Charger not charging batteries when they are low

2007 Aixam 500.5 Mega City Electric
Car: Aixam 500.5
Year: 2007
Variant: Mega City Electric
Categories: Running Rough, Starting & Power Loss
These units are Mega City Electric Cars with 12 X 12 V Lead Acid batteries in a combination of Parallel and Series. I have 2 of these Mega City Electric Cars and they both have the same issue. When the batteries are low after usage i.e. reading 47.5 to 49 Volts the onboard charger will start to charge them - cycle up 3 or 4 Volts above the batteries V and then drop back and cut out at the batteries V or just above it. If I bring the batteries up to 52 or 53 V by using an external charger then the onboard charger will charge them from that point forward. The batteries have been idle for some time but are taking the charge and running for 70 or 80 KMS on it at the "Lo" speed ratio.


Any suggestions would be appreciated.
Problem added: Jun 3, 2013 (10 years ago)
not familier with these vehicles all ican advise is that you have all the batteries tested one or two of them could have faulty cells
Answered Jun 4, 2013 (10 years ago)
^ x 2
Answered Jun 4, 2013 (10 years ago)
The problem was that the Fan's within the On-board Chargers were not working and consequently the Chargers were cutting out when the Heatsinc's hit a certain Temperature. Fans sorted some time ago and this in turn sorted the Charging issue.
Answered Sep 29, 2013 (10 years ago)
hi Kevin75

just like to say thank you for posting this solution, i have exactly the same problem with my mega city electric, the fans in the charger not working, but so far i haven't been able to source replacement fans, do you, or does anyone know where i can get them? a new charger btw costs £2,280.00 from aixam!!!

thanks
Answered Apr 30, 2014 (9 years ago)
Keith17. Apologies I have not logged in since sometime in the Spring or before it and only saw your query yesterday. I presume you have got it sorted at this stage - if not this is what I would do;

1. Remove the Charging unit from the Car and open it - snip the wires to the two Fan's midway (I would expect there is excess cable with them and you will be able to re-connect them again). Using a Car Battery check if either or both of them are working.

2. If either one is working do the following - take the Charging unit to an Electronic repair place and ask them to check the components within the unit. They should find a component down and in my case it was a Resistor with a value of a couple of Cent. My local Co only charged €35 for this service.

3. If (2) applies now reconnect the good Fan or Fan's and the Charger unit will do it's job.

4. If both Fan's are dead I can find the Invoice / US Company that I bought my replacement Fan's from and give you the details of same.

My direct e-mail is [email protected]

My Car is going fine but I am not using it enough.

Answered Oct 4, 2014 (9 years ago)
Hi, I'm a bit late to the party but I've had exactly the same issue...

I recently bought an Aixam Mega Van. Everything seems to be working fine, except the battery charger stops working after about 10 minutes of charging.
Turns out both cooling fans are broken (bad design, they are forward-facing, so moisture and crud can get in through the vents!). An inline resister in the fan circuit has also blown.
Can anyone tell me the value of the resistor? it is too badly scorched to read the coloured bands.
Hopefully, when I replace the fans and resistor, ill be up and running again.

Cheers
Answered Jan 18, 2020 (4 years ago)

This problem is archived

If you're having a similar problem please click below to re-post this problem, you can then customise it to suit your situation.

Helpful & Related Pages on AutoInsider

Parts referenced on this page
More problems with the 2007 model year Aixam 500.5

We have 1 problems and solutions in our database for this model year of the car.

View all Aixam 500.5 Problems