Electrical confusion?

nigsuz
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Electrical confusion?

Postby nigsuz » Tue Sep 29, 2015 9:04 am

Hi Everyone,

We have an ex rental campervan (2008 VW Crafter) with an AA Solar 130 A/H gel battery for the house battery and a wet cell start battery on the van.

The float charge just sitting in the driveway is 14.1 v.....at both batteries measured with my volt meter, sun shining.

There is a VSR installed as well. No matter where i turn the VSR, on or off, the charge voltage at the van battery is still at 14.1 v as though they are still connected.

My question is that this seems excessive for the van battery, and that there seems to be no way to isolate the van battery from the house battery. So my batteries are sitting there at this voltage all the time. Is this ok, normal for a setup like this.

When the VSR is turned "off" the van starter just clicks like the battery is dead but the battery voltage measures 13 v??

I am confused and am really not sure how this is meant to work.

Any help for me to understand this would be great.

I have assumed its all installed correctly as it comes from a reputable campervan manufacturer.

Cheers, Nigel.
Nigel & Suzanne.
Palmerston North.
2003 Hymer Nova 390.
#55272

Neddy
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Re: Electrical confusion?

Postby Neddy » Tue Sep 29, 2015 9:52 am

Nigel, that sounds like a stuffed Starter battery and that you are relying on the House battery being connected in parallel to provide cranking power. See if you can measure the Starting battery voltage when it is on its own and the start key is turned. You could see if it can be charged from a mains-powered charger. Failing that, remove the starter battery and take it in for testing.

What brand/model is the VSR?

It is likely that the 14.1 volt reading is not, in fact, the Float voltage, but a low Charge voltage, with the nominal rate of +/-14.4v held down to 14.1v by the bad starter battery.

It is important that you sort this out because your Gel House battery is less than ideal for engine starting purposes.

Neville.

mattn
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Re: Electrical confusion?

Postby mattn » Tue Sep 29, 2015 9:57 am

It could also be a stuffed VSR. I would disconnect the VSR so the house and cab systems are isolated and see if the picture gets clearer.

The 14.1 is probably temperature compensated - Applying temperature compensation of -3.9V/degree C/Cell to 13.8@25C gives 14.1V@18degree C
Don't be alarmed when you see me talking to myself, I am getting expert advice.

nigsuz
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Location: Palmerston North

Re: Electrical confusion?

Postby nigsuz » Tue Sep 29, 2015 10:52 am

Thanks guy's.

I think I will remove the van battery and take it to be load tested....the "green eye" on it is green but i'm guessing that is not the whole story.

Is there any way I can check the VSR with my volt meter?

Also is it normal that both batteries are used to start the van? That is what it is doing now.

Cheers for the help...

Nigel
Nigel & Suzanne.
Palmerston North.
2003 Hymer Nova 390.
#55272

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Andrew and Debbie
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Re: Electrical confusion?

Postby Andrew and Debbie » Tue Sep 29, 2015 11:02 am

I'm confused too. Any VSR that I have seen is an automatic device, opened and closed by voltage level on the starter battery. Sometimes by the house battery too, if it is a two way VSR. So how are you manually turning it on or off?

If the van battery is flat, and the house battery is providing current to the van starter, then there must be fairly heavy duty wiring between the van battery via the VSR. And it will probably be getting warm! Maybe the high current needed by the starter has fused the contacts closed in the VSR, in which case the VSR needs to be replaced, along with your starter battery.

Cheers,
Andrew
2014 Leisureline 7.0 metre Elite Caravan towed by 2017 Ford Ranger. 4 x 150 watt solar, eTracer 45 amp solar controller, 1800 watt PSW inverter, 300 amp/hrs gel batteries, Votronic battery monitor. 180 fresh water, 180 grey water.

BUSRSQ
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Re: Electrical confusion?

Postby BUSRSQ » Tue Sep 29, 2015 11:34 am

nigsuz wrote:Thanks guy's.

the "green eye" on it is green but i'm guessing that is not the whole story.


Nigel

The issue with the green/white/black eye is that it is only in one cell of a battery that consists of usually 6 cells, so that cell can be good and the other five can be toast
You could disconnect the VSR, then using a multi meter attached to the start battery crank the starter, battery should drop much below 10v

Neddy
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Re: Electrical confusion?

Postby Neddy » Tue Sep 29, 2015 11:40 am

Nigel has almost certainly got a Dual sensing VSR.
This charges from the Starter battery to the House battery when the alternator is running and charges from the House battery to the Starter battery when solar panels or mains charger are connected.
The relay connects when voltage at either terminal reaches 13.3V
In other words, so long as the House battery is above 13.3 volts, it will be connected in parallel with the Starter battery. That is what Nigel is seeing.

Neville.

nigsuz
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Re: Electrical confusion?

Postby nigsuz » Tue Sep 29, 2015 11:56 am

Yes Neville, this is exactly what is installed on the van and how the VSR book says it works. So this is correct then? I essentially have 2x start batteries?
I had the van battery load tested at Century.....they tell me its fine.
The house battery is ok as well.
So the VSR has a switch, a largish rotary switch, that I thought would isolate one battery from the other. Not so.
Should the VSR be able to switch off and on?

Cheers, Nigel
Last edited by Mark on Tue Sep 29, 2015 1:07 pm, edited 1 time in total.
Reason: Redundant quote of immediately prior post.
Nigel & Suzanne.
Palmerston North.
2003 Hymer Nova 390.
#55272


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