battery charging procedure

[Joel Ashley]

Well, I just got the inverter circuit boards replaced and the thing installed (by me) earlier this year, after squirrels nested atop it.  This weekend I went out for my usual check and hit the 12v light switch.  Nothing.  The Multiplex buttons would flash orange and go blank.  When I hit the 110v overhead the lights just flashed on and off.   Okaaaayyy.  Checked the multiplex controller in the bathroom and its lamp was green, so I surmised low battery power, even though the coach has been plugged in to 30 amp.  The inverter remote over the door has been reading 13.5-13.7v all summer, including the day before, but was blank now.

I unplugged the coach and hit the inverter's onboard reset (learned my lesson last time - never hit the reset while plugged into 110), still nothing.  Checked the four "new" 6v deep cycle AGM house batteries with my Fluke 365... they read 3+v each, 6+v per pair.  So in the inverter bay were new droppings and dry leaves.  NOT Again!  Yup.  Winter is coming.  A nice warm inverter top makes a great home, and toilet apparently.  This time the bay doors had never been left open for even a few minutes.

First things first.  Luckily I'd had reason a few weeks back to air up the coach via the remote quick connect (per Dave and other's advice, I haven't started the engine while stored for almost 6 years), and raise it to level.  This meant the rear happened to be high enough that I could crawl underneath, looking for the confounded critter's entry point.  Nearest I could find was where the wire and hose looms pass through the bay "box" along the inside of the rails.  Couldn't get my head up far enough to see clearly, but looked like maybe small gaps between looms through the portholes.  BCS' Becky told me when I asked about what kind of foam is proper, that some have used a rodent deterrent type.  I found some at my local Ace and tried squirting it up in amongst the looms, but being overhead (over face) that was a trip, and I made a pretty messy job of it.  Hopefully I got enough in where I couldn't see and blocked any access.  I sure can't see anywhere else they're getting in at.  Those two ports along the inside of each rail can't be accessed from inside the bay because of the two waste tanks, pipes, wires, and other components;  no way to get to the inside of the rails even if I could see the ports.

Anyway, so hopefully the foam will keep them out now.  Second job is get the batteries back up.  Apparently the inverter charger wasn't working for awhile, and even the chassis set is down to 11.8v.  I'd left the battery Mains on because when they're off the solar controller incessantly clicks on and off;  another issue I'd hope to have fixed by now but was going to have BCS or a solar installer update it... if I could ever get on the road again.  If the mains had been off they wouldn't have been parasited down.  Don't know what took them down so fast though.  Regardless, I put my charger on the house set yesterday, but it runs for awhile and then goes to blinking "0.0" and not charging, like there's some sort of fault.  It might be my charger, although I tried setting it for "Deep Cycle" and then tried "AGM/Gel", and all three charge rates, 2amp, 15 amp, and 40.  It still quits after awhile, with the house batteries stuck at 6.1v or so.

I hook the charger up with what makes sense to me, the red clamp on the positive post where the large positive cable from the loom connects, and the black clamp to the post on another battery where the large negative ground cable connects.  That should emulate the inverter's charging, right?  Or do I need to disconnect the positive and negative cross tie cables that create parallel, so that I'm only charging two series 6v batteries at a time?  The charger doesn't do 6v, so regardless I need two in series.

I should know this stuff, but my memory functions since Gabapentin dosings years ago has not served me well.  Glad you fellows are here to revive it a bit.

When I get the batteries charging I'll clean out the bay again, crawl in there with the vacuum and cleaner/disinfectant, and try to see atop the inverter to confirm my suspicions.  Getting the 40 pound thing off the ceiling took some engineering last time... at least I have experience now.  My rolling floor jack was handy.  But not fun alone.  Hopefully one or both circuit boards can be rescued, and I know where to take it now...but $$$$.  When I reinstall it, this time I'm considering hardware cloth surrounding the inverter's top perimeter;  at least if they still get in they can't park atop it where their leavings can get inside it.  Whenever we get to BCS, Henderson's, or somewhere, I'll have the bay box scrutinized for possible vermin entry points better than I can do it.

Thanks,
Joel

[Joel Ashley]

Seems to be working with the + jumper disconnected.  But my charger still gets to a point where it flashes and indicates “check” as if something’s not right.  It’s done that before on my car and F-150, so I suspect it may have a bad thermosensor inside that kicks it’s charging function off after 5 minutes or so.  At least it got a series pair up to 8.5v before crashing this time.  I’ll just keep unplugging and plugging it back in.  It’s set on 40amp (what I’d deem “Bulk” charge) and AGM/Gel.  Should I put it on “Deep Cycle” instead?  When it gets to 13v I’ll cut it to 15 amp, then 2 for awhile, and then switch the clamps over to the other 2 house batteries in series.

Joel

[Eric Maclean Co-Admin]

Joel
It seems like it's time to break out the artillery and get rid of that dam squirrel.

Eric

[Joel Ashley]

Yeah, there was a long-dead one found under the supposed entry point the other day.  Had to clean that up and throw a tarp down before crawling under.  But today I ran off 3 of them transiting the cedar fence.  It’s become a freeway route, next to the coach, to somone’s quince tree a couple street blocks south.  I’ve been trying to discourage them around the coach with various animal repellants, because the neighbors love the damn things and feed them.  But now it’s nuke time.  If nothing else it’s trap and haul off to nither woods across the river I reckon, although there’s some that frown on even that.  Those folks haven’t spent $$$$ and precious hours dealing with the damage.

As to the charger I suspect I may just need to disassemble the case and clean its heat sink.  Since reaching over 11v it’s not crashed.  I think as it creeps closer to full charge it’s rate auto-slows, so it doesn’t overheat.  It’s hanging around 12.1-12.4v and reads 60%, so from now on it may be awhile to full charge.  I’d guess the second pair of house bats will have to wait till tomorrow, as this set will likely not be done for hours yet.  Then I’ll boost the chassis set.

Joel

[Gene Obie]

Do you think the batteries were permanently damaged at that low voltage? Would an equalizing charge help?

[Joel Ashley]

No, they are AGMs.  Not supposed to equalize I understand.  Their structure is gel mat, not lead plates that sulphur condenses onto.

[Eric Maclean Co-Admin]

Joel
The slower charge rate is easier on the batteries anyway, trying to recover them from stone dead at a fast rate of charge would likely damage them .

Eric

[Joel Ashley]

They weren't dead-dead, but just over 3v each (6v deep cycles).  And the charger has an AGM/Gel setting.  It also has a Deep Cycle setting, but not being sure which was best - given the Full Rivers are AGM deep cycles, I opted for the AGM/Gel.  The first pair finally came up to 100% yesterday on the 40amp rate, and today the second pair was just as stubborn at first.  The machine would shut down every 5 minutes or so, and I'd have to stay there to reset it.  Eventually it got up to 11.5v or so and stopped the shutdowns.  It got to 12.4v and I switched it to 15amp charge rate just to be safe and went about my business.

I think the charger senses the conditions and charges accordingly,  so it should be safe set at AGM/Gel.  It likely took a lot of power at first, so it shut itself off more readily to protect the batteries and itself.  It has a heat sink in it that's probably got decades of dust and grunge contaminating its full ability to cool the unit even with its fan.  So I'll disassemble it later and clean as necessary.  As the unit got above 12v it probably automatically lowered its power output and/or charge cycling accordingly, and I surmise that's why it quit shutting down.  It should be good to go for awhile now at 15amp, and eventually hit 100% charged.

The chassis pair are at 11.9-12v, and next on the list.

Joel

[Eric Maclean Co-Admin]

Joel sounds good it looks like your on track to getting them back up to snuff.

[Joel Ashley]

Update.
Got the inverter back from ASE.  They spent a good deal of time testing it, and discussing the results with me on the phone and over the counter.  Great guys.  Didn't charge me.  The inside and boards were pristine.  The only thing was the unit is rated at 100amps but wouldnt charge over 60.  They're not sure that's a fault, so I'll ask Magnum tomorrow;  it'll have to wait - Lee's in the hospital now for short stay epidural for her leg pain issue.

The ASE techs want me to connect  the inverter 110v leads together before remounting the inverter so to check the transfer switch.  I know that's been discussed here as a way to bypass a faulty inverter,  and I was going to do that anyway to have lights, etc. if I sent the inverter to Magnum,  something I hopefully won't need to do now..  They said the flashing 110 lights and microwave were probably caused by the inverter's internal relay trying to switch power sources... to invert or pass through.  So I need to check the transfer switch, though it's been okay and no critters were in that bay... I don't think 🤔.

Joel

[Fred Brooks]

   Joel'
Is the remote panel an RC-50?

[Joel Ashley]

I thought I wrote it down in the manuals on one of my prior researches, but can’t find it.  I remember the Magnum tech determining it was a “level 1” remote and there were now better choices if I were going to lithiums, which I ultimately didn’t.  From their manuals website and their publish dates, I figure that, yes, it must be an ME-RC50 remote, Fred.  My manual just says ME series, of which there is more than one.  With the mains off until I get the inverter back in, I can’t see the digital ID info on the remote.

Joel

[Fred Brooks]

  Thanks Joel,
The ME remote is the original series for the Magnum modified sine wave inverters. The MS series came out when the demand for pure sine wave inverters became more apparent because of current technology including lithium.
  The reason I am asking is because I have had some customers experience similar experiences. This happens primarily to those who have their coaches plugged into shore power while being stored. I am not sure if this applies to you, however I will share it for the benefit of those following this thread. It is not uncommon for those who use their inverter in transit to just leave it on because they know the coach is going to be plugged into shore power. They also know it will go into "standby" when shore power is present. Here is the problem, if shore power is interrupted or lost, the inverter comes on automatically and starts draining your house batteries. This will continue until the LBCO (low battery cut-off) threshold is reached and then turn off. The house batteries will continue to discharge because of phantom demands for 12volt power and no shore power for the converter. When the owner finally discovers this situation, the house batteries could easily be below 9 volts or lower. If shore power is restored, the inverter/charger will ignore the batteries because their voltage is too low for the charger to safely come on. Once the house batteries are charged externally above 10 volts, the charger will recognize them and go into bulk charge then absorb then float. I recommend a 30 amp stand-alone battery charger to trickle charge the house batteries slowly to restore them. I donot recommend starting the engine because the alternator will be over stressed trying to charge the house and chassis batteries under this condition. Hope this helps, Fred

[Joel Ashley]

Thank you for the input, Fred.  Yes, I had gone from leaving the battery main switches off while parked to leaving them on. 

The reasoning for that was that the solar controller had done strange things a year and a half ago when I switched from wet cells to AGM's, even after I set the controller's dip switches for AGM (sorting that out was a whole other issue).  The controller would incessantly switch from Bulk to Float to Bulk every few seconds, constantly clicking.  I finally discovered that if I left the battery mains on it wouldn't do that, probably because some parasitic house drain then kept it from switching to Float.  But I left the coach plugged in to our 30 amp RV outlet here at home to be sure the batteries stayed up, whereas for over a decade the solar system always kept the wet cell batteries up by itself while parked here by the house.  I figure that's one reason the wet cells lasted over 12 years before showing signs of failure. 

I've never had the remote automatically go to invert while unplugged.  If I wanted 110v while dry camped I deliberately pressed the invert button.  By the time I found the batteries shot this time there wasn't power enough to keep the remote lit up, so I can't say if the invert lamp might have been on.  I vaguely remember that a day or so before this last situation I may have double-checked that the remote was set for 30 amp service, or 20, so the charger wouldn't overwhelm the available current if someone was to use a couple of 10 amp appliances while in there.  It's possible I suppose that I inadvertantly got the remote set for automatic inversion, and thus your possible scenario.

This time I'd assumed that the squirrels had damaged the inverter again, simply because their presence was obvious, and they'd knocked it out last April.  But the ASE techs found no "debris" inside the inverter this time.  It was pristine, unlike its outside.  When plugged in, I'm guessing the inverter's heat attracts them atop it.  So now it sounds like the issue was the remote and/or its settings, not the inverter.  The only hitch the ASE techs noted was that the inverter had a 100amp rating printed on it, but it wouldn't charge over 50-60 amps.  I'll run that by Magnum, but what it actually charges at max may not necessarily match its stated rating.  During Bulk charge I don't remember ever seeing anything much over 40 amps., whereafter it would slowly drop the rate of charge.

With initial difficulty I got all the batteries back up 12 days or so ago.  As you note, my external charger kept shutting down at first, and I had to stay there resetting it every few minutes until it stayed on after the 10-11 volt point.  Had to do that once for each of the two serial-connected 6v house sets.  The chassis pair weren't too bad, having not drained much below 12 volts. 

I've left the house set positive cable disconnected until I get the inverter back in.  I hope to build a hardware cloth "cage" around its top in case I haven't finally sealed out the critters, but wiring around it and tight quarters will make that job difficult.  I hope to consult with a Magnum tech also, to cover the bases.  I just don't need to be crawling in and out of that bay every few months, hauling a 40lb device back and forth to its ceiling.   An updated remote may be advised, and I have been wanting to replace that Heliotrope HD30D solar controller.  Magnum said last year that they can't advise regarding another company's solar controller and any charging issue that might affect their equipment.

To others here with ME-2012 inverters, be aware that even ASE Supply has no more circuit boards.  I dodged a bullet as I thought sure I was going to have to buy at least one again, and then was told there weren't any at all now.  The supply chain situation has not eased for Magnum.  So baby your inverters, and don't leave a bay door open for even a few minutes.  The next time the rig is up in the air in service, have the wire and hose loom bay ports, along the inside of the rails, double-checked for complete foam sealing.

I appreciate that once more you've provided insight based on experience, Fred.  You're an asset we are fortunate to have.

Joel