What am I missing?

[pbansen]

Originally Posted by Flux

Here's the closing and opening voltages for the 7620. A quick read here will tell you what you need to know.

http://assets.bluesea.com/files/reso.../990180180.pdf

Thanks for that - great information!

Originally Posted by Flux

Sounds like you have a meter so test your house battery directly at the terminals.

Trace the house battery positive cable back from the battery terminal and look for a fuse. It should have one inline someplace. If the house battery had voltage then look for that fuse and check it.

Very difficult to get to the terminals on the battery without lowering it, but I did what I could and got 0 volts there as well. Traced the cables from the battery to where I had access to a terminal and again got 0 volts.

Originally Posted by Flux

Check the fuse on the wizard as well. Check all inline breakers etc.

Checked the AC cable on the wizard (which is only about 20") and the fuses - everything looks OK.

Originally Posted by Flux

Even a really beat down battery should have a little voltage on it.

I know, right? I don't know how long it was stored or how long it's been since the SMB stuff worked, but I'm inclined to think that the huge Deka AGM battery is completely discharged.

Originally Posted by Flux

Good luck.

And oh yeah, did you check that 13.09 volts right after you had the van running? Batteries that were just under a charge will read a bit high and will normalize after a bit. Check that again when van has been sitting.

The vehicle battery reads 13.01 volts when it has been sitting for a while and slightly over 14 under charging conditions.

Thanks for all of your suggestions and insight!

[arctictraveller]

As others have said, the automatic charging relay will not close to provide charging voltage to the house battery once that battery gets below a certain voltage. At that point, the battery can only go one direction, and that's closer and closer to 0 volts. I just went through this while helping another forum member troubleshoot a dead house battery. You could install a jumper across the terminals of the relay to bypass it, and connect the house battery directly to the starting battery. Then you should see some voltage at the house battery. If you do see voltage, that eliminates bad cables, blown fuses, loose connections etc. In my opinion, it's a pretty dumb design that doesn't allow charging of a very dead battery.

[Scalf77]

Given this chart: (from the 12 volt side of at Welcome to Mark's Fulltime RV Resource)


It would safe to assume that a battery below 10.5 is completely discharged. Taking into account loads bringing that lower I believe we see that a disconnect lockout voltage 9.5 volts is pretty safe if we are trying to limit having the alternator charge a completely dead battery.

Obviously, loads, long cable runs can have a impact on this. I think the intent of the designers was to make sure they created no harm (destroying a alternator).
There are plenty of debates on the topic: No, but seriously: Your alternator doesn't charge your battery the way you think it does.

There is also the operating coil voltage of 9 -16 volts, so they need to design to the operating levels of the coil voltage.

If the OP had the 7622 he could use the manual knob to connect the batteries, thus Blue Sea gives you a option around this protection. In this case the user has to go out of their way to connect a discharged battery.

I am not sure which Progressive Dynamics Unit the OP has, as I believe he just referenced the charge wizard, In any case the trouble shooting guide list bad battery as possible cause of low output. It is not that uncommon for charger manufactures to also have a low voltage lockout.

I would say that 0 volts means it not connected or a very dead battery.

-greg

[Flux]

Originally Posted by pbansen

Thanks for all of your suggestions and insight!

I learned from everyone here!! Everyone has been very generous with knowledge, help, and suggestions and I wouldn't have done a home build without this place.

It does sound like your house battery is done. The good news is you have some nice equipment in your system so putting another battery in is $$ and a pain, but you will be set for a long while.

[arctictraveller]

Originally Posted by Scalf77

Obviously, loads, long cable runs can have a impact on this. I think the intent of the designers was to make sure they created no harm (destroying a alternator). -greg

I"m sure your correct, but it would be nice, if rather than making it so difficult to recharge your totally dead house battery, there were some sort of current limiting or an alternator temp sensing circuit instead. That way it would still be automatic, rather than having to somehow manually bypass the combiner.

[pbansen]

I pulled the battery out this morning, checked the voltage at the terminals: .01 volt

Going to try a long, slow charge and see what happens. This looks like the original battery installed by Sportsmobile in 2009(?), so I'm not optimistic that there's life left in it - will probably just bite the bullet and replace it with a comparable unit.

[daveb]

I'd put a higher 10-15 amp charger on it for a few days but watch the batteries temp. If it does hold some kind of charge you might consider equalizing it.

[pbansen]

Originally Posted by daveb

I'd put a higher 10-15 amp charger on it for a few days but watch the batteries temp. If it does hold some kind of charge you might consider equalizing it.

What does 'equalizing' mean, Dave? How would I go about that?

Took the charger off briefly and checked the voltage - 10.98. I'm not getting too excited about that, because my experience has been that batteries that are failing will show normal-ish voltages, they just lack the reserve of current needed, but we'll see.

[DCHitt]

Originally Posted by pbansen

Took the charger off briefly and checked the voltage - 10.98.

10.98 looks like a shorted cell. If you can measure each cell independently you might find that to be true.

[boywonder]

Originally Posted by pbansen

What does 'equalizing' mean How would I go about that?

Do a web search for equalizing a battery....your Progressive Dynamics with charge wizard will equalize the battery if plugged in long enough....do a search for the user manual for your charger model number.

It charges for a time at a higher voltage to churn up the electrolite...not so long that it boils off fluid.

Originally Posted by pbansen

Took the charger off briefly and checked the voltage - 10.98.

See Scalf77's voltage chart in post number 13....battery is likely toast. Full charge after letting the battery relax for awhile after charging is 12.8V.