California Electrics

[Dave Wickham]

Hi
I am no vehicle electrician but when the leisure batteries are charging from the alternator (G in the control display) why does it show 12.5 V but a negative amp rating (varies from -18A to -6A for example). Is this something to do with current flowing OUT of the leisure batteries?
Thanks

 

[Lightning]

Hi
I am no vehicle electrician but when the leisure batteries are charging from the alternator (G in the control display) why does it show 12.5 V but a negative amp rating (varies from -18A to -6A for example). Is this something to do with current flowing OUT of the leisure batteries?
Thanks

Yes, it’s a function of the Blue Motion technology, which off loads the alternator under some conditions.
You can override this temporarily by turning on the headlights and/ or heated seats, this prevents the leisure batteries discharging when the engine is running, the current on the display remains positive.

 

[Dave Wickham]

Thanks but what do you mean by 'offloads the alternator'? Does this discharging by the leisure batteries cause any damage?

 

[Lightning]

Thanks but what do you mean by 'offloads the alternator'? Does this discharging by the leisure batteries cause any damage?

It doesn’t damage them, it just limits their charge to a maximum of 80%.
When the alternator is under load it is powering systems, when it’s not under load the leisure batteries are used to power the systems instead.
Off loading the alternator can reduce fuel consumption.

 

[Dave Wickham]

Thanks again for the lesson. But when you are driving the alternator powers things like the headlights, it wouldn't be the leisure batteries (I know it charges the leisure batteries). Does it mean the fridge (which would be the only device possibly on when driving) would be powered by the alternator unless the leisure batteries drop below 80%??

 

[paradise city]

So when the display says you're leisure batteries are 100% charged they're really only at 80% of their capacity?

Sent from my CLT-L09 using Tapatalk

 

[Lightning]

Thanks again for the lesson. But when you are driving the alternator powers things like the headlights, it wouldn't be the leisure batteries (I know it charges the leisure batteries). Does it mean the fridge (which would be the only device possibly on when driving) would be powered by the alternator unless the leisure batteries drop below 80%??

The blue motion technology offloads the alternator under conditions when the demand is low. Increased demand, by for example turning on the headlights, is detected and the alternator is placed under load again. Even while the leisure batteries are not being charged by the alternator, they are still being discharged by the fridge and any other connected systems. I have seen the negative current go quite high, much higher than the fridge draws, so I think they must also be powering other systems in these circumstances, but I’m not sure.

The leisure batteries can be charged to 100% on hook up, and only 80% by the alternator. Even if you charge them to 100% on hook up, the blue motion can discharge them to 80% while driving. The percentage reading on the display is not accurate in my experience. The display voltage reading is accurate.

 

[Dave Wickham]

Thanks - yr assistance much appreciated

 

[haydnw2]

Every day's a school day! Very interesting, thanks.

 

[TripleBee]

I am still glad I don't have Bluemotion Technology.
Once my batteries (3) are full, the alternator doesn't have to work hard too, so I am using less fuel too?
And when I arrive on a campsite, my batteries are full, and not 80%. Still a strange thing to do...

 

[Lightning]

I am still glad I don't have Bluemotion Technology.
Once my batteries (3) are full, the alternator doesn't have to work hard too, so I am using less fuel too?
And when I arrive on a campsite, my batteries are full, and not 80%. Still a strange thing to do...

It’s not ideal on a Campervan. Loz has a thread about replacing the split charge relay with a DC DC converter to overcome the limitations of this system.

 

[Dave Wickham]

I'd like to know more about that, or where you could get it done as there is no way I am going to faff about with a vehicle electrics when its under warranty...…..

 

[Lightning]

I imagine doing this is likely to invalidate the warranty. Maybe get it done after the warranty has expired.

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

 

[Dave Wickham]

Yes, possibly. I have a 5yr warranty so don't want to invalidate that!! However, I don't like the idea of arriving at a site with no hook up and relying on leisure batteries being only 80% when you think they are 100%!!!! That will cost you a day or more of off grid camping (depending on what level you have the fridge at or if you run the heater much).

 

[Lightning]

Yes, possibly. I have a 5yr warranty so don't want to invalidate that!! However, I don't like the idea of arriving at a site with no hook up and relying on leisure batteries being only 80% when you think they are 100%!!!! That will cost you a day or more of off grid camping (depending on what level you have the fridge at or if you run the heater much).

The alternative is to turn your headlights or a heated seat on, on the drive there to override it. I do this, it’s easy to forget though.

 

[WelshGas]

Yes, possibly. I have a 5yr warranty so don't want to invalidate that!! However, I don't like the idea of arriving at a site with no hook up and relying on leisure batteries being only 80% when you think they are 100%!!!! That will cost you a day or more of off grid camping (depending on what level you have the fridge at or if you run the heater much).

A solar panel will ensure a 100% charge of the Leisure Batteries.

Solar Camper Solutions - Home

Solar Panel Kits for Mazda Bongo & VW T4 / T5 /T6 and California camper vans.

www.solarcampersolutions.co.uk

Can supply a No Drill kit, or they also do a fitting service. The owner, Roger Donahugh, is a Forum member.

 

[Dave Wickham]

Thanks yet again for good help. I guess the best thing is to set the headlight switch 'off' automatic so you can manually switch 'on' when you drive. Heated seat not too comfortable in a hot climate!!!

 

[Lightning]

Possibly just leave the headlights ON as they auto turn off when the key is removed anyway, or my LED lights do.

i also have a solar panel and a Honda generator to cover all summer and winter eventualities.

 

[Dave Wickham]

The VW manual says NOT to fit any external power supply (apart from 240V mains hook up obviously)

 

[Lightning]

The VW manual says NOT to fit any external power supply (apart from 240V mains hook up obviously)

Using generator is the same as using a mains hook up.
Solar panels with a charge controller are used by many without problems. Again, warranty may be affected though.