Dumb question perhaps?

Deltran, (the company that makes the Battery Tender models), now makes this nice compact unit, that a fellow could probably permanently attach under the hood, perhaps with Velcro, or epoxy. You could wire it directly to the terminals, rather than use the clamps. Simply run the 110v plug out the grille area, similar to a block heater, for easy access.

http://batterytender.com/products/motorcycle/waterproof-800-usa-western-hemisphere.html

I just had a similar problem with my Jayco Greyhawk. We are getting ready for a Florida trip. I had the unit hooked up to shore power in my drive. When I went to start up for a shakedown drive, there was no power to start the engine. Used the "emergency" button and the coach batteries started the engine fine. I took it to the dealer and explained my problem. I was told that the chassis battery only charges when the alternator is working i.e. when the engine is running. They said that I needed to put a trickle charger on the chassis battery when I shut down for a month or so.

So to satisfy my curiosity, and to insure I wasn't boiling my batteries, I opened up the hinged door on the shore power unit, as apparently all the information about it is contained within.
Turns out is a common system, the Magnatec series 6300, model 6345. I was happy to see that it also came with the option code C, which indicates it has the charging unit with the automatic sensor. No indications from the batteries themselves that they were being overcharged, IE; acid bubbling out, and the test switch showing the batteries are in good charged condition.
Well that is a relief!

Thanks for everyone's advice/ideas on this matter.

One question remains. Is there a way to run 110 v into the coach, without going through the shore power system? Seems needless to have the power unit working away, when all I really want is to run a 60 watt light bulb for a little warmth. Other than removing a screen, and cracking the window open to run an extension cord through it, is there another method commonly used?

It appears as suspected, that the chassis battery is not being charged. I decided to run the engine up to operating temps, and noticed it turned over pretty slow. I used the dash button for the coach batteries to assist, and it spun much faster. Looks like I will need to stick my regular charger on it from time to time, to keep it up to snuff over winter. I will look into the other options for this matter in the future.

Our chassis battery gets charged by starting the MH for few minutes. We know when to do this because the steps slow down.

Dieter_Heinzer wrote:
Yes, when plugged in, both the house and cab batteries are being charged.

Not unless you have one of these or something similar to it.

BIRD

A BIRD (BI-DIRECTIONAL ISOLATOR RELAY DELAY)

My RV came with one and it works great, just keep it plugged in and all batteries are always charged up with the help of my PD9245C 4 Mode Smart Converter/Charger

I just replaced the original "dumb" WFCO converter/charger with a PD 9245 unit. Replacement installation is simple. Unit includes an optional "Pendant" which you can mount outside of the enclosure to monitor what the converter/charger is doing. I replaced the two 6-Volt T-105 house batteries with two cheaper same type US brand 6-Volt batteries. My Trik-L-Start is working properly with the new converter, house and starting batteries keeping the starting battery up when rig is plugged into my garage 30 amp outlet.

http://www.bestconverter.com/PD-9245C-45-Amp-RV-ConverterCharger_p_170.html#.UoVSvnmA203

We have an Itasca on an '02 E-350. It has a rocker switch on the dash that if you need extra power to the engine battery for starting you hold the switch. When the MH is in storage, about once a month, I block that switch on with a pencil for a day, this charges up the engine battery from the converter charger, which is plugged in to shore power.
The Trilk-L-Start would be better, but this is cheaper and the relay between the batteries is very difficult to get to.

We had one of those old converter/chargers and it had separate charge wiring coming out of it. Disconnected that and used a better charger in its place.
That said, a new multi-stage, smarter, unit would be better.

A commonly used converter is the Parallax/Magnetek 6000 and 7000 series. They put out a steady 13.8v. That provides a not very fast charge and then when the battery is fully charged is too much voltage and tends to boil the water in the battery. The solution is to check the water level on a regular basis, say every week or 2 until you find out how long it takes to need distilled water.

Many Motorhomes have a battery disconnect switch, mine is located by the door as you come in. You can disconnect the battery, but don't let it get too discharged. With the battery disconnected you can still have 120v power in the coach. My battery disconnect switch does not remove all the loads on the battery so the battery may still get discharged.

You could also turn the circuit breaker for the converter off but I would also disconnect the battery negative lead to disconnect all loads on it.

I personally turn the CB for the converter off and leave a Battery Minder Plus connected to the coach battery during the winter. This guarantees that the battery will stay in good shape. I use a trickle charger on the chassis battery.

ac bill wrote:
I will do some more digging, perhaps there is a make/model on the convertor itself that can be seen. I haven't dug into the spot it is located yet, but appears there is a door of sorts on front of it under a cabinet. Odd little fasteners I'm unfamiliar with holding it on.

So if the unit does not actually sense when the batteries are fully charged, wouldn't this be an issue every time your plugged into shore power, even when out camping? I'd sure hope that even back in 93, they used the technology to prevent battery overcharging.

I've been keeping it plugged in so I can leave a 120v light on inside the unit for some warmth and to help prevent dampness, or sometimes an electric heater if we have company visit overnight.

Is there usually a way to shut off the convertor's charger feature manually, and still have 120v available in the coach? That would be a nice feature, if it's not automatic.

I have a separate automatic battery charger, which I guess I better hook up to the engine battery from time to time, to keep it up over the winter. It has the auto trickle charge feature, so it won't overcharge it, if say it's left on overnight.

Tenbear, they are definitely two 12 volt batteries in the coach.

Look on the converter and you will see the make/model. In all likelihood it's a single stage Parallax or something similar which charges at a constant rate but does not sense charged. It is the worst of both worlds. What you want is one that will charge at the capacity the battery will take it and then go into maintenance mode once done. For a couple of hundred bucks you can buy a Progressive Dynamics converter which will do this. You can also add a Trick-L-Start which will poach a bit of power off the coach batteries (only when charging) to maintain the chassis battery.

Right now if you don't want the battery to charge while you're plugged in to AC power just switch your battery switch to OFF (or STORE depending on labeling). You can buy a couple of Battery Minders or Battery Tenders and hook them up to AC power to keep the batteries happy. One on the coach set and one on the chassis battery.

I would highly advise going to a PD converter (you can get them on Amazon). Not hard to install. Take the old one out and wire in the new one. If you are comfortable with wiring it's a pretty quick job. You can go to their web site and figure out what swaps in for yours. It is a very common mod. Once you get the converter I would advise two 6 volt real deep cycle batteries as big as you can fit in the compartment for the coach. You can wait on that upgrade until your 12 volts go soft.