RV car charging problem

[Emile]

Hello

I pull my RV 24 ft Mallard Trailer with my Jeep Grand Sherokee 2002

My Jeep does not charge my battery compleetely but it is charge full when connected to AC Power

I have measure de voltage on my Jeep battery and it measure OK 13.5 V but if i measure the battery of my trailer when my Jeep running i only measure 12.7 V, so i have 0.8 V difference which tells me that there is a diode drop between the 2 batteries and thats why the battrey of my trailer never charge compleetely.

Is someone can tell me if that is the problem or something else before i start working on it

I know verry well all kind of inverters since i work most of my life of designing these type of inverters for military applications

Is someone can tell me where i could find the skematic of my inverter ? which is an :
Intelli Power PD9130

Is that a problem of my inverter charger ?
Is there a way i can solve my problem ?

Also is that normal that problem or i have a problem somewhere in the inverter ?
Is someone else has that problem ?

Thanks for your answers
Émile

[Roy in TO]

Are you using a battery isolator or solenoid on your Jeep?
What guage wire to the rear?

[Emile]

Thanks Roy for your answer

My Jeep has not been modify to add any parts
My wiring gage is a #8

Since I am just coming from vacation i will be doing more test to day and come back to you after

Thanks again
Émile

[john warren]

did it ever charge it fully?
your alternator may not be a heavy duty one. your putting out plenty of voltage,,,but its amperage you need,not sure what stock is on a jeep, but part of the tow pack is a high output alternator i think.

[DMAC1]

make sure to check for poor connections, escpecialy at the tow vehicle receptacle. what you have is a voltage drop accros the circuit. the charge from the vehicle to the rv battery doesn't really use the rv converter. .8 of a voltage drop is huge and almost always from a poor connection. the wires going into the back of the tow vehicle receptacle very often corrode

[cpaharley2008]

Most Jeeps need a separate power wire as the factory wire is too small for any volts to charge your trailer. That said, most auto's alternators are adequate for lights and your propane detector on your trailer bit little is left to charge your battery, unless you drive in day with no lights then there is more reserve available to charge your trailer battery, if the wire is up to size.

[DMAC1]

Using the vehicles altenator to charge the battery doesn't always work that well unless you are running down the road at speed so the altenator is turning fast enough to produce enough amperage, that said the run of wire to the rv battery is long and ushaually incorporates many connections/ junction points to restrict the flow of the juice. the voltage should still be close between the two batteries while hooked up and running though.

[P. Raz]

13.5 --> 12.7 as others have said is due to I squared R losses, corrosion, or a diode to isolate and prevent discharge of the Jeep battery. I have not been able to find a schematic for any of the newer (switching) Progressive Dynamic converters. If your battery charges fully when you are connected to AC. your converter is probably fine. The converter is not part of the charging system when you are driving. Raz

[Emile]

Thans everybody for your answers

I beleave your are all very close to my problem

I just come to make few tests and i found a 27 ohms both directions between the Jeep connector and the converter and that would cause my problem i beleave

My RV manual shows a 40 amps breaker in that line as you can see in the picture and that could be the cause of my bug But i cannot find that breaker since the wirer is going under the floor of my RV.

Is that possible that they would have put a breaker under the floor ?



Thanks again for your help
Émile

[cpaharley2008]

There is a main breaker, around 30-50 amps on the trailer that can blow. It is a little square box with 2 copper lugs. This may be somewhere in your system. It is shown above as a 40 amp breaker. That will prevent you being able to charge while towing if it is blown or defective.

[Ron in BC]

It looks to me that the circuit breaker only protects the converter circuit, not the car charging circuit. It appears that the wire from the trailer plug only uses a terminal of the circuit breaker as a connector and the car charging current doesn't actually pass through the circuit breaker.

When you find the circuit breaker check for corrosion on the terminal. I'd remove it, wire brush it and re-install it. I'd also check the voltage at that terminal as compared to the plug voltage and also for voltage drop between the circuit breaker terminal and the battery terminal.

Good luck locating the circuit breaker.

Ron

[P. Raz]

I'm unclear if this is the actual wiring diagram for the trailer from the trailer manufacturer or a suggested wiring from the converter manufacturer. The phrase "Electrical system wiring diagram (typical)" in the lower left leads me to think the latter. Raz

[Emile]

Raz the picture of the skematic has been taken from my RV Mallard manual

[P. Raz]

I agree with Ron, your issue is between pin 4 on the plug or where ever you are measuring beyond that and the terminal on the breaker. Since the converter charges the battery, the breaker should be ok. Since the distribution section is shown separate but is probably part of the converter, the breaker might also be. Raz