Scott: Last of the Summer at the Lake

This summer has been an absolutely great summer. Just the right temperatures and the right amount of rain. The grass was green, the hammock was out all the time. There was a warm breeze blowing off the lake. Generally you couldn’t have asked for a nicer summer.

There was no new construction projects this summer and the hammock owner spent a lot of time in the hammock!

Beware! shadows always lurk in paradise!
Sitting on the deck late one afternoon a strange smell permeated the normal summer smells of pine needles and flowers. What’s that smell the lady of the house asked?

I don’t know said the hammock owner, but it smells like sewer. I got up and checked the holding tank on the coach. Nothing coming from there. A bit of wandering and inspecting soon narrowed the offensive odor down to the engine bay on the coach. NOT GOOD! What can smell like rotten eggs in there? Further inspection and poking determined that the odor was coming from the batteries. Hydrogen gas was being vented form the engine batteries because they were boiling and very hot! “Yikes”
Quickly I ran to the garage, and got the tool box and pair of gloves and removed the smoking battery.

A check with the volt meter indicated that the chassis batteries were being heavily charged by the Xantrex inverter below and it appeared that one of the batteries could not take it.

Since it was late in the day and everything appeared to be normal now with the boiling battery removed I shut the battery compartment and adjourned the technical foray in electrical systems and headed to happy hour.
Early the next morning just before breakfast the offending odor returned. Since I knew right were to look this time I headed for the battery compartment again and sure enough the second engine battery was now venting hydrogen. Now I’m thinking bigger problems than just a bad battery and I shut down the electrical system.
After breakfast I put on my dress shorts and with my handy volt meter started tracing wires to see what was going on.

Turns out that this large relay circled in red below is constantly engaged connecting the coach and engine battery systems together so as long as the Xantrex converter is running the coach batteries are being charged.

A little more poking and I discovered that I could pull this fuse circled in red below and cause the relay to disengage separating the battery systems. That fixes the immediate problem for now until I can get new engine batteries and determine what the larger picture here is about the connected battery systems and potential over charging.

After packing everything back up leaving the fuse out for now I returned to my hammock to ponder the electrical puzzle and I spent the rest of the weekend between the hammock and the hot tub. (Life is rough)

Next weekend is Labor Day weekend and there will be plenty of time to work on the coach.
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Back in civilization again with access to a high speed internet connection, the research on the electrical problem started in earnest. Electrical schematics and parts descriptions were downloaded, RV repair forums were searched, and a picture and a plan starts to form.
Several owners have seen problems like this on their coaches. Usually the problem is bad or old batteries. If one cell is bad in the battery it cannot take the constant charge rate that is applied when the relay is open.(Which was the case with my batteries).
So first thing is new chassis batteries.
Second several of the long term coach owners that have learned by the school of hard knocks, do not allow the coach and battery systems to be connected constantly as is the design of the system. They leave them disconnected most of the time allowing them to connect only a day or so before they want to start the coach. This allows the chassis batteries to charge enough but doesn't constantly charge them while the coach is plugged into shore power. Chassis and coach batteries are fundamentally different batteries one is quick start the other is deep cycle. Optimum charging patterns for these are different and while they can be connected for short time frames long term connections of the systems could be bad for one set of batteries or the other.
So the plan on Labor Day is install two newly procured chassis batteries to the tune of $250, and monitor the system closely. Long term when connected to shore power on an extended basis disconnect the systems until the chassis batteries need a charge.
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Labor Day 2010
Saturday morning Labor day weekend dawns gloriously over Crow Wing 11, as documented by Margaret below. ( I was sensibly still in my warm bed at this time of the morning)

First thing this weekend is put in the new batteries.

Supporting the old adage that nothing is ever easy my conscious wouldn’t let me put the new batteries in to the old rusted battery tray that was corroding and full of battery acid.
It looks like this battery venting has been going on for a while because on closer inspection of the battery compartment there was some long term corrosions apparent and if left unchecked would destroy the tray in the future. So the whole tray was going to have to come out and be sanded clean and repainted with rust proofing paint.
What was going to be a simple “put in the new batteries”, turned into a day long cleaning, and painting adventure.

All of the inside of the battery bay then the tray components themselves.

Finally the tray is all cleaned and the the painting begins.

Nothing is every easy! On disassembly the big bearings that slide the tray are found to be full of dirt and grim and need to be removed and cleaned before reinstalling them.

A job well done! New chassis batteries, new hold down straps, nice clean well operating battery tray. Much better!

After the work is Happy Hour on the dock for the last time in 2010, because tomorrow the dock and boat lift come out for the winter, and the hot tub and water get drained for the season.