Charging leisure battery with jump leads.

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Turboponzy

Member
I have just swapped all my furniture and electrics over from my old T5 to a 2019 T6, including leisure battery and wiring but I haven’t fitted a dc to dc charger yet.
I had a standard split charge relay on the old van, and if the leisure battery started going low we just ran the engine for a while to top it up.
We are away for 4 days at the camper festival this week and I’m worried if I run the leisure battery flat I’ll damage it.
Its earthed to the van so if needed could I connect a jump lead from the van battery + to leisure battery + and run the engine, would it put some energy back in or do nothing, or worse damage something?
I’m not sure how newer alternators work. Cheers
 
Your T6 will have a smart alternator, which I’ll confess, seem to have a mind of their own. If you connect the SB + to LB + then they will try to equalise charge and you risk flattening your SB. I guess you could hope that running the engine will top up the SB, but be careful not to run the SB so low that you can’t start the engine.
 
Running the engine on a modern diesel just to charge the battery makes me shudder.
Aside from short journeys idling for long periods is another sure fire way of causing problems for your modern diesel.

Maybe get a big portable solar panel and use that. Sure, they cost a bit (although you’ll always find an offer somewhere) but it’s cheaper than a new dpf.
 
Assuming the LB was a SLA AGM, so the same chemistry as the SB, technically to could do that.

Seeing as that's all a SCR will do anyway. The relay just joins the batteries POS together.

But if you have the SCR fitted already? Why not just run the engine, you may need to turn the fan on or lights to get a higher voltage.

Also remember it takes 10 hours of driving to charge a flat battery.

Also if the LB is not an AGM or EFB it won't mix with the T6 AGM starter battery in any case.

Id get the multimeter out and check voltages.

If your not sure about any of the above, don't do it.


Post some pics of the van and batteries and we'll have a look?

As above..... On a T6 it's a DC-DC for best results.... And a lithium LB.
 
More info

Dellmassive

Thread 'Battery Monitoring -- How I Done It --'

Battery Monitoring -- How I Done It --

Part #1

Battery monitoring is a very important part of your 12v system . . . . whether its just the vans starter battery or your leisure setup keeping an eye on the power in your battery bank will keep you from breaking down and make sure your weekends are not cut short from lack of power.

Battery monitoring is even more important with Lithium Lifepo4 batteries as the voltage stays fairly constant for 90% of the capacity.

first off lets look at a few basic 12v meters.

here a great little unit that I've been using for ages....

you can plug it...
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Dellmassive

Thread '[Guide] DC-DC Charger (for leisure battery) -- How I Done It --'

DC-DC Charger (for Leisure battery) -- How I Done It --

**************************************************
Dellmassive`s -- "how I Done It" -- Thread
**************************************************
Kit List And Stuff -- How I Done It & What I Use --
**************************************************

I thought it was about time i addressed the whole DC-DC charger thing. . . .

The subject and viability is discussed at length over here > Stop/start...regen...smart Alternator... Dc-dc Charger For Leisure Battery Or Not?

51-WMHCNB9L._SX425_.jpg

Long story short the...
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Dellmassive

Post in thread '[Guide] DC-DC Charger (for leisure battery) -- How I Done It --'

DC-DC related info . . .

just checked on the Renogy DC-DC (has an ignition feed)

same thing is happening here.

The starter is on EHU Victron 12v/15A charger, which is charging the starter battery.

The Renogy DC-DC is seeing the raised starter voltage and indicating the ALTERNATOR is running (even with IGN OFF)

The Renogy has started charging the Leisure battery.


Seems this is a feature of most modern DC-DC chargers . . . that even when they have the IGN/BCM RUN feed connected and switch off. They will startup when the starter battery voltage is high enough.


So with either EHU...
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Dellmassive

Thread 'Stop/start...regen...smart Alternator... Dc-dc Charger For Leisure Battery Or Not?'

So

With all the talk regarding the Bluemotion thing and regen breaking and leisure batteries our T6 has finally arrived.

The first thing we done was to checkout the factory fitted setup,......
Stop/start=check,
Regen Braking=check,
AGM starter battery=check
leisure battery under passenger bench-standard lead acid=oops!
standard relay and fuse holder for charging thge leisure battery=check . . . hmmm?

So the factory standard setup is stop/start/regen with AGM starter battery, ok, so i ask the sales guy why i haven't got a second AGM battery under the passenger seat, (for balanced...
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Cheers for all the info everyone, I’ll leave it alone and just carefully manage power consumption until I get it finished.
 
Turboponzy said:
Cheers for all the info everyone, I’ll leave it alone and just carefully manage power consumption until I get it finished.
Click to expand...
But you have not spent any large sums of money on a gismo! That is not what people want! They want you to spend, spend, spend, then say how good it was so that they might consider it or to say should have bought something else!
 
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