How do I know if my start batteries are frozen?

[belfert]

I tried to start my bus the other day, but the batteries were dead.  The volt gauge was showing just under 20 volts.

Temps have been very cold here lately.  (It was zero F this morning.)  Before I charge the batteries, how do I know if they are frozen?  I have no idea how the batteries got that low, but I think the batteries really should be replaced.  They got completely discharged several times this summer due to stupid moves on my part.

Also, any suggestions on where to get a 24 volt charger at a decent price?  I've been disconnecting and charging each battery seperately but that is a pain.  JD of C&J Bus Repair says I won't hurt the DDEC or WTEC if I charge the whole bank at 24 volts when it is still connected.  (I'm a little bit gun shy on charging at 24 volts with everything connected because I have heard of people frying DDECs by doing it wrong.)

Brian Elfert

[boogiethecat]

Don't know about the frozen parts but you can simply put two 12 volt chargers in series... ie hook one to battery #1 and the other to battery #2, without having to disconnect anything, and they'll work fine.  Best if both chargers are the same model and used at the same settings to keep things balanced... so instead of buying a 24 volt charger, just buy one more of what you already have, and they'll be useful for other things as well...
G

[Nick Badame Refrig/ACC]

Brian,

If you suspect that they are frozen... Don't try and charge them.. Defrost them first.

If they were very low on charge, that would be what caused them to freeze.

Nick-

[Buffalo SpaceShip]

Your batts are shot if they're under 10v each in the cold. Seems a phantom load is somewhere. Do you have a disconnect? Or maybe they're just abused. At any rate, Sam's has new 8D's for about $110 (I bought two there last month). If you go with Grp24's, you have lots of options.

If you want to float your new set, you can do as Gary suggests with two 12v chargers, or get a 24v charger... or parallel your house bank float with a 24v inverter/ charger if you go that route. You can find "plug and forget" 24v three-stage chargers at www.batterystuff.com for around $50 and put them anywhere in your system. Mine is going in a bay, near a power source (away from the exposure of the coach batts) near a big #00 wire that feeds the old blowers. I'll have a disconnect downstream of there, esp. for the one that feeds the spaghetti mess of my old driver's elec. panel (God knows there's some phantom load possibilities in there)  .

HTH,
Brian B.

[Stan]

Take Nick's advice very seriously. Putting a charger on a frozen battery can cause a violent explosion..  Put the batteries in a warm room for at least 24 hours before attempting to charge them.  Connecting a jumper battery to a frozen battery also results in the battery blowing the cells out the top along with a shower of acid.

[beatsworkin]

Got my 24 v charger at Harbor Freight  about 40.00 as I recall




Red

[belfert]

Yes, the batteries have been abused and I do have a battery disconnect.  Over the summer I forgot to turn off the disconnect several times at the same time leaving the selenoids for the baggage door locks engaged.  In one case the batteries showed no voltage at all.

I last started the bus about two weeks before this starting attempt.  (Temps were in the 50s just over a week ago and it was zero this morning.)  For about a week in between the battery disconnect was left turned on.  The bus has survived the battery disconnect being left on a for a week before without issues, but that was in warm weather.  (No more selenoids left enabled.)

I guess I'll have to throw an electric heater inside the battery compartment to warm things up or it is supposed to be close to 40 degrees this weekend.

Brian Elfert

[Brian Diehl]

Brian, It can take over 24 hours to thaw out a frozen battery in a 70 degree room.  Don't count on a couple hours above freezing this weekend as a way to thaw out the batteries...

[belfert]

Brian, It can take over 24 hours to thaw out a frozen battery in a 70 degree room.  Don't count on a couple hours above freezing this weekend as a way to thaw out the batteries...

Do you think a 1500 watt heater stuffed in the battery compartment will defrost the batteries in a day or two?

I really don't want to remove them as it is a fair amount of work in the cold and I would have to figure out how label all the wires to get them back on the right posts.  Some posts have as many as three terminals.  Dina didn't make the four starting batteries easy to remove. 

If I have to remove them it would probably make sense just to buy new ones.

Brian Elfert

[Nick Badame Refrig/ACC]

Brian,

You just gave yourself good advice......

[If I have to remove them it would probably make sense just to buy new ones.]

FWIW
Nick-

[DrivingMissLazy]

Brian, based on your statement that the batteries read 20 volts, then they are a long way from dead. They are just discharged and would freeze easier if left in that condition.

If they were frozen, I do not think you would get any voltage at all. I would hook a 12 volt battery charger to one battery and see how many charging amps it draws. I would keep a very close watch on it for an hour of so if it is running several amps charging and if it starts getting hot.

If you think it is drawing too much current, then try connecting the charger across both batteries. IE a 12 volt charger to a 24 volt battery. That should slow the charge rate down considerably.
Richard

[buswarrior]

Hello Brian.

Open the caps and look inside. Use a good flashlight. You'll see ice down there if they are frozen.

I suspect they aren't. Lots lower voltage when I've found a set frozen.

As advised, do not put a big battery charger on those batteries. High power levels can cause catastrophe. However, if you have a small charger, just put it on there at the 2 amp setting and let it try to charge and see what happens. At the low power level, nothing bad is likely to happen.

One at a time is fine, if you only have the one 12 volt charger.

The batteries might only take enough charge to show a higher voltage, but that's a start to raising the settings and then doing a little battery exercises to see if they really are taking the charge.

Report back your findings!

happy coaching!
buswarrior

[bobofthenorth]

Even if they're not frozen its still going to help to warm them up.  I have battery blankets wrapped around mine - it is amazing how much improvement a warm battery makes.  Its going to take forever to warm them up with a forced air heater though.  Something like a waterbed heater that you can put underneath them would be a lot better bet or a heating blanket of some kind.

[DrivingMissLazy]

Even a small electric heating pad draped over them and then a blanket of some kind, or insulating pad, over that to help hold the heat in.
Richard

[belfert]

Last night I bought another 12 volt charger of the same model so I can put them in series to charge the bank at 24 volts.  I will charge at 2 amps as suggested and also warm up the batteries. 

I will eventually need to get new batteries, but I would like to delay that purchase until spring if I can.

Brian Elfert