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Charging System project

This project has been completed in its present form for about a year now, but I apparently didn't post about it as I was running out of time to leave our home base for our Canada/Colorado/Texas trip last year. I was reminded about it because of Chuck's recent chassis battery options thread and responses to it giving pros and cons to various approaches to the issues of chassis battery charging while not moving and battery isolator and boost switch options from fully automagic to full manual as well as Foretravel's OEM approach which has worked and continues to work for many. These are important issues for all of us reflecting expensive failures and reliability concerns. After all, who wants to be stuck at a busy truck stop fuel pump (or anywhere for that matter!) when the coach won't start after fill up?

So this post is my approach to the issue and I wouldn't dream of suggesting that this is the one best approach. Only time will tell how well it works for me. First some background as to what motivated some of my decisions. While on the way back from our first trip to Canada in 2014, the OEM diode based isolator failed resulting in some expensive repairs. As I remember it, we were leaving Soledad Canyon Thousand Trails campground near Acton, California. The first thing I noticed is that my backup monitor went black. Then I noticed that my SeeLevel 714 tank monitor display was showing 17 volts. I immediately pulled over on to the dirt shoulder which was fortunately wide enough to get completely off the road with plenty of safety margin. I hopped out of the coach and opened the house battery compartment and was hit with the strong smell of hot sulpher :o . I fairly quickly diagnosed the isolator failure but was puzzled by the failure mode. Somehow, the sense wire must have been connected to the failed side of the isolator and then the alternator's regulator put out the MAX voltage in order to try and bring up the chassis battery. This is several years ago, so I don't remember the details about what I figured out. I still had the two MK 8D Gel batteries at the time, and although they undoubtedly suffered some damaged since they had obviously vented, they appeared to be still functional. The two Red Top starting batteries were probably needing replacement by then, but this episode certainly helped them along. The first casualty I noticed however was that the SeeLevel 714 display was dead and smelled like burnt electronics, though ironically, the voltage part of the display was still working.

Anyway, once I figured out that the isolator died I got on the forum and got the skinny on how to bypass the isolator to get her back home (Thanks Brett Wolfe!). Once again, the forum came through for me and got us back on the highway in short order... I almost felt like I was cheating ^.^d . Unfortunately, the start batteries and the SeeLevel 714 were apparently not the only casualties of the Isolator failure. I don't remember them all, but shortly after we got back to Pio Pico Thousand Trails (our home base at the time), the HWH computer failed. It wouldn't go into travel mode, though the leveling controls still worked. I worked through the trouble shooting steps in the manual and finally got through to HWH's tech support via a call back after leaving a message. All diagnostics leat to the dreaded statement "Replace the control box". That one cost me a coach buck! I opted to get HWH to build me a new one rather than repair the old one. The old control board had a bunch of jumpers on the motherboard which, in my opinion, should have only been used on a prototype. The new one was basically jumperless, meaning that the revisions had been put into the circuit traces on on the motherboard. The repair likely would have been much cheaper, but I felt more peace of mind replacing it, so I paid the toll. The actual cost of the new one was about $1400, but they gave me credit for sending back the old one. The price of the most expensive possible repairs on the old would have been $948, so that was the price I could get a new one for, provided I sent the old one back. There were some other less significant failures as well, but I have forgotten the less costly ones.

I lived with isolator in bypass mode for a year or more while I pondered my approach and bought the components I would need. Bypassing the isolator meant that the house batteries were not getting charged via the alternator, unless the boost switch was on. This was not much of an issue as I had by that time added solar, and with the four 8D AGM batteries I installed in the mean time, we had plenty of capacity. The boost switch worked intermittently, as it had since we got the coach. I would often have to cycle it on and off several times to get it to connect the two battery banks together, so finding a better solution for that function was on my radar as well as redoing the battery cables for the chassis batteries. I had previously redone the Inverter set up, added solar, moved to four 8D AGM house batteries, etc. I also wanted to put in a chassis battery disconnect switch like the one I had put on the house batteries. I had already replaced the two Red Tops with a single O'Reilly AGM8D, but I was occasionally experiencing slow cranking without the boost switch. I had always planned on changing the chassis battery cabling to 4-0 marine cable and adding bus bars to better manage the DC cabling and connections down by the chassis battery. Also, the isolator panel always struck me as looking a mess and along with replacing the disintegrated engine compartment insulation, had long been on my wish list to clean things up.

I wanted to prevent the possibility of having the alternator cook various expensive parts of the electrical system, so I decided to add a Sterling alternator to battery charger. This is a multi stage charging system regulator which take the output of the alternator after the built in regulator and outputs a multi-stage output to the house bank while sending the unaltered alternator output to the starting battery bank. At least that is how it is designed... As designed, the Alt-to-bat charger could replace the isolator. However, I wanted to have both batteries to have the multi-stage charging output, so I added a Sterling ProSplit R Zero Voltage Drop Battery Isolator to the mix, as well as a Sterling Battery to Battery Maintainer (3 Amp) for the chassis battery while parked. This last is similar to other charge stealing battery maintainers and only steals current form the house bank when the house bank is above 13.3V. As for the boost switch, I decided on the Blue Sea 7713 RBS (remote battery switch). It is a 500 amp continuous magnetic latching relay with a lighted remote switch and a manual lockout on the unit itself. I did have to run a pair of 16 gage wires up to the side console up front and put the switch in the same place the original boost switch was. Since I also decide to replace the voltage gauge in the dash with a Victron battery BMV-702 monitor, I also ran a couple of cat 5 cables up there as well.

The first part of the project after disconnecting the chassis battery cables, was to remove all of the deteriorated insulation in the engine compartment. Not a pleasant job, but not rocket science. After that was done, I rigged a support to suspend the old isolator panel from the bed platform. The isolator panel on our coach was three 11 gauge steel panels with rivet nuts arranged in a pattern to hold the various components. An important part of the process involved trying to figure out what each of these components was for and which would be replaced during this project. I also made a platform which spanned the engine compartment to stand on while working on this project. The old steel panels were rusty and the way they were mounted to the bed platform seemed rather improvised to me, so I went to the local recycle place and found some black ΒΌ" thick aluminum sheets that were just about the right size when stacking two of them vertically. I also used the same aluminum sheets for the Alt to bat charger which I decided to mount in the alcove where the transfer switch and electrical panels are. In order to make the connections accessible on the alt to bat charger, I mounted it on drawer slides with a lockout feature with enough cable slack to pull it out fully. I used 2-0 marine cable for the alternator high current connections. I used the same basic relative locations of the isolator board components so that the wire management for the new parts stayed the same as the components they replaced. For instance, the old boost solenoid  was located near the bottom curbside of the isolator panel and the large 3-0 cables that connected the two battery banks together were just long enough to reach the Blue Sea remote battery switch which I mounted in the same location.

Wiring the A2B was straight forward and I made it easy to bypass should the unit ever fail, in which case changing a couple of connection points will use the alternators built in regulator to charge both banks through the Sterling isolator. I was concerned about sufficient air flow for cooling for the A2B (Alternator to battery charger), so I took out the speakers that were in the bed base and put in a computer cooling fan. It has been working well for over a year with one four month trip to test it. There are many possible choices for each of these components. So far, I have been satisfied with the ones I chose. The batteries seem happy and I rarely see the Victron battery monitor show 14 volts for more than a minute or so. It usually settles in at around 13.6 or so by the time I get to the road. No battery bank combining is necessary to spin the starter, but I sometimes use the Blue Sea switch just to test the function. This sort of option is not for everybody, but it really isn't that much different from the OEM as far as basic function. There is an isolator (that is computer controlled), a boost function (with a relay that doesn't consume power while operating except for changing state), and multi-stage charging for both battery banks. While it wasn't a simple install, I had fun doing it and the operation is a simple as can be. Works for me...
Don

Re: Charging System project

Reply #1 –
Here are a few pictures while in the process of doing this project, including labels of what the components on the isolator panel are based on research that I did at the time.
Don

Re: Charging System project

Reply #2 –
Don, thank you for the post.  I too have been following the previous posts in the discussion of various charging system projects.  Since I have a 97 40' 295 with the isolator and relays mounted in the rear on the drivers side frame outside, I am carrying spare isolator and relays.  (Previous coach, Monaco, I also had isolator and relay failures), so I'm also interested in any one that has completed changes on a coach similar to mine (outside isolator location).  I realize many have moved the isolator into the foot of the bed area, and that may be a possibility if I choose to install the new spares.  Pictures of course are so usable as seen from Don's post.

Re: Charging System project

Reply #3 –
Ours sounds like it's in the same area as yours Jack,we redid ours and kept it in the same spot,new everything on the metal
plate and painted the plate and surrounding frame areas,we only drive in the rain when we have to so that helps with the water.

Re: Charging System project

Reply #4 –
Don, well done as usual. Where did you put the Sterling A2B ?

Here is a link to another one of these projects I did.
Delco 40si 240 Amp Alternator, Sterling ProSplitR Installation

One of the pictures incorrectly says the excite wire goes to the Delco, it does not, it goes to the ignition post on the Sterling ProSplitR to power it up when ignition is on.  The Delco only gets a battery voltage sense wire.

Re: Charging System project

Reply #5 –
Thanks Roger. The A2B is located on a pull up aluminum plate that is in the center of the alcove directly behind the isolator panel.
Don
Quote from: Roger & Susan in Home2 –
Don, well done as usual. Where did you put the Sterling A2B ?

Here is a link to another one of these projects I did.
Delco 40si 240 Amp Alternator, Sterling ProSplitR Installation

One of the pictures incorrectly says the excite wire goes to the Delco, it does not, it goes to the ignition post on the Sterling ProSplitR to power it up when ignition is on.  The Delco only gets a battery voltage sense wire.

Re: Charging System project

Reply #6 –
Thanks Don for another great write up with pictures! All of these post pertaining to this topic ( and others) helps us members who will need to that sooner or later.

Re: Charging System project

Reply #7 –
Excellent discussion.

As several have already posted, there are quite a number of good choices ranging from very KISS to completely automatic.

Do what fits YOUR needs/desires.

Re: Charging System project

Reply #8 –
A 14.17 house and a 13.97 volt to the engine batteries are more than I would run into the batteries over a long drive.

In cold weather maybe.  Way too high in hot weather for hours of driving from what I have seen.

Wolfe 10 mentioned here using a 13.6 volt setup at both batteries banks to avoid overcharging the banks on long warm drives?

Foretravel I think set the adjustable LN alternator at 13.6 new?

Batteries will only accept a certain amount of Amps.  The magnum gauge tops out at 115 amps for our 30-40% discharged house batteries on the start of a daily drive.

As some have much larger battery banks the extra alternator output may well be used.

The 1/5th C charge rate is reportedly the optimum rate to ensure the longest battery life.

The alternate is 1/20th C slow charge.

This is, I assume, why a new Foretravel has a 320 amp alternator and 6 8g8d's and two 120 amp inverter/chargers?

Everything needs to match.

As trying to  temp controll engine start batteries is difficult without a separate alternator the compromise is to reduce the automobile type voltage setting of the alternator to reduce overcharging IMO

My info says the float voltage is less than the 14 plus volt stuff at 70 degrees.  And much less at warm temps.

The inverter drops the volts in hot weather to around 13.2 volts. 

Re: Charging System project

Reply #9 –
I had intended to give a shout out to Alan at Bay Marine Supply., but I neglected to do in my post. So here it is! I bought all of the components for this project at Bay Marine after some lengthy discussions with Alan of the pros and cons of each product category. I didn't necessarily go with his initial recommendations, but I appreciated that he doesn't push the highest profit or most expensive option for any given purpose. He actually looks for what he believes is the most reliable way to achieve a given goal at the least cost. In some cases, he talked me out of some of the more esoteric options. At any rate, I can say that he enjoys discussing technical issues and is willing to admit when he doesn't know something and is happy to place a call to the manufacturer's to add to his knowledge base with the goal of helping customers achieve their goals. I have no affiliation with his business and don't receive any promotional consideration. I am just a satisfied customer seeking value for my dollars.
Don

Re: Charging System project

Reply #10 –
Another 👍 for Alan.  He was very patient going through all of the variations with me and like Don says was more concerned about the end result meeting my objectives than trying to sell one thing or another to me.  He always had the small parts I needed ... the battery lugs, fuses, fuse holders and they all came 2 day mail.  He was careful to suggest safety considerations in wiring diagrams too all of which gives me a safer and more reliable system.  You just don't get that kind of help from somebody on eBay or a bulk parts place.  And all of his help came with prices that I rarely found less elsewhere.  He made a customer for life here.

Re: Charging System project

Reply #11 –
Let me join the Alan shout out.
I bought all my Victron equipment from him. He talked me down several times from spending more than I needed to and making projects bigger than they need to be, all accomplished with common sense.

Re: Charging System project

Reply #12 –
Quote from: Lon and Cheryl –
Let me join the Alan shout out.
I bought all my Victron equipment from him. He talked me down several times from spending more than I needed to and making projects bigger than they need to be, all accomplished with common sense.

Same here... Alan Knows his stuff and what he didnt know he double checked on.. Great guy, Great Company!

Re: Charging System project

Reply #13 –
Alan sounds like me when I have a new building HVAC system to design. I am going to give this guy a call for sure, as I have been putting off the inverter decisions.
 

Re: Charging System project

Reply #14 –
If buying a new inverter/charger ask to get the most recent firmware upgrade and document what version it is.  Xantrex only lets this get done by an authorized dealer.  (This is a downside for me, however, I still like their products and reliability, bought a new SW2012 last year for the FT).

One of the reasons I liked the Morningstar solar products is they post and let you do firmware upgrades over wifi so I can keep myine current.