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Discussion Starter #1
Hi All,

I am recently bought a Aixam Van and the previous seller claims that the batteries and the ECU were replaced 4 months ago. I notice that the battery indicators would show full charge and drive without a problem until it uses up 3 bars out of 6 then the level will drop to empty in a split second. I would like to get the Aixam Mega-Diag software to check what may be the problem but couldn't get a copy of the software. Or if any of you could kindly suggest what may be the cause of the issue that would be very much appreciated. Thanks in advance.
 

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Hi whereabouts are you based? There are some good independent EV specialists garages about.

Are you able to inspect the batteries themselves to verify if they look like they have been changed? Was there an invoice for the battery change?

Thanks,

Gary.
 

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Sounds like a single weak cell which drops to the low voltage limit early and causes the software to indicate no charge. Can you check the voltage of each cell individually being careful not to get a shock across more than one?
 

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Discussion Starter #4
Hi whereabouts are you based? There are some good independent EV specialists garages about.

Are you able to inspect the batteries themselves to verify if they look like they have been changed? Was there an invoice for the battery change?

Thanks,

Gary.
Thx. I am from North London, I do have the receipt from the previous owner but I need to prove that it is the battery problem before I can go back and claim. I have been told that I need to measure the voltage of individual battery when they are fully charged. Is there any other way to check the health of the batteries?
 

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You dont need to remove the battery interconnects to measure the individual battery voltage but you do for safety (or be extremely careful and wear insulated gloves) if the battery total voltage is above about 80-90v.

I would measure the voltages at approx 20% charge - then poor cells will show up as being lower than the rest. At full charge they will all be at full voltage.

Thanks.
 

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Thx, I will try and I was also told that I need to disconnect the parallel connection between the individual batteries before measuring them. Is that right?
You dont need to remove the battery interconnects to measure the individual battery voltage but you do for safety (or be extremely careful and wear insulated gloves) if the battery total voltage is above about 80-90v.
Do you mean parallel or serial? If you have parallel connections then you do need to remove them as the better battery will support the worst. As @G.a.r.y says if you have to go near the battery wear appropriate gloves like these.
I would measure the voltages at approx 20% charge - then poor cells will show up as being lower than the rest. At full charge they will all be at full voltage.
Agreed - the BMS will balance out the weaker cells when fully charged. From your description in your first post the issue occurs at low charge so measure it in that state. If you have an electric heater in the cab run that to get the battery flatter than just driving it if you are unwilling to drive it until it stops.
 

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Discussion Starter #8
Thanks for all the advice, I will give it a try this weekend. Much appreciated!
 

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According to this thread:
the batteries are lead-acid, so I guess they do not need a BMS.
 
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