Odd house battery problem

[Pusherpilot]

I know I saw this discussed somewhere before but can't remember where. Since I replaced our house batts back in july the charge/discharge patterns have changed completely. While running down the roadthe batts havn't discharged more than 20% even with the new Samsung refer running. This is good. The strange thing that is happening now is the batts will show 100% charge while we're stopped and on shore power then out of the blue drop to lesser value, lately around 66% then slowly build back up to 100%. This happens on a daily basis while on shore power. We were on 30a for a couple of day and it did it but now were're on 50a nad it's still doing it. Who remembers what it is?
Thanks,
Ron

[OneRVer]

I have been experiencing kind of the same problem so if you do not mind I would like to follow your post.

[tomwalt]

Some things to think about:
Do you have a battery minder that could be cycling you batteries into a maintenance mode? I have not seen what you describe, my battery minder just goes from 13.2 to 14.2V every other day or so.
I assume that you are parked, so a loose ground/wire wouldn't show up this way but a corroded terminal might - but with new batteries in July i would assume the terminals are clean.
Your 2004 and 1997 units might just need a good cleaning of the 12V terminals all the way back to the fuse box/converter. If the batteries look good, take a look at the generator connections. Look for corroded wires at the connections as well.

[wa8yxm]

Sounds like a circuit breaker (Self resetting type) Cycling.. You have a basic overload on the batteries when on shore power.. Alternative.. And this, depending on your wiring, is in fact SUSPECT #1 with a voltmeter.

If your inverter is also your converer (In-Line type inverter) like my Prosine 2.0 then it MAY (or may not, again like my Prosine) monitor the input (Shore side) voltage and waveform.

IF the shore power is going either too low (Voltage or less likely frequency) or too high (Same) of if there is suddenly a whole lot of noise on the line (Someone running an arc welder nearby perhaps) the inverter may be switching to INVERTER MODE to protect your sensitive loads. When it does this it stops charging and starts discharging.

This 100% fits what you are seeing unless it's like 10 seconds high 10 seconds low or 10 minutes high 30 seconds low (Steady cycle, I"m grabbing numbers out of thin air) If it's random.. You have bad shore power and the inverter is working as designed.

[Robi.1014]

Ron,
Sounds to me that (while on shore power) the Inverter is not keeping the batteries "float charged" ....but none-the-less is still sensing the status of the batteries...hence when the batts get quite low (down to 66% as you write), the Inverter finally begins the charging process (that you have observed on a somewhat 24-hour cycle).

Because you recently installed new batts, my first thought is "what changed?" One "oops" might be that the Inverter's battery-sensing-temperature-probe didn't get re-attached as it had been attached with the old batteries.

[Pusherpilot]

Thanks for all the great suggestions.
We've had the RV on nine shore power hookups 2 of which were 30a one hookup was the 50a at our cabin in Mo. It has done it on all of them so far. The temp sensors are seculely fastened to the batts by rtv. I just went thru the settings on the inverter/converter (the modified sine wave variety) and found them to be the same as when I had the old batts. The batts are apparently being charged properly and have used no water since installation. I'll start checking the power paths. Would still like to know what's casing it.
Ron

[wa8yxm]

Stick a monitor on a NON INVERTER POWERED outlet and keep an eye on the park voltage.

NOTE: My inverter tells me what this is under any conditions, and it also has a "log" of why it did what it did.. That said.. Mine and yours are different inverters.

[Pusherpilot]

I do have a recording voltmeter but it's at the cabin, not on the road with me. I agree that the most logical reason for the condition is the shore power failing for a period of time and the coach running on inverter. The only thing I can think of to do is put an electric clock on the now unused shore power only outlet in the refer compartment and sycronize it with my battery powered Swiss Army watch and check for a difference occasionally. Now to find a plug in clock........
Ron

["007"]

Haven't seen any mention of the ground side of batteries or converter- inverter.
All grounds to chassis are tight and clean plus your batteries are the same type the old ones were or were they changed to AGM's possibly.

[Pusherpilot]

It happened again. This time there was a definate interruption of shore power. I don't think the power off the pedestal was interrupted but the system did go to inverter power for a period of time. Now I think I'll turn the inverter off so when it happens again I'll know immediatly instead of when I notice the RC7 GS Xantrex panel lites indicating that the system is charging. The coach has an Intellitec 50a smart EMS if that means anything.
Ron

[Pusherpilot]

Quote:

Originally Posted by Pusherpilot It happened again. This time there was a definate interruption of shore power. I don't think the power off the pedestal was interrupted but the system did go to inverter power for a period of time. Now I think I'll turn the inverter off so when it happens again I'll know immediatly instead of when I notice the RC7 GS Xantrex panel lites indicating that the system is charging. The coach has an Intellitec 50a smart EMS if that means anything. Ron

Well guys, I finally resolved this old problem. We boondocked in Quartzsite for 4 days and the inability of the house batts to take a charge was evident after the first day. We ran the gen for 4-5 hrs ith no positive charging going on and the hydrometer showed flat batts.
When we got back to Corona, Ca where we bought the GC2 batts from Sams (Sept 30 2011) I exchanged them under their 1 year free exchange guarantee. The new batts immediatly started charging at 23a 14.5vdc and went to float charge after 5 hrs. The hydrometer shows all bats fully charged.
End of problem of erratic inverter behaviour too.
Ron