Community Forums

tbethurum · 03-16-2013, 08:12 AM

My three 12 volt batteries are dead won't even run the radio but they show 13 volts on my meter and on my panel in our 2000 Winnabego Ultimate Advantage 40J I have a 1500 amp interverter and all my lights work the batteries are deep cell 2 1/2 years old rated at 105 amp hours each, they are sealed on inspection they are clean we are hooked up to 50 amp currently does anyone have a idea on my problem

Also our refer said low ac from time to time but seems to be working now.

86bigred · 03-16-2013, 08:28 AM

Battery's can show good with a volt meter but be bad. What I would do is pullthe caps fill with distilled water, next is pull the battery's, put them on a high charge for about 1 hour then put on trickle charge for a few hours. Then measure your voltage and write it down. Put an auto motive light bulb on and leav it for 24 hours, then record your voltage, if light is out when you check battery is toast,if light is on record voltage. Should not be under 12 volts. This is what we do at the shop.
One bad battery can kill the rest of the battery's. Let us know how it turns out.

Gary RVRoamer · 03-16-2013, 08:33 AM

Are we talking about the dashboard radio? That probably runs off the chassis battery rather than house. What else doesn't work? You said the lights are ok, so you do have 12v power for major things.

tbethurum · 03-16-2013, 08:35 AM

These batteries are sealed unable to add distilled water, looking at the inspection glass they look low on water

YC1 · 03-16-2013, 08:36 AM

Your meter panel is probably showing you your converter voltage. You need to put a voltmeter on the batteries directly and work from there towards the charger supply. If you see 13.5 across the batteries then unplug from shoreline and measure the voltage across the batteries again. Turn on a couple of inside light switches so there is a small load on the batteries. If the voltage across the batteries drops dramatically then you need new batteries. Dramatic to me would be below 12 volts with that light load.

tbethurum · 03-16-2013, 09:13 AM

Thanks I will make the test also my dash radio runs either on the house or chassis batteries and it works fine on the chassis batteries.

GaryKD · 03-16-2013, 10:07 AM

Hi tbethurum,
One can not tell much about coach batteries when connected to shore power. Some of this has already been posted however consider doing the following, it requires no tools, just time:
1. take a reading of the batteries connected to shore power
2. disconnect from shore power
3. take a reading (using the device or your choice, but the same device as in step #1).
4. let the coach sit overnight. There should be nothing on except the minimum you need to use.
5. In the morning, before you turn anything on, take a reading using the same device as in step #1.
6. Reconnect to shore power.

If the battery VDC dropped from the 13.5 to <12.4 overnight, with a minimal drain, gut feel says the batteries are worn out. They will not hold a charge.

The next step is to take the fully charged batteries to your favorite battery store. Ask them to do a load test. This will tell you if there is a bad cell. It may not tell you if the batteries are just worn out. When batteries just wear out, with no internal defect, they can pass the first load test.

However, if they loose considerable charge over night with minimal drain, they are worn out.

YC1 · 03-16-2013, 12:33 PM

Quote:

Originally Posted by tbethurum

These batteries are sealed unable to add distilled water, looking at the inspection glass they look low on water

I believe that "inspection glass" is actually a charge indicator. On some batteries you can cut or pull the decals off the top and then pry the covers off.

Lakeman1 · 03-16-2013, 05:30 PM

Charge and load test.

Eddie Foy · 03-16-2013, 05:45 PM

If you are on shore power your 12 V power is not coming from the batteries. 12 V batteries show 12.6V when fully charged. Check things out with a voltmeter with shore power off.

Koop · 03-16-2013, 06:24 PM

Quote:

Originally Posted by Eddie Foy

If you are on shore power your 12 V power is not coming from the batteries. 12 V batteries show 12.6V when fully charged. Check things out with a voltmeter with shore power off.

Not exactly...12V batteries read with a volt meter can show a surface charge in excess of 12.6V. This is really a meaningless test. The surface charge needs to be bled off and then a voltage reading can be made. There are much better diagnostics that can be used - in the "old days" we took specific gravity readings. Nowadays I use a Midtronics battery tester that electronically calculates the cold cranking amps available from the battery being tested.

TQ60 · 03-16-2013, 06:55 PM

Don't get me started with midtronics...

May be okay for automotive batteries...float systems not so much...

Search Battery testing on the Forum there is enough to keep you reading for days

Tony Lee · 03-16-2013, 07:48 PM

It is quite unlikely that all three batteries are toast unless they have been left discharged for several weeks.

Given that 12V DC doesn't seem to be your strong point, I'd like to suggest a simple series of tests.

We know the converter or the battery charger is working because you are reading 13V when on hookups (bit low but there could be reasons for that) and the lighting is working

Still plugged in to shore power, use the multimeter on DCV range to measure the battery voltage right on the battery terminals of each battery.

Then unplug from shore power and with nothing major switched on, measure the voltage on each battery again after waiting for an hour or so.

Let us know what the readings are.

Switch on say half your interior lights (unplugged from shore power) and repeat the voltage measurement after 30 minutes and again at 1 hour.

Switch off the lights.

Those set of readings should be enough to make a reasonable guess as to what the problem is.

tbethurum · 03-17-2013, 09:39 AM

Thanks to all on the input, I did the tests and with shore power unpluged I had 12.4 volts on each battery I turned on several lights and the voltage didn't drop at first but dropped to 12 about 15 minutes later to me it looks like my batteries are on the slide I will have them checked when we return to home port currently we are at the Salton Sea SRA State Park as Volunteers.

Maybe I will look into a different brade of battery and upgrade, don't have the height for the 6 volt will have to stay with the 3-12 volts.

Thanks to all have learned alot