Chassis batteries

[Harold and Gloria Skipworth]

After having charging problems due to the xantrex RS200 throwing fault codes (M0 F26) trying to charge very depleted coach batteries. I found that I had to replace the coach batteries which relieved the problem.  In the process of looking for solutions in various posts I noted comments regarding a "Echo Charger" which is supposed to maintain the chassis batteries when connected to shore power.  Try as I might I cannot find a Echo Charger anywhere.  How are the chassis Batteries charged if there is no echo charger?  2005 Monterey IV

[Gerald Farris]

Harold,
Your coach does not have an Echo Charger. Instead your coach uses the "Bird" system. With the "Bird" system both battery banks are automatically tied together with the "Big Boy" solenoid when either battery bank is being charged, and isolated from each other when not being charged.

Without a properly functioning "Bird" system on your coach, the chassis batteries would only be charged by the engine alternator while driving, and the house batteries would only be charged by the inverter.

Gerald

[Andy Clark]

I added a Battery Maintainer/Charger to charge the chassis batts when hooked to shore power. I mounted it to the forward wall of the batt compartment above the chassis batts, and connected it to the 115VAC plug in the engine compartment that's also used for the block heater. Now both sets of batts get charged when on shore power. A cheap, easy and reliable fix.
Andy

[Keith Oliver]

Warning.  Constant vigil is required in order to avoid chassis battery death.  
I replaced my batteries in the first week of owning this coach, after unwisely leaving the coach unplugged with the batteries connected. I also added a dedicated "smart" charger and a positive cut off switch.  These are necessary due to the constant draw to the ECM of something over 2 amps, and the limited, or non-existent trickle from the roof top soar panel (the small one, 14x14).
Most recently, plugged in for a solid month, dedicated smart charger hard wired to the chassis batteries and plugged in, my chassis batteries died again.  Turns out the trickle charger failed.  The amount of current coming from the solar panel on the roof was obviously not enough to keep up with demands from the ECM and whatever else is wired to the chassis batteries.
The fix (? I hope this works) is a cheap battery charger that is not hard wired, but will sit on the ground below the batteries, so that I can see it working. No longer will I rely on the quality of an electronic unit hidden behind a closed door.

[Harold and Gloria Skipworth]

An update to my earlier reported problems.  After 3months of having to monitor the xantrex control panel for failure codes requiring a reset to restart the charger I made an appointment at Crusing America RV Service Co. in Celina Oh.  I had the Xantrex RS2000 replaced with a magnum MS2012 along with a new AGS and remote control panel.  On the way the Xantrex completely failed and my chassis batteries were near dead.  I got road service out they said the alternator failed and replaced it.  I had to use the boost from the house batteries to start the engine but the engine died as soon as i released the boost.  Road service said the chassis batteries were bad and replaced those.  This got me back on the road but I still was not showing a charge from the alternator.  I made it to the Magnum dealer and got the new unit installed.  I could now charge both batteries with shore power and with the gen set.  Still no output from the alternator.  I drove home with the gen set running and plugged in to shore power.  I now have to find out why a new alternator won't charge the chassis battery.  It seems to me that the charging problems started after I had work done at a Cat dealer who updated the progaming for the engine.  Does anyone know if the software can control the alternator output?  I am almost afraid to go back to the Cat dealer if they caused the problem.

Any help will be appreciated, Harold
2005 Monterey C9-400

[Steve Huber]

Harold,
It's possible that the new alternator blew when they replaced it, but not the nearly dead chassis batteries.
Steve

[LarryNCarolynShirk]

Harold,

Did road service check the alternator output, after installing the new chassis batteries?  Dead batteries put a heavy load on the alternator.  That load may have been too much for the alternator.

Larry

[Edward Buker]

Harold,

The engine CPU has no capability to control the output of the alternator. That is done by an internal alternator voltage regulator. Seeing it is a new alternator, you may be able to get it replaced under warranty, at least for the part. If not, I would take it off and bring it into a reputable alternator service shop, and have them check it and replace any defective parts, if cost effective. Beyond the alternator is either a big boy system or an isolator that could play a role in not supplying charging current, but my guess is that the alternator itself is at fault.

Later ED

[Roy Warren Co-Admin]

Have you replaced the "BIRD" (Bi-Directional Isolator Relay)?  This is the unit which charges your chassis battery when the coach batteries are charged.
Roy

[Gerald Farris]

Harold,
Your 2005 Monterey uses a "Bird System" to tie the battery banks together if either battery bank is being charged. The engine alternator is tied directly to the chassis batteries, and will charge them if it is not defective.

So you definitely have a defective alternator or a wiring problem to it as well as a defective "Bird System" if the chassis batteries are not being charged when the inverter is charging the house batteries. The ECM (Engine Control Module) or its programing can not effect either system.

Gerald  

[Keith Oliver]

I just installed a "BIRD", actually it is a Blu Sea Systems Start Isolating Automatic charging Relay (SI-ACR) part no 7610, that I paid $124.81 for at Benlo RV in Indio.  I had a local auto supply shop make up a pair of connector cables for another $15.  This replaces the defective Echo charger and failed separate trickle charger.  

[Harold and Gloria Skipworth]

The end of a long story and expensive lessson, I hope.  I contacted the Cat dealer who said he would try to locate the problem.  he asked if I had wiring diagrams, so i looked.  Lo and behold I had the book with diagrams for nearly everything but a Monterey, but it did have a DC wiring diagram for the chassis.  With a little study I saw the alternator output comes through a fuse block first.  I found the fuse and it was blown.  I have two on order and am hoping for the best.  I did also note that usilng the genset to maintain the chassis batterey will only work if the inverter/charger is functional.  Mine wasn't.  Praise be to Magnum and Crusining American RV Service Co.  They are the best.

[Edward Buker]

Kieth,

I also looked at the 7610 and actually worked on that system on a friends boat with dual 60 amp alternators. It is a nice compact system. One thing that concerns me is that the 7610 is rated for 120amps and the alternator is rated at 160amps. We have some pretty heavy duty battery banks that can send a lot of currrent between them depending on the differing bank charge state, along with the alternator output current coming into play at times. It may be fine but keep an eye on it.

If it were me I would consider adding an ANL 120 amp fuse and holder in series with the charging relay. It is less than $20 and beyond protecting the 7610 it will let you know if the inrush current exceeds the 7610 rating at times. If that fuse does not have issues then I would also go this way when my Echo Charger bites the dust....probably just jinxed myself.

http://www.amazon.com/Amico-120AMP-Subwoofer-Amplifier-Installation/dp/B00BM3B8ZA/ref=sr_1_8?ie=UTF8&qid=1363752729&sr=8-8&keywords=anl+120+amp+fuse

http://www.amazon.com/Littelfuse-298900-Automotive-Single-Terminal/dp/B001FXL4Q0/ref=sr_1_5?s=hi&ie=UTF8&qid=1363752974&sr=1-5&keywords=anl+fuse+holder

Later Ed

[Edward Buker]

Keith,

I took a closer look at the 7610 specs and I found that the 120amp rating is continuous duty. It actually has a 210Amp intermittent 5 minute rating so you could either skip the fuse or put a 200 amp fuse in series with it just in case you got a shorted battery or some other abnormal load. The device itself should be heavy duty enough for this application.  

The only good things about the old echo charger system is that it tapers the charge current independenty on the starting bank as the battery voltage rises stopping any overcharging and limits the current flow with a fuse to 15amps. With the 7610 whatever the House Bank sees for charging characteristics will now be the same for the Chassis Bank, there is no monitor/charge function. That should not be a significant issue given the house charging system should eventually taper the charge based on the charge state of all of the batteries that are now combined by the 7610.

Later Ed

[Keith Oliver]

Ed:

Thanks for looking at this issue.  The literature that came with the 7610 certainly didn't provide any analysis of the characteristics of the unit, so I was reliant on the knowledge of the vendor, who, by reputation in the area, seemed to be the best guy to ask.