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Old 11-24-2020, 12:54 AM   #1
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2016 SMBW Lithium Battery Upgrade (DIY)

Let me start by sharing a little bit of background with my Sprinter Sportsmobile by Fresno, CA.

In 2014 I ordered my first Sprinter 144 4x2 with Penthouse. There was one item we wanted that we did not get. The reason was Sportsmobile West was not offering Lithium Batteries only AGM at the time. We used the 2014 SMB until October 2016 and loved the way the vehicle worked for us.

We had ordered a new 2016 144 4x4 with Penthouse from SMBW that was to be delivered in December 2016. Once again we wanted Lithium batteries but SMBW was still working on developing a system and not available. The only working option was to install the AMG battery that works fairly well but lacking because you only get the use of 50% of capacity.

We have been using the 2016 with great success but in March of this year while camping in the Mohave Desert the battery started to fail causing the refrigerator to stop working at random or the D5 heater would run with no heat. This was all caused because the battery voltage was dropping below the safety features causing them to quit in the middle of the night. It was time to replace my three year old AGM and started researching the lithium option.

There is a lot of information available on lithium since its use has increased rapidly. This also caused folks having all kinds of hiccups installing lithium batteries. Thereís information relating to Alternators and side effects of charging lithium batteries. Some folks burned up their alternator during charging cycles requiring them to invest In Dc to DC chargers, second alternators. All of these at a high cost to make the switch. I did not want to spend a lot on switching out components and adding additional chargers
when I already had a charger and a system that was working just fine. I only wanted the advantages of lithium.

Here is what I learned and did and the reason why I choose this direction.
First off Lithium Batteries cost much more that a AGM Battery. But this cost can be offset by the life of the lithium Vs AGM or Lead Acid. Of all the brands on the market I decided on the LionEnergy UT1300 105 Ahr, they are located in Utah. I started with two and quickly increased my capacity to three for a total of 315 Ahrs of capacity. I installed the first two back in March and added the third battery in October. Iím not going to get in to and lot of details on the battery since this info in readily available on the internet.

My SMB has 200 watts of solar on the roof with Zamp 30 amp controller. Magnum 2000 watt inverter with charger, Blue Sea 7620 automatic charging relay. The Sprinter has standard a 220 amp alternator for charging while driving. LED lighting, Microwave, TV, D5 Hydronics heating and hot water system and Noncold refrigerator. This gives a pretty good idea what is inside the SMB which is somewhat standard issue.

I was able to purchase the lithium batteries from Costco at $700 each which is a pretty good savings. My Magnum Inverter is compatible with Lithium using the remote and custom setup settings for the lithium batteries. The Zamp Solar Controller is compatible and has a lithium setting built in to the controller. This leaves the Sprinter Alternator is it compatible or not with lithium. What I learned about alternators is there is basically three different types and the one used in Sprinters does work. Mine has a steady 14.0 volts
output. The thing that saved me from having to add a DC to DC charger was the fact the Blue Sea Battery Isolator charges the batteries to 80-90 percent charge, not 100 percent. Because of this fact it prevents the high charging that is known to burn up alternators using lithium batteries. Here is the trade off using the Blue Sea, you only get a max of 90% charge while driving. If you are one of those who has to have 100% charged batteries, you can spend the extra money for that last 10% of charge. Having solar takes care of charging the batteries to 100% during the day, and if you have shore power you are all set.

When I started this upgrade there were a few what ifs that needed to be answered, so I progressed very cautiously. I did this to minimize any damage to the existing systems if I could. As it turned out the Blue Sea was the secret and having a good steady alternator. I have put a few off the grid trips on the new setup and it has lived up to my expectations and more. Right now we are in the winter season and the solar is keeping up with charging
duties while the SMB is parked. On a good day in full sun the solar charges approximately 50 Ahrs and on a short day about 21 Ahrs.

Some of the benefits of doing the upgrade make life a little easier. In the morning after the refrigerator running, the heater running and staying up late watching TV the batteries have plenty of power available to make a full pot of coffee in the morning and run the portable induction cook top for breakfast. I do a lot of incidental charging of phones, laptops and other portable devices. By the end of the day the solar has everything ready for another night of entertainment.

Some of the additional benefits is that I have learned that if you donít charge lithium batteries to 100% you increase the life cycle of the battery. With this little benefit it turns out battery life could exceed 10 years, these could be the last batteries I ever have to purchase. Of course there is a big weight saving Vs other batteries. I was able to install the three lithium batteries in the same space as the one 4D AGM battery.

In Summary, I was able to make the switch to Lithium without any additional major expenses except for the batteries themselves. Having equipment that was compatible eliminated any hardware changes that would have pushed the price higher. During solar charging the battery voltage goes as high as 14.4v but averages 13.3v and goes as low as 12.9v during high use. When using the coffee maker with 85 amps being used the voltage goes to 12.4 as the lowest and as soon as it stops it shoots right back to 13.0v. I find the controller electronics works better with the built-ins appliances in use. I know this report makes it all sound simple but believe me when I say I moved very
cautiously, reading everything I could find on the subject before making the battery purchase. Once this was done it was game on!

I hope you find this informative thought provoking, it works for me.
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Old 11-24-2020, 06:02 AM   #2
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I do find this thought provoking, but I would still have to disagree with your thoughts on the Blue Sea ACR. First and foremost, it is not that smart, it doesn't know anything about Lithium batteries, so it certainly is not shutting off at 90%. I would then ask the question why? I suspect that your charging voltage of 14 volts is the reason why you are not getting above 90% I also suspect that this will have a negative effect on the longevity of the batteries.

The second assumption I would question is charging to 100% as the reason to burning up alternators. Why is that, going the extra 10% is not where we get the heavy current draw that causes the alternators to work at 100% for long periods of time, which causes the alternators to burn up.

The big reason for a DC to DC charger is to limit the current going from the alternator to the batteries, the lithium batteries can except a high charge rate and also demand a high charge. So just allowing the ACR to function as normal will not have change that relationship.

Not trying to be disagreeable, I would just need a little more data to change my mind on some of the considered norms a moving to lithium.

Thanks

-greg
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Old 11-24-2020, 04:36 PM   #3
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To expand on Scalf77's comment:

"The big reason for a DC to DC charger is to limit the current going from the alternator to the batteries....."

Without some sort of limit to the amperage coming out of the alternator, if your lithium house batteries are drawn down to say 50% or more (eg due to extended boondocking, shade or overcast skies, etc) once you start your engine the alternator's going to want to recharge the Lithiums (as well as the starting batteries) as quickly as possible, which means the alternator's going to try to push as many amps as it can, up to the limit of your alternator (220amps). This may burn out your alternator prematurely.

In addition to the potential detrimental effect on the alternator, most lithium batteries have a charging amp limit. I have Renogy lithiums and their specified charging limit is 85 amps. So if the alternator does not have some sort of limit to the amperage coming out of the alternator, you also risk damaging the batteries.

I run a Renogy 40a DC-DC charger (also avail in 20a and 60a, versions) wired between the alternator and the lithium batteries. It provides over-charge protection to batteries and over-draw protection to the alternator. It wasn't cheap but less than the cost of a reman alternator.
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Old 11-24-2020, 04:43 PM   #4
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Good to hear from you Scalf77,
When I posted this update on my experience with Lithium Batteries, I just knew there would be some questions and debate about lithium. So I had made the commitment to myself to try and answer the questions I receive with yours being the first. I will do my best to answer all your questions with a little more clarity. However I also made the decision not to debate lithium, since there enough on this topic online for folks to seek out and get the facts. The problem being not everyone's situation is the same and results are all over the board. With this said I can only discuss what I did and why it works for me and may work for others with things being the same or similar.

Let's start, you are absolutely correct about the Blue Sea ACR not knowing anything about Lithium. However it does know to switch off at around 13.7v. I think if you do the math it would equal that 80-90 percent charge status you see in the SMB manuals for house battery charging. I have come across a couple of manufactures that make something similar but has an adjustable voltage setting allowing you to increase or decrease the switching point. I find the Blue Sea doing what it does best and no need for the 100% charging during driving. When I arrive at a site 80-90 percent is plenty to get me through the night. The next day the solar will pickup or I will be driving again. From everything I have read lately is that by not charging to 100% you increase the battery life of lithium batteries. This is a big plus considering the cost of lithium batteries.

The alternator was my biggest concern because I didn't want to do something that was going to cause an adverse affect and cause me problems with the existing system. I mentioned that there is basically three different types of alternators currently in use. For obviously reasons the older are the most problematic just by design. Then there are those a little newer in design but most of these mentioned are reported to not reach the higher voltages that lithium batteries operated in.

Being this was my biggest concern I searched the internet for information and found actual test results charging lithium batteries. Scalf77, you are correct that lithium batteries can handle large amounts of current, they are power hungry creatures. I found actual test results demonstrating just how hungry they can be. During bench testing they were able to show the alternator actually going into a meltdown trying to charge the battery. It was this catastrophic failure I wanted to avoid if at all possible.

There are differences between the AGM and Lithium battery. The AGM is pretty much the same as a lead acid battery where the Lithium is the new kid on the block and improving on a regular basis making it the battery of choice if we could get he cost down. The AGM operates in the 13v range where the Lithium operates in the 14v range. Using the Blue Sea ACR switches off the lithium charge around 13.6 volts. This eliminates the high charging demand that the lithium would suck up in a heart beat if it could. By disconnecting the alternator operates in its normal capacity as the lead acid start battery and everything is normal. With this said the system may take a little longer to charge both batteries simultaneously because of sharing the charging taking place. But it is well within the normal charging ability of the alternator.

My SMB is not a daily driver but a long distance driver for trips. The shortest drive time might be 3 hours to the longest being 9 hours in a single day, stopping just for fuel and a quick meal. I have monitored the temperature of the lithium batteries during these drives and have not observed any excessive heat buildup in the battery other than normal ambient temperatures 22-27 Celsius.

The DC to DC charger was always a way out of this charging mess but it brought with it the additional cost and a place to mount it. This was not a stumbling block for me but just hoping to avoid the additional cost. This option eliminates the charging issues for the older type alternators by regulating the charge cycles being demanded by the lithium battery, it is hungry. The sole purpose of the DC to DC charger was to allow charging the battery to the 14v range that was destroying the alternators. By regulating the charge cycles it keeps the alternator within its normal operating design. This is about all I know about this option and very glad I did not have to go this way.

Greg, I do not find any of your information to be disagreeable at all. They are questions I had going through this process as well. For me this was uncharted territory. Some things mad sense to me while others did not but I had to find my way through it all. I hope my thoughts above help to clarify what I believe worked for me in getting the question of installing Lithium Batteries answered. That little Blue Sea ACR as dumb as it is made this possible without going crazy in the hardware and wallet. Rest assured that if things go south on me I will make sure to let everyone here know asap.

Now for the good part: No egos, batteries or animals were injured during this endeavor. Only the long searches during the wee hours of the night were lost and maybe a meal or two along the way.

Sam
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Old 11-24-2020, 05:06 PM   #5
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Porschedpm, I read your feedback and cannot say I disagree with the scenario you put forth. I do feel it is a mission critical situation that I have not seen or experienced and hope never to, only time will tell. Remember in my situation I have 200 watts of solar that has the ability to fully charge the batteries. To date I have not seen anything lower than 13.0 v during boondocking. We boondock anywhere from 2 to 14 days straight. With the AGM 200 Ahr battery I would find my self starting the SMB in the morning hours to make my pot coffee after a good long night of entertainment. My battery would show between 12.0 to 12.5 volts. It is this scenario that pushed me into researching the Lithium option. Since making the switch I no longer find myself starting the SMB in the morning for that pot of coffee or even that good old country breakfast. The voltage reading in the morning after a comparable night is 13.3 to 13.0 volts. At this point I don't think I will find myself in the position you described in your example. But if I did you are probably right, I would blow the whole thing up over breakfast.

Thanks for sharing your thoughts and have definitely opened my eyes to scenario I was not thinking about. What do we call this Catastrophic Failure...!!! OUCH

Sam
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Old 11-24-2020, 06:43 PM   #6
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I installed my bank of lithium batteries in Jun 2019. I found early-on that basing state of charge (SOC) decisions on just voltage readings would give me a false sense of security. I found this out the hard way last winter when I woke up one day to find the low voltage alarm on my carbon monoxide detector going off and discovered the lithium batteries were completely dead, even though the batteries read above 13 volts not more than three days before. Because the lithiums were still relatively new I assumed at least one of the four batteries in the bank suffered a catastrophic failure. The only thing that had been running in the van was the refrigerator, about 3.5amps, and another .5 amps for CO and LPG detectors, and other misc displays and USB chargers. And I had assumed the 480 watts of solar panels would be sufficient to keep the lithiums charged. What I didn't take into account was during the two months the van had been parked we had more overcast days than sunny days. And where I parked the van, except for a couple hours each day, at least two of the three solar panels were always shaded. The result was the electricity I consumed exceeded the electricity provided by the solar panels resulting in the near complete depletion of the lithium batteries. Fortunately for me, the batteries weren't 100% depleted and they were able to be recharged through shore power without any apparent permanent damage.

The lessons I learned here are that using voltage to determine the SOC of any battery, especially lithiums is unreliable. You really need a dedicated battery monitor that reads not only voltage but also amperage and calculates SOC.

Second, I found lithiums are either working or they're not. You'll be going along swimmingly along at 13v and then you have nothing. Whereas the voltage of AGM/lead acid batteries' taper off somewhat linearly as they're depleted, with lithiums they'll maintain 13 volts and above until their SOC is charge is nearing 10%.

Also you can't use voltage to determine how much current (read in amps) is going to or from your batteries. In other words, even though your BlueSea ACR limits voltage to 13.6 volts, it does not limit the amperage going through it. The alternator will keep pushing the amps the batteries absorb. In fact, the amps will actually increase to compensate for the voltage limit.
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Old 11-24-2020, 08:30 PM   #7
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Sam, I am challenging your assumption that the blue sea ACR is why your system is working. Certainly I am open for debate, as it is the way we learn. you learn more when things are not working

The blue sea ACR combines (joins the two battery systems) when the voltage on either battery is above 13.5 volts for 30 seconds or 13.0 volts for 90 seconds. It disconnects (splits the two battery systems) at 12.75 for 30 seconds or 12.35 for 10 seconds. Those are the parameters of the Blue Sea 7620.

Did your van come with the #2146 Switch? probably not as it appears SMB does not like to install. It would show you if the 7620 was combined or disconnected.

The charge range for most lithium batteries is between 14.2 to 14.6 volts. AGM batteries have an absorption voltage of 14.3 to 14.5.

I believe your alternator voltage is low and is the real reason you don't charge above 90%. The question is why is it low? Is it at capacity?

I will stick with my assessment that the DC to DC charger is there to provide a specific voltage for the battery, and to limit the charge rate.

-greg
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Old 11-29-2020, 01:59 PM   #8
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Where did you mount your Lithium batteries?
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Old 11-29-2020, 07:56 PM   #9
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Originally the AGM 200 AHr battery was mounted underneath the vehicle just behind the driver seat. I replaced the D4 battery with three 105 AHr LionEnergy Lithium batteries. I don't live in a area where it freezes but we travel to colder climates. The batteries are not in an insulated box so they are subject to the direct temperatures outside. I will see how the batteries are affected when we go into the colder climates before making any decisions, regarding the need to insulate and possible warming pads or blankets.
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Old 11-29-2020, 08:25 PM   #10
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Greg, your data is correct. However your comment regarding the alternator putting out 14.0v is low I have to question. I had the Sprinter since new and the voltage from day one has always and continues to be a constant number. Maybe you mean it is low by lithium standards but is normal for this vehicle. The voltage is what it is and I have no problems. As I mentioned before my solar does reach peaks of 14.6v during charging and addresses my boondocking needs when out on the road.

You are correct again that SMBW did not install the 2146 switch option. I have been reading up on this option and find it to be something I plan to install in the near future. I like have control over my systems and understanding there functions. I mentioned also that I have read up on some isolators that have manual voltage settings that would allow me to change the switching patterns. My concern is that by raising the voltage to a higher setting may put me at risk or over charging. The upside is it has the same setting as the Blue Sea.

All I can say is it works very well and the only downside of this is the fact that after a 3-5 hour drive my batteries are displaying 13.3 volts. This allows me to comfortably setup for the night or for several days knowing the next day solar will restore the charge for another night of whatever. When I ordered my Sprinter I ordered the variable high speed idle. This would allow me to start the vehicle and charge the battery when needed with the AGM battery. I use this feature regularly while Boone docking but since the change to Lithium there has not been a need to do this. So I think this is a win/win situation for me with the vehicle.

If I encounter problems I will for sure post it here but for now we are good.

Sam
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