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Electrical questions

As a follow-up to my furnace problem of last night, several people mentioned that it might be a low voltage issue. I'm out in the coach now, and have the Audit system connected to the television (which gives a reversed image). I can see the information in the mirror, though, and it is so I can easily read it. Just now both furnaces were running, the light over the two chairs (LED now, not the original fluorescent) and two of the three "night lights" or floor lights (one not working, probably a bulb out). When the refrigerator kicked on the inverter started screaming, the lights started flashing, and the coach battery voltage started dropping. I jumped up, pulled the plug on the refrigerator,and the screaming stopped. Voltage went right back up to where it normally is, 13.1-13.5 VDC. I then plugged the refrigerator in, got one quick beep, and all is fine. AC voltage seems to be fine. I'm hooked up to the house on 30A, and the meter in the coach is showing 115-120 VAC.

The inverter is "off" by means of the remote switch, but the main switch on the box itself is still "on." It, and the two battery chargers, are all new within the past few months. I know the house batteries are old and in need of replacement. Questions:

1. If I crawl in and turn the inverter "off" at the main switch, I know that I will shut up the screaming. Will that also stop the flashing lights?
2. Should I be seeing a somewhat higher VDC reading when only one or two furnaces are running? Both furnaces are off right at the moment, so I played with some of the light switches and was able to make the voltage drop from 13.5 to 13.4. The front furnace just came on and voltage has dropped to 13.4
3. We were gone for a few hours this afternoon, so everything was turned off except the refrigerator. Don't know if the inverter screamed when things came on or not, but all was quiet when I came back into the coach. Does that mean that maybe we will have a quiet night's sleep tonight?
4. Do I need to order some new batteries first thing in the morning? (Yes, that's a rhetorical question. I know I do.)

Re: Electrical questions

Reply #1 –
Does the inverter power the refrigerator all the time? On most inverters there is a transfer switch internal that allows shore power to pass through and then the refrigerator would be running on shore power as long as you were plugged in or on the generator. Are you sure that your converters are charging the batteries? Possibly they are only supplying power into the coach and not charging the batteries, which is what it sounds like to me. Might have a fuse between the converter and the batteries that is bad. Lots of possibilities. I hope that the coach got through the night without freezing any water lines.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Electrical questions

Reply #2 –
On day strange things started happening.  Some things stopped working some did odd things.  Found that I was running on batteries as the charger had been inadvertently tuned off.  Looked at the house voltage and it was 10.3 volts.  If you have bad batteries and your draw exceeds the rate of charge of the battery charger(s) then you will be drawing the batteries down.  Voltage will drop and things will get weird.  I think it's time for new batteries and a charging system check.

FWIW

Keith
Keith, Joyce & Smokey the Australian Cattle Dog
1995 U320 SE Extreme 40' WTBI Build # 4780, with a Honda CR-V hopefully still following behind.
Motorcade # 17030
FMCA # F422159

Re: Electrical questions

Reply #3 –
The forecast is for 40 and sunny tomorrow, so I'll crawl under with a meter and see what I can find out. I just hope that I'm not killing the new chargers by having them hooked to the old batteries.

Good question on the inverter. It has only one AC line attached to it, so I'm assuming that it provides power to that line whenever it is needed. Since I can't physically follow the line I don't know where the other end is. I thought the inverter powered all the outlets in the coach, but from what I've been able to find out that isn't the case. The old Taytronics had a switch in the kitchen that would send power to either the television or the microwave. That switch no longer does anything.

Re: Electrical questions

Reply #4 –
If I remember correctly there was also a transfer switch under the front of the bed that would pass shore power to the microwave or tv and when the inverter was turned on then it supplied the power to the microwave or the tv. Looks like you have a mystery to figure out. When you get it figured out will turn out to be simple.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Electrical questions

Reply #5 –
I am thinking bad or corroded connections; probably on the batteries themselves. The contact is good enough when low current devices are on but if the current goes up the voltage available goes down in inverse proportion. When I had my "no start" issues I went through the battery cables and connections carefully and it made a big difference.

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: Electrical questions

Reply #6 –
Looks like I'll be poking around tomorrow. I do know that the battery voltages drop fairly quickly when they don't have power to them, which is why I think they need to be replaced. I'll look for transfer switches tomorrow. Jo Ann just came out, so it must be time for bed.

Re: Electrical questions

Reply #7 –
Personally I have learned NOT to take any Rv into winter weather without every single part in the coaches electrical system in perfect vetified condition. Dangerous and potentionally damaging.

Try it in the driveway first.

Got caught at -32 long ago.  Everything good did not help btw.

Exposed tanks.....ored.  Not near the insulation that the unicoach has...

I think our 320 with aqua hot might actually survive that temp.  Windshield area would be the issue.  Would need more layers up front.  Bubble wrap?  Aero gel?

Behind every window shade.  May buy a large roll if available.  Can't fix the skin but the windows might help. 

Done ultra low temps several times.  Requires prep and correct equipement and luck and skill?

Battery heaters on a gel?  How much power  drop at minus degrees..?

Part of the adventure.

Remember barbecuing at -15F at a rest stop at June lake, ca.  Took a while to heat up the Barbie. We wanted the barbied food.  What the heck.

Not recommended btw.  We were 30-40 respectively then. it was an adventure

Bob

"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Electrical questions

Reply #8 –
I know this in no way is related to the OP but with light bulbs everywhere.

In an effort to reduce the amp draw, I've replaced the G4 and the other
lights (18" long tubes) with SMD/LEDs. 
According to the calculator, dropped the demand by a fairly good margin.
In the bath alone there are more than a few.  Add in the BR and front of the coach, put a pencil to paper and be surprised (cheap too.)  pc
S/W Houston 95" U320C SE/40' 
Build #4778  Cummins M11
Repairs & Covered RV Parking (BAO)
PPL is close..

Re: Electrical questions

Reply #9 –
All of the long fluorescent lights have been changed to LED and most of the smaller ones, too. I still have four ceiling lights and the one over the sink to do yet. Not a peep out of the inverter all night long, and furnaces came on and went off as needed.

Re: Electrical questions

Reply #10 –
I slipped and slid around the coach, crawled into the bay, and turned off the inverter. I also tried tightening the terminals on the house batteries. One moved slightly, but not much, and the others not at all. Now we'll see what happens when the refrigerator comes on. According to the two meters in here, I'm at 118 VAC and 13.2 VDC right now. Front furnace just kicked on and dropped to 13.0 VDC. Furnace is off and back to 13.2 VDC. Must be at 13.25 because it is bouncing between 13.2 and 13.3 VDC.

Re: Electrical questions

Reply #11 –
I am still wondering if the total draw when the fridge kicks in is higher than the charger is capable of keeping up with.  If so you will then be drawing the rest from the batteries.  If they are bad then you will drop down pretty quick.  Try putting the volt meter on the batteries and see what happens as you add the loads one after the other.  If you have a amp meter that can measure the load, try that.  The clamp on types are best.  All this supposes that the amp draws for all the items are within specs and wiring and connections are good.


Keith
Keith, Joyce & Smokey the Australian Cattle Dog
1995 U320 SE Extreme 40' WTBI Build # 4780, with a Honda CR-V hopefully still following behind.
Motorcade # 17030
FMCA # F422159

Re: Electrical questions

Reply #12 –
All your voltage measurements look like they were with the charger on. I wonder what they'd be with the charger off. If you do this, give it an hour or so. Anything less than about 12.5vdc would indicate a problem

You might also measure by putting the leads ON the terminals (as opposed to on the cable connectors). And also measure between the battery terminals and the cable connectors.

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: Electrical questions

Reply #13 –
I was poking around today looking for leaks and decided to take off the panel in the utility bay where the electricity connects. All 120 VAC stuff was shut down except for the refrigerator, but whatever 12 VDC stuff there is still had battery power. Sure enough, the front furnace came on a couple of times while I was working. After a bit, though, it seemed to slow down, and finally stopped. I got out a meter and checked the batteries on the terminals. Just under 10 VDC. Yes, I definitely need new batteries.

Still haven't found the leak, but at least I have this questions settled.
 

Re: Electrical questions

Reply #14 –
Just got back from getting the new 8D AGM batteries from O'Reilly's. I ordered them Thursday but couldn't get down there until today. Two strong young men brought out the new batteries, pulled the old ones out, and put the new ones in. They commented on how large and heavy the batteries were, noting that they hadn't seen any like that before. This morning I was seeing 12.6 V on the old batteries. This afternoon I saw 13.3 with the new ones. Didn't try the inverter yet, but I suspect that it will be much happier now.

Also, the audit system was showing that the propane tank was nearly full. That would be nice, but the gauge on the tank itself says it is only about 1/4 full. After we got home and the television set up, I checked to see what was what. In addition to the 13.3 v on the batteries the propane showed about 1/4 full.

Nice to have working house batteries again.

Oh yes, in case anyone is interested, the price is $449 each (plus tax).