2 Brand New Interstate 6v Deep Cycle-75%...then 0

[88keys]

Just bought 2 brand new Interstate 6v Deep Cycle "Extreme" for the Icon 24A before going deep into the bush for some fishing way up North....10 hour drive, so, the Batteries were fully charged @ "Full."

The batteries performed perfectly for two days, pinned at "Full."

The third day, the batteries registered 75% so I decided to top them up using the Onan LP Generator.

The generator itself was a real bugger to start requiring 10 tries (with the requisite pause between) before it finally turned over. However, I noticed that after running the generator for 15 minutes or so, the panel still read 75%.

So, I gave up on the generator turned it off and ran the diesel instead. Much quieter and topped up the batteries in no time. 100% full.

However, that night, the batteries completely drained. To virtually zero. Each and every day after that, the batteries had to be topped up to full, but, drained to zero at night.

Any thoughts ?

[Skip426]

Your charge indicator was showing the surface charge of the batteries.
The gauge , puts no load on so after a short time with alternator output, particularly immediately after engine shut down they will show full charge volts. After the furnace fan load for the night they were fully dead.
At 75% the charge time would have been 5>7 hours. MINIMUM.

More info;

The 12volt Side of Life (Part 1)

[pasdad1]

You need a good battery gauge that will accurately tell you what is going on
With your batteries .

This is the one to get.


http://www.bogartengineering.com/sit...0low%20res.pdf

[88keys]

We didn't run anything at all on the batteries overnight, but thanks for the link...I'm going to give it a read now.
What I do not understand is how the batteries went from 75% to 0 with nothing running on them overnight.

[Mr_D]

They weren't at 75%, you were reading the surface charge only. With our 8.0KW gen it takes at least 2 hours to bring our four U-2200's back to about 80%, which is not fully charged but easily gets us through the night. To get that last 20% would take another 2 to 3 hours of gen run time.

[Arch Hoagland]

Buy a hydrometer, about $10, and check each cell to determine if the batteries are good. One bad cell can draw down both batteries.

Using a Hydrometer - E-Z-GO Product Training Manual

[Skip426]

Originally Posted by 88keys

We didn't run anything at all on the batteries overnight, but thanks for the link...I'm going to give it a read now.
What I do not understand is how the batteries went from 75% to 0 with nothing running on them overnight.

With the batteries showing full charge for 2 days then 75%, then down to, 0 overnight with no load. Either your battery monitor is no good, or one of the batteries has issues. Fully charge the batteries and have them load tested, and consider a different monitor.

BTW; it would be helpful to know more about your RV, year make and model.

[88keys]

Hi Skip :
Yes, thanks for the info on Gen. charge times.
It's an '09 Fleetwood Icon 24A....Dodge/Merc Diesel.

[Skip426]

Originally Posted by 88keys

Hi Skip :
Yes, thanks for the info on Gen. charge times.
It's an '09 Fleetwood Icon 24A....Dodge/Merc Diesel.

If you go to the " Edit Signature " on the left side of your " User CP" page you can type in the info, on your coach, then click save at the bottom of the page, it will automatically appear below your posts , as mine does below this one. Saves typing it in every time, you post.

[88keys]

Originally Posted by Skip426

If you go to the " Edit Signature " on the left side of your " User CP" page you can type in the info, on your coach, then click save at the bottom of the page, it will automatically appear below your posts , as mine does below this one. Saves typing it in every time, you post.

Done !

[wa8yxm]

To fully charge a set of Flooded wet cells from 75% to full with the PROPER converter (30 percent of the c/20 rating of the batteries) That is a 70 amp converter Would take:... About an hour to find 90% then 3-4 hours for the last 10%.

Smaller converter add to the first step

But you are looking at 4-5 hours generator run time to fully charge IF you have a 60-70 amp converter if you only have a 45-50. will take longer.

Oh and this also assumes a 3-stage converter such as the Progressive Dynamics 9200.... IF you have a single stage Parallex.. Longer still.

[simonsrf]

Why not just run the generator when you need power?..like at night while cooking and watching TV?....and allow the batteries to charge during that time?

[88keys]

Update....
We drove home from our trip...about 10 hours drive. The batteries charged up to 100% and, again, stayed 100 % charged for two days and then dropped to 75% with nothing at all running on them other than the "Aux ON."
...will need to check for a parasitic drain, amongst other things....will keep you posted....interesting electrical gremlins.

[RV Norm]

Check to ensure everything was connected correctly after replacing them. I have some items that pull directly off the batteries lugs and if they were wired to only 6vdc of the series it would kill one of the batteries pretty quick