Bluemotion tech using the leisure batteries

motacyclist · Jan 26, 2019

Is the California a (very) mild hybrid?

On a drive out today up the North Wales coast, after about half a mile I checked the MFD out of interest and the batteries were taking >20 amps on the display. A short time later, it was showing minus 14 - 15 amps discharge, and this continued for the rest of the journey, apart from a downhill stretch when I tapped the brake to disable coasting and the display then showed >20 amps charge again.

When we stopped after about 40 miles, the leisure batteries were on 70% and 12.3 volts. So the technology appeared to have been using the leisure batteries to power the ancillaries and thus presumably save fuel? (Not much use if you arrive on site for a few days off grid with only 70% though!)

Coming back, the situation changed and the battery constantly received a fairly steady charge of 4 - 5 amps, rising to around 17 amps on braking/decelerating. Arriving home, the batteries showed 100% and over 13 volts.

There was a small change in fuel consumption each direction, going out we got 39mpg, coming back it dropped to 38.5mpg overall. Wind was coming from the side, so shouldn’t have had much effect.

I wonder if anyone else has noticed this, or has any opinions on the assumption that the fuel saving algorithm is making use of the leisure batteries? I seem to remember reading a thread somewhere that it does, or maybe I was dreaming .....

Loz · Jan 26, 2019

Yes exactly that and what I reported in my thread about changing from a split charge relay to a DC DC charger.

motacyclist · Jan 26, 2019

Loz said:
Yes exactly that and what I reported in my thread about changing from a split charge relay to a DC DC charger.

Yes I seem to recall that but couldn’t think of the correct search term to find it again.

Where was it?

Loz · Jan 26, 2019

motacyclist said:
Yes I seem to recall that but couldn’t think of the correct search term to find it again.

Where was it?

Search redarc
https://vwcaliforniaclub.com/thread...arger-to-replace-vw-split-charge-relay.23466/

motacyclist · Jan 26, 2019

Loz said:
Search redarc
https://vwcaliforniaclub.com/thread...arger-to-replace-vw-split-charge-relay.23466/

Thanks, I’ve just read it and got a headache now!

Just a bit more info, the reason I was checking the MFD charging current was because I fitted a solar panel last week, with a Western Co MPPT control unit which has the facility to charge the starter battery as well (automatic, or selectable via app). Since I’ve fitted the PV panel the voltage on both batteries has been over 13v at the end of each day so I didn’t expect >20 amps to be getting shoved into the leisure battery in the first half mile, and later didn’t expect the 14 - 15 amps to be drawn off the leisure batteries for 40 minutes or so; surely it can’t have been draining into the starter battery as that was fully charged when we left.

Where would the 14 amps go? DRL’s, media player, injectors, fuel pump etc, would that add up to 14 x 12 = 168 watts?

Signed ...... confused.com.

WelshGas · Jan 27, 2019

motacyclist said:
Thanks, I’ve just read it and got a headache now!

Just a bit more info, the reason I was checking the MFD charging current was because I fitted a solar panel last week, with a Western Co MPPT control unit which has the facility to charge the starter battery as well (automatic, or selectable via app). Since I’ve fitted the PV panel the voltage on both batteries has been over 13v at the end of each day so I didn’t expect >20 amps to be getting shoved into the leisure battery in the first half mile, and later didn’t expect the 14 - 15 amps to be drawn off the leisure batteries for 40 minutes or so; surely it can’t have been draining into the starter battery as that was fully charged when we left.

Where would the 14 amps go? DRL’s, media player, injectors, fuel pump etc, would that add up to 14 x 12 = 168 watts?

Signed ...... confused.com.

What was the ambient temperature?
Was the Webasto Coolant Heater On?