Community Forums

arnold931 · 10-21-2019, 05:35 PM

I have a 2008 Fleetwood Southwind. As with most motorhomes (I assume) I have one 12 volt battery in the engine compartment and two 6-volt batteries daisy-chained for the coach. The 6-volt batteries were new this spring. We are going to Florida in January so I am leaving the batteries in the RV until we get back to Iowa in February. I am going out once a week and starting the engine for 15-20 minutes to make sure all the batteries stay charged. The last few times the 6-volts have been dead. My Aux indicator shows blank while the Main shows 12-13 volts. The interior lights won't turn on. After running the engine for a few minutes, I then have voltage in the 6-volts. Is it possible the 6-volts have gone bad?

TriMoot · 10-21-2019, 05:41 PM

Quote:

Originally Posted by arnold931

I have a 2008 Fleetwood Southwind. As with most motorhomes (I assume) I have one 12 volt battery in the engine compartment and two 6-volt batteries daisy-chained for the coach. The 6-volt batteries were new this spring. We are going to Florida in January so I am leaving the batteries in the RV until we get back to Iowa in February. I am going out once a week and starting the engine for 15-20 minutes to make sure all the batteries stay charged. The last few times the 6-volts have been dead. My Aux indicator shows blank while the Main shows 12-13 volts. The interior lights won't turn on. After running the engine for a few minutes, I then have voltage in the 6-volts. Is it possible the 6-volts have gone bad?

Curious..do you have the RV plugged into shore power? If so, do you have it in the "storage" mode or just normal? Meaning, is there power for the lights and microwave inside or no?

If it's plugged in and there's power inside your converter should be charging the batteries.

twinboat · 10-21-2019, 05:48 PM

If they went dead, in freezing temps, they will freeze and the ice will short out the internal plates.

You would have been better off disconnecting the house batteries during storage. But that would be after having them fully charged.

If not frozen, then you will need to put a charger on them for 8 hours or more to recharge them. Only then can you test them to see if they are usable.

arnold931 · 10-21-2019, 05:49 PM

No. There is no "outside" electricity. I wonder if I need to pull the 6-volts and take them back to store and have them tested.

Shadowcatche · 10-21-2019, 05:50 PM

Fifteen or twenty minutes is not any where near enough to bring them even close to 100% SOC (state of charge). At this point they are probably totally un-salvageable.
Take the batteries out and take them to some place that can try and charge.

arnold931 · 10-21-2019, 05:51 PM

Also, it hasn't been really cold yet. The worse has been upper 30's overnight.

chindog · 10-21-2019, 07:06 PM

You can get a chemical cell tester pretty cheap, and check the specific gravity of the cells after you have fully charged the batteries. (bulb type tester with floating balls, or a floating needle that points to a reading). That can give you an indication if you have a bad cell in them.

GMoore · 10-21-2019, 07:41 PM

Start your generator and charge the house batteries. Start off with two hours.What is the voltage during charging?
when you are camping when do you charge the house batteries?

HopsBrewster · 10-21-2019, 07:58 PM

10 or 15 minutes won't charge those high amperage batteries. They need a good 24 hours or more on a good charger when they're that low. But you need to begin by checking the condition of the electrolyte. At the very least, look at the water level and top it off with distilled water if needed, to the top of the plates.

Also, what power drains do you have in the coach? New batts in good condition shouldn't drain like that unless something is drawing power from them. When you're storing the RV, disconnect the house batts and turn off any power drain. Or keep a maintenance trickle charger on them.

Sonic · 10-21-2019, 09:51 PM

I would plug it into shore power (hopefully you have an extension cord that can reach to an outlet) and as Twinboat said, remove any loads and let the batteries charge overnight. Once the charger is turned off, remove let the batteries settle for at least 4 hours, then measure the voltage at the terminals where you should see around 12.7 volts.
Then as another poster indicated, test the specific gravity of each cell with a hydrometer to make sure they're all good and consistent with each other.
Once you have this baseline, you can measure voltage on an hourly or other consistent basis to see how fast they're losing their charge.
If you suspect a current drain coming from the motorhome, a fairly inexpensive digital AC/DC clamp meter can be useful to measure the current being drawn from the inverter as well as the 12 volt side of the house without having to disconnect any wires.
I use this one:
https://www.amazon.com/UT210D-Digita...42515090&psc=1

Let us know what you find.

450Donn · 10-21-2019, 09:57 PM

15 minutes is a total waste of your time. To charge the batteries it need to be run for an hour or so at the minimum.
Instead of putting all that moisture in your engine why dont you have your coach plugged in? This will charge the house batteries and a simple trickle charger for the chassis battery will keep it fully charged. I left all my RVs plugged in 24/7 at home. Check the batteries water level monthly.

Roy1 · 10-21-2019, 11:04 PM

Using the engine alternator to charge dead batteries is hard on the alternator. Best to use the converter or a battery charger.

followingsea · 10-21-2019, 11:49 PM

Quote:

Originally Posted by arnold931

Is it possible the 6-volts have gone bad?

Not only possible but probable. It is easy to check with a hydrometer and load test.

More likely your batteries are just run down. I had to leave my coach with 4 batteries parked because of a family emergency. With the frig on propane, batteries were dead in a week.

Rocketman3 · 10-22-2019, 12:26 AM

Another item that can be very useful is a battery monitor - like the Victron BMK-712. You install a shunt on the negative wire that all your power goes through. Then you can see exactly what is happening to those batteries.

A solar panel or two can be very useful to keep batteries charged when not using the rig