12 volt battery charging

[julian295]

My 12 volt warning light is going on & off, mostly first thing in the morning, after an overnight charge.

To start with I found a cracked battery clamp, which I changed & I thought the problem was cured. But now it's back & worse. This morning I decided not to drive the van because the main contactor dropped out a couple of times while I was trying to set off.

Has anyone else had this problem?

When the 12 volt battery fails does the warning light come on & stay on?

The open circuit voltage of the 12 volt battery was about 12.3 today, which I thought was a bit low. When I checked it a week or two ago it was about 12.8

Does anyone know when the 12 volt battery is charged?

Best regards
Julian

[ChrisB]

Hi

The 12volt is charged during a number of stages.
1. General driving
2. During the time the vans plugged in and taking a charge
3.The controller checks the voltage every 10hrs or so and if it falls below a certian level will charge the 12v batt regardless of what state the vans in i.e even if the van is sat idol for a number of days not plugged in or doing anything, until the main pack is pretty much dead.

It does sound like you've got a problem ?? more so if the main contactors popping out, sounds like a loose connection or something worse in the contoller

Must admit to never seeing my aux warning lamp on at all

12.3 is very low, is that with the van switched on ?? as it should read 13.8 or there abouts.

You could try a bench charge over night on the 12v, the main thing is seeing if the controller is charging it when the vans switched on first I would say, then go from there.

ChrisB

[julian295]

Hi Chris

Thanks for your reply.
It seems that the 12v battery voltage is dropping below 12 volts towards the end of the main charge. So if you try & drive the van as soon as the main charge is finished or if you interrupt the main charge near its end & then drive the van you have problems. When the main contactor is in the 12v battery is being charged (voltage 13.8 to 14).

So it seems that the 12v battery is not being charged sufficiently during the main charge.

I did disconnect the 12v battery & charge it seperately & it charged up ok.

Best regards
Julian

[ChrisB]

Mmmm thats odd, sounds like somethings gone a bit odd with the controller ?? and all the aux stuff is being driven off the 12v without it being charged during the main charge cycle i.e circulation pumps etc

Not sure what to suggest , EVan might spot the post and have an idea ?

But I'm thinking it might be a controller open up and investigate

ChrisB

[julian295]

I'm still having problems with my 12v warning light. If you drive the van soon after a full charge the 12v lamp comes on sometimes, particularly when slowing down. I wondered if this pointed to a loose connection, but can't find anything obvious, or if the regen braking for some reason puts a large load on the 12v system; perhaps someone knows about this?

Also when charging it seems to take a number of hours to go from 95% to switching off & the 12v warning light is on for some of this time.

Any bright ideas you have would be gratefully received.

best regards

Julian

[ChrisB]

Regen shouldnt place any load on the 12volt side, the 12volt side to my knowledge is only for all the AUX and some control stuff.

The charge cycle does seem to get slower at the top end of the charge as the current reduces, mine takes a while to go from 95% to full yet it can quickly gain 30% to say 40% in a hour or less.

It sounds like you've got a controller fault or going faulty to be honest theres some discussion of the DC-DC convertor going poof on Robins site berlingo-e.co.uk might be an idea to take a look there. But I think its going to be a top off the controller job to be honest

EVan might be able to shed some light on the subject ??

ChrisB