Why did my coach batteries die?

[mtn_wife_530]

On a recent boondock trip,I started with fully charged coach batteries. The first nigh my CO2 detector goes off.The windows are already open, I shut down the LPG.The next morning,aux batteries are completely dead.I have to use the engine to get enough power to start the gen. Ran it 4hrs,but an hour later they were dead. Charged them again, but hit the cut off switch. Couple hours later, guess what, DEAD! Anyone have any ideas?Please

[mtn_wife_530]

I've even started turning off the aux breaker, thought that would prevent any draw,they still went dead.

[Harvey51]

RoyB wrote:
When a battery is fully charged it will read 12.6-7 Volts DC just sitting there. When I get back from a camping trip I like to read the battery terminals when I shut down everything and then the next morning Ilike to read the terminals again after it sits over night. If they are down to 12.2 or lower after just sitting there in place for 8-10 hours then this is indeed a red flag.

Sorry to beat this to death but I wrecked my first pair of batteries misunderstanding this good advice. The trouble with the voltage method of measuring state of charge is that the voltage is meaningless until the 8-10 hours after all charging has ceased. 12.0 or less means battery life has been damaged. You don't get to know if your furnace has damaged your batteries until the next day. A battery monitor indicating amp-hours or per cent of full charge gives a very useful indication all the time.

A solar panel, even a 100 watt one, is very helpful for keeping the batteries close to the 100 per cent charge that prolongs their lifetime.

[mtn_wife_530]

OK,I bit the bullet, drove the 30 miles into town, they said both coach batteries were bad,(somehow I expected that) They only had 1 6v,so I switched to 2 12v deep cycle Marine.I'll keep my fingers crossed. P.S. Maintenance Free!

[wolfe10]

mtn wife 530 wrote:
Quick, can anyone send me a diagram to connect 2 12v coach batteries from 26ers?

Don't know what "from 26ers" means, but to connect two 12 VDC batteries in a 12 VDC RV:

Positive lead from coach to positive post of battery #1. Positive post of battery #1 to positive post of battery #2.

Negative post of battery #1 to negative post of battery #2. Ground/negative cable from RV to negative post of battery #2.

[mtn_wife_530]

Quick, can anyone send me a diagram to connect 2 12v coach batteries from 26ers?

[ksg5000]

...delete

[mtn_wife_530]

Thanks for the suggestions, I'll be able to check those things tomorrow. I bought distilled water and picked up a good amp meter today, now I just need to read the book, ( sorry guys,I tend to read the book that come with new toys,kind of like directions, lol)

[erniee]

buy a battery load tester- around 50 bucks- take the cables off- if the tester shows low on one battery, that will drain charge from the others

[mtn_wife_530]

I had removed the face plate from the stereo, double checked things like the mirror heaters, all basement lights, everything. The only thing that seemed to use ANY power was the water pump, which is why I decided to use the breaker disconnect
But the pump still kicked on,. But I had no lights,nothing else worked, not even the indicators panel.

[ksg5000]

Have you batteries load tested - when batteries start to die they tend to look fine using volt meter but when you place a load on them they quickly loose a charge. Most tire/auto parts places will load test for free.

If batteries need replacing give some thought to upgrading your converter - for about $200 you can purchase a new converter like a Progressive Dynamics which will charge your batteries quicker and will help them last longer. Lastly - consider purchasing an inexpensive Trik L Start which will allow charging of your chassis battery when your connected to shore power - popular product for many RVers.

Hope this helps.

[RoyB]

It is most likely your 94 model RV is not equipped with a modern smart mode converter/charger unit. Your converter/charger may a unit that is only producing 13.6VDC when you are plugged into shore power or generator and this is the DC voltage that is used to keep your RV batteries charged.

13.6VDC is known to boil out battery fluids if left ON for long periods of times. One must start a battery maintenance program to at a minimum start checking the battery fluids and not ever let them get drained below the battery core tops.

When the fluids get below the cores inside the batteries then this allows the cores to start building up crud and eventually creates a short circuit. When that happens it is usually game over for the batteries...

Unless you just have lots of money and like to keep buying batteries everytime you take your old rig out for trips this is going to continue to happen.

The batteries is the center function of the 12 Power Distribution Center and one needs to learn all they can on how the battery system works and what to watch for to maintain the great performance. You just can't install new batteries and thats all you do from then on...

I measure my battery terminals with a hand held multimeter every time I walk around the unit. When a battery is fully charged it will read 12.6-7 Volts DC just sitting there. When I get back from a camping trip I like to read the battery terminals when I shut down everything and then the next morning Ilike to read the terminals again after it sits over night. If they are down to 12.2 or lower after just sitting there in place for 8-10 hours then this is indeed a red flag.

A multimeter can be picked up at WALMART-LOWES- or any number of auto parts stores for less than $20. Harbor Freight used to give you one free when you made purchases there...

Then I will engage shore power or generator and read the battery terminals again with my multimeter and it should now be reading 13.6VDC or what ever mode my converter/charger unit is in at the the time. This tells me my charging is working fine and the battery cable path and connections is all connected properly with no tripped DC circuit breaker if equipped or blown in line fuses. When looking around the battery terminals it will be very noticeable to see when they have been boiling out fluids... When they boiling out is actually occurring you may smell something like rotten eggs and your battery case case may also be warm to hot.

I check my battery fluids about every two weeks now but never find them low any more since I upgraded my converter/charger unit to a modern three stage smart mode charging unit. This almost takes care of your batteries for you...

My trailer came setup with four 85AH 12V Interstate batteries in 2008 and I lost one right away due to my inferior single mode converter/charger unit. Boiled out the fluids in one and I didn't catch it. Then this battery ended up with a shorted cell inside it and would not hold a charge. I have been using the remaining three 85AH 12V Batteries every since doing just great. These batteries are just failing and need replaced... Pretty good for being eight years old I would say...

Just things I do here in the battery department on a regular basis with my pride and joy Camper unit.

I usually don't respond to CLASS A forums comments as all of this is way above my $$$ class. But you did ask "Why did my coach batteries die?"

Hope some of the comments help...

Roy Ken

[dougrainer]

Odds are the Battery acid/water is low. Doublecheck the level. Doug

[rgatijnet1]

If you have a radio, as well as the CO detectors, you will always have SOME draw from your batteries. This is to keep the channel memory intact and the CO detector functioning. There are other things that may also be causing a power draw such as leaving the Inverter/charger/converter on full time, lights in the basement compartments, mirror heat, etc. Check to make sure that all 12 volt items are turned off and you will probably find something that you left in the on position.

[Tom_Barb]

mtn wife 530 wrote:
OK,I'll try that. Their only 2 years old and this was only the second dry trip.

If the batteries check good, try this:
after re-installing the batteries, leave the positive cable off, mount a amp meter between the positive post and the positive cable and see what the load is. there is either some thing left on providing a load or a high resistance short.
When you don't have a good meter, mount a 12 volt bulb between the battery and the cable. a bright bulb = a big load. dim light small load.