Battery problem

[ECones]

Our battery in the RV went down this weekend and wouldn't stay up while running down the road.

I checked it once back home, and with the switch in "Store", the battery puts out about 8.5 volts whether plugged into 30 amp or not. In "Use" with the truck engine running it checks about 12.5 volts across the terminals, and with it plugged into 30 amp, and the battery switch in "Use" it reads 13 volts across the terminals. It seems to be charging.

Since it went down while driving down the road with the switch in "Use", I'm thinking the battery is done for, but I'd sure like other opinions.

Second part of the question:
If it does need a battery, this RV is only 6 months old. Should the dealer replace it under warranty?

[ECones]

burlmart wrote:


if your rig uses an intellitec BIRD

not plugged into your shore AC...with new house batt installed and maybe using thick gloves, put house disconnect toggle to STORE and go disconnect and reconnect pos batt cable checking for sparks. if sparks, batt is not totally disconnected.

When I installed the new battery I checked for a spark as I connected the cables, but I connected the negative cable last. Maybe I should have done the positive cable last, but I've just formed the habit of disconnecting negative first and connecting negative last. It helps avoid the fireworks.

At any rate, I installed the new battery at 8:00 am Tuesday and checked it. I left the switch in "Store" and checked it again Wednesday morning at 9:00 am. It had lost less than 1/10 of a volt. I think that shows that there's no appreciable draw while it's just sitting in "Store."

burlmart wrote:


if no sparks, then set house disconnect to USE, then turn off every DC device you know about (don't miss stuff liks TV batwing amplifier), and repeat sparks check. if sparks, there is still a current draw somewhere.

Unfortunately, there are two radios in the thing that can't be powered down completely. When turned off the displays still sit there displaying a clock on one and a menu on the other. I guess I could figure out what fuse operates them.

burlmart wrote:


regardless of any sparks, still in USE, plug in 30 amp shore and read house and engine batt voltages. your converter should be putting out over 13.2V measured at house batt, and if BIRD is working, its solenoid should go on and you should read same over 13.2V at engine batt (engine is off). if this happens, your AC power converter and BIRD & its solenoid are good as house is charging all things it should in USE and on shore AC

I have checked the house battery in "Use" and on shore power, and it does give me 13.2 volts. I'll check the truck next time I'm out there.

burlmart wrote:


unplug shore AC and keep house batt in USE. check engine batt voltage - really best if 12.6 or more. turn on engine and alternator should send hi 13V or even over 14V to both batts (bidirectional charging). if alternator is still only 12.5V, it may have a loose fanbelt or some inner elec malfunction.

I have checked the house with truck running and not on shore power, and it only showed about 12.5 volts. I had my wife rev the engine to about 2500 rpm, and it didn't improve. I have not checked the truck battery. I'll get that as well.

But according to my book, if the charge rate doesn't stay at 13.2 volts, the house battery stops charging until it gets to 13.2 volts for ten seconds. Since this thing seems to go down while driving and the battery in "Use", I think this may be the culprit.

burlmart wrote:


hope this helps in some way.

Absolutely, and many thanks for the effort.

I charged the battery to 13.2 volts on shore power today and turned the battery back to "Store." We're leaving tomorrow for about a three-hour trip and will have the battery in "Use" while driving to keep the rear camera and fridge going. I plan to check the house battery on arrival and see what we've lost. If we lose anything, I'll have some ammo for the dealer.

[tenbear]

I presume your Use/Store switch is the same as my battery disconnect switch and when set to store it disconnects the battery.

If you have been plugged in and the switch is set to Store, the coach battery would not be getting charged. At least that is how mine works. I believe the Store position is to prevent the battery from being being discharged by parasitic loads while sitting in storage and not plugged in. However not all battery disconnect switches actually disconnect all loads, so there may still be a small drain on the battery in Store.

If you can get your hands on a clamp-on DC ammeter you can measure the current into and out of the battery and see exactly what is going on.

[burlmart]

i last edited 4:30 CST

if your rig uses an intellitec BIRD

not plugged into your shore AC...with new house batt installed and maybe using thick gloves, put house disconnect toggle to STORE and go disconnect and reconnect pos batt cable checking for sparks. if sparks, batt is not totally disconnected.

if no sparks, then set house disconnect to USE, then turn off every DC device you know about (don't miss stuff liks TV batwing amplifier), and repeat sparks check. if sparks, there is still a current draw somewhere.

regardless of any sparks, still in USE, plug in 30 amp shore and read house and engine batt voltages. your converter should be putting out over 13.2V measured at house batt, and if BIRD is working, its solenoid should go on and you should read same over 13.2V at engine batt (engine is off). if this happens, your AC power converter and BIRD & its solenoid are good as house is charging all things it should in USE and on shore AC

unplug shore AC and keep house batt in USE. check engine batt voltage - really best if 12.6 or more. turn on engine and alternator should send hi 13V or even over 14V to both batts (bidirectional charging). if alternator is still only 12.5V, it may have a loose fanbelt or some inner elec malfunction.

hope this helps in some way.

[ECones]

burlmart wrote:
ECones

tenbear means for you to measure the engine battery while it is running - its alternator should be hi 13 to 14+V, depending on engine battery charge state.

i am suspecting something in house is drawing a lot (maybe a short), or else the BIdirectional Relay Delay unit that controls when to charge both batteries at once. this BIRD turns a solenoid (switch) on or off depending on the charge state of either and/or both the house and the engine batts (this is what your quote was discussing).

the cheap $30 solenoid that BIRD controls notoriously can get stuck and cause all sorts of strange things

Thanks for the post. That's what I've done. I checked it with the engine idling and got 12.5 or so. I need to get my wife out there to rev it to about 2000 rpm and see what it does.

If it's not putting out 13.2 while the engine's running down the road, I'm thinking that could be the problem based on what I finally found in the book and copied above.

We've discussed it this morning, and she's been in the habit of plugging it in at home and turning the battery switch to "Store". Then on the road, in order to run the fridge* and radio/rear camera, she turns the battery switch to "Use". Then at camp grounds, she turns it to "Store" again when she plugs it in. If it never gets an opportunity to charge while plugged in and can't charge while on the road, it's no wonder the radio/rear camera and fridge* gradually pulls it down.

I put a new battery in it this morning and made a note of the exact voltage. I'm going to let it sit with the switch in "Store" until tomorrow afternoon and check it again. If it's dropped, I'll know I've got a short while in "Store."

Then I plan to put in in "Use" and let it charge off the 30 amp, which I know it will. I should be able to leave Thursday morning with a full charge. We'll run it in "Use" until we reach our destination a few hours later, and before plugging in, I'll check it again.

* For clarification, the fridge is either LPG or 110 volt. When running LPG it only needs 12 volts to start.

[burlmart]

ECones

tenbear means for you to measure the engine battery while it is running - its alternator should be hi 13 to 14+V, depending on engine battery charge state.

i am suspecting something in house is drawing a lot (maybe a short), or else the BIdirectional Relay Delay unit that controls when to charge both batteries at once. this BIRD turns a solenoid (switch) on or off depending on the charge state of either and/or both the house and the engine batts (this is what your quote was discussing).

the cheap $30 solenoid that BIRD controls notoriously can get stuck and cause all sorts of strange things

[ECones]

tenbear wrote:
12.5 to 13 volts is lower than I would expect to see when being charged by the alternator or by the converter. I would expect the alternator to put out 14+ volts. The converter, depending on the converter, could be anywhere between 13.2 and 14.4 volts.

What is the voltage on the chassis battery when the RV is unplugged and the engine is running?

I didn't note the exact number, but it was about 12.5 volts.

I've been reading up on this tonight and found the following.

If the charging voltage drops below 13.2 volts for a period of 4 seconds due to low idle speed and or excessive load, the isolator will disconnect the auxiliary batteries until the voltage returns to a level of 13.2 volts for about 10 seconds.

That's certainly interesting. I checked it with the engine idling, and it was at about 12.5 volts. With the engine off and the battery switch in "Store", the battery was at about 8.5 volts.

It's most confusing. I know it was charging with the engine running, but it was well below 13.2 volts.

I've got a new battery that'll go in tomorrow. I'll just have to monitor it closely.

[tenbear]

12.5 to 13 volts is lower than I would expect to see when being charged by the alternator or by the converter. I would expect the alternator to put out 14+ volts. The converter, depending on the converter, could be anywhere between 13.2 and 14.4 volts.

What is the voltage on the chassis battery when the RV is unplugged and the engine is running?

[ECones]

Bordercollie wrote:
Look for a short or some device that is drawing a lot of current. Check battery cable connectors and ground cable connection to frame. Battery may be useable.

Thanks. I did check the connections at the battery, which were fine, but I didn't chase down the other end. At any rate, if charging voltage is 12.5 to 13 volts with the engine running or plugged into a 30 amp connection, wouldn't that rule out a bad connection?

At any rate, I took the battery to Camping World today, and they said it's "probably" a bad battery. Or, they said, we're trying to run too much stuff at once while driving down the road. But all we're running is the radio/rearview camera and the refrigerator on automatic, which is running on LPG. It needs the battery on to do that, but surely that's a minimal draw. And if it's charging at 12.5 volts while going down the road, why wouldn't that keep it up? :h

Of course, they didn't have the proper battery, so we went to another local dealer for a battery and got to talking to him. He had the same concerns I have. Why wouldn't the charging system keep it up while driving, even on a marginal battery?

I have a new battery to install tomorrow, so we'll see.

Thanks for all the suggestions.

Edit:
Oh, by the way. Yes, a short is my concern. Since we had our first problem in July that didn't occur again until Friday, I fear we have an intermittent, infrequent short that's draining the battery. I guess if the new battery goes belly-up I'll know it's not the battery. But I hope that happens before the manufacturer's warranty expires.

[Bordercollie]

Look for a short or some device that is drawing a lot of current. Check battery cable connectors and ground cable connection to frame. Battery may be useable.

[ECones]

I appreciate all the advice. I charged the battery overnight by plugging the rig into a 30 amp. I took the battery out and it's in my shop now holding 13 volts. If this were my car, I'd check for voltage drop by hitting the starter. So, I attached a small 12-volt compressor and checked for drop, and it only dropped to 12.8 volts. But maybe the compressor isn't enough of a draw to matter.

All cells were fine on water. I'm flummoxed.

[Bordercollie]

Sounds very much like the battery is dead or has shorted cells. You could have it tested. A 12 volt battery that reads 12.5 volts is nearly dead. A good battery that has been kept charged properly should read over 13 volts in storage mode or when disconnected from shore power, on shore power it should read around 13.6 volts. With engine running, and charging via the engine's alternator it should read around 14 volts. Cleaning connectors at battery of corrosion and keeping electrolyte levels above the plates with distilled water helps prolong useful life of batteries.

[harold1946]

Generally it would be covered under the battery manufacturers warranty, not the dealer.

[ECones]

Yes, I didn't make that clear. I know from the readings with the engine running or it plugged to AC with the battery switch in "Use" that I'm reading the charge voltage.

I couldn't see how it could be a problem with anything but the battery, except the first time it went down we were driving down the highway with the battery in "Use." But maybe there's a dead short in the battery.

I've left it charging, I'll disconnect it tomorrow and see if it holds, which, I expect, it won't.

And I'll pull the warranty papers and see what I can find.

Many thanks

[gbopp]

Have you ever read The 12 Volt Side of Life?

It depends on what your warranty covers if the dealer will replace the battery.

[Coach-man]

Sounds like the battery is dead, at 8.5 volts! The 12.5 volt reading is from the alternator. The battery should have some sort of warrenty, you probably wont get full refund but should get something!