2009 TourMaster 425 - battery charging issue

[RoosterAndRabbit]

Just bought this unit used and still trying to learn everything. Thanks in advance for the help.

Have 4 12 volt batteries in rear, 2 that start the coach and I think the other 2 start the generator (just bought them brand new 2 days ago). Then I have 4 6 volt batteries in front by the generator. Ran the generator and 2 of the 3 air conditioning units yesterday. My new 12 volt batteries were completely drained. Front 6 volt batteries drained also. What would cause the batteries to be drained, even though the generator is running?

[Chuck v]

For your coach, the 4 golf cart batteries in the front are there to run the inverter and to start the generator. If you have the inverter on all the time with the coach not connected to shore power, that bank will discharge in about a day or less -- because it runs the residential refrigerator. Age and condition of the batteries will also determine how short a discharge time you may experience.


The other two pairs of batteries located near the rear wheel are for engine starting, and for 12 volt coach lighting, etc.


I will try to attach a drawing of the DC systems in your coach...


Chuck

[RoosterAndRabbit]

Chuck,

Thanks so much! Appreciate the wiring diagram. Another quick question; so are you saying if I am running only the generator, (no shore power) I need to leave the inverter off? Should the generator charge up any of the batteries and which ones?

Thanks again,

Mike

[Chuck v]

The generator does not need the inverter to be off, but the inverter powers only a sub-set of the AC loads that the generator does, so having it on is not needed.


The generator charges the cart battery bank that is used to start it and supplies DC to run the inverter when that is active...


I don't recall if the generator also can charge the Coach battery bank that runs the interior lights, but it definitely does not charge the Chassis battery bank that starts the big diesel engine.


If you look at the diagram I posted,, you will see the IRD control module and the main IRD relay. IRD stands for isolator relay delay...which is a circuit to allow the ENGINE ALTERNATOR to charge the battery banks when they are temporarily cross connected under very controlled time and voltage conditions. Lets discuss a bit what all the rest of the circuitry on the diagram means:


The Chassis and Coach Disconnect relays are mechanically latching relays that can hold the loads of the RV either connected or disconnected from their respective battery banks. The disconnect relays are remotely controlled/switched by the controls in the stair well of your coach. You should set these controls to "disconnected" whenever the rig is stored or unattended.


Reading across the top of the drawing, the Coach disconnect determines if the Coach battery bank (upper left pair of 12 volt batteries) is allowed to power the DC loads in the RV such as the electric slide-outs, the bed tilt, the lighting, etc. via various fused circuits. Below these batteries is shown an 80 amp CONVERTER -- which is powered from shore power and both charges the house batteries, and can supply DC to the loads mentioned above.


In the lower left part of the drawing you find the four inverter batteries, which are 6 volt golf cart units connected in series/parallel to form a 12 volt 450 AH bank. These power your electronic inverter (may be 2KW or perhaps 2.5 KW depending on year and model of coach...) The inverter powers some but not all of the 110 VAC loads in the rig -- notably the residential refrigerator, the TV, a few convenience outlets and the microwave. It does NOT power the washer/dryer or any of the air conditioners. Note that this battery bank also provides the starting power for the diesel generator.


The lower right battery bank is the Chassis bank which is used to start the big diesel engine and to run the "vehicle" DC circuit like the headlights, wipers, etc.


This diagram does not show the engine alternator -- but when the IRD is active, the alternator can charge all three battery banks (given the proper time and voltage requirements are met...)


My 2007 Tour Master came from the factory with no shore power capability to charge the engine bank of batteries, so I added a high quality float charger that can stay connected for long periods without overcharging the batteries and causing electrolyte loss. I did this because I was living full time in my coach, and not driving it much so the engine did not run all that often.


Hope this helps -- ask more questions as you need to...


Chuck

[RoosterAndRabbit]

Chuck,

Lots of great information, thanks. So if I am out somewhere boondocking (no shore power), what would recharge those 6 volt batteries? The generator?

Mike

[Chuck v]

Mike,


Boondocking (dry camping...) is not the Tour Master's long suit...but it can be done. Does your rig have the 23 cu ft. residential refrigerator that only operates on 120 VAC as mine did? If so, that means that you need the inverter (or the generator, or shore power...) to provide 120 volts alternating current to give refrigeration for your food. You can plan to keep the unit full if possible and open the door a little as possible, both of which helps keep food cold longer -- but you need to run the fridge about 4 to 6 hours a 24 hour day in any case. You can do this with the generator if you don't mind the noise.


Yes, the generator can charge the inverter batteries...but fully discharged inverter batteries may take more than 8 hours to recharge, even at the high currents available from the charger built into the inverter. Is your inverter the factory original Xantrex unit? If so, do you have the operator's manual? These units can charge at about 80 amps initially and will taper down as the bank gets recharged. Your control panel will have a digital meter showing the rate of charging when in that mode.


I only used my inverter to run the fridge while driving, and used the shore power or if needed the generator at other times when at a site. If you have a situation where you wish to reduce the noise (i.e. not run the generator) while camped, then judicious use of the inverter can be made...as long as the batteries are recharged regularly during non-quiet times.


What is important in all of this is to have a clear understanding of how the AC power is wired/provisioned in your coach. Shore power takes precedent over all other sources, and when available it is selected by the main transfer switch to power all AC loads. When the shore power is not available and the generator is running, the main transfer switch selects the generator as the power source for all circuits. In this way even the air conditioners and the laundry appliances can be run as desired. Inside the inverter there is a secondary transfer switch -- as long as AC power is present at the input of the inverter/charger (either from the shore power or the generator) then that source is passed to the AC outlets connected to inverter system. These would include the residential refrigerator, the TV, the microwave and a few designated convenience outlets in the galley area. Absent the presence of shore power or the generator running, the inverter secondary transfer switch then allows the inverter to supply AC power to just those few loads.


You should have two separate breaker panels in your coach. The main one has the breakers for the laundry, the air conditioners and similar primary loads. The secondary breaker panel has those loads that are additionally backed up by the inverter, and should have the refrigerator, the microwave, etc.


Hope this clears a few more things up...


Chuck

[Chuck v]

Mike,


Attached is a picture from a 2008 TM brochure, with some added annotations. If you can post a higher resolution image of your panels, we should be able to discuss the circuits as labeled that are part of the inverter supported 110 v load layout...


Chuck

[RoosterAndRabbit]

Chuck,

Thanks again for helping me diagnose the issues with this coach. I replaced all 4 of the 6 volt batteries that I thought were working. It appears there were not keeping a charge and now the 110 VAC loads are working without issue.

I am still having one more problem. I ran the generator for about 5 hours. Everything in the coach seemed fine, including the one air conditioning unit that I had running. All of a sudden, the air conditioning unit stopped, after that long period of time. The generator continued to run. This same issue happened the other day and it was a different a/c unit that I had on. I shut down the generator after the a/c unit stopped and plugged in shore power. The air conditioning unit fired right back up again with shore power. Any thoughts on what might cause the a/c unit to just stop while the generator is running?

Thanks again,

Mike

[Chuck v]

Not sure, since the description you give is perhaps not a complete one. Did the Air Conditioner unit stop cooling, or did the fan and everything stop running completely?


There are sensors in the AC units that can shut them down if they sense an icing condition -- I have had this happen on my units once or twice. Usually it happens when environmental conditions are high humidity and temps above 90 or so. Make sure the fins on the evaporator coils are free from accumulated debris or dust, etc. and air passages are not blocked.


Have you had the air conditioners run continuously for more than 5 hours on shore power under similar conditions?


There may of course be other issues with the air conditioner that you need to have checked out. I can't imagine any substantial difference in power quality between shore power and generator power...


Chuck