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Old 10-24-2019, 02:56 PM   #1
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Isata 3 Lithium Diet

Everyone who enjoys the benefits of the Mercedes Sprinter rv platform, is equally aware of the CCC limitations that exist after we add all the features we want on our rigs. The CCC of my particular 2020 Isata 3 24FW was 240kg. It doesn’t take long to add 528lbs and anything that can increase the CCC, even marginally, can be a real benefit. Having followed the R&D of solar and Lithium Iron (LiFePO4) battery for marine use, I was already aware of the advantages, disadvantages and limitations. Still, significant weight reduction coupled with alot more usable power, made the decision easier. I won’t go into details here other than to say I followed the path others have laid out in this forum and sought advice from BattleBorne, a leader in the marine lithium market. I will post pics of the installation later, but it was a fairly straight forward replacement. Each battery weighed 36 pounds less than the AGM it replaced. The next step is alot more controversial and required more research. There were even some who advised against it. Yes, I replaced the chassis battery with a Lithium battery. The battery only weighs 21 lbs, 45 lbs less than the OEM battery. It is a battery designed to be an automotive starter battery. I not only consulted with MB first, they installed it and tested it. It has a built in BMS and a safety cut off that shuts the battery off in low voltage situations, preventing a total drain of the battery. Both the house batteries and chassis battery were installed in their original locations. Even though I live in the Southwest, one has to be aware and prepared for low temperature issues associated with charging of LiFePO4 batteries. The battery enclosures were lined with a battery warmer (rather than wrapping the battery) and it is connected to a thermostat control that can be adjusted. I have it set to come on at 32F and shut off at 40F. Each battery has its own temperature sensor probe, ensuring that as it is discharged, the warmers do not allow warmers to come on once battery temp reaches 40. The temps have not been low enough here to trugger warmers but So far , it has all worked to perfection and the Eastup 100ah starter battery has more than enough power for the MB diesel and chassis systems. Total weight reduction was nearly 120lbs.. That may not seem like much but it helps and the additional house battery power means more time living off solar and saving the genset. Total spent to convert was about $3000. We will see how it works out.

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Old 10-24-2019, 03:21 PM   #2
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As a lithium convert, I'd never given consideration to swapping the coach battery. Perhaps more to that end, we live in Michigan where CCA's are a consideration for nearly 5 months a year for general use vehicles. Glad to hear you about your conversion. The weight reduction is such an added benefit on top of the useable Ah's.
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Old 10-24-2019, 04:40 PM   #3
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I appreciate you posting this information. I live in NE Washington and I plan on doing this conversion in the spring. I store my coach inside in an unheated garage on shore power all winter, but temperatures are commonly below freezing and do get below 0 as well. I am interested in how to best address this problem as well as how the converter/charger deals with the different charging profiles for Lithium batteries vs AGM. I guess if you swap out the chassis battery as well, then the charging profile for all the batteries would be the same.

I look forward to your further posts.
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Old 10-24-2019, 05:30 PM   #4
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Out of curiosity, how low of temperature do the Lithium cranking batteries work to? What chemistry are they? Are they LiFePPO4?
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Old 10-24-2019, 06:25 PM   #5
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Quote:
Originally Posted by Battchief View Post
The battery enclosures were lined with a battery warmer (rather than wrapping the battery) and it is connected to a thermostat control that can be adjusted. I have it set to come on at 32F and shut off at 40F. Each battery has its own temperature sensor probe, ensuring that as it is discharged, the warmers do not allow warmers to come on once battery temp reaches 40.
Hi Chief,

What type of warmer and thermostat control did you use? And what powers them?
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Old 10-24-2019, 08:59 PM   #6
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Everyone who enjoys the benefits of the Mercedes Sprinter rv platform, is equally aware of the CCC limitations that exist after we add all the features we want on our rigs. The CCC of my particular 2020 Isata 3 24FW was 240kg. It doesn’t take long to add 528lbs and anything that can increase the CCC, even marginally, can be a real benefit. Having followed the R&D of solar and Lithium Iron (LiFePO4) battery for marine use, I was already aware of the advantages, disadvantages and limitations. Still, significant weight reduction coupled with alot more usable power, made the decision easier. I won’t go into details here other than to say I followed the path others have laid out in this forum and sought advice from BattleBorne, a leader in the marine lithium market. I will post pics of the installation later, but it was a fairly straight forward replacement. Each battery weighed 36 pounds less than the AGM it replaced. The next step is alot more controversial and required more research. There were even some who advised against it. Yes, I replaced the chassis battery with a Lithium battery. The battery only weighs 21 lbs, 45 lbs less than the OEM battery. It is a battery designed to be an automotive starter battery. I not only consulted with MB first, they installed it and tested it. It has a built in BMS and a safety cut off that shuts the battery off in low voltage situations, preventing a total drain of the battery. Both the house batteries and chassis battery were installed in their original locations. Even though I live in the Southwest, one has to be aware and prepared for low temperature issues associated with charging of LiFePO4 batteries. The battery enclosures were lined with a battery warmer (rather than wrapping the battery) and it is connected to a thermostat control that can be adjusted. I have it set to come on at 32F and shut off at 40F. Each battery has its own temperature sensor probe, ensuring that as it is discharged, the warmers do not allow warmers to come on once battery temp reaches 40. The temps have not been low enough here to trugger warmers but So far , it has all worked to perfection and the Eastup 100ah starter battery has more than enough power for the MB diesel and chassis systems. Total weight reduction was nearly 120lbs.. That may not seem like much but it helps and the additional house battery power means more time living off solar and saving the genset. Total spent to convert was about $3000. We will see how it works out.

Battchief

Not only did your conversion have weight benefits, consider the number of years before you'll have to purchase batteries again.

Money well spent.
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Old 10-25-2019, 07:02 PM   #7
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Lithium diet plus get rid of spare (I don't know ) = >1,000 lbs CCC for me!!!
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Old 10-25-2019, 07:23 PM   #8
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I was exploring BattleBorn batteries this week.

They told me the batteries will not accept a charge below 25 degrees but will continue to discharge to -4 degrees.

For my purposes I could get away with 1 battery, a heating blanket and a lithium converter.
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Old 10-26-2019, 08:54 AM   #9
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It is true that "charging" of LiFePO4 batteries becomes a problem below 32F. Discharging of the battery is possible down to -4F. There are several recommendations on how to deal with this characteristic. One is to turn on anything that draws on the battery for a few minutes prior to charging. Discharging of LiFePo4 batteries causes the battery to warm internally. I chose the second option, keeping the ambient temperature around the battery above 32F. Rather than relocate the batteries to some interior space, I decided to keep them in the original location. LiFePO4 batteries do not "gas" so they do not have to be vented. They do need adequate air circulation to keep the batteries in an optimal temperature range. The two 100ah BB fit nicely in the space occupied by the factory AGM's.. It was recommended that instead of wrapping the batteries, that I line that compartment with a warmer, tacking it to the sides. I used a Zerostart 2800071/72"/80 watt that is connected to an Inkbird ITC 308 thermostat controller. This controller simply plugs in to a 110 outlet and includes a temperature probe that I attached to the battery case. For the chassis battery compartment, I did the same thing but used the zero start 2800063/36"/80watt and routed the wiring to a separate Inkbird ITC 308. All of this stores nicely under the driver's seat. When I am storing the RV, I simply plug in the thermostat controllers. The solar controller that came with the ISATA 3 is already LiFePO4 capable and you simply select that battery type on the GOPower controller. The house battery charger requires a module swap out that is very simple to perform and costs less than $200. Based on recommendations of others on the forum who had already made this conversion, I added a VIctron 712 battery monitor as well. This is another $200 but well worth it as it gives real time battery status, charging status, draw, and predicted time left at current rate of draw and solar power production. It even allows me to monitor all of this on my iPhone. The chassis battery selected is rated at 105ah and 1200 CCA. MB has been using lithium batteries on some of its vehicles and they provided some input on some issues. The battery I selected was one that they were familiar with and had a feature that they highly recommended , an on / off button on the BMS. If the battery voltage drops too low, it automatically shuts off so that you cannot drain the battery all the way down. You simply push the button to turn the battery back on. This also gives you the option of turning the battery off if you are going to be storing for an extended period of time. The total spent on the thermostats and warmers was $150.(all purchased off Amazon) BTW, the chassis battery is an Eastup model 12100100, 105ah, 1200 cca. It is specifically designed to be an automotive start battery. Temps where I live will occasionally get into the low 20's and I intend to see how things work when it gets that cold. If I lived somewhere much colder, I might wait and see how the chassis battery swap works out for others first. I plan on keeping detailed records and providing a report to the forum on my experience. The Victron will enable me to see battery temps before I use them. I will post pics of the installations. The help I received from reading the posts of others provided a great guide on the house battery conversion. Special thanks to RiverBend and TitanMike.

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Old 10-26-2019, 11:08 AM   #10
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The Victron will enable me to see battery temps before I use them.
Another feature built in to the Victron that few use is the internal relay.

If worried about the charger kicking on when temps are too low, the Victron Relay can be programmed to control external devices (relay, etc) that will turn off charger when temp approaches freezing and will then turn the charger on when temp rises to a safe range. All automatically.

I use mine to prevent the Progressive Dynamic's 9160AL converter from charging the batteries more than 90% while my TT is just parked and hooked to shore power. This keeps the charger from "float charging" the LiFEPo's which can be detrimental long term. (PD9160AL's output is steady 14.6v)

I then just leave my batteries connected so I can have lights when I go out to check or do some work. Relay is programmed to turn charger on when SOC reaches 10% which only occurs every 30 days or so. Parasitic draw on my TT with everything but LPG (only) detector off is ~.1 amp.

I use my TT year around so even if batteries are at the low end, I can flip my override switch to turn the charger back on, charge while loading groceries etc, and the batteries are charged the rest of the way while I drive. Since the converter is turned off when the module leads are connected (relay closed) I just put a simple SPST rocker switch on my "panel" and labeled it "Auto" and "Override". Override opens the lead between module and Victron relay so charger is now ON.

Note: Progressive Dynamic's makes "TMS Modules" for their 9100 series converters. One module for the Lithium models allows external control of the charger like I am doing. If one has a PD9100 series non-lithium converter, and wants to upgrade to lithium batteries, they offer a series of modules that "lock" the converter into the proper output voltage for charging the Lithium's.

This "TMS Port" is the same port one plugs their Charge Wizard pendant into on the 9100 series.

For anyone who's considering a Converter upgrade/change I'd recommend they go the PD-9100 route rather than PD9200 series. That way, should you ever decide to upgrade to LiFePo batteries, you merely need to purchase the module for the proper fixed output voltage which is $8. A lot less than having to buy a new Converter along with the pricey batteries
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Old 10-26-2019, 11:35 AM   #11
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Great information. I did go with the 9100 series for LiFePO4 and yes, it is locked at 14.6vdc. I had been thinking about utilizing the Victron relay capability. The concern is cranking the engine if the chassis battery is too cold and having the alternator send max output to the battery. I am hoping the warmer solution eliminates that possibility but at least the victron on the chassis battery allows me to check the temperature before cranking. The chassis battery has a low amp continuous draw on it as well and I am wondering if a LiFePO4 charger like the Techmate would not only keep battery at 90%, but the continuous draw and intermittent charging would keep internal temps above freezing? I have a friend in R&D at A&M checking on this. Thanks

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Old 10-26-2019, 12:00 PM   #12
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Great information. I did go with the 9100 series for LiFePO4 and yes, it is locked at 14.6vdc. I had been thinking about utilizing the Victron relay capability. The concern is cranking the engine if the chassis battery is too cold and having the alternator send max output to the battery. I am hoping the warmer solution eliminates that possibility but at least the victron on the chassis battery allows me to check the temperature before cranking. The chassis battery has a low amp continuous draw on it as well and I am wondering if a LiFePO4 charger like the Techmate would not only keep battery at 90%, but the continuous draw and intermittent charging would keep internal temps above freezing? I have a friend in R&D at A&M checking on this. Thanks

Battchief

Wouldn't the battery BMS handle this issue. If battery is too cold the BMS should "refuse charging".
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Old 10-26-2019, 12:05 PM   #13
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I then just leave my batteries connected so I can have lights when I go out to check or do some work. Relay is programmed to turn charger on when SOC reaches 10% which only occurs every 30 days or so.
Battleborn says that long term storage should be at least 50%.

https://www.solar-electric.com/lib/w...orn_Manual.pdf
Storage and Maintenance section
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Old 10-26-2019, 12:24 PM   #14
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Yes, of course. Forgot about the built in BMS. The low here was in the 40’s last night and I couldn’t tell any difference when I started the motor this morning. It is amazing the amount of power out of a battery this size and weight. 21lbs!


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Old 10-26-2019, 12:28 PM   #15
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Yes, of course. Forgot about the built in BMS. The low here was in the 40’s last night and I couldn’t tell any difference when I started the motor this morning. It is amazing the amount of power out of a battery this size and weight. 21lbs!


Battchief
What brand battery is your cranking battery? You may have said but I can't find it.
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Old 10-26-2019, 03:48 PM   #16
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Old 10-26-2019, 07:21 PM   #17
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Battleborn says that long term storage should be at least 50%.

https://www.solar-electric.com/lib/w...orn_Manual.pdf
Storage and Maintenance section
I guess the question is what is "long term". When I spoke with them last and explained my "strategy" and how often I used the trailer they told me it was just fine.

So far this year my TT hasn't remained parked longer than 45 days. Not exactly what I'd call "long term". In fact my plan is to cut the "storage time" to more like three weeks, max.

Being a retired widower with a bit of wanderlust I expect to travel more frequently. That ought to keep the batteries charged (mine too).

Thought about going full time but right now my house is appreciating far faster than any other investment I might put my money. I for all practical purposes own it so my costs for my 4 bedroom 2100 foot house with large lot are less than what my Son pays for a 1 bedroom apartment nearby.

But that's a whole different discussion.
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Old 10-27-2019, 08:26 AM   #18
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Great posts and information shared for those of us thinking what to do when coach batteries need replacement.

Thanks.
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Old 10-27-2019, 05:36 PM   #19
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Here are some pictures of the install. The first are of the house batteries. The Victron requires use of a shunt which I mounted in the battery box. I also used a large gauge negative bus bar to make the installation easier. The other pics are the chassis battery. A hard rubber spacer (my wife is now missing a yoga block) to fill the gap between the mounting bracket and battery. The dollar bill is only for perspective of how small the chassis battery really is. Another photo shows the victron display for house batteries.

Battchief
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Old 10-27-2019, 05:59 PM   #20
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Here are some pictures of the install. The first are of the house batteries. The Victron requires use of a shunt which I mounted in the battery box. I also used a large gauge negative bus bar to make the installation easier. The other pics are the chassis battery. A hard rubber spacer (my wife is now missing a yoga block) to fill the gap between the mounting bracket and battery. The dollar bill is only for perspective of how small the chassis battery really is. Another photo shows the victron display for house batteries.

Battchief
Thanks for posting the pics. However, at least on my computer they came across as 1.5" thumbnails which can't be enlarged. Any chance at sending them at a higher resolution? Thanks.
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