Help! Oxygen Diva woes

[Sparkster]

Hi All
New here and hoping for some assistance.
I have a DIva, which was running well upto a couple of months ago.
Intially, the power was very reduced. when operating with the wheel off the ground it was spin fast for a very short burst and then drop to a crawling pace. It was then pretty much useless the moment anyone tried to ride it.
It has now stopped all together.

The battery is charged and there is 36V at the controller. So I am left trying to find out if it is the Throttle, The Controller, the Motor...or something else.

I've been through the setup process a few times so I happy with that.

Any tips on the best fault finding process to follow now?

Thanks
Simon

 

[JuicyBike]

Have a look at your charger output.
If your battery output does not match what your charger tried to put into it then your battery is faulty.
For instance if your charger outputs 42v the battery should maintain 42v for a few miles.
If it drops to 36v quite quickly then the battery is not holding its charge and should be replaced.

 

[Sparkster]

The Charger is 42V, however the battery is labelled as 36V 11Ah.

Currently the Battery is giving 36V, but it was charged sometime ago and I have been fiddling with the bike ever since.

Surely, with 36V coming out of the battery, I should be able to twist the throttle and the wheel spin? But it doesn't. So what is wrong

 

[vfr400]

Your statements are too nebulous. You need to measure the exact voltages of the battery and the charger and tell us what they are. Measure the battery in the charge socket and at the terminals underneath to get two values.

 

[Sparkster]

But regardless, if the battery is providing and this has been measured at the connectors to the motor controller, then surely if everything else is fine the wheel should go round?

 

[vfr400]

Don't waste time, just get the measurements. Only measurements will tell you what's wrong.

 

[Sparkster]

Your advice is erroneous. You are not answering the question I asked.

One simple question: If I am measuring 36V output of the battery, and everything else is correct, should I expect the wheel to spin when the throttle is twisted?

 

[vfr400]

I can only wish you good luck then.

 

[Nealh]

A 36v battery is it's nominal voltage it will charge up to 42v.

A reading of 36v doesn't mean the battery will work if it isn't balanced, any one of the 10 cell groups may be low and can trigger the BMS LVC. If this happens battery will not supply power and will not allow charging to take place.

 

[Sparkster]

Nealh - Thank you for the explanation. Is there any way I can confirm this before spending out on a new battery?

 

[Nealh]

VFR and Juicy have already asked for some readings to be taken to try and rule out a couple of fault issues that may a rise. The battery discharge reading and charge point reading should both be the same with the battery switched on and no charger attached, also measure the voltage reading from the chargers charge connector to confirm it reads 42v when plugged to the mains (depending on the connector you have to be carful so as not to cause a short).

If all the above pans out try charging the battery first to see if it charges to 4.15 - 42v, if so this means it is well balanced but doesn't mean that cell capacity or cell resistance isn't poor. An aging battery or poor battery coming to end of life will provide little power/current draw though it will read good voltage wise. As cells age they have more resistance, more resistance leads to cells warming quicker and induces voltage sag, really poor end of life cells will see voltage crashing the instant you apply current draw/loading.
How old is the battery and do you know what cells are used ?

If the battery does read 36v and does not allow the charger to perform then chances are a cell group will be too low voltage wise, the only way to confirm unbalance is by opening the battery and carrying out a series of voltage readings.

If battery charges fully temporarily connect a volt meter to it whilst on the bike, operate the throttle or PAS and see what the voltage reading does. Most batteries will see voltage sag of up to 1 -2v under load (dependant on current drawn) if it crashes badly then battery is knackered.