A wire can easily break where it solders onto the plug, but then still make some occasional contact.
So you plug in, red light comes on, charger is working. You walk away, and 5 min later the green light comes on. You come back in a few hours, green light is on, and you think you have a charge. In fact, you only charged for 5 min.
34v is definitely not charged. That's your problem. The charging wires could also be disconnected other places, inside the battery, or inside the charger. Or there could be some other reason the charger doesn't work now.
The bms is working as it should, trying to use it at 34v causes it to shut off as it should. Then when you unplug, that resets it turning it back on. But still not charged, it will only shut off again. You need it to charge to at least 42v, and possibly as high as 45.
So you plug in, red light comes on, charger is working. You walk away, and 5 min later the green light comes on. You come back in a few hours, green light is on, and you think you have a charge. In fact, you only charged for 5 min.
34v is definitely not charged. That's your problem. The charging wires could also be disconnected other places, inside the battery, or inside the charger. Or there could be some other reason the charger doesn't work now.
The bms is working as it should, trying to use it at 34v causes it to shut off as it should. Then when you unplug, that resets it turning it back on. But still not charged, it will only shut off again. You need it to charge to at least 42v, and possibly as high as 45.
Similar threads
