Battery Isolators,Separators, and Switches?

[gahamby]

Engine at idle: House=12.5vdc Start=14.1vdc
Shore power: " 14.6 " " 12.8 "
It appears as though the GFCI outlet in the van is shot.
more to come

[gahamby]

The pulsing was rapid maybe 4/sec.
I disconnected the Sure Power ground. The gauges still deflected at start.
The part of the wiring that concerns me is the segment of #8 between the positive terminal of the battery and the #2 that goes aft to the isolater.
I'm going to replace the GFCI so I'm back to stock. Right now I have the Intellapower plugged directly into an outlet.
Thanks all for the replies. GH

[gahamby]

I replaced the GFCI and restored the plug from the Intellapower and everything worked as it should. The isolater still gets hot. There is not enough heat sinking or ventilation
in the electrical compartment.

[marret]

Originally Posted by gahamby

I too wonder at SMB's wiring. The hot line from the start battery to the isolater has a short jumper of #8 AWG that then splices to a run of #2 AWG that then connects to the large fuse lug in the box under the hood. It then travels back to the isolater. I'll try metering the house battery with the van idling.
Do your dash gauges all bang to zero when you turn the key on?
My house electrical is under the gaucho at the rear.
ps: thanks for the link. it looks like a marine supplier is a possible source. Amazon also lists them. More stuff to look into.
Is this the one?
https://www.amazon.com/Blue-Sea-Syst...gateway&sr=8-2

Based on your last post sounds like the GFCI was interfering some how.

For the ML-ACR 7620, it was not the 77xx series. Like this: https://www.amazon.com/Blue-Sea-Syst...ay&sr=8-1&th=1

Weird on the wiring.

I have not noticed my van voltmeter going back to 0 when started. Can't check it now, I'm not with the van.

[gahamby]

I'm puzzled at the 120VAC GFCI affecting the 12VDC charging system but the converter/charger does plug into the GFCI. I've a Blue Sea 7622 0n the way.

[marret]

Me too, strange.

[Scalf77]

There is no way that the GFIC plug could directly cause an issue with your 12 volt system.

First, you need to step back a little and go through your symptoms.

#1 It has been working as normal since you purchased in 17.

#2 All gauges bang to zero, when you start.
It seems this has been happening since you purchased it correct? So this is not a new symptom? I don't have GMC so I can't verify, but I would suspect that this is normal start up. It could be a large dip in voltage caused by engine crank, etc. If you pull the wire on the start assist tab on the Surepower, you can eliminate that. Also when you pulled the ground from the Surepower did the gauge bang issue still exhist? If so, it didn't come from the Surepower unit.

#3 Wire gauge, 2 Awg wire spliced into 8 Awg wire is only good if your trying to create a fuse-able link. While I don't like that, it again has been there the whole time thus not likely the culprit to your issue.

#4 The issue, what exactly was the issue, unable to charge house battery when running starcool , refer, and charging house battery. The surepower unit was hot and pulsing in 4 sec cycle.

So after you replaced GFCI did you test by running starcool?

I am trying to understand how you determined the problem went away.

When running starcool, depending on blower setting it can be a pretty large current draw, add into that charging the house battery and anything else that may be on and you could have a significant load on the house side of the separator.

When the alternator comes up and starts charging the voltage will go above 13.2 and the separator will connect the two systems together. Now your alternator will have to supply the load of the house and the van systems at the same time, this load may become to much for the alternator to keep up with. When this happens the voltage of the alternator will drop below 12.8 and the separator will disconnect the two systems. The alternator will now go back above 13.2 volts.

I have never been able to run my starcool on hi with other loads at Idle. So pulling up to a stop light could make my old surepower disconnect. As I said, the surepower takes power to stay closed, so it get warm. If it is getting really hot than I would suspect internal resistance.


-greg

[gahamby]

Thanks for the reply,
I agree that the GFCI should have no effect on the 12VDC system.
The gauges bang to zero when I switch to ACC and when cranking.
Disconnecting Surepower ground has no effect.
Disconnecting Surepower start assist has no effect.
I did not check charging voltages with engine running, refer on, and Starcool 12v on.
That is a very good point. I will look into that.
I metered the batteries with the motor running and came up with about 14VDC each
I metered the batteries while connected to shore power and came up with about 14VDC each.
I'm going out there right now to check how things run under load.

[marret]

I was wondering if it had something to do with how you had the converter/charger plugged in.

Do your house batteries charge directly from your alternator as well as the converter/charger?

[gahamby]

Current readings: Shore power, no load, Hse=13.59 Start=12.63
Shore power, Starcool 120vac on, Hse= 13.48 Start=12.63
Engine idling AC on rear fan Low,12.02 med=12.00 Hi=11.92 Start=14.05
" " plus fridge Low 11.95 med=11.92 Hi=11.85 13.85