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Duke48 · 10-25-2016, 03:28 PM

Bad battery, but why? We replaced the chassis / engine battery during our road trip about four weeks ago; have now been home for less than three weeks and the battery is again low / bad. Yet to determine if it is just a bad battery or if some faulty circuit pulled the battery down. To aid in my troubleshooting I would like to locate an owners manual and a shop manual - at least an electrical distribution schematic. (Ford V10 w/ F53 Chassis)

Any help will be greatly appreciated.

Current Status:
After tests using a hydrometer indicated all six cells were low, the battery was placed on charge for several hours and currently shows 12.32 VDC w/ battery totally disconnected for more than an hour. (I know a fully charged battery should indicate > 13.0 VDC.) I'll check in the morning to see if it is holding any charge.

Question:
Should the chassis battery be receiving a charge when connected to shower power?

Thanks,
Duke

CJBROWN · 10-27-2016, 04:03 PM

Sorry, can't help you with specific wiring, but here are a couple of points on 12V RV systems...

After full charge you should see 12.7 or higher. Here's a chart on SOC (state of charge). If they were flat then a couple or a few hours isn't gonna do it - a 10A charger could take up to 24 hours to fully peak it.

I was going to ask what you have to maintain the chassis/starting battery(s) when parked. If there isn't anything consider a 4-6w solar panel or a trickle charger. They will go flat and ruin the battery as a starting battery is not deep cycle and cannot tolerate being left in any kind of discharged state at all.

Generally speaking, shore power does not charge chassis/starting battery(s) unless there are provisions for such. Sometimes an additional small charger is built in, or on a more elaborate system a separate charge circuit. Standard converters for house 12V and charging the house batts do not address the starter battery.

My old winnie came with a 6w solar panel to trickle the house batts. Yeah, right, what's that gonna do for 200+ah of batts, so I moved the lead over to the starter battery and it keeps it fully charged.

Duke48 · 10-28-2016, 06:16 AM

The RV is parked next to the house and is attended almost daily for maintenance and projects. Typically, I extend and retract the RV's steps - that are connected to the chassis 12 volt circuit - as needed to keep the steps clear of any additional vehicle movement in the driveway. So, if there isn't a trickle charger feeding the chassis battery when on shore power, it is probably me that is draining the battery.

I'll have to add a charger or solar panel to maintain the chassis battery; any suggestions?

l1v3fr33ord1 · 10-28-2016, 07:54 AM

Duke-

I can't speak to the Thor coach wiring, as I have no experience. You should contact Thor and ask for the wiring diagrams and any other information pertinent to your coach.

There are options for getting Ford wiring diagrams, but they won't help you for this issue.

I assume your chassis battery disconnect switch is on, or the steps wouldn't work. But, it would pay to ensure that it is in the "on" position.

A 2004 model year coach from many manufacturers usually does not have provisions to charge the chassis battery from the house battery charging system. So people add something like the "Trik-L-Start" or "Amp-L'Start." There are other options, such as the charger you're using, but these devices are a simple to implement and maintain (in my opinion).

CJBROWN · 10-28-2016, 10:24 AM

While I'm thinking about it, for a 2004 vintage it likely has a PARALLAX power converter - 12v to house and battery charging. They are complete junk, a lump that needs to be tossed in the recycle bin.
First of all there is nothing 'smart' about them, probably the dumbest chargers ever invented. How the manufacturers got sold on them is completely unclear. The charge voltage is set - at about 13.8 volts or so, which is not enough to peak up a battery - absorption charge should be more like 14.6-14.8 depending on your battery type, and is also too high once the battery IS charged up, which should be about 13.2-13.4 so it boils the water out of it. Even the owners manual for a RV will tell you not to leave it plugged into shore power for long intervals due to this failing - THEY WILL RUIN YOUR HOUSE BATTERIES!
Evidently the reason it isn't more of an issue is because most motorhome users are usually plugged in at a RV park so they are not dependent on the best longevity of their batteries, and because they generally unplug them in storage and in some cases apply some kind of smart-charger maintainer separately.

So if you haven't done so already, replace your converter with a IOTA or Progressive Dynamics charger converter with smart charging capability, true multi-stage charging including equalizing (burns off sulfate on plates and equalizes cells).

Likely one of the best mods/upgrades I've ever made to our coach. And my golf-cart batts - 2@6V in series to get 12 - last and last and provide long lasting power.

Here's a pretty good article on this topic: Best Converter Charger for an RV - Smart VS. Dumb

Duke48 · 10-29-2016, 12:47 PM

In truth, I don't know if the charger for the hose bank is a PARALLAX power converter or something else; I haven't located it. I am assuming it is mounted under the bed, adjacent to the AC breaker panel.

I learned years ago that just checking the voltage on a battery isn't enough; I also check the water levels and use a hydrometer to test individual cells.

Because the house bank did well being connected to shore power for several months last year and, though we want the capability, we are not big on boondocking, a new charger is not in my list of priorities.

Sweetbriar · 11-01-2016, 08:21 PM

My 2006 31D Hurricane will maintain a charge on both battery banks but no telling what came down the production line in 2004. It's going to depend on what they were using as a Battery Control Center (BCC) for your model year.

I suspect your are correct concerning the location of the converter/charger. Mine is located under the bed behind the AC breaker panel. It could also be incorporated into the breaker panel. Just pull off the false panel and you find the back of the AC and DC panels, the shore/generator transfer switch and a few other items. The original Parallax didn't see 2011 and was replace with a Progressive Dynamics PD 9270C 70 Amp RV Converter/Charger. Not a battery problem since.

A good charger is a must for a coach. 12VDC is its life blood. Boondocking or not without DC power nothing works in the coach but plug in lights and the microwave. No hot water, no fridge, no TV (antenna booster needs 12VDC), no ceiling lights, no heat or A/C,,,,

Concerning the owners or shop manual there are Ford shop manuals for the chassis. EBay might be you best source of finding one at a reasonable price. For the house side your need to give Thor a call but have both the house and chassis serial numbers handy. But you have to consider stuff like the transfer switch or the BCC won't have much more than a box on any diagrams they have. You'll need to go deeper and contact the OEM for the product you need info about. If they don't have your model year move up or down a few years. They didn't change much behind the walls from year to year.