kermit_rr said:
Normally I'd disconnect to charge up, then test.
To put it another way, can you damage anything by pulling a large current/dropping the voltage while it's connected to the car?
Thinking about all the BMS stuff they put on modern cars.. pyrotechnics etc
Click to expand...
Yes, you definitely need to disconnect the BMS from the -ve post. worst case, you buy a new one, best case, you need to reset the throughput due to implausible values.
 
RangeRoller dt said:
Yes - Why would you chance it considering the risk?
Click to expand...
Well I'm asking for a friend🫣 had a battery battery problem, went to garage and now had all sorts of issues. Been told the car is scrap (cam belt gone) and offered £300 for it!
My gut feeling is they've damaged a wire somewhere and/or are just thick or they've done something stupid.
Engine still runs so cam belt is fine. I'm trying to think of options before he goes any further
 
kermit_rr said:
Normally I'd disconnect to charge up, then test.
To put it another way, can you damage anything by pulling a large current/dropping the voltage while it's connected to the car?
Thinking about all the BMS stuff they put on modern cars.. pyrotechnics etc
Click to expand...
You could certainly confuse all the ECU's
 
Its fine to charge a battery on a vehicle with a BMS provided you connect the negative charging lead to the body, not the battery terminal. That way, the BMS is aware of the charge input and will 'account' for it. If a battery is going to be tested by means of a heavy electrical load being applied, the negative terminal should always be disconnected regardless of whether the vehicle is equipped with a BMS or not.
 
Graculus said:
Its fine to charge a battery on a vehicle with a BMS provided you connect the negative charging lead to the body, not the battery terminal. That way, the BMS is aware of the charge input and will 'account' for it. If a battery is going to be tested by means of a heavy electrical load being applied, the negative terminal should always be disconnected regardless of whether the vehicle is equipped with a BMS or not.
Click to expand...
thanks for that, whenever i'd done a test its always been on a battery taken off for charging so i've never had do consider it
 
Graculus said:
Its fine to charge a battery on a vehicle with a BMS provided you connect the negative charging lead to the body, not the battery terminal.
Click to expand...

Is there a reason for this not to use the negative terminal.
Earth is Earth surely?

J
 
Any car with a battery management system!
2010 is pretty much the implementation date for LR, other manufacturers vary.
 
Surely whether you connect a charger to one end or other of the battery earth cable (terminal/chassis) makes no difference?
Forgive me if I'm being thick

I can see you wouldn't connect to the business side of the bms
 
In fact. I charge using via the trailer socket, surely that can't be an issue?
What about folks who use solar chargers?
 
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