Electrical confusion?

Neddy
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Re: Electrical confusion?

Postby Neddy » Tue Sep 29, 2015 12:14 pm

I'm not at all sure that the VSR is the problem and it would be unwise to zero in on it prematurely.
My reasoning is this. Your vehicle began life with a bog-standard Starter motor/Starter battery/Alternator set-up. This is all still there, intact and unaltered. The VSR simply parallels-up your House battery under certain conditions. Fact is, you can't start the engine with the inherited standalone electrics.
First suspect :- Stuffed battery. Tests OK.
Second suspect :- Battery terminals. With a little bit of corrosion or a loosened terminal, proper contact can be lost. Clean up the battery posts, clean all connections, smear on a bit of protective grease and tighten everything up.
With the VSR turned off, disconnected or disabled, attempt to start the vehicle. Maybe the problem will be fixed! Otherwise, measure the "no-load" starter battery voltage and then, with the key turned on and held on, measure the battery voltage at both the battery terminals and at the cable terminals and report back.
We may yet get to the third suspect (the VSR), but one thing at a time is good.

Neville.

nigsuz
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Re: Electrical confusion?

Postby nigsuz » Tue Sep 29, 2015 12:44 pm

Hi Neddy,

I disconnected the house battery.
Checked tightness of van battery terminals and van starts fine. Perhaps a terminal was not tight? Are they that fussy as they "seemed" tight?

Re connected the house battery now.

So I have an agm house battery (from AA solar) and a wet cell van battery and they are both being charged by the solar panel correct?
I can set the solar controller for either gel or liquid electrolyte. I have set it on liquid electrolyte.

All seems well now but I am still not sure what the rotary switch on my VSR is supposed to do? It says house "on" or house "off" but does not disconnect the batteries from each other.
Is this just to isolate the house battery from the van charging system, but not the van battery from the solar panel?

Cheers for the patience.

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

nigsuz
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Re: Electrical confusion?

Postby nigsuz » Tue Sep 29, 2015 1:09 pm

Ok...the VSR switch (it is actually a separate switch on a common mount plate) is simply to disconnect the house electrics from the batteries.
So the batteries are in parallel and the van basically has 2 start batteries. After starting the van the VSR was warm to the touch so the starter is pulling from both batteries?
The only device between the van and house batteries is the VSR.
Nigel & Suzanne.
Palmerston North.
2003 Hymer Nova 390.
#55272

Neddy
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Re: Electrical confusion?

Postby Neddy » Tue Sep 29, 2015 1:39 pm

"Checked tightness of van battery terminals and van starts fine".
Success!

"Perhaps a terminal was not tight?"
Right. One or the other was not making full contact, passing enough current to trip the starter solenoid and make it click, but not enough to turn the engine over.

"Are they that fussy as they "seemed" tight?"
They are very fussy. Starting currents are so high that the connection must be pretty much perfect.
Sometimes the cause is minor corrosion from the battery acid.

"So I have an AGM house battery (from AA solar) and a wet cell van battery and they are both being charged by the solar panel correct?"
Yes - if your VSR does what I think it does. .

"I can set the solar controller for either gel or liquid electrolyte. I have set it on liquid electrolyte."
It would be good to know what the actual voltages would be, but in the absence of that info, I would suggest that
If you have a GEL House battery, set it to Gel.
If you have an AGM battery, set it to liquid.
(You had said you that you had a GEL battery........)

I really can't tell exactly what is going on, but if the Starter and House batteries are permanently in parallel (not a good idea) as you suspect they might be, it is hard to see what the VSR is for at all. The usual setup is for the VSR to parallel the two batteries whenever the engine is running, so you only ever use the Starter battery for starting.
Is your VSR single or dual action? What make/model is it? How much solar power have you got? Does this seem to be adequate for your needs? What make/model solar controller have you got? Have you got a Battery Monitor? Are you running an electric fridge?

Neville.

nigsuz
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Re: Electrical confusion?

Postby nigsuz » Tue Sep 29, 2015 2:09 pm

Neville,
Sorry yes its an AGM house battery so controller is set to liquid.

"The usual setup is for the VSR to parallel the two batteries whenever the engine is running, so you only ever use the Starter battery for starting.
Is your VSR single or dual action? What make/model is it?"

Its a Dual Sense cut in 13.7V cut out 12.8 V. Each battery is on opposite sides of the VSR.
BEP marine 125amp Dual Sense VSR

"How much solar power have you got? Does this seem to be adequate for your needs?"

125 watts panel that seems fine for our needs at the moment. We normally move after say 3 nights because of the waste tank and that works out well. The van charges the batteries.

"What make/model solar controller have you got?"

FANGPUSUN PR3030 30amp solar charge controller.

"Have you got a Battery Monitor?"

No we use the voltage reading on the solar controller to see what's going on, sort of. I always felt if the power went out I would start the van. Hasn't happened yet though.

"Are you running an electric fridge?"

Yes we are but as I said all seems ok...

I guess i'm maybe being pedantic but it seems to me that I should not be using the house battery in the van starting circuit at all.
I found this out by accident as I was doing maintenance on my van and had disconnected the van battery but still was able to short out the starter with my wrench...so discovered I need to disconnect both batteries to have a dead van. I assumed this was normal.

Nigel
Nigel & Suzanne.
Palmerston North.
2003 Hymer Nova 390.
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Neddy
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Re: Electrical confusion?

Postby Neddy » Tue Sep 29, 2015 4:28 pm

"I guess i'm maybe being pedantic but it seems to me that I should not be using the house battery in the van starting circuit at all."
It feels wrong to me too - but normally I don't think you would be. Turning the key to start the engine would drop the Starter battery below the 12.8 volts threshold and the VSR would disengage, separating the batteries. You do get to using some of your Starter battery capacity for House purposes, though - something of a mixed blessing, I guess.

Running an electric fridge with 125 watts of solar power means that you probably need supplementary charging from the engine. Accordingly, I would be inclined to leave everything just as it is.

Nevertheless you need to be aware of the fact that such a set-up can mask the failure of one or the other battery. You could have been running "without" your Starter battery for quite some time.

Neville.

nigsuz
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Re: Electrical confusion?

Postby nigsuz » Tue Sep 29, 2015 4:34 pm

Hi Neville,
I appreciate your thoughts mate.
I too think it's ok as is but just seems a bit weird. Yes the wiring from the house battery to the van is much lighter gage than from the van battery to the starter.

We have had the van about 18 months now and after the first 6 months I did replace the wet cell house battery (it was dry and stuffed) with the AA Solar AGM one (130 AH) and have been more than satisfied with the performance of everything in the van.

The van charging system charges both batteries no problem and I have no issue with this. I started digging into it a bit more when I found out that the house battery provides 12 volt power to the starter motor with the van battery disconnected. So I have both batteries in the starting circuit but am happy with it I guess because it's been like that from day one (I assume).

So am I correct in saying the VSR always has the batteries in parallel unless the voltage drops below 12.8. It then disconnects the van battery to save it for starting.

So what is the 13.7 volt cut in for....is that so the VSR reconnects the batteries when the voltage is above 13.7 again?

One final question. Is it ok to have my batteries on 13.9 volts all the time? Like on a sunny day. They won't overheat will they?

Cheers, Nigel
Nigel & Suzanne.
Palmerston North.
2003 Hymer Nova 390.
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Neddy
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Re: Electrical confusion?

Postby Neddy » Tue Sep 29, 2015 9:42 pm

"So am I correct in saying the VSR always has the batteries in parallel unless the voltage drops below 12.8.
It then disconnects the van battery to save it for starting."

The VSR always has the batteries in parallel if the voltage of either exceeds 13.7 volts. The VSR never has the batteries in parallel if the voltage of either is below 12.8 volts
Between 12.8v and 13.7v, whether the batteries are in parallel or not depends on whether the voltage has risen or fallen to that point.

So what is the 13.7 volt cut in for....is that so the VSR reconnects the batteries when the voltage is above 13.7 again?
The aim of that is to connect the two batteries when one or the other is being charged - regardless of the power source.

"Is it OK to have my batteries on 13.9 volts all the time?"
It is OK if they are still charging - but if they are already charged, that might be just a little high as a Float voltage. Check on the battery makers recommendations.

Neville.


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