2019 Thor Miramar 35.2 Lithium battery upgrade

[CountryFolk19]

Has anyone upgraded a 35.2 Miramar to lithium batteries. My stock batteries are about dead and looking into this upgrade.

Victron Energy - MultiPlus-II 12/3000/120-50 2x120V etc.

Did you move the batteries back to shore plug in bay etc. any tips

[RACarvalho]

Have you done the conversion?
I'm planning to do that but have some questions on the BIM.
I'm planning to add 200A of Lithium batteries , change the converter to WF-9855 LiS, change the BIM to Li-BIM 225 and add a Victron 712 Battery monitor....

[CountryFolk19]

Originally Posted by RACarvalho

Have you done the conversion?
I'm planning to do that but have some questions on the BIM.
I'm planning to add 200A of Lithium batteries , change the converter to WF-9855 LiS, change the BIM to Li-BIM 225 and add a Victron 712 Battery monitor....

No. I have not done the conversion yet buying parts now.

I just got back from the RV show yesterday where I did buy the Victron Multiplus II 12/3000/120 50amp 2x120 for $1335.18 which I thought was a good price. Didn't find much else for the upgrade other than that. will be buying more parts today online to get this started.

I'm just a DIY guy no expert on this but have done a lot of research and after dry camping testing (which we did at the RV show in Quartsite AZ 2 weeks on BLM) I can now move forward on this as I know a bit more on what some of my needs and wants are.

(testing)
Looking at my Miramar if you do any off grid camping you will quickly notice the batteries don't last like you would think. (two 6v 200ah) If you connect the victron 712 monitor you'll notice it charges at 13.5v and mine has about 34-40ah draw over night for the refrigerator. Ice maker on pushes up to 43ah ish and batteries will be at 12.1v-12.2v. I still need to do a bit more testing on the WFCO 9800 to see what's going on but distance seems to be an issue. Your alternator will charge in the 14.+ range.

These golf cart batteries from what I found need the 14.2-14.5 volt charge to be fully charged. So right now I can only get less than 50% of the 50% of 200ah (43ah will fully discharge them at 13.5v charge) on lead acid batteries with Generator power. I believe the issue is distance from charger. my charger is under the bed and batteries are 22 feet away and the wfco doesn't really know the state of the batteries 22 feet away due to wire sizing etc. because I haven't seen it go into bulk charging on the three stages it has.

Again this is comes a none expert but I believe this is what I finding on my RV. I also do not like lead acid batteries so that's how I'm justifying the upgrade as well.

My plan is to build a racking system to install two 12v 200ah (400ah) Li batteries and components into the cargo bay where shore power plug comes in which on my RV is one bay behind the rear wheel and under the bed where all the electronics are placed. Why "Distance" batteries will be right next to Multiplus and 5 feet from generator, circuit panels, ATS etc.

Reposition shore plug, and my inline surge protector, install Multiplus II and 712 battery monitor, usb adapter, battery shut off and 600amp buss bars, 400amp t fuse etc.

Sorry for the long story but it may be useful for others that dry camping too.
Yes I'll replace the Bim with Li BIM and as it stands that will stay in the same location but run heavier wire to the back for the batteries.

[CountryFolk19]

Originally Posted by RACarvalho

Have you done the conversion?
I'm planning to do that but have some questions on the BIM.
I'm planning to add 200A of Lithium batteries , change the converter to WF-9855 LiS, change the BIM to Li-BIM 225 and add a Victron 712 Battery monitor....

just wanted to add I'm going to be using two SOK 206ah LI batteries at $1030ea.

https://www.us.sokbattery.com/produc...-pack?ref=LOST

[RACarvalho]

Originally Posted by CountryFolk19

No. I have not done the conversion yet buying parts now.

Thank you for the information.
Our electronics are under the bed too but my batteries are not that far from the controller.
The only boondock we do are overnights at Walmart so I'm not investing too much on this and my main reason to beef up the battery system is that I have a full wall slide and I think part of the problems I had was because the batteries can't keep the voltage under high draw which leads the controller to shut down the slide motor for high amperage.....

I don't have an inverter/charger, just a Xantrex 2000W inverter which makes the change easier.
I had a question about the BIM 225A capacity vs the engine alternator 240A power but I noticed that the battery I intent to use can only accept 100A max. when charging so I should be ok with that.
This is the battery I plan on installing:
https://www.amazon.com/dp/B088RM4W48...v_ov_lig_dp_it

[CountryFolk19]

Sounds like it should be ok too.

We were not interested in boondocking at all but towing a jeep and being close to the desert we took it for a spin. Was fun. I think it will open opportunities up for longer trips if can't find RV parks as they are getting harder and harder to get reservation at popular attractions. Having this options to kill a week at blm or other off grid camping expands that reservation windows.

[CountryFolk19]

My RV has a full slide and on other side has half slide.
I've also had issues with the batteries not fully charged with the generator on trying to bring in that large slide. Making sure the batteries are closer to being charged helps with smooth retractions and extensions.
I've learned while off grid I'll even start my Motor home and run it for awhile so I get full 14.4v and higher amps to these lead acid batteries before trying to operate them.

will be nice when it's upgraded. Only a few more things to order today and then Friday going to get metal to design and build the racks, walls etc to hold all the electronics in the cargo bay.

[CountryFolk19]

Originally Posted by CountryFolk19

just wanted to add I'm going to be using two SOK 206ah LI batteries at $1030ea.

https://www.us.sokbattery.com/produc...-pack?ref=LOST

After further review and recommendations of max current of the sok batteries I'm now leaning towards the DC to DC charger. Several issues with that libim 225 pushing to much amperage to batteries, needs bigger wires and harder on alternators etc. But you can't just swap out old bim for libim a lot more amps using it.

[RACarvalho]

Originally Posted by CountryFolk19

After further review and recommendations of max current of the sok batteries I'm now leaning towards the DC to DC charger. Several issues with that libim 225 pushing to much amperage to batteries, needs bigger wires and harder on alternators etc. But you can't just swap out old bim for libim a lot more amps using it.

As far as I understand the LI BIM use should limit the size of the house batteries based on the size of the alternator.
For example, I believe I will be ok because I intent to have only one 200ah li battery which the BMS limits the current to 100ah.
Since my alternator has a rating of 210A, I should be ok BUT if I add another 200ah battery then both combined can draw 200ah and potentially burn the alternator...

[Scubawise]

Originally Posted by CountryFolk19

Sounds like it should be ok too.

We were not interested in boondocking at all but towing a jeep and being close to the desert we took it for a spin. Was fun. I think it will open opportunities up for longer trips if can't find RV parks as they are getting harder and harder to get reservation at popular attractions. Having this options to kill a week at blm or other off grid camping expands that reservation windows.

Yes we do off grid a lot. Some free some $5 some donation...bigger site. Private off lakes expand your camping !