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Chumley 08-25-2015 07:33 PM

Re: My SMB Sprinter Van conversion building experience
So my current situation has led me to believe that I have a bit more to learn about the batteries and charging. There is a lot of information out there so I will need to do some filtering.

Here is what has happened in the last 4 days.

I picked up Charlie Friday afternoon and drove home 140 miles. I felt this should have left the batteries fully charged right at 12.7-12.8 volts but it was 12.4 volts. I was surprised but just pushed it to the back of my mind. I now accept the explanation that the refer and the water pump were on as well as me cranking the stereo with the new subwoofer so I understand (the refer was empty so it was constantly trying to cool, the water pump probably no load since there was no demand). The SMB West crew will be more diligent in the future about leaving items on after a test.

Sunday morning I saw the voltage had dropped to 9.6 volts and I was pretty freaked. I had always been warned that deeply discharging deep cycle batteries could kill them and was trying to stop the drain but to no avail. This is when I actually discovered that the refer and water pump had been on the whole time. I tried driving to let the alternator charge the batteries but nothing happened. This leads me to believe that there is a minimum voltage threshold at which the charging system will do its job, apparently right at the 9.6 volts mentioned by Scalf77. I tried shore power charging and nothing happened so I was really bummed. Voltage continued to drop and I ended Sunday afternoon at 7.7 volts.

Monday morning the voltage had dropped to 4.6 volts and I was sure the batteries were toast and I was getting just a wee bit angry... Peter from SMB took a while to get back to me but in the mean time I found out (or feel it was likely) that I had possibly tripped the GFI on the receptacle normally powering up Charlie so after a pushing the reset the charging system did work! The batteries started charging and when Peter finally called we had a long talk about what was going on. We agreed that I would leave Charlie charging overnight and then check it in the morning. At the end of day Monday the batteries were on float charge at 12.8 volts. Great news but wondered why it didnít read 13.1 volts.

Tuesday morning the batteries were on float charge and sitting at 13.1 volts so I felt much better.

I drove to the dealer to get the major service done and I checked the voltage before I left the dealership and it was at 12.6 volts after sitting for about an hour. I was a little unsure about why it wasn't a little higher but had the service writer agree to check it for me sometime later. I called back about 5 hours later and he said that it read 12.7 volts. Not sure why it went up but I feel much better, whew!

Peter called and we spoke a little more in depth about the battery situation.

He said that the batteries that they normally install provide 90 amp/hours each so we had a combined 180 am/hrs. The Optimas that were installed (2) were 66 amp/hrs each (model SC27DM, new on 11/11/14) so we have 132 amp/hrs now which would explain why I felt that the batteries were not holding their charge as long. I was told that they should charge more quickly but I would like to have that additional time before charging. So there is the trade off that was made and I think the next batteries will be the ones originally installed because I want more time between charges vs. the perceived quality of the Optimas vs stock.

At this point there has been no talk about a special charging regimen to bring the batteries back up to their full potential. I am being told that the batteries are new enough that there should not be an issue.

So I have been told that at 12.4 volts the battery has been discharged 25% and that is the lowest regularly achieved level that is acceptable before long term damage will occur. I have to say that for me the batteries normally drop to that level in about a day from a full charge. I am used to putting Charlie on shore power for charging 1x a week and the voltage has usually dropped to somewhere in the low 11 volt range before being hooked back up for charging. I just saw a chart that states that at 10.5 volts the battery should be 100% discharged which would explain why anything under that point would allow the battery voltage to drop even more quickly under a load since there really isn't any juice to keep the voltage up. Make sense? This means that I need to change something or expect to lose the effectiveness and longevity of my batteries.

My local shop said it could be the detector/alarms that are creating the biggest issue with parasitic drain. I tend to agree and would sure like to know which fuses I should pull when Charlie is resting in the driveway to eliminate this.

So I will be keeping an eye on my batteries and appreciate the lesson I just learned but wish I didnít have to learn it the hard way.


Here is a handy guide from Optima that might be informative:


daveb 08-25-2015 08:46 PM

Re: My SMB Sprinter Van conversion building experience
The vehicle alarm should be on the starting battery system not the house system. Lots of conflicting info here. I'd let SMB sort it out.

Scalf77 08-26-2015 07:40 AM

Re: My SMB Sprinter Van conversion building experience
i expect that your fuse box has a three amp fuse for CO & Propane detectors, those are the normal always on loads for the house side. That doesn't mean that some sort of custom equipment could bypass that. You will need to be more diligent now about charging back up, especially with your smaller battery bank. I would also assume that your previous regime was not working so well, based on the life span that you got out of your original batteries.

My personal opinion is that I either disconnect the load on the battery bank or I keep it plugged in at on a float charge. Your battery life span will be determined by the number of discharge - charge cycles that you put it through. The depth of discharge will lesson the number of cycles you will get. If you consistently draw your batteries down 80% you will get less number of cycles than if you draw it down 50%. Other factors include time between discharge and charging, and bringing the battery to full charge. You now have about 66 amp/hrs as your 50% target.

The major problem with using voltage as a health indicator or gauge of your battery is that the charts are mostly based of a no load condition, and usually under the understanding that it has been that way for a couple of hours. You then bring in where the voltage is being measured (larger current carrying wires don't lend them selves to accurate measurements), so depending on where and by what takes the measurements, there could be some inaccuracy in that method. Add to that phenomenons such as surface charge, and it could get confusing.

That is where a good solid battery monitor comes in, they determine State of charge by other means then just voltage. The amp counters basically count amps in and out of the battery. The major draw back will be that as your battery bank diminishes overtime, you need to adjust the capacity of your battery to stay in sync. The smartgauge user proprietary methods to come up with a SOC reading, it is much simpler to install, and more of a set it and forget device. I do not have one myself, but do consider it. The feature I like about the amp counters is that you can use it to monitor your actual current usage. You will know how CO & Propane detectors. See excel chart of data I captured using my XBM.

You don't have to dump the data, you can just turn on a device and check the before and after current draw. I think this really gives you a better understanding of where your power draw comes from.

Another thing that you may run into is temperature compensation, your charger may vary well be monitoring your battery temp (at least on in your case). The temperature of the battery will determine what the proper charge voltages are, most of the documented data is at 25 įC. There is lots of good data out there. I have found the 12 volt side of life a great place to start.


Chumley 08-27-2015 05:57 PM

Re: My SMB Sprinter Van conversion building experience
I thought Iíd report back one last time on Charlieís batteries and then tell you about the other issue I have been holding back on.

Daveb, the guys at SMB West think that everything is fine and there is no reason to go back to see them. They do not recommend any special regimen to deal with the extreme discharge down to 4.6 volts. If anything they say that I have a legitimate claim to go to the battery manufacturer for a cure.

I have no idea what would have happened if I had not gone out to work on Charlie and the batteries were left to discharge for a couple more days. I do think that I would have eventually noticed the chirp from the detectors since I like to sit on our deck, which is right over our driveway, at the end of the day right before retiring to bed.

Scalf77, that is one peck of a lot of info you have there. I do think I may end up adding a better battery monitoring system but wonder if that is really necessary if the generator works well, in theory anyway.

Yesterday early afternoon after I got back from the dealerís service ($961 for the B service here!) I checked the van and it was at 12.7 -12.6 volts after an hour or so. About 24 hours later it was bouncing between 12.5 and 12.4 volts. I guess a drop between .2 and .3 volts over a 24 hour period is not bad but it leaves them at the point where I have to charge them virtually every other day. Not feasible for me.

Of course where is the juice going? I spoke to Peter about the detectors (which I also called alarms) and have found out that it is now legal to have them connected to the fuse panel which can be disconnected for storage, previously they could not be disconnectable. This is something that I will definitely try to do as I donít think that there is anything else that might be draining the batteries other than that they have wires connected to them that lead to something (in other words I always feel that there will be some drain unless the battery is disconnected at the terminals).

I have been holding off on reporting one of the issues that I believe I found after the roof vent repair and roof paint touch up. This issue is a series of dents on the roof right next to the vent that was recently removed and reinstalled 2x (once back about October 2014 and again just last week).

I noticed the dents right after I got home from SMB West last Friday since I wanted to see how the paint job looked. I immediately noticed that something was strange about the reflection on the roof. Upon closer observation I could see a whole bunch of little dents between the driverís side edge of the van and the vent itself!

Other side of vent, no dents.

Of course I just immediately thought that SMBís painter did it because I have seen the elaborate ramps with platforms that SMB uses to work on the roof area of vans. I notified SMB but Peter had left early and was out of town. I would have to wait until Monday to talk to someone about this. In the meantime I put a stop payment on the payment made to SMB for both the stereo work and the other work they performed themselves. Sorry but that is what I do when I see an exposure on the horizon.

Apparently Peter had already gotten the news by the time I tried to reach him on Monday. He got back to me and we discussed the issue and I heard what I believe every consumer has heard and dreads hearing Ė ďthey didnít create the dents and that they were already thereĒ!

OMG what do you do without creating a fatality in the relationship?

I see the van from my deck virtually every day and these dents got my attention right away when I saw them!

No one at SMB had seen the dents but supposedly the painterís guys said he saw them after he painted or something like that. So I am thinking that the person who most likely created the damage was the one telling them it was there before he started?

I can tell you that even though I have had the van for almost 3 years no one has ever gone on that roof. The only people ever on that roof was the original build team and repair guys for SMB West and then the painter. I know this to be true but SMB West says that they have no proof that I never went up there.

This was just very disappointing after I have been as honest as I have been with them over the years. I even caught a mistake on their billing where they missed an $85 item and told them to charge me.

I guess I resent essentially being told that I am lying or didnít know that someone secretly climbed on the roof of the van and then missed seeing it all of that time.

If you were to talk to anyone at SMB about the condition of my van when I took it in they would say it was immaculate. We take incredibly good care of our stuff. This is just really annoying because I will likely take it to a painter after our vacation and have them use body filler and then repaint it. I know it is on the roof but we can see it every day from our deck. We just take really good care of our stuff and I am also worried that SMBís painter might not have done the best job (like proper prep before painting in areas where the silicon sealant was that might create problems with paint adhesion). The painter has left thick paint edges where he pulled the masking tape since he did not go back to feather them and there was some overspray (the overspray comes off with paint swirl remover, already did some).

I am very disappointed in what has just happened but if I look back over what has happened in the past then maybe I should not be surprised. SMB West has stood behind their product but it was me who had to continually point out the issues that were seemingly so apparent.

I also have to say that I guess I understand where SMB West is coming from since they are convinced they know they didnít do it and have been told by what is likely a regular vendor that they didnít do it. I am just surprised that with everything that I have been through and how reasonable I think I have been that they would take this course. Peter has been great to work with and he has bent over backwards to help but he is just one person in the organization.

I never should have let them repair the rust issue, it was under the waterproof seal so it should not have seen any more moisture in our lifetime if the seal was properly taken care of. Sometimes you have evaluate the benefit versus potential loss in these things.

Bottom line is we still love Charlie but a little bit of the luster has tarnished again in my eyes.


Sprinter4WD 08-28-2015 09:28 AM

Re: My SMB Sprinter Van conversion building experience
Hi Chumley

First I want to express my sympathy with your battery/power issues. As a long time RV-er I have encountered and dealt with such issues regularly.

Secondly I think that Scalf77's post is spot on - you probably have parasitic loads (like the propane detector) that kill your coach batteries when the van is sitting for days at a time without being started.

One thing I have learned is that as an RV-er you end up learning to be a power-grid manager - and your power repository is - you guessed it - your coach batteries. If you are like me you will find that over time you grow your battery bank larger and larger - it's just so nice to have a big buffer.

I'm assuming you have checked your coach battery voltage with the van engine running - it should be at least 13 volts - do this with the refrigerator and other loads active. If you don't have 13v or above then I would say you have a problem with the van charging system.

You should ALWAYS use deep cycle RV batteries in your coach. This is because they can withstand many many more discharge/recharge cycles compared to a typical starting battery. I personally recommend and use the Lifeline 6V deep cycle batteries (sealed AGM), but I've also used the Trojan T105's which are wet cell, but much less expensive.

Once the "typical" starting battery is dropped to zero charge (like your 7.7 volts) you have just destroyed a substantial percentage of the battery capacity, meaning it will never hold nearly the same amp-hours it would have when brand new. While the deep cycle RV batteries are more tolerant of this, they should never be run down to zero charge either.

To be honest, in your case I would replace the batteries with some new deep cycles, and put a 100W+ solar panel on top. Why? Not because of the extra power from the solar panel, which is actually quite small, but because it will keep your coach batteries topped off every day assuming you aren't running a power drainer like the refrigerator or 120V power inverter. Then you don't need to put your van on a battery tender when storing it. Once you replace the batteries I would measure your current draw as Scalf77 suggests looking for parasitic current draw. But you could postpone searching for parasitic draw until you come back from Alaska as long as your van alternator is properly charging the coach batteries every day.

REF 08-28-2015 02:29 PM

My SMB Sprinter Van conversion building experience
X2^^, we had similar issues with unknown battery drain years ago that would draw down the the house, then because of an unknown at the time non-functioning isolator, would also draw our starters down, leaving us dead in the water after 2-3 days of being parked. Replaced all batteries with Deka AGM's (east penn), and added a Kyocera panel with now a blue sky SC30 charge controller, we haven't had issues with battery drain since going with solar and our batteries are always topped off, which is better for them in terms of lasting much longer, plus we can extend our time off grid pretty much indefinitely, in fact, we never find the need, nor do we want to stay anywhere anyways to plug in. Good luck but I really think going with a simple solar system will cure the problems you're having, these rigs have so many different electronic systems and miles of wiring, there's always going to be a draw, I would stop trying to track them down, never going to find them all, that's my experience anyway. I wouldn't think you would need to go back to SMB for solar install either, find a good local shop that deals with RV's or solar.

JJSporty 08-28-2015 06:49 PM

Re: My SMB Sprinter Van conversion building experience
Iíve wanted to share our experience with the electrical and heating systems in our 2014 silver Sprinter SMB for a while and Chumleyís latest posts motivated me to chime in on this thread. Before sharing our experience, I want to thank Chumley for all he has shared throughout the trials and tribulations of his build. I think weíve probably all learned a lot from his contributions to our community. I know his experience contributed heavily to our design and second SMB purchase. If you want to see our new silver Sprinter SMB, go to the following link.

Note: we are NOT the couple pictured on that page nor is the white van they are standing in front of with cherry cabinets and light gray counter tops the van shown in the rest of the photos. We purchased this Silver Sprinter in the photos with maple cabinets and black counter tops which was built for the 2014 Pomona RV show right out of the SMB West showroom in January 2015. It is a modified RB 151S and shares a lot of its floorplan with Chumleyís. We love the openness and functionality of the design.

Our electrical system consist of the following components, all installed by SMB West or ordered by SMB West as options on the original Mercedes-Benz Sprinter chassis.

(2) 100 watt Zamp Solar panels & Zamp controller. The van was pre-wired for solar and the panels were installed for us by SMB West as original equipment following our purchase of the van. They did an excellent job mounting them to the factory roof rails using custom fabricated brackets. They sit about three quarters of an inch above the roof allowing ventilation between them and the roof. Iím pretty picky about this kind of stuff and Iím extremely pleased with how they mounted the solar panels.

(2) 90 amp hour group 27 UB12900 sealed lead acid AGM batteries also installed by SMB West as part of the original build. I was initially concerned about the UB brand because my research indicated Lifeline or Concord AGMís were the top rated batteries for this use. This is why we put new Lifeline AGMís in our 2006 E250 SMB in 2013. However, so far Iíve been quite pleased with the performance of the UB batteries SMB installed.

Our 2014 silver Sprinter came with a 12 volt master shutoff switch which completely shuts off any 12 volt draw on the house batteries. In our 2006 SMB, we needed to remove the fuse for the CO detector when not using the van for several days. Since this van is all diesel, with no propane, it doesnít have a hard wired propane detector. It does have a CO & smoke detector powered by a replaceable battery rather than hooked up to the 12 volt system. If there is any 12 volt phantom draw, the 12 volt master shutoff switch would protect the house batteries. I find the 12 volt master shutoff switch to come in handy when letting the refrigerator dry out between trips. Because there is a light in the refrigerator and the door needs to be open to let it dry out, the light would stay on if it wasnít for the 12 volt master shutoff switch.
For delivering AC power, our SMB has a 2,000 watt Magnum true sine inverter which was installed by SMB West as a component of the original build. Weíve found it works great. It seems better than the 2,000 Triplite modified sine inverter we had in our 2006 E250 SMB. It seems more efficient and the microwave oven sounds happier than in our previous SMB.

The final component in our electrical system is the MB factory installed high idle control which enables the vehicleís diesel engine to act as a built-in generator. Equipped with a 220 amp alternator, by starting the engine for a few minutes to warm up, then setting the high idle to around 1,200 rpm, then turning on the invertor and microwave, we are able to take the massive load off the batteries for the few minutes the microwave is running. A few minutes after weíve finished cooking in the microwave, we turn the engine off and the batteries are unscathed.

Before commenting on our heating system, I want to say, the (2) 100 Zamp solar panels, the Zamp controller, the (2) UB 90 amp hour group 27 AGM batteries, along with the 2,000 watt Magnum invertor and high idle have made our setup well balanced and more than sufficient to meet our electrical needs. I was skeptical at first but Iíve been extremely impressed by how well this setup works. I donít know what Zamp does but it seems like thereís some proprietary magic going on in their solar panels and controller. Iíd highly recommend this setup to others. This being said, my wife and I come from a camping background where electricity is a resource to carefully monitor and meter out. We tend to be on the miserly side and conserve wherever we can. We also usually only stay in one place for 2 to 3 days before driving several hours. But with good sun and this setup, we could probably stay much longer in one place. We also donít need to plug in to shore power to keep our batteries charged like we used to have to. Our batteries stay at 12.5 to 13.5 at night and when the sun comes up, jump up to 14+. Good sun will pump as much as 11 amps into the batteries from the solar panels and as much as 80 amp hours in a day. When you combine this with the high idle for heavy loads, this setup provides a balanced electrical system for us.

Since this post has gotten so long, Iíll save our Espar diesel D5 hydronic heating system for another post. Itís all good and we are happy campers.

Chumley 08-31-2015 05:36 PM

Re: My SMB Sprinter Van conversion building experience
Okay, there is a lot to work on to get the battery management situation to where I would like it now.

Charlie is at the local shop getting the generator worked on. I should start a thread about the PowerTech diesel generator but maybe I'll do that later...

One thing that I just had done was taking the power for the gas and carbon monoxide detectors back to the main coach switch. Now there will be no draw from anything active when parked for storage. Storage for us means just a week or so at a time but it should make a difference.

I also ordered a 12 volt solar battery charger that will plug in to a cigarette lighter type plug and perform a trickle charge. At least that is what I am hoping. It is a 6 watt, 400 mA. Please tell me if you think that it's a waste, of course it's too late as Amazon Prime is whisking the product to me so I can see what'll happen in just a couple days.

So planning for a nice long trip always brings out the maintenance guy in me. I'm normally very good about day to day stuff but I will admit that I have not taken care of some of those little things I usually do because of all of the community work I am involved in lately. So now I wax, treat the plastic and vinyl, clean and treat the leather and generally get into the nooks and cranny's to do a good cleaning. Driving around in a clean house for 3 weeks will be nice.

Weekend before last I was watching in horror as my batteries declined to an alarmingly low level but kept myself occupied by detailing the exterior. Very effective distraction.

I waxed the exterior with NuFinish car wax. Itís become my favorite and has served me so well that I havenít tried anything else in years so if you have a personal favorite please let me know what it is and why you like it so much.

I love the slippery feeling of the wax and I swear that when combined with the recent big service Charlie seems to move a little more smartly down the road. I swear Iím seeing increased power and fuel mileage. Might have something to do with the service but I think the only thing that might effect performance at all was a fuel filter change.

This last weekend it was all about cleaning the exterior plastic and vinyl.

The vinyl bumpers and side cladding were looking a little oxidized so I did some extensive research and think I have a winner. Of course these days extensive research takes about .39 seconds for over 2 million results.

I pushed the order button and 2 days later I had a bottle of Meguiars 39 Professional Heavy Duty Vinyl Cleaner. It was brilliant and cleaned the vinyl quickly and effortlessly. Of course thereís enough vinyl to keep a person pretty busy for a while.

This weekend I will use the ReNu Pro Plastic Restorer to protect it and give it some of its richness back.

I applied 303 Protectant to the interior plastic and vinyl parts and it made a subtle difference but the interior really looked pretty good to begin with. I use 303 because it leaves no residue, slippery or anything and no dust, and Iíve had luck with it for over 20 years.

What made me feel really good was cleaning and treating the leather.

Our entire interior is upholstered in leather so we always keep an eye on how itís doing. We have noticed that the nice light tan inserts in the driverís and passengerís seat was starting to show some dirt. I always wondered if that would be a problem but with just a little leather cleaner the dirt came right off! I used some Lexol leather conditioner and everything is nice and supple.

I took a moment and just looked inside at our build and smiled.

I think we all love our builds and I do really appreciate ours. It just works so well and it still looks great to this day. I really like the colors of the materials and the fit and finish is pretty darn good (well, I did have to have some of it redone to get to this point though). Everything still feels solid and we have a few rattles but I guess you canít avoid them.

I was outside and the sun hit the side window and showed me what a recent repair to the upholstery looks like from the outside.

Not very pretty to me but then I guess SMB does not consider this to be a concern. Iíll let you decide what you think about this repair which was completed to re-secure some upholstery that was pulling off the backing panel. Doesn't look like they removed the panel to secure the edge of the upholstery... Looks like someone got a little overzealous with the stapler and a spray can of adhesive tooÖ don't run your hand back there because there is a least one staple that broke off... don't ask me how I know...

So weíre getting Charlie ready for about 7,000 miles of open road. We will be avoiding most of the main freeways where possible and enjoying some nice back highways. The van handles so well and has enough power that mountain roads are a joy.

This may not be the best time to head north to Alaska but sometimes we canít control everything like we would like. Heck, last year our September vacation got pushed back to end of November so weíre doing pretty good this year.

Iíll keep you all posted about how the generator repairs come out but I canít help but think back to what my sales guy said about generators being more work than they are worth. It sure is nice when it works thoughÖ


Chumley 09-03-2015 04:47 PM

Re: My SMB Sprinter Van conversion building experience
Just got Charlie back and the local shop could find no problems and they said the generator started right up multiple times. I picked up the van and it started right up for me too!

Pretty frustrating.

For now I will just use the generator until it stops running and hope that it stops altogether and gives me a real opportunity to diagnose the problem or maybe it will just run normally. Of course just running normally would be a lot to expect.

The good thing is that while speaking to the shop owner the other day he recommended that I consider using a small portable solar charging system that I can plug into a cigarette lighter outlet. That sounded good so I went out and ordered one. Of course the one I ordered was too small... it is a 12 watt solar panel with 6 watts and 400mA.

So now I'm ordering another one which I hope will take care of our battery maintaining issue, 12 volts and 15 watts and 830 mA. I just want the charger to keep the batteries at a fully charged level when I start out close to a full charge and park it. This solar charger does not appear to be able to charge anything quickly but the goal is to keep the batteries topped up while sitting in the driveway. It is not something we will count on for use when on the road, although I hope they help reduce the need to start that generator as often.

The other thing is that the gas and CO2 detectors are now powered from the 12 volt main panel and can be switched off with the main switch. That should help with the drain when switched off. The only little issue is that the switch has to be on to charge the batteries with the solar charger since it works through the 12 v cigarette lighter. I think that's one of the reasons that the little 6 watt solar charger wasn't the right answer, it can't maintain the batteries and overcome that drain. Oh well...

Hopefully I'm getting a handle on the battery situation. I had lived in ignorant bliss this whole time just doing what I was told. After about $550 for a new set of batteries and seeing them go flat you realize that you have to pay attention, at least it did for me.



twogone 09-03-2015 05:05 PM

Re: My SMB Sprinter Van conversion building experience

Originally Posted by Chumley
Pretty frustrating.

I have been amazed many times in my life... happens to this day... a problem with a mechanical thing self-corrects when the mechanic is there. I often tell my mechanics "it'll run perfect while you are here"... same with plumbers... electricians... A/C dudes... amazing

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