Crazy charging system is driving me mad.

[G-A-R-Y]

My leisure battery is fully charged according to the victron app. This morning I start the engine and drive to the beach, display panel shows -16 amps taking my leisure battery down to 70%. Pressing the battery boost button just increases engine revs with no increase in voltage. I think the only way forward is to fit a B-B. I've tried using the heated screen and seats to trigger battery charging but nothing works. I think it's a poor system.

 

[G-A-R-Y]

Engine running, button pressed.

 

[G-A-R-Y]

Today I drove to the beach, I pressed the battery button, 14.6 volts all the way to the beach. Battery fully charged in 20 minutes.

 

[Ikbarltrop]

Hi Gary. If you are drawing 16amps, that’s a load of 192 watts. The screen shot shows you are drawing 23 amps which is a load of 276 watts. What have you got plugged in that’s drawing this load?

The most I’ve seen my 680 draw is about 4 amps, 48 watts, with everything turned on, and charging phones, iPads etc.

 

[G-A-R-Y]

Yes, that's exactly my problem. Leisure battery was fully charged via solar. When I started the engine I had a 25 amp draw. In effect my leisure battery was now charging my engine battery. It took it down to 12.2v. Even pressing the battery boost button did nothing. But today boost worked and my battery was nearly fully charged driving to beach.
How do I explain this to a dealer.

 

[temporarysecretary]

Low stater battery and blue motion trying to balance it out?

How-To install DC-DC charger to replace VW Split Charge relay

This guide takes you step by step through fitting the Travelvolts DC-DC charging kit for California leisure battery charging. Why fit this kit: VW are still installing their standard split charge relay on vehicles fitted with leisure batteries, however, the latest Bluemotion technology has a...

vwcaliforniaclub.com

Guide posted as shows BMT behaviour

 

[ampedcampers]

Hello Gary!

Did you find the root problem of this discharge? How did you fix it?

I have been to our local VW dealer 4 times, every time it takes weeks to get an appointment, they do some "adaptations"/software updates and say it will be fine, but the issue is still there.

We have replaced the leisure battery less than a year ago, at VW dealer, so they did something to "encode" it.

Thank you

 

[G-A-R-Y]

This is how it's meant to be. Engine battery is never fully charged so that it can accept regenerative braking charge. It basically a commercial van system, NOT for leisure.

Leisure battery gets fully charged via solar, then when engine is started both batteries are linked via dumb relay under bonnet. So leisure battery affectedly charges engine battery.

Easy fix, my son has a camper electrical company. He fitted, Victron Orion B2B relay under bonnet and a Lithium battery, also fitted a lithium specific charger for leisure battery when on hook up.
He removed fuse 6 (under seat) to disable leisure charging from under seat battery charger.

The original under seat charger still charges engine ay 1amp when hooked up.
Been testing for 18 months and never gone done below 85%.