Dead starting battery, fully charged house batteries? Is this possible?

[daveb]

Originally Posted by TechTonics

Right! I’ll get a pic of my isolator later.

Either way, it sounds like just a low battery, and the full-charge on the house batteries won’t mean the starting battery is full...right?

Hypothetically, if I got stranded and this happened when I was on a solo trip, could I jump the starter battery off the house batteries? (Given long-enough cables?)

Correct. One problem with long cables is their size plus most house batteries are usually a fairly long distance away and long cables have a voltage drop. A lot depends on how easy you can get to the house battery.



Another solution (Provided you have an inverter), would be to consider a standard car charger with a 50 amp jump feature. You could use it to throw a 12A charge at the starting battery for a few minutes, then switch to jump and get the vehicle going. An AC extension cord is much smaller and easier to store.

[Scalf77]

Originally Posted by boywonder

I was thinking that was the smallest isolator yet! Should have asked if he had the usual blue anodized unit...





Obviously...Greg is quite fond of the 7622

Yes, you are correct. Ok, it should have said 7622 or 7620.

-greg

[boywonder]

Originally Posted by Scalf77

Yes, you are correct. Ok, it should have said 7622 or 7620.

-greg

What's the difference between those two models?

[boywonder]

Originally Posted by TechTonics

Hypothetically, if I got stranded and this happened when I was on a solo trip, could I jump the starter battery off the house batteries? (Given long-enough cables?)

Sure....if you have a little time just jump the batteries together and wait 15-20 minutes if it won't start immediately. The house batteries will charge the starter battery and at some point there will be enough cranking amps between both batteries to turn it over.

[Scalf77]

Originally Posted by boywonder

What's the difference between those two models?

The 7622 has the yellow manual knob. This gives you the ability to close and open the relay manually, with or without power. It would be a purely redundant part of the system, especially if you wire in the control switch. The big difference is that it needs no power or ground connection.

greg

[Twoxentrix]

Another option would be to carry a Jump Starter pack - Another Thread somewhere on the subject, but you would have to run a search.
I have a "NOCO GB150 Genius Boost Pro 12V 4000A Jump Starter" (needed one with enough duty to get a Diesel going)
https://primebattery.com/product/noc...r-gbc015-case/

EDIT: I had issues with my Viper Alarm doing odd stuff when my Stater batteries began to go (alarm would go off occasionally, Locks would lock & unlock themselves, etc.). As soon as I replaced the Batteries it all stopped.

[Charliesmom]

This why I carry a jump starter with me in the van (i.e. Audew, NOCO, DBPower, etc) since my isolator is unidirectional.

[Ruthless]

We carry The Zeuss portable jump starter. Stays charged up for months and works great in case of a dead battery.

[gahamby]

https://www.bluesea.com/products/762..._-_12V_DC_500A
This one here is the ticket.

[CaptainBilly]

I carry a set of jumper cables. They are long enough to reach from the house battery inside the van just forward of the left rear tire to the engine battery in our '92 EB250 SMB.
They were a real blessing when we needed to jump start the engine out in the boonies a couple of years ago. The house battery started the engine immediately.

Our solar installation is wired (by a previous owner) independently of the engine battery. The only (remote) connection between the two batteries is that when the engine is running it charges the house battery. Otherwise they're independent.
I'm not the greatest with electrical installation so the low-tech jumper cables are best for us. YMMV.