Charging/power experts question within.

[Bob86ZZ4]

Question about my 12 volt charging system. I have 2 deep cycle batteries for the house 12volt system. I have a Iota 55 amp charger/converter. There is a big round switch that can connect the deep cycles to the house wiring, or the 3 truck batteries to the house wiring, or all 5. United Specialties said when I'm hooked up to shore power or running the generator I should set that round switch to "both" so the charger/converter charges up all 5 batteries. If I'm not hooked up I should set the switch to run the house 12v on the deep cycles. That way if they run down I can still start the generator or truck motor. Here's my quandry. I check the voltage at the charger terminals when I'm plugged in to shore power. 13.4 volts. Right what it should be. Then I go over to the terminals by the large round switch. 12.4 volts from the deep cycle batteries. 12.8 volts from the truck batteries. I check the voltage right at the 3 truck batteries, 12.8 volts. No voltage drop from there to the back. The deep cycle voltage right on top of the battery is 12.4 volts. Voltage in the circuit/fuse center up in the master bedroom is 13.4 on the 12v side. I can see the charger has two + (red) wires coming off it. I can follow one of those up to the circuit/fuse center. I can't tell where the other one goes. It doesn't go directly over to the deep cycle/switch location. It looks like it goes off somewhere forward. It seems to me there is something wrong here. Shouldn't the voltage at the deep cycles be 13.4v when the charger is working/powered on? I don't think it's charging up my batteries properly. I would think that there should be a red/positive wire coming directly from the charger over to the switch so it would supply the correct 13.4v to whichever set of batteries I have that big round switch set on. How could the rig have gone 5 years like this if something is wrong? Did the previous owners just keep replacing batteries since they were never charged up completely properly? I don't have any history since I bought if used on a lot.

 

[Bob86ZZ4]

Also, shouldn't the voltage at the truck batteries be 13.4v when the switch is set to that position and the charger is powered from shore power? Something is goofy here. I don't have any problem running a 8 guage wire from the charger directly to the main switch terminal if that's going to solve my problem. The main reason I am trying to figure all this out is that right after buying my rig I had to replace all 5 batteries. They were all crap. The truck had been sitting on the dealers lot for almost a year and a half. So, I just figured they hadn't kept the batteries fully charged and let them freeze over the winter and killed them. But, I also now notice when I've got the fantastic fan running in the bathroom and I flush the toilet the fan slows down noticably, like it's losing amps/volts. Then after the head is done flushing it speeds back up. That's when I started checking everything with my voltage meter and found this.

 

[geofkaye]

.,..contact United with your serial number and ask for the specs book reprint and the original owners name-threaten them with ANOTHER law suit if they don't give it up....they have been bent over for this before and will avoid this if they can....they are hurtin' big time now and I hear that there is a "Credit problem" looming in the background also...or maybe it has happened already-I can't keep up any more with united and renegade or ever showhauler....all these guys sleep with one another on a regular basis now-things have sure changed in the last 2 years!-when you get the owner on the phone pick his brain-the United might be a repo and you will get a dead end-if he is close take him drinking....then pick his brain. usually speaking...they will under size the wires rather than over size them so your charging circuits will be less than perfect!....may need to add welding cable to the mix as a upgrade....I use #2 at least on 12 volts and stranded # 12 on the 120 volt side....never single strand unless in conduit with soldered connections[which, I just don't do anymore at all]....I know I'm NUTS but I have a lot of experience with this stuff/and boats and it hasn't all been good....."do you smell something burning"....is a immediate panic issue with me.....I can come out of a sound sleep when one of the girlz whispers that...-....usually it is a hair dryer/curler issue but I still react like a maniac.....geofkaye

 

[Bob86ZZ4]

Hay Geofkaye, I sent that same text to United tech support e-mail. Guy named Ed. He replied pretty quickly. Turns out that other red wire runs up to the dash mounted house 12v shut off switch. So, if that switch is "off" it isn't connecting the charger/inverter to the battery system (either the deep or the truck batteries depending on the position of the rotary switch). So, when plugged in to shore power I need to make sure that switch is turned on and it will charge the batteries. Or, he said I could run a 8 guage wire from the charger to the rotary switch. He said that's how they do it now, they don't run that wire to the 12v shut down switch. Oh well.

 

[geofkaye]

...electricals seems to be the main issue what requires a spec sheet and a guy that can read it in most MH and Toters....I have spent too many hours-scratching my head-looking for 12 vt shorts/problems-..I don't know what happened to the term "simplification" when it comes to wiring a commercial unite/boat but it seems to me that the designers needs his/her azz kicked for some of the things i have seen in expensive equipment......I'm very glad you don't have to spend your free time on your back trying to figure it out....this is just another reason I do all 120vac and don't fool with inverters and charging systems for the coach part of the unite that i redo/build....it is just makes things too complicated....and that is where the fire thing comes in....most all the fires are 12 vt and not the `120v ac side of things....also a small number of refrigerator fires[in the vent to roof] and a few wall interior wall fires because of the gas heating unites-both stove and heating....all can be eliminated with 120vac electricity....and can be used without problems even while driving down the highway at 65 mph......great luck for you!-it was your lucky day!....geofkaye

 

[Bob86ZZ4]

Geofkaye. I agree electrical can be confusing at times. I don't agree that 12 volt systems are inherently more likely to catch/cause fires. There is no way you can prove that a 12v system is more dangerous than a 120v system. It's just not possible. Nor can be said the reverse. Now, I would posite that the installation and materials would be nearly 100% the cause of electrical failures/fires. Damage and misuse would fall in to make up the 100%. I'm with you on simplification too. I guess there must have been a reason they wired the charger to the switch. I suppose if the charger isn't plugged in to shore power and it's 12 volt output terminals are wired to the batteries they could provide a drain path for those house batteries back through the circuitry of the unpowered charger? I'd have to check that with an ohm meter but I wouldn't be surprised if that was the case.

I don't think I'd want a coach with 100% 120v systems. Wouldn't that require constant running of the generator? Especially since you don't endorse inverters? I like being able to have most systems useable in total silence with just the house batteries. My previous coach was a Allegro 27' class A gasser. It was equiped with 4 deep cycle 6 volt golf cart batteries and 3 LARGE solar panels. The only time I had to run the generator was for the roof air or the microwave. I sure liked that.