One Charger to recharge vehicle battery which will then charge leisure battery?

[Shanz]

Hi All,

I have have read many posts on here about charging 2 batteries and now my head is fried.

I have a T6, 16 plate and after reading about VSRs and the new alternator charging technology, I understand my existing Split Charge VSR is doing nothing to charge my leisure battery.

Am I correct in thinking this?

This leads onto my other question - If I buy a Victron Energy Blue Smart IP22 Charger 12/15(1) 230V - BPC121542002 will it charge the starter battery and also provide enough volts to increase above the 12.9 volts required to activate the voltage sensitive relay and then charge the leisure battery?

Thanks for any advice.

 

[Deleted Member]

I get confused too, my factory leisure battery set up works fine, despite reading it does a poor job.

Send a pm to @travelvolts who can sell you exactly what you need.

 

[Dellmassive]

If I buy a Victron Energy Blue Smart IP22 Charger 12/15(1) 230V - BPC121542002
will it charge the starter battery and also provide enough volts to increase above the 12.9 volts required to activate the voltage sensitive relay and then charge the leisure battery?

Yes.... you can tweek the Victron Chargers voltage via the app to get the required effect.

FYI we done that setup here:

Charging Starter and Leisure batteries with same charger - Victron

Hi, Inspired by @Deaky build post, I was planning on installing a Victron IP65 Smart charger next to the Starter Battery and a 2nd one to charge the Leisure batter (110AH AGM). I've discovered the CTEK D250SE will still charge the leisure battery as long as the volts on the starter battery are...

www.t6forum.com

.

 

[W1bb1y666]

I can second this, I have a Victron Blue Smart charger as above, and have the terminals connected to the input coming from the van battery (under the driver's seat but just before it goes into the Victron DC-DC). I have an isolator there which means I can disconnect the DC-DC charge if I want, but it also allows me to have the Blue Smart mains charger connected ONLY to the van battery OR (if I leave the isolator in it's normal position) also the DC-DC, which then fires up and feeds the lithium as well. The mains charger is only connected when I need it, ie when I'm on EHU.

I don't have solar yet, so it allows me to top up the the van or lithium or both if I'm on EHU

 

[WillC]

This is fascinating. So the charger doesn't just charge the LB, but 'back charges' the main batt too, if you tweak the charger... off to read Dellmassive's musings...

 

[Dellmassive]

This is fascinating. So the charger doesn't just charge the LB, but 'back charges' the main batt too, if you tweak the charger... off to read Dellmassive's musings...

No it's the other way round, you need to connect the mains charger to the starter battery which will then intern charge up the leisure battery via the dcdc charger.

 

[WillC]

Ah OK, so attach charger to inbound fat red wire from main batt (and earth), *before* the DC-DC charger (which feeds LB)?

 

[W1bb1y666]

This is fascinating. So the charger doesn't just charge the LB, but 'back charges' the main batt too, if you tweak the charger... off to read Dellmassive's musings...

No, it charges the van battery primarily, and I can switch the isolator that connects the DC-DC so can only “see” the van battery. If I have the isolator in its normal position so the DC-DC is doing its job it fires up as normal just like when the alternator is doing it. I’ve some diagrams somewhere. I’ll root em out and post em later

 

[W1bb1y666]

 

[WillC]

View attachment 317046

That, is absolutely brilliant. Thank you.

 

[WillC]

Right, a morning well spent. I’ve inserted another isolator before the Victron Orion XS DC-DC, so I can isolate the entire LB system. I’ve wired into the isolator the positive from a IP65 blue smart 12/15 mains charger (earthed to my earth busbar). The second isolator cuts off the 12v output that feeds my fuseboard and thence lights, fridge etc. I upped the voltage on the mains charger to 13.6v in order to convince the Orion the engine is on, as per @Dellmassive advice. Also set the charge preset to Lion.

A quick test says the DC-DC is working as it was before. Start engine, see 30A flowing to LB (14v).
LB (Drift 105) showing 13.4v.

Now I hook up my mains charger to the system (engine off). I see the Orion XS with 13.1v and 10.7A 141W input and 13.7v 10.1A 138w output. I conclude that the charger is charging the LB. The charger itself shows 13.42v and 15A. So 5A is flowing somewhere else… could it be the main battery as desired?

I isolate the LB system. Victron input shows output at 13.4v, which makes sense as this is attached to the LB. It also shows 1.6v input at 0A, though this is falling as I watch, presume some capacitance in the Orion gubbins leaking away, now at 1.2v as I type…

Back to the charger, this shows 14,2v and 6.6A, so the main battery is charging. Brill.

Switch the LB isolator back on. Charger app now showing 13.54v and 15A. Those extra amps must be flowing to the LB again.
Check the Victron app, yup, 11A in and out.

So I think it all works. Thanks to everyone for helping.

One question: I’ve set the charger to Lion preset, because I’ve got a Lion LB. Does this affect the charging of the main battery, which is a lead acid as far as I know?

Cheers, and pics below of my LB setup while the seat was off. And this time I didn’t turn the ignition on until the seat was back on and airbag cable reattached…

 

[Dellmassive]

The vans energy management system keeps the starter battery around 80% soc..

So you will always see the starter battery take charge when it's connected to a charger.... IE your 5A.

Id normally see the starter take around 10-20Ah before being fully charged....

Then, after, you will see funny behaviour... Where the starter battery stays low on the next drive, say around 12.2v...... which is the van dropping the starter back down to 80% soc again.... It's all good though.

Having AGMs fully charged is a good thing.

And this is all assuming that the starter battery shunt is not bridged out when charging.

 

[WillC]

Should I have the charger set to Lion mode then? Or should it be set for the main battery, and the Victron Orion will handle the LB needs?

 

[Sim60]

View attachment 317046

I’m reading your diagram as having parallel 25mm2 cables to your inverter ( and also from LB to bus bar. I think you don’t have adequate fusing of these 25mm2 cables . If you get a short on one of the cables, then the only protection shown is the 250A mega fuse which is rated too high to protect the 170A cable.

Simon

 

[W1bb1y666]

I’m reading your diagram as having parallel 25mm2 cables to your inverter ( and also from LB to bus bar. I think you don’t have adequate fusing of these 25mm2 cables . If you get a short on one of the cables, then the only protection shown is the 250A mega fuse which is rated too high to protect the 170A cable.

Simon

I think I see what you mean. If just one of the parallel cables shorts then yes, the full 250A could potentially traverse (or try) the single 170A cable. I think this is mitigated by the fact those 2x 170A cables are pretty short (<300mm) so the short would have to occur through the insulation by maybe some chafing or cut or something. I've insulated the life out of them and also covered them in that nylon tape stuff like you have on wiring looms so the chances of that happening are tiny, especially over such short distances. I see your point though. I wonder if a single 40mm (I think that's 300A isn't it?) would be flexible enough to rewire, just to be uber safe... hmm, cheers

...and finding some lugs to fit on those chunky monkeys