-
need boost!
A friend of mine has a Liberty with a 24V charging system, batteries are too low to start and he needs a boost. Can anyone tell me how to boost a 24V system? I believe that there are lugs at the back of the coach for boosting just not sure of the proceedure?
-
18 Replies
-
He can try, but don’t expect much success unless he is lucky.
The problem when chassis batteries are not fully charged is the 24 volt side is too weak to spin the engine, but even if you get a 24 volt boost, it is probable the coach will not start because the 12 volt side of the chassis battery set up is also weak and as a result the DDEC computer is not going to fire the engine.
You have two viable choices. Get a 24 volt charger on the system and make sure the equalizer is balancing the 12 and 24 volt sides of the chassis battery system. As an alternative separate the batteries and charge each one individually until float. Then hook the cables back up.
The reason I am suspect of jump starting is the starting current is substantial and only the best cables will work and they must be provided with strong 24 volt input.
-
I agree with Jon what Jon says.
But unhooking the four batteries and charging them individually and reconnecting them is a long, laborious, time consuming process that is can be potentially dangerous (to the person doing the work as well as the coach) if the proper precautions are not taken and the positive terminals of the batteries are shorted out against the coach or the wiring.
What year is this Liberty? Many Liberty coaches were delivered with an onboard, 24volt battery charger that is already properly wired into the battery pack and is plugged into a dedicated 120volt outlet in the engine bay and is often on its own circuit with a dedicated circuit breaker on the electrical panel in the coach.
If this coach has a charger … has he tried to charge it with this charger?
How old are the batteries? Are they run down? Or are the batteries “old” (greater than five years) and unable to really hold much of a charge? Bad batteries might be the problem.
The problem has been brought to the best venue in the world. We’re all sitting here waiting to help!
-
My system is set up with seperate batt for gen set. With it running it will feed the power side of the inverter= charge battery. Not all are set up like this. If person that has coach has no mechanical knowlede of system he needs someone that does. Can cost him Big $$$$ with a polarity mix up. If battery replacement is needed tripple check connections.. as these are 12V batt hooked up in a special pos neg configuration to = 24 volt. worse case could end up with 48 volts or 12 volts.
-
Thank you all for the advice, I will get with him and see if he can get his gen to charge the system. I agree with everything said and that his best option is onboard charging.
-
I have had the 24v sides of my chassis and house batts hooked together for years so they charge and discharge together. Offhand, I can’t remember where I tied them together but it wasn’t tough. This should start the coach assuming the 12v output side of the chassis batts aren’t completely dead. I would also think a big rig tow truck would be able to jump. Let me know if you want me to go to my coach and see how it’s wired together.
-
Jim: I tried to email you directly using the email in your forum name, but it bounced back with the following message:
Remote host said:
550 #5.7.1 SPF unauthorized mail is prohibited.
-
The generator WILL NOT CHARGE CHASSIS BATTERIES THROUGH AN INVERTER, but may allow an on board 24V battery charger to charge the batteries.
This makes a huge assumption. It presumes the coach has a battery charger. If in fact it does, it presumes the equalizer is functioning so when it is charging the 12 and 24 volt circuits are charged equally. If further presumes the batteries are capable of being charged and holding a charge.
As long as he is a Prevost enthusiast have him register and once we get sufficient information we can walk him through all he has to do to safely get the coach running, but I am almost certain unless he is lucky just jump starting it might not work.
Sometimes there ain’t no short cuts.
-
totally depends how it is set up and who converter was. I hate to comment on possibilities of elect orgin. too many ways to configure a system. I can start my gen set and charge coach batteries. and house batt. No more comments from me! Been there done that. Bob
-
Jim: If he wants to talk to someone who has been through this experience with a Liberty he can call me. 262-365-9088. I will try not to lead him astray and know enough when things are over my head. I would have rather have him call me with what he feels are dumb questions than see you post in a couple of days that his trip was ruined or he has seriously injured his coach. Dick
-
There are lugs in the engine compartment on the passenger side. However, I would go to the owners model for his year model for instructions. A manual can be accessed on this site under the ‘Links’ module.
-
Dick, not sure why that happened but try jimdoel@me.com
thanks -
Bob,
Since he described the coach as a Liberty he will not be able to charge the batteries through the inverters if it has any. Early Liberty coaches did not even have inverters. But if he does run the generator the coach may have a Liberty installed chassis battery charger, but that is only going to work if the equalizer is functioning, something equally true if he tries jumping it. Even if the equalizer is working a bad battery on the 12 volt side may not allow DDEC to function, if it is DDEC equipped which necessitates a different set of questions and answers
Before risking anything it is best to walk slowly through this starting with the basics.
Right now we don’t know anything more than it is a Liberty that won’t start.
-
Tough call without knowing the year of the Liberty!
-
Don’t know if newer Coaches are still 12 and 24 volt. Our newer semi(like wreckers) are straight 12 Volt–Peter could comment here. Just know $$$ involved by reverse polarity or wrong voltage. I started to hit erase on my post! Prob should have and let the chips fall. Lots of electronics fried by good intentions.. Bob Guilty but lucky..
-
All are trucks have 24 volt or 12 volt both separate from one another for this reason
Log in to reply.