Battery woes, I should know better!

Emcemv · February 04, 2014, 04:46:41 PM

I went to start the bus over the weekend since it was in the 40's here finally! Plugged the block heater in for several hours, turned the key and it barely turned over. Battery voltage was about 12.65v indicating about 75% charge. During cranking, voltage dropped way low, less than 9 volts measured at the battery. Wondering if cranking current was high, I felt all the cables and terminals and didn't find any that were warm. It was looking like the batteries were just not putting out the current. The batteries are DeKa 908D, 2 12v monsters rated at something like 1200 CCA in series for 24v starting system. I was told that these were new batteries when I bought the bus 2 years ago and they look new. After discharging the batteries by trying to crank it over several times and recharging them, they finally had enough charge to start the engine and everything ran fine but I have an obvious battery problem. I called Deka and after much investigation, my batteries were never marked with a date code, nothing punched out and no additional date code label to be found. So there is no way to tell how old they are. Of course they are out of warranty

I have been charging them from time to time over the winter but I'm obviously doing it wrong, the batteries are right now sitting at 12.5v and 12.6 volts, which is far from a full charge.

These babies cost about $230 a piece and I'm wondering if I really need the 908D units, is anyone running smaller batteries (these are just for cranking).

I went in the technical archives and found a lot of good information there. I bought a BatteryMINDER today, this unit maintains the battery when not in use and also de-sulphates the battery using high frequency, not high voltage. I'm going to give this a try to see if I can save these batteries.

I've seen many posts from you all about using a good battery maintainer and even after all that, I have to learn the hard way.....feeling pretty stupid right now and I'll feel it in my wallet this spring!

I found my house AGM batteries sitting at 13.2v , my Genny battery is the worst at 12.2v
I need to get the charger on them tonight and cycle that BatteryMINDER through all of these.

Bruce

Lin · February 04, 2014, 04:54:18 PM

I was very loyal to my 8d's but this past summer I changed them out for group 31's. Others had said they found this switch adequate. So far, I have not noticed any difference in cranking. However, we live in Southern CA and don't have to deal with extreme cold.

RJ · February 04, 2014, 08:19:14 PM

Bruce -

For best results on your start battery charging, disconnect all the cables and charge each individually.

Be sure to label which cable goes where, so you don't let the smoke out when you reconnect them.

Check the water level, too!

FWIW & HTH. . .

Emcemv · February 05, 2014, 05:49:53 AM

Thanks guys, water level is good, never had to add water to these in the last 2 years. I learned to disconnect them all over the winter so I have no phantom loads. Very disappointed in the batteries, I'm sure it was "operator error" .........I learned my lesson, I just hope I can de-sulphate them and bring them back for at least another year.

When I was talking with Deka, they mentioned measuring the specific gravity, what do I need to do that?

Bruce

luvrbus · February 05, 2014, 05:54:21 AM

I saw a nice MCI 9 at the Riverside RV park from Canada that use 3 -8 volt for starting and had 6-8 volts for house batteries told they 10 years old and he was expecting another 3 years from the setup fwiw

Jeremy · February 05, 2014, 06:16:39 AM

Quote from: Emcemv on February 05, 2014, 05:49:53 AM
..they mentioned measuring the specific gravity, what do I need to do that?

Bruce

A hydrometer - cheaply available from auto stores etc

Jeremy

Emcemv · February 05, 2014, 02:16:37 PM

Going to get the the hydrometer,thanks Jeremy. I know I didn't take care of them properly, going to treat them like gold now! House batteries seem fine, Genny battery needs charging....tonight. It's the 8D's that I'm trying to save, they are over $200 each.

Clifford, I think 10 years for a battery is fantastic, I would be happy with half that considering the temperature extremes that we have here in the northeast.

Bruce

Taibob · February 05, 2014, 03:02:06 PM

Once upon a time, long, long ago, I recall my dad putting Epsom salts and water into a battery that had expired. He said something about de-sulphating it. He put it on the charger for a while and it appeared to be almost as good as new. Lasted until he sold the car many moons later.

What say y'all. Was it hocus-pocus or is it something that works.

Bob

luvrbus · February 05, 2014, 03:44:22 PM

I never got 10 years from a battery but some say they do lol but I did get 8 years before

wg4t50 · February 05, 2014, 05:11:45 PM

When we can control the battery voltage, we get 10 years of service, meaning keep battery floating between 12.9 and 12.95 VDC, have had a single 8D on a Waukesha 817 CID LP Gas engine go 10 years, not real unusual.
Today with the automatic chargers, keeping batteries about 13.35 VDC, they have a shorter life, about 3 years we have to replace them in our generator business, besides they consume water and make corrosion.
Yuk !
Dave M

opus · February 05, 2014, 08:01:06 PM

Do you throw the master disconnect switch when the bus is sitting unused?

zubzub · February 06, 2014, 03:46:39 AM

fwiw i can start my 671 on a cold fall day with one 31. pretty sure a couple of 31s will do ya. also batteries can be weird...i have thought that i had bad bats that after a few charging cycles really behaved well. as you have an on board gen and house bats you will always be able to start somehow so no rush on new batts. finally a poor starter will drag down a decent bat really fast. keep it simple.

luvrbus · February 06, 2014, 03:56:58 AM

One will pay the price with the 39 or 42 Delco starter without enough volts and amps they don't like it and they don't care for too many CCA

Len Silva · February 06, 2014, 05:10:57 AM

Quote from: Emcemv on February 05, 2014, 02:16:37 PM
Going to get the the hydrometer,thanks Jeremy. I know I didn't take care of them properly, going to treat them like gold now! House batteries seem fine, Genny battery needs charging....tonight. It's the 8D's that I'm trying to save, they are over $200 each.

Clifford, I think 10 years for a battery is fantastic, I would be happy with half that considering the temperature extremes that we have here in the northeast.

Bruce

If you are going to use a hydrometer, get a good one with a thermometer and temperature compensation scale. Don't waste your money on the floating balls type.

gus · February 06, 2014, 01:58:02 PM

Cold batts have nowhere near the power of warmer ones. Cold oil is like molasses.

Get a small smart charger for each batt and leave them on all the time - and a cheap load tester ($25 at WM).

Float chargers are a risk, many boil out all the water. Been there.

Or a good 3-4 stage batt charging converter/inverter.

You can't check batt condition with a volt meter. A hydrometer is of little use unless you really want to know which cell is dead!! A load tester will tell you if the batt is too weak, all you really want to know.

4D or Gp 31 are fully adequate for starting except in extreme cold. Those monster 8Ds are just not worth the trouble and their warranties are not good. I have two 4Ds but will switch to 31s when they are dead. The only reason these buses had huge batts was to support the AC systems.

Admittedly this has been a colder winter but a block heater will solve starting problems anywhere.