All Batteries discharged

[Roadking52]

I have had two instances where my '02 Horizon had battery power when I went to bed while dry camping, and the next morning both coach and chassis batteries were so low that I couldn't crank the generator or engine. Both appeared to have the same voltage, about 9.5 volts. Nothing was left on during the night except 2 small footlights. Both times the weather was cold, well for S. Ga., but only in the 40's or so.

Tieing the batteries together would still not get enough juice to crank the generator. Brought in a pickup truck and charged the house batteries a few minutes and the generator cranked. Once I had voltage up on the house bateries, I tied the batteries and was able to crank the engine.

I know there is an isolation solenoid that ties batteries so the engine can charge the house batteries. Does it work in the other direction? Has anyone experienced a solenoid failure that kept the batteries tied together? When I check voltages at the power panel they are rarely the same, so if that is happening it must be intermittent.

Anyone have any ideas? This has become a big enough bother that I am installing a EC30W autostart to keep an eye on battery voltage.

[Ottawa]

Not an expert, but if the batteries are fully charged and discharge to that level overnight, you have a serious battery drain. It sounds as if the batteries are connected. You could completely disconnect the chassis battery and sees if it maintains it's charge, and then do the same for the house batteries. This would prove whether the batteries can hold a charge.

[steelheadbluesman]

The first thing I would do, is check all the cells in both batteries, because a bad cell in either system will draw the other down, and the system will have a hard time holding a charge. If one or more cells are bad, you should IMHO consider replacing all. You mention that the weather was cold and you were dry camping... did you run the LP furnace? Because if your batteries are weak, and without shore power charging through the converter, the furnace fans running throughout the night will bring the batteries down, especially if they have a problem holding charge. If the batteries are good, I would look for drains (like corroded terminals/posts), and then I would be looking at the charging systems for both the auto and house batts. I know you'll get some good responses from others, best of luck.

[Roadking52]

Here's more information that I should have included in the first post. All batteries are relatively (less than a year old) new, I have looked at the connections closely and they all appear to be good. The heater was on the first time this happened, but not the last (extra blanket). The generator was run immediately before going to bed, but possibly not long enough to bring the house batteries to full charge.

I agree, to drop 5 batteries to full discharge overnight would take a load that should make something glow in the dark. I will re-examine the battery connections, and check the water in all.

I worked last night installing an outlet for the EC30W I will be installing, and pulled the shore power and cut off the feed to the inverter. After running flourescent lights in the galley and lounge for several hours on battery alone the voltage was still 11.5+ when I reconnected everything. The inverter (1500w Xantrex) did go to bulk charge immediately, drawing 15 amps of shorepower. I didn't stay around to see how long it stayed in the bulk mode.

Thanks for all the ideas, I will follow up on them if the monsoons abate a bit.

[Roadking52]

Results of more testing. While installing a Trickle Start I had to disconnect all my batteries to keep from shorting something with a wrench. I measured the voltage of the disconnected start batteries and found 10.5 V. After reconnecting and testing connections they were still reading 10.5 V. Surprisingly, they crank the engine reasonably well at that voltage, although they may not be doing the starter a big favor, as I am sure the amp load is really kicked up by the low voltage. Anyway I am leaning toward a bad starting battery. Time to call the dealer that installed the batteries and see how good the warranty is on them.

[dirko]

Hi Ho: The question is what the voltage is when the batteries are fully charged? Maybe the charge system isn't doing it's job? What voltage do you read when plugged in to shore power? It's pretty easy to do a load test after charging the batteries to determine if the batteries are bad.

Dirk

[Roadking]

An easy test for your charging systems (either engine alternator and Xantrex charger) is a voltage test. With your engine running you should measure at least 13.5 volts at your chassis batteries. During charge a reading of 14.2 volts is good. Likewise with your Xantrex running (shore power or gen power) once batteries are charged you should measure about 13.2 to 13.7 volts on your coach batteries. During heavy charge (stage one and two) you should measure over 14 volts.

On my rig with the Xantrex running and batteries fully charged (3rd stage of charge) the internal voltmeter indicates 13.4 volts on the coach batteries and 13.2 volts on the chassis batteries. During stage two charge the battery volts is in the 13.7 to 14.2 volts, depending on charge state.

With engine running the voltmeter indicates about 13.7 volts when batteries are charged.

Once batteries are charged and engine if OFF and XANTREX is OFF both batteries indicate 12.6 volts which is a full charge. My coach batteries are old, and weak, so with minimal usage my battery voltage drops quickly (a couple of hours) to 12 volts. While just setting I know the chassis batteries will maintain a solid 12.5volt reading for several days, however, I have to charge my coach batteries daily so the chassis batteries also get charged.

[Roadking52]

Well, 2 new chassis batteries later and a Trickle Start addition, I think I have a handle on the situation. It turns out the starting batteries were not as new as I thought, and apparently had a bad cell, as they wanted to dive to 10.5 volts every chance they got. Time will tell. Now if only my back will quit hurting from lugging those batteries.

[JayLodge]

Not forgetting your concern that both battery sets were somehow still connected together........... I just bought a 2006 Tour and have noticed that sometimes I attempt to hit the aux disconnect switch, and if I've left a light on, it will dim, but not go out completely. I started disconnecting the engine batteries in storage (Michigan winter). Recently noticed that when I turned my AUX on, the steps worked (they're supposed to be connected to the ENGINE batteries, like the jacks and slides.

[MARANATHA]

Hi there,
I hope your problem is solved. But if your new chassis batt keep on having low voltage say 12v in the morning, it means your house batt are still drawing current from your chassis batt which should not be the case. Check your batt isolator condition, very important. Batt isolator isolates your chassis batt from your house batt while "trick L start" charges your chassis batt from your house batt, that is if you are plugged from the shore and your house batt volt is above 13V. Just want to help.

[codgerbill]

I dont hae a weesel engine on my coach but rather a gas powered ford. I had a battery problem that turned out to be a problem with the starter. It sucked down the battery without the starter being set in motion.The chasis battery had depleted so badly that it had to be replaced. I had purchased an Interstate battery for the chasis about 10 months prior to the problem. I had charged it at home and it wasnt really holding the charge. When I brought the battery back to the lot where I store the coach the Interstate battery guy just happened to be there. He exchanged the battery for a new on on the spot and it didnt matter that the problem was created by my starter motor failure. The warrenty calls for free replacement within one year and (Ithink) a pro rateing after that.