Towing with generator running

[JohnB]

Originally Posted by Jim-Bev-2363

John,

Here is a diagram for thought. Connect D-Cell batteries as a flashlight circuit to the appropriate voltaged lightbulb. In that circuit insert a common wire, bus bar. Do that with different voltaged "flashlights". It will make no difference where along the Bus Bar you tie each flashlight to they will all operate properly without interrupting the other system or doing damage.



You could take a 110V power source and tie into the bus bar and it would not blow the flashlights. Only once the circuits become mixed will there be problems.


Now replace the bus bar with the house battery. Connect the TT converter to the house battery. off to the side connect the TV alternator. The converter will operate as the one cell flashlight. The alternator will operate as the two cell flashlight. Each has its own circuit.

Now say the converter senses the battery level, what will it really sense? Could that be the output of the alternator? Doesn't the alternator also output for demand? Low battery means higher output, right? If the converter is putting out the 14.4, or whatever voltage, the alternator will adjust appropriately. Both pieces of equipment run according to the needs of the battery which in my example is really the bus bar.

Back to my original thought that each piece of equipment is a seperate circuit and only if there is a problem, damage to, with other systems will there be interaction between the sytems. Voltage will seek its source. converter 14.4 seeks the converter. Alternator 13.8 seeks the alternator. Unless you have a power source greater than the bus bar/ battery can handle will there be problems. Now that 110V input would blow the sytem all to blazes.

jim

Jim

Sorry, I was not getting my point across correctly on the concern. On the compressor I do not know. The only concern I thought of may be an issue is the bouncing of the compressor. It may or may not be a concern. If there was to be a concern I would think it is in that area.

Now to the converter, we have a different opinion of what is going on. The diagram you have above with the 3 batteries I totally agree that hook up on that diagram will not cause any issues. All you did was tie the DC commons of 3 different power supplies common to each other. This is done all the time in the industrial machine building world. OK so far so good.

Here is the unknown concern area. I do not know what will happen when that we have 2 battery packs separated by different resistances of wire gages with 2 different charge controllers trying to control the rate of charge. When we put 2 very different battery charge controllers on the same common power supply line that is the concern. What are the charge controllers doing? This is what I see going on.



Gary has a high end PD9260C smart converter with a boost mode. That charge controller using no 6 awg wire to the 1st battery bank and senses the resistance through that battery bank. By knowing the resistance through the battery it shifts the charge rate to the battery in both volts and amps. It will give the battery all the amps the no 6 awg wire will be able to pass. Which is less then 30 amps unless he ups the wire to be like a no 2 awg. If the coach batteries are drained down far enough it will kick into high charge.

Now lets add the truck. He starts the truck, the Ford relay in the trailer battery charge line closes. The truck has it's own charge controller. I do not know if it has a boost mode, I "think" it only goes up to 13.6 volts. May be wrong on that one. If the truck battery is fully charged that controller will sense the resistance thru that battery hooked up with very large cables and drop down to a float voltage. Again so far so good.

But, there is always a but..... we have the very small no 10 awg 25 feet plus long wire heading back to the 5er battery bank. That wire is very limiting. Here is the unknown, the truck charge controller is putting out lower voltage and low current as the battery in the truck hooked up by heavy cables is 100% charged. The 5er needs higher voltage and higher current as that battery is say 50% charged. The 2 charge controllers are not sensing as they normally do being connected by the 7 wire plug wire that has 2 different voltages on each end of it.

I do not know what that condition will do to the PD9260C converter. I do not see it creating smoke... but for sure I do not see it knows how to sort out the correct charge rate since it is not normal to have a secondary charge controller on the same line doing different charge rates.

It may shut down the PD converter from high charge to normal charge thinking that the battery is more charged then it is as all of a sudden an extra supply of power showed up. Does this hurt anything? It may not hurt it but it may also not be charging at the rate it should. Since there is no smoke.... one may assume everything is fine but it really is not working the way it is suppose to.

If all batteries are 100% charged when you turn both charge controllers on, well they are both in float mode and the problem is no longer as both are putting out 13.3 volts. When 1 battery bank is greatly different then the other, that is the concern.

Gary may need to call Progressive Dynamics tech service and just ask. Can the PD9620C handle a secondary charge controller on the same line at the same time doing different charge rates and voltages and what effects does this cause?

I'm going camping for the next 4 days and odds I will not be back on line (no internet) until Sunday to respond.

Hope this helps

John

PS This is why we where saying pull the battery charge fuse in the 5er heading to the truck. That way both systems are independent. If you are running the converter in the 5er, why do you need the charge line to the truck hooked up?

[EMD_Driver]

Originally Posted by JohnB

PS This is why we where saying pull the battery charge fuse in the 5er heading to the truck. That way both systems are independent. If you are running the converter in the 5er, why do you need the charge line to the truck hooked up?

You actually do not need the battery charge line hooked up, if the generator is charging the battery. With the temps being so hot today, I plan to try running the A/C on the way to Buttonwood. In my case, with so many unknowns, my plan is to simply turn off the breaker going to the converter. That way, there won't be two different charge controllers fighting each other.

[Jim-Bev-2363]

Hi John,

To me it seems that you will still have two seperate circuits, however they are powered, and they both will sense the house battery state of charge. That means each will react as designed to the battery need. The truck system will react to the charge need and furnish what it is designed to do. The TT converter will react to the condition of the same battery and react as well.

Like with the flashlights, if the three battery system is turned on then only the lightbulb sized for the three cell flashlight will work. That would be like the truck chargeing system sensing the needs of its design. Now, if the two cell flashlight is turned on then only the two cell flashlight will burn. That would be comparable to the TT converter sensing battery needs and reacting as it is intended. Each system does not react to the other but rather only to the need of the battery. Where the two charging systems will influence each other is in how the other system reads the condition of the battery.

If the actual condition of the house battery is that it needs charging each power supply will give what it is designed to do for existing conditions. Nothing more, nothing less. And, only controlled by the conditions of the battery/batteries in the controlled system. That battery condition controls output of both charging systems.

If the truck alternator needs to supply more power to the truck system, I think the converter will tell a higher condition in the house battery, because of the voltage supplied by the alternator as sensed across the house battery, and reduce output accordingly. If the house battery is low and needs charged and the converter pumps power to the house batteries the truck will not sense a low battery and not allow increased alternator output. The two systems will balance each others conditions in the end to keep all batteries properly charged.


Enjoy your time off.

jim

[Jim-Bev-2363]

Gary,

Your turning the converter off is what I did with the off/on switch on the dash of our motorhome. It allowed me to turn one charging system off, the alternator. If I felt the house battery was charged enough I would turn the truck alternator circuit off. Otherwise I would allow the house battery to charge. In the end, when running the genset and the truck charging system together I had no problems and all batteries were charged properly.

Have a good trip.

jim

[Jim-Bev-2363]

Edit my last post to add:
IF I let both charging systems run while traveling it was for only shorter trips of a few hours. The reason for that was the house battery is a deep cycle and is isn't good to leave them on charge all the time since deep cycle batteries are made to charge and then discharge instead of topping off and still dump a charging voltage into them like the regular vehicle battery. I'm not talking about the trickle charge used by converter battery chargers but the minimum charge from the truck alternator. I felt that was not good for the house battery to be continually under those charge conditions. Perhaps that is why the motorhome had the manual switch for eleminating the alternator from the charging system.

[mainah]

I would disconnect the charge wire or pull the fuse to many things that can go wrong if you lose a ground for instance it is going to spike some thing the charger or the alternator most modern trucks/cars have some very sensitive electronics I would not take a chance of back feeding them from the camper wiring. I can not say for fact but most factory wired 7 pins disconnect with the key off so that would not be an issue if the TV is still hooked up when you use the generator or plug in.

[EMD_Driver]

Originally Posted by Jim-Bev-2363

Gary,

Your turning the converter off is what I did with the off/on switch on the dash of our motorhome. It allowed me to turn one charging system off, the alternator. If I felt the house battery was charged enough I would turn the truck alternator circuit off. Otherwise I would allow the house battery to charge. In the end, when running the genset and the truck charging system together I had no problems and all batteries were charged properly.

Have a good trip.

jim

Thanks Jim!