Charging system

[bigred]

Hey Guy's :Someone walk me through the steps for checking the charging system on my 8v92 . If I let this set for any time at all with out starting it ,the batteries are to weak to start it .I can see how this might happen in cold weather but it happened today .Hadn't been started for about three weeks .Going to pull the batteries and take them for a check .They are about two years old give or take .Not old considering I have gotten any where from 7 to ten years on batteries bought from these folks before .As always I really thank you for your advice and knowledge .By the way ,this is a belt driven alternator ,so removing it will not be a major issue if it comes to that.

[gumpy]

It's probably not an issue with your charging system. More likely it's an issue with your loads. It's likely you have phantom loads on the batteries when the bus is turned off. That's fairly common. Check for current draw on the batteries.

I assume you've been checking and filling the water level in the batteries.

Try disconnecting the ground cable when parked for a period of time. Opening the disconnect switch may not completely shut off the phantom loads if they are connected directly to the batteries, but disconnecting the ground will. 

You can check your charging system by putting a volt meter on the batteries when the bus is running. Should see something like 13.6 if the bus is 12v or 27.2 if the bus is 24v. My numbers might be off slightly, and I'm sure others will jump at the chance to correct me, but you get the idea.

[Lin]

By disconnecting the positive terminal on the battery and using the multimeter inline, you can see if there is an amperage draw when everything is turned off.  My cheap multimeters will read only up to 10 amps.  If that is the case with yours, make sure there are no big loads left on.  You will also probably need to switch one of the ports on the meter.

[luvrbus]

You have a DDEC ,electronic transmission and probably a Vanner then some alternators are hot all the time, they all draw current and with the wet cell flooded natural lost charge each day. I say if it takes 3 weeks without a maintainer for the batteries you are not doing bad

[chessie4905]

Turn off that light in the back closet.

[buswarrior]

Beware the old PA amplifier...

unplug it, it takes power all the time

happy coaching!
buswarrior

[bigred]

When we leave the bus ,I have three disconnects ,24V--12V and house which we always turn off .The alarm and clock actually run off the generator battery, yes Luvrbus ,it is a DDEC with two Vanners. I may have to bite the bullet and rent a space that has electricity ,That doubles the lot rent ,but what the heck!! It is only money .LOL

[lostagain]

A solar panel, if parked outside, will keep the batteries up.

JC

[Dave5Cs]

Put an on/off switch on the vanner ground and turn off when leaving it.

[bigred]

The 24v one or the 12v one or both Dave?? Also for some one who can remember every detail of something that happened 50 years ago but don't have a clue where I put my glasses 5 minutes ago,what is the penalty if I forget to turn them back on when starting the bus??

[B_K]

Rhet if you pn/off on the ground of the vanner it should in effect kill the 12/24V both. Also if you put it next to one of the main disconnects you already turn off/on it will be easy to remember!

[bigred]

I see what you mean B K .The one ground feed's from one Vanner to the other one.Am going shopping for a switch and a piece of number 6 DLO cable.Thanks folks for all your advice!!!

[bigred]

Took the batteries out of the bus and took them back to the place where I bought them.I checked the voltage.Two were 12.5 and two were almost 12v.They have charged them up and checked them for cranking amps and are telling me that all four batteries are dead.How can I check to be sure this is the case .If the po of this business had told me this ,i would never have doubt it but I am not to sure I trust the present owners.These batteries are 30 months old but the last batteries I bought from these people lasted over seven years.

[Jon]

Batteries can fail due to an internal fault, but when they all fail it generally has to do with how well they have been maintained and if they have experienced total discharges which can pretty quickly ruin good batteries.

I have never turned my chassis batteries off in any of my Prevost coaches unless I was doing some work on the coach and typically I can go three months before the battery charge is below 50% (12.3) at which time I am either using the coach or recharging. But if someone has hooked phantom loads to the batteries the time between charges is going to be a lot different depending on loads. I have had one or two Vanners on all my coaches and if the Vanner has drawn current it is negligible. The Vanner is only working to maintain the same voltage across the four batteries by automatically adjusting so the 24 volt side is exactly twice the 12 volt side. If one of the four batteries is weak or has an issue the Vanner will be adjusting current to follow the poor battery to its lowering voltage. That is why all batteries need to be in date matched sets and replacing just a single bad battery in a set eventually shortens the life of all batteries in the set.

[Scott & Heather]

Another data point: my MCI nine bus always had to have the disconnect turned off when we parked. For whatever reason the battery would drain if I did not do this. I still don't know why. It was a mechanical 6V92 and I did not have any vanner equalizers installed. My new bus the 102C3 I leave both the 12 and the 24 V connected while we park. I have two vanner equalizers and I have a ddec ii system.  i've never had the batteries drain even while everything is connected for months. So go figure.


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