Originally Posted by willisclarke
Its probably too far down the line for any of this groups interest, however, I was out of town for a few days and said I would wrap up when I return. The new PD9245CV Power Converter was waiting for me when I returned, and I installed it today. It works perfectly, putting out 13.67V DC; the house batteries are at full charge, and the chassis battery, which had decayed to 12V, came back up in less than 2 hours. The Pendant which came with the Unit showed the three mode steps as the Converter was doing its job, and the Battery Monitor which I also bought, is giving the results of the chassis battery on a real time basis. I am a little concerned regarding the chassis battery decay, since it is a fairly new Interstate, and I left with the shore power and both Disconnect Switches off. I don't presently know what could cause a "drain" under those conditions, maybe the battery itself.
I am still following this thread, I am glad to hear that once you decided that the converter was not putting out charging voltage you replaced it. All modern chargers will take of the correct voltage output. As you will find out, having a easy to understand indication of what the converter is doing will be nice. The decay of the Chassis battery may be completely normal.
I run a DP with a Allison 6 speed. My Chassis batteries have two ECM's on them 100% of the time. Even though I can hit the disconnect button on the battery control it only disconnects those loads controlled by the ignition switch accessory position and those that have been added to the chassis batteries that would also count as a switched or non switch accessory.
This little quirk has caused the prior owner to have to replace the ECM for the Allison 6 speed (I think).
There is a emergency start switch on the dash. It closes a relay that connects the coach batteries to the chassis batteries. In the coach instructions it says if the chassis batteries will not start the engine, push the emergency switch and try again. So, one morning after the coach had sit for 6 weeks or so it was time to start and warm up the engine. It had batteries that would not crank over the engine, well I followed the instrictions. The results were a flashing of the lights all over the coach, alarms going off due to low voltage all over the coach and a 125 amp fuse going to the cable running back to the chassis batteries to blow. All of this happened while I was listening for the engine to turn over. Useless emergency start switch was my thought.
No matter what I do at this time I cannot get the coach and chassis batteries connected together because of the bad fuse. My delayed thought here was GOOD!.
So first I check out the coach batteries and converter, good for me is that everything on the coach side is OK.
Checked out the chassis batteries and everything is looking good except that the batteries are low. So, NOT USING the emergency switch I try again to crank over the engine. Batteries are about to the point that they can't hardly move the engine. Classic dead batteries and they are following the expected path. So, out comes the little brown box of a battery charger that my DAD used for the riding mower and waited two days for it to charge the chassis batteries. When they quit drawing current I put the charger away and tried to start the engine again. It started up just fine the dash voltage indicator indicated that the alternator was good and my hand held volt meter also said that the chassis system was working OK.
Warmed up the engine and shut down. Hum, what next? Check out the emergency start switch system. Found the blown fuse. Found and replaced the fuse protecting the cable between the two systems at the coach end. Now the system would connect the two systems together. I will never use the emergency start switch to compensate for dead batteries again. It's only use is to boost the chassis batteries if they are slightly slugish, not if they will not turn over the engine. The voltage drop caused by the starter is just to great to crank over the engine on the coach batteries.
Modified the system so the converter keeps the chassis batteries charged at the same time that it is keeping the coach batteries charged. My system is a dumb system. It only works if the coach/converter is pluged into power and disconnects the two battery banks when the converter is disconnected from AC power. When in use the the system sees itself as one system, that is to say that all five of the batteries are seen as one battery bank. When not in use, the chassis is two batteries with the alternator as the charging source, and the coach is three batteries with a converter as the charging source.
There are smart battery combiners available that control the current to the secondary bank (chassis) and also disconnect when the secondary bank is charged.
But being that my Converter keeps up with the 12 volt load with a little extra and the fact that my coach is almost always connected to shore power every day. This dumb system has worked just fine for two years now. I may upgrade someday.
Never have had a problem starting on the chassis batteries even after a two month storage time. The ECM's are powered up with clean power all of the time. I have one more thing to do that I think is related to this story, the software in the Allison ECM reads out as corrupted. It has been since before the story. It will not read out oil level at the drivers seat. Need to have the computer reprogrammed.
Hope this little story helps someone. Glenn
And yes I am aware that the common system can end up having two charging sources if the coach is pluged into the genset and the genset is running while you are running the engine.
Remember the smart combiner?