Yes it's my own D***N fault

[Canadian_Rainbi]

First part of this was posted Sunday on the "What Did You Do to Your Class A MH Today" Forum.

Not really asking for help. Sympathy maybe. Just really a comment. Perhaps someone will learn something. Maybe even me.



It was going into the tech Monday to replace (on warranty) the Coleman basement heatpump. So since I would need an early start on what might be a drizzly Monday I decided to get things all ready the day before. The rig hasn't moved since winterizing in the fall.

Before pulling the shore power and storing the cords I thought to check things over: NO SHORE POWER incoming. The Maxx fan had been left on, as well as the ham radio in beacon mode. Neither were working, nor were the lights. Not even the LEDs. :E

Switch them off, go check the plug on the shore power extension: Plug hanging loose from the socket. Looks like a deer or a neighbour or what ever had bumped it and partially pulled the plug. It's under tall trees so the solar wouldn't have been able to keep up.

Batteries: 4 6V GCs, rated at 484 AH

Xantrex Prosine 2.0 Inverter/Charger (Max 100 A charging)

420 Watts of Solar, BlueSky MPPT controller.

The Xantrex charger voltmeter was reading nothing.

Plugged the shore power back in--nothing. (Tripped the breaker down by the house as I discovered later.) Started the Cummins, waited until I could see a decent (13V+) on the display and started the Onan 7.5 gen, checked that the Xantrex was charging.

Here is one interesting/puzzling thing:

It charged away at 80 Amps for several (4+) hours before tapering. Hmmmm. The max charge rate is set for 96 Amps, max voltage set at 14.8V. Never saw it above 14.0 but I didn't stay there watching it.

Once the charge current had reduced (around 30 A at 13.8V) I shut down the gen and moved the rig out of its parking pad into the drive, hooked up Wrangler for towing, ready for morning. After sitting for an hour or two, Xantrex voltmeter reading 12.9 We'll see what it says in the AM. (Forgot to check before starting it up.

On picking up the rig next day (Tuesday) about noon, the batteries were showing about 12.5 volts. The rig was parked under trees but the solar would have been on for a few hours.

Took the rig to the wash for a quick rinse (The solar panels were FILTHY)

Back home I pulled the solar controller input and killed all the internal loads to let the batteries sit undisturbed. About 6 hours later the batteries were reading 12.54V according to the BlueSky readout.

This morning (Wednesday) displayed 12.45V (Solar panels still disconnected).

Around noon today I plugged the shorepower in and energised the Xantrex charger. Charging at about 60 Amps. Solar still disconnected.

More later. I'll keep this thread going until I decide if I need to replace the GSs or not. We're likely going to Mexico for the winter so I don't want iffy batteries.


I know I have probably seriously damaged these 4 2 year old GSs, how badly remains to be seen. Batteries: 4 6V GCs, rated at 484 AH

:S

[BFL13]

You will have to change your name from "Rainbird" if this keeps up.

You need a bus bar for all those wires that go to one post.

[Canadian_Rainbi]

The rain started just as I got the last negative lead on. Can't seem to find enough room on the post for the Xantrex temp sensor. Still a little re-thinking to do which will wait for a sunnier day.

But the rain is welcome; we are officially in a drought. At the stick house 5.4mm of rain in May (Normal is 67mm) same in June, none in July until a couple of days ago when we had 4.5mm. Today's is forecast to be more. At least the neighbour's well still has water and mine is 300 feet deeper than his!

For the non metrics still left in the world, 4.5 mm is approx 0.177 inches, or 11/64 inch.

Or 1/4 inch = 6.35mm

[MEXICOWANDERER]

My string of shrunken heads resemble that remark...

[Cloud_Dancer]

Battery Wizards! Science with a little bit of voodoo, it keeps you learning even after 65 years of trying (speaking for myself). You guys got a lot of nerve...:B

[pianotuna]

S.G. of 1.2 = 50% state of charge

Assuming 1.285 is 100%, 1.265 is about 88%

Self discharge on golf cart batteries is in that ball park over a 5 week 'rest' period.

I'd say the batteries have been recovered and should be kept in service.

SG and Voltage

[Canadian_Rainbi]

Update:

After being left disconnected for 5 weeks (we were away) batteries are S.G 1.265 across the board. Another 15 Amps with the 6V charger, (Max voltage reached was about 7.75V) on each battery brought the S.G up to 1.275 in all cells.

Next test: I'll put them all back in tomorrow if it doesn't rain and reconnect the Xantrex (Prosine 2 inverter/charger) and then in a couple of weeks we're off to 4 days of boondock camping with the Vancouver Islanders FMCA Chapter.

[Canadian_Rainbi]

Things are looking up. 🙂

All four batteries are now showing an SG of 1.285 across the board.

One frustrating puzzle explained: One of my DMMs (the most expensive one) seems to be reading about .2 to .3 volts low as compared to my cheapo DMM from Canadian Tire, which agrees pretty much with the Xantrex voltage reading.


The batteries are back in there trays and and the door locked, disconnected from everything as we are leaving Wednesday for month in Europe. :C Baby sitting the batteries would be one thing too many for the house sitter who has to look after water system--softener and distiller, the dog (including meds), water the hanging baskets and the garden--He'll have fresh tomatoes in week or two! Oh, and looking after the hot tub, though he doesn't seem to mind that. :B

On my return I'll reconnect the batteries. I noticed when disassembling the cabling that it appeared that the tech had not connected them in a balanced manner: He had the load and solar buss on one set and the Xantrex on the other. :S I noticed when I took them out one pair was slightly lower than the other.

It's going to be very tight but I think I can switch the two + leads for a balanced system.

Oh. And I need a new Xantrex Echo Charger. It appears that I left the bin door, to which the echo Charger is attached, open when I washed the roof! :E :S

[Canadian_Rainbi]

westend wrote:
If you have solar, why is it disconnected?

I'm trying to resurrect these batteries which were inadvertently allowed a reallllly deep discharge. To do this I need to control the charging current and voltage carefully.

The solar is problematic with two main concerns:

1) A long run of undersized wire between the controller and batteries. In full sun this can result in a full one volt drop at 20+ Amps. This causes the controller to taper the charge way too early--It thinks the battery is at 14.8 when it is only 13.8. If I increase the output voltage to make up for the drop at a high charging current, then as the battery chargers and current decreases so does the voltage drop until at a very low current the battery voltage would increase to nearly 15.8 Not a good thing.

2) At the moment the rig in parked under very tall trees so they are severely shaded. Best I can get out of them is 4 amps or so a few hours a day. Once I have the batteries back in shape I'll start worrying about the solar. I think the easiest fix will be to change to a controller with remote battery voltage sense. The other option will be to run at least #4 wires. But that is another project. The first is to save these batteries.

[westend]

If you have solar, why is it disconnected?

[MEXICOWANDERER]

Careful 🙂

You're gonna turn it into a true "smart" charger. Hint: Heat sink a 40-amp bridge rectifier for a ten amp rated charger for 1/2 wave rectification. If the charger has a cool running transformer I choose a 40-volt rated Schottky 40-amp rectifiers to squeeze a few more amps out.

[Canadian_Rainbi]

Saturday morning all 4 batteries showed 6.3V

Saturday after noon, tested SG: a little uneven.

Bank B: B1 1.285 1.275 1.275, B2 1,285 1.275 1.275

After charging each of those batteries with 6 volt manual charger:

Bank B: B1 1.285 1.2855 1.2855, B2 1,285 1.285 1.285

The charger, supposedly at 15A started reached more than 12A and slowly tapered over about 2-3 hours, highest voltage noted was 7.77V. After that time the current, measured by a clamp on meter was cycling between 10.9 and 7.5 (by a few hundred mA at a time) over maybe 10 or 15 seconds. I think it must be a function of the charger. Supposedly a manual charger--I think I am going to get in there and see if I can remove everything except the transformer and rectifier. I might add a digital ammeter and voltmeter. This won't happen for a month or two.

Tomorrow, I'll do the same to the other two batteries.

[Canadian_Rainbi]

5 hours after charging, B1 and B2 showed 6.3 Volts each.

Battery bank A1.-A2 showed "Full".

Time for bed, back at the batteries late Saturday morning.

[Canadian_Rainbi]

Thanks for the encouragement but:

This was strange: Checked the battery voltage reading on the Xantrex (not in charge mode as this morning, 12.6 V Removed all 4 batteries to the ground--not as easy as it sounds, it's very tight! Also took photos first and during.

Once on the ground checked each battery: 6.2V ! :h

Reconnected back to series-parallel in the exact same format, reading 12.4V! What happened to the 12.6 of half an hour ago? The DVM has brand new batteries. I'll take up another voltmeter and compare.

Here is the SG: (closest to negative post first):

A1 1.285 1.275+ 1.275+ A2 1.275+ 1.275+ 1.275

B1 1.275 1.270 1.275 B2 1,275 1.275 1.275

I'm a bit surprised to see only 12.4 volts with those S.G.s

In any case, I connected two in series (B1 and B2) and put my good old Canadian Tire charger "Smart" charger on at 40 A

I must remember to check the main cables to make sure that the tech hadn't put the Xantrex charge line on one bank and the load buss on the other. That might explain the small difference in SG between set A and B

Guess I won't get these all done today! Good thing the weather is good.

[MEXICOWANDERER]

This is what they pay GC batteries to survive. A car jar battery would never have been the same. Credit lots and lots of acid and less porous plates. The boys at Rolls asked me for specs for my proposed single cell bank.

"Lead and antimony so pure it could stand tall against Mother Teresa.
Paste so thick it needs a chisel to get it out of the batch drum".

They laughed and quipped "Hey Ed, twelve of the usual". Not really accurate, but they are 2-cells per cage, with three quarter inch thick straps paralleling them.

The higher quality the construction the more they can take abuse on the chin.