Solar connection to leisure battery’s

[v-tec]

Hi all
You may have read on a previous post (Charger fuse location) that my battery charger under the fridge has failed (internal fault)
So I’m considering 2 options
1) Replace the charger (and possibly relocate to a cooler place)
2) Or don’t spend £300 on a new charger and fit solar system,

My question is, it’s my under standing that when charging 2 battery’s that are wired in parallel the correct way to connect the charger (or solar supply via controller) is to connect the positive to 1 battery (say the rear) and the negative to the 2nd battery (in my case under the passenger seat) This is so they get a balanced charge (am I correct)
As you can see in my photo the plug that is circled is the DC plug that is connected to the charger output plug, (This plug has battery voltage at it)
So if I decide not to fit a new charger, what would be wrong with fitting a VW female plug to the ends of the solar wires and plugin it in to the existing connector (circled )

The problem is I don’t have a proper VW schematic wiring diagram of this circuit,
Any help please from someone with good knowledge,
Many thanks.

 

[WelshGas]

Hi all
You may have read on a previous post (Charger fuse location) that my battery charger under the fridge has failed (internal fault)
So I’m considering 2 options
1) Replace the charger (and possibly relocate to a cooler place)
2) Or don’t spend £300 on a new charger and fit solar system,

My question is, it’s my under standing that when charging 2 battery’s that are wired in parallel the correct way to connect the charger (or solar supply via controller) is to connect the positive to 1 battery (say the rear) and the negative to the 2nd battery (in my case under the passenger seat) This is so they get a balanced charge (am I correct)
As you can see in my photo the plug that is circled is the DC plug that is connected to the charger output plug, (This plug has battery voltage at it)
So if I decide not to fit a new charger, what would be wrong with fitting a VW female plug to the ends of the solar wires and plugin it in to the existing connector (circled )

The problem is I don’t have a proper VW schematic wiring diagram of this circuit,
Any help please from someone with good knowledge,
Many thanks.View attachment 50523

Any help?

 

[WelshGas]

My Solar setup is just wired direct to the +tve and -tve of the Rear Leisure Battery.

 

[westfalia]

The problem is I don’t have a proper VW schematic wiring diagram of this circuit,
Any help please from someone with good knowledge,

Thats not me but i see what you're trying to do.

If you're batteries were low, would a 20min drive or running the engine for a bit
or even hooking up put more juice in them in a short amount of time over solar???

Its a good question you've asked.

 

[v-tec]

Thats not me but i see what you're trying to do.

If you're batteries were low, would a 20min drive or running the engine for a bit
or even hooking up put more juice in them in a short amount of time over solar???

Its a good question you've asked.

At the moment my charger is toast, so the only quick way for a top up is a drive,
I like the idea behind Solar because I’m off grid a fair amount with my racing,
So solar makes sense , not cheap but I love my Cali,

 

[v-tec]

My Solar setup is just wired direct to the +tve and -tve of the Rear Leisure Battery.

I understand your set up WG , would definitely work fine, but I’m just wondering with a new install would it be better connected to the original plug, (only if I don’t renew the charger)
Are there any VW tech’s on our forum, or solar installers that understand my question , I don’t want to screw up any of the electronics

 

[westfalia]

@Roger Donoghue is yer man.

 

[v-tec]

The charger is fairly complicated then,
Transformer looks like it been pretty hot,
I think this one is going to heaven,
I bet there’s not much wrong with it that a good electronics engineer couldn’t fix,

 

[Roger Donoghue]

No need for a "balance charge" .

Connect to any combo of both batteries and they will both get charged equally. Equally enought that you'd never notice a possible 0.xv difference between the two.

Regardless of how you charge them, when the charging is not active, the physical link between the two batteries will force them to equalise and be of the same voltage.

 

[v-tec]

No need for a "balance charge" .

Connect to any combo of both batteries and they will both get charged equally. Equally enought that you'd never notice a possible 0.xv difference between the two.

Regardless of how you charge them, when the charging is not active, the physical link between the two batteries will force them to equalise and be of the same voltage.

A bit like 2 water containers joined by a small bore pipe, fill 1 to the top and they will eventually even there selves out,

 

[Roger Donoghue]

yep!

 

[TripleBee]

And if you connect earth of the charging system to body mass, and not battery mass, it might even be possible to see the charging current on your display, someone here on the forum told once.

 

[Skewif]

And if you connect earth of the charging system to body mass, and not battery mass, it might even be possible to see the charging current on your display, someone here on the forum told once.

I tried that and it didn’t work for me. Showed the combined net drain / charge but if charge greater than drain would only show zero. I connected the solar back to the battery so at least I can see what is being used from the display and what the solar is doing from the phone App.

 

[Feggers]

Any help?

View attachment 50524
Hi Thanks for the diagram: I have a question...(I am not Eletrically minded so bear with me...)
I have a Victron Blue Smart IP65 Charger (120V and 230V and was wondering: is it possible to run this from the 12v Lighter engine battery...and then charge my leisure batteries via the 12v near the back seat door...kind making use of the car battery while running to charge the auxiliary batteries in a more efficient way that the VW ?---

 

[WelshGas]

No idea. Personally I wouldn’t as if the engine is running it is already charging your leisure batteries so I wouldn’t like to hazard a guess how the electronics would handle having 2 Charging systems working simultaneously.

 

[kp64zl]

At the moment my charger is toast, so the only quick way for a top up is a drive,
I like the idea behind Solar because I’m off grid a fair amount with my racing,
So solar makes sense , not cheap but I love my Cali,

1) Solar doesn't really work terribly well in the winter (e.g. October-ish to ?April-ish)
2) Driving the van will only charge leisure battery to ~80% (explained in other posts, something to do with regenerative braking, but I don't really understand )

Therefore I think you may need a new charger -- as from my reading of other posts on this forum, it needs to be topped up to 100% about once per month to keep it working properly.

Solar is absolutely brilliant though.

 

[v-tec]

Yes I bit the bullet and purchased a new one, But I have relocated it to a cooler position, I never did like it above the fridge compressor.

 

[TripleBee]

2) Driving the van will only charge leisure battery to ~80% (explained in other posts, something to do with regenerative braking, but I don't really understand )

On older cars, while driving, the alternator will charge the battery (ies) up to 100%, always, all the time.
On newer cars, with start/stop, bluemotion technology, or everything else it's called, the alternator will only charge the battery (ies) to 80%. This would mean that the alternator doesn't need to charge always while driving, and you see the battery voltage drop to as low as 12,3V while driving. This should mean that the engine doesn't need to give extra power to make the alternator charge the battery (ies). This should lead into more fuel economy. While you brake, the alternator is engaged fully, charging the battery (ies) over that 80%.
All those "stupid" things are invented for environmental savings, just like start/stop.

On the other hand, if I go camping for 2 weeks, don't drive my van, and those 2 weeks my van stays on the mains, all my batteries (3) will be charged to 100%. If I start driving then, without any consumers engaged (no fridge, no USB chargers, no heater), I can clearly see on the display: 14,1V (alternator working) 0.1A (no need to charge). I sometimes notice -0.2A while driving. This means my alternator doesn't need to work hard, apart from charging the starter battery because of the 12V consumers in the cabin (ECU, BCM, all the other computers, instrument cluster, ....).
This also leads to less fuel consumption for me. So from my point of view, I don't need to have bluemotion technology for better fuel economy, and all my batteries are always topped up to 100% while driving, even if I don't plug in the mains.
At the time, for my van there was an option for bluemotion technology. I would cost me €450. For this money I would receive a 5 speed gearbox instead of my 6 now, low resistance tyres, start/stop, AGM starter battery instead of my simple Lead Acid. This could have given me a saving of 0.5 liter/100 km less fuel.
I don't know if I could have gone lower than the 6.8 liter / 100 km I have now sometimes.
For me it would have been money to the drain.

I hope this explanation is quite understandable?

 

[campandfly]

I am going to connect my solar input to my battery in the boot area.
Where is everyone mounting their Solar Controllers??

 

[WelshGas]

I am going to connect my solar input to my battery in the boot area.
Where is everyone mounting their Solar Controllers??

In the rear Wardrobe on the internal wall with double sided tape or small screws.

 

[campandfly]

In the rear Wardrobe on the internal wall with double sided tape or small screws.

Thanks. Yes I was thinking that may be a good spot. Hopefully while I am sitting on the rear seat I can have an occasional look and see how things are going.
Thought I would run a cable with fuse up and over the rear cupboard wall to the solar controller. Don't fancy drilling any holes anywhere.

 

[Feggers]

Hi everyone...I've got my solar panel 100w installed with MPPT controller connected to rear leisure battery and its working fine...just wondering if anyone knows if it will also charge the leisure battery under the drivers seat...

 

[campandfly]

Yes it should do they are connected together.

Hi everyone...I've got my solar panel 100w installed with MPPT controller connected to rear leisure battery and its working fine...just wondering if anyone knows if it will also charge the leisure battery under the drivers seat...

 

[Feggers]

ok thanks...what power of solar panels have you got

 

[Roger Donoghue]

Front and rear batteries are linked so act as one double capacity battery , so yes, they both get charged, equally.

Our current panels are 120W each. Somego for a pair at 240W though 120w is enough for most general summer camping.