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what would make new drive batteries 12 and 24v go
In November last year bought 4 new napa type31 truck batteries. I trickle charged them all b4 install. i ran the engine for 15 minutes and later for a few hours in all. I did hear a sound that i thought was gas release from the battery area kinda like the air brake system when the prssure is high enough to stop building pressure. there was sum smell like sulfer but not strong. The original batteries were taken out to get charged by my uncle and they had a melt down so he put new ones in. it has the 4 battery 12 and 24 v setup with 2 side by side and 2 more side by side. I am just wondering now if the wires are all on the right posts. There was always the balance light on when i ran it last year. I have since installed more new batteries and things seem fine and the balance light did not come on yet. I turn off the 12 and 24 volt disconect every time just to try to keep from blowing 4 more new batteries. the engine computer wire does have a small spark when connected and one of the eqaulizer wires sparks when connected with all switches off. the prevost is a 1994 the Liberty Coach 40′ is 1996. Has anyone run into this? Thanks
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8 Replies
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I would spend some time and compare the Wiring diagram for the batteries that is on the door of the battery compartment to how you batteries are currently wired.
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If it is found the cables at the batteries are correct the first thing I would do would be to check the battery voltage with the coach running at high idle. It should be in the range of 27.5 to 28 volts. I would measure the 12 volt side of the system and it should be one half of the 24 volt side within 1/2 volt.
The next question to be asked is if the batteries were charged while the bus was not used? If the answer is yes the follow up question would be what kind of charger and for how long? Chassis batteries do not need to be left on a charger but if they are the charger should be one suitable for long term use such as a 3 stage charger at the very least.
Usually when chassis batteries fail prematurely it is because they are overcharged which from the description appears to have happened. If the coach voltage regulator is not the cause of the overcharging then it is likely a trickle charger is the reason. If the coach voltage regulator is allowing charging voltage in excess of 28 volts the coach electrical system can be damaged.
The balance light might have been caused by a battery failing to hold its charge or even take a charge, thus creating the imbalance between the batteries.
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Was hopeing Jon and other Liberty owners would be able to point to some converter mod that might cause it. The prevost system is straight foward. To down load it coach specific go to prevostcar.com Then look around site for tech publications… you will need the last letter in your serial # plus last four digits Example mine is W-6553 that will give you the info on how the shell was provided to Liberty for conversion. Swollen bateries sometime old batt without charge that have frozen in the winter..also one bad battery will kill the whole set./ck them indivual disconnected from set. You shouldn’t have sulfur smell unless you are boiling battery.. Hydrogen gas is generated during high charge rate on acid batt==very explosive. Trivia if you get acid in you compartment a regular can of coke will stop the reaction. Note some new batteries are sealed to the outside /not all! Just food for thought to get conservsation going. bob
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Liberty tends to not alter the Prevost systems with the exception of the leveling system.
But Liberty does install on some coaches a 24 volt battery charger. This charger is not intended to be left on, but merely to top off the charge on the batteries after extended storage. Continuous use of the charger might “cook” the chassis batteries.
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Thanks for your reply . I charged each of the new batteries with a small 12 volt auto type charger with the 2 amp setting around 6 hours each. then i installed them. i found a book on somthing about a charger and there somone had drawn a diagram of the way the wires on the batteries are connected looks the same but one does not seem right. The drawing has the 12v going to the positive post on the first battery on the left and the 24v to the negative post on the same battery then a long wire off the equalizer going the the negative post on the back right side or street side battery . I have been turning off the 12v and 24 v switches just above the batteries in case there is a charger. There is some type of black box up top over the batteries looks like it could monitor the batteries. i have not seem a switch for another charger other than the 2 in the main controll box. i think they are for the two heart inverter chargers.Does anyone know the location the fuse or breaker for the tv antenna it will not go up but the dash light says its up. the red and green lights are not working but the small glass fuse behind the controll thats like thinner than a hair looks ok.
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If your Liberty has a charger installed by Liberty it will be mounted over the batteries for the chassis. In the electric panel it will have a switch that says 24 volt charger.
It is unlikely if you have a charger that it will be a three stage. It might be a converter that will just supply 24 volts (actually more likely 27.5 or so) and continued use will cook the batteries.
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On my 1994 Liberty, the charger was in the 2nd bay, drivers side. A long way to the engine compartment for the chassis battery, but that’s where it was. The previous owner changed out the original Liberty installed dumb charger to a 3 stage as seen in the picture.
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Thanks guys, I will look over both areas for charger or converter. back in the winter when the outside temp was down and everything was off there was a very warm feeling in the area of the batteries. and the hiss sound from that area was without the engine running. sounded like air brake govenor cutting out. this was before i knew about the 3 8D batteries sp i was thinking the heart inverter chargers were for the 4 batteries in the engine area. no charger found.
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