Solar Trouble

[RollingRio]

I guess the loss of draft of the original post will be a good thing -- less rambling.

I bought a van with a Windy Nation system installed -- 2 100w panels roof mounted connected to 2 full-sized 12v batteries and 1 35w 12v battery. An 1100 inverter that I never used because the 2 110 outlets never powered (inverter was on). The van has 6 12v/USB outlets installed with LED readouts for battery status.

The outlets have never read over 11.8/9 on a charge. Running one 12v fan overnight would drop the charge to under 10. The wiring is a mess with naked ends of wire bundles hanging all over the place. The floor is "hardwood" laminate. The walls are tongue-in-goove. The roof is covered luan. 

The Vantastic fan has never worked because the original owner had rewired it to work off a switch -- which has no live wires running to it.

Last week the system went completely dark. A guy at O'Reilly's tried to get a read on the batteries which are awkwardly located to say the least. They appear to be wired in series and he got 6v reads on the two fullsize batteries.
While this does indicate the batteries are bad, they're just too darned expensive to run out and pick up two more without being sure they are the problem -- I just dropped $4600 on a new transmission so I'm expense shy.

If anyone can make any suggestions, I would truly appreciate it. Windy Nation is great with overly technical suggestions, which doesn't help me, but apparently they have no suggestions for anyone who works on their systems. Living in Arizona, I find that odd.

Anyway, thanks all!

 

[mpruet]

I'm confused. Two 12-volt batteries wired in series would result in a 24-volt system. Two 6-volt batteries wired in a series would result in a 12-volt system.   Generally speaking 12-volt batteries would be wired in parallel so you would double your amperage output.   Are you sure that you have 12-volt batteries?

 

[B and C]

11.8/9 is very indicative of a "dead" battery under charge. A 12V battery at rest should be 12.7/8 volts.

Batteries should be matched, that is all the same (size, age). You probably do have two 6V batteries in series and a small 12V battery in parallel. Previous owner probably added the small 12V battery to "help" the other two. Not a good idea as it drags the smaller one down.

You 120V outlets off the inverter probably don't work because the battery charge is below the low voltage cutoff of the inverter.

If you want to be sure the batteries are indeed dead, remove them from the vehicle (odds are you will have to anyway) and have them tested.

 

[Manyways2go]

Simple as I can
If wired in "series" it adds the voltage together. example = two - 6volt batteries would equal 12volts,
Use DC (direct current) voltmeter on each battery one battery at a time at the posts if you need to find out.. A charged 6v would measure 6.3 in general & A charged 12v measures 12.6       Also in "series"  positive (+) on one connects directly to negative(-) on next battery.

Myself I would remove and charge the batteries - if not sealed open caps and check levels - clean connections then have them load tested after charging. We used to use hydrometers to check for bad cells. The auto parts stores can charge and test. It is better if you can remove or have someone remove them. Take picture of connections if not confident going back together

It would be correct to verify good batteries before looking for additional issues, a weak battery would drain quickly and not recovery normally
Last in parallel connection would be (+) on one to (+) on next. Two 12v would still equal 12volts when hooked together

good post above from B and C you could have series and parallel both - so start with verification of battery setup

 

[John61CT]

You are wise to not just replace the bank.

Testing and fixing the infrastructure can be done with a cheap or borrowed Starter style batt, long as it's known good, ideally new but not necessary.

If you can get to Northern Arizona Wind and Sun https://www.solar-electric.com/marine-rv.html

See if they can give you a thorough hands-on diagnostic report.

Separately, ask for a detailed breakdown of their proposed fixes.

 

[abnorm]

Come to the Van Build...……...we can sort it out...…

Jamie closed the schedule out at 176 jobs for the 2 weeks.......what's one more ?...…


Look for me out there.....I'll be in the white van !!!!!.

 

[RollingRio]

Amazing and thank you for the responses!

Yes, I'm sure I have 12 v batteries but, with the awkward setup, I can't actually be sure whether the setup is series or parallel.

I have been suspicious of the low reading but wasn't sure if the third (35w golf cart) battery was causing it. With only two panels, I couldn't see why the smaller battery was added.

Flagstaff isn't that far from me -- the drive might be worth it.

And, I'm in a white van too! lol

Again -- thanks so much!

 

[highdesertranger]

if you have 12 volt(v) batteries they would have to be parallel or you would have a 24v system. it's impossible to have one 6v battery connected to a 12 or 24v system no matter how you do it. 6v batteries must be used in pairs. highdesertranger

 

[abnorm]

The Van Build is in/near PARKER...………...and currently we're camped in Craggy Wash near Lake Havasu City