After many years of studying and researching the option of lithium batteries, we feel we are ready to make the jump from FLA to lithium for our 5th wheel RV. We have been using 4x Trojan T-105 6v FLA batteries since 2018 and they have done well, but are starting to show their age. They are used for ~9 months out of the year off and on for local and cross country trips. They are checked for water level at least twice a year and are monitored with a Victron BMV-712. We have 400w of solar panels on the top and a Victron MPPT Smart Solar 150/70 to maintain the batteries when the sun is available.

• I am in the market for a converter charger to replace the existing converter charger and be in line with the new (lithium) charging profile. Not looking for a power house, just something around 50A or similar to the converter charger we have which I think is 50A, but I will have to verify the gauge of the 12v wires and the specifications before pushing the buy it now button.
• I am also in the market for batteries and have decided on SOK or EPOCH as our products of choice. That is unless someone is able to steer me clear of them as things may have changed a bit since I slimmed down the options to these two over a year ago. I conversed with @HRTKD a while back about building my own lithium batteries, but I have swayed away from that as sometimes it is just more efficient to go with a manufacturer when factoring in time, resources, parts, labor and effort.

We are looking to be in the 300 - 500 Ah range and are not concerned about size as if the batteries do not fit in the front "garage" space under the front of the 5th wheel, I will move them to the space under the stairs with 4/0 cabling. We live in north GA and the risk of the batteries being utilized in near freezing conditions is not a concern. We put the 5th wheel in "storage" status during the winter couple of winter months and I plan to remove power via the panels from the MPPT controller via the breaker and then use the main battery cutoff switch to let the batteries sit idle with no loads at all. We have 30A service to the 5th wheel, so lights and what not are supplied 12v power from the converter charger.

Any suggestions or lessons learned about SOK, EPOCH or converter charger solutions are welcomed.



Below is a small spreadsheet I built with some comparisons between the options. Price is not the biggest concern, but it is a consideration.




Below is a rough diagram of our solar and power system that I created in Power Point. I used this as a reference in order to keep myself in line when assembling and installing the equipment and wiring.





Below is a picture of what the equipment panel turned out to be and has been working flawlessly (knock on wood) since installing it.

 

Last year I upgraded from 2 AGM batteries to 3 lithium. I used 3 LiTime 100ah Mini, Progressive Dynamics PD9160ALV converter and Renogy 12v 20 amp DC to DC charger. I used the mini batteries because of space, Progressive Dynamics converter because I've used them before with great results and the DC to DC charger to keep the batteries topped off when going down the road. We run our residential refrigerator and freezer going down the road so I want to be able to keep them topped off when traveling. The setup works great with the only thing I'm going to add is a shunt volt meter to keep a closer watch on the voyage.

​​​Denny

 

how many watts is that Xantrex? I have a 12 volt 2000w pro inverter sitting taking up shelf space... send it to you for the cost of postage as I no longer mess with 12 volts. it would make a nice spare for your rig.

 

It is a true sine wave Xantrex Prowatt Sw2000. We have only used it one time for testing, thankfully. It is there for the moments when we are boondocking and need to use something that takes 120v. Although, we also have a dual fuel 2400w generator that is in the 5th wheel at all times too.

I am torn between 2x 206Ah SOK and 1x 460Ah EPOCH Essentials. I am going to call Current Connected today to hear their take on the two options. They don't sell 12v SOK batteries, but they are a dealer for SOK and as I understand it they are very open minded to help the customer find a viable solution.

I'll talk your generous offer over with the boss and see what happens. Thank you sir.

 

@kenn_chan , your PM inbox is full sir.

 

After hemming and hawing about the SOK vs. EPOCH choice, we decided on the EPOCH 460Ah Essentials battery with heater and bluetooth. When purchased directly from EPOCH, there is a 15% off coupon code (CHAMP15) that saved us $224.85. Also, EPOCH is located in GA, just like we are and are moving their manufacturing, testing and distribution to Marietta GA which is less than 2 hours away. In the unlikely event that we had a warranty claim over the next 11 years, I would be able to deliver the battery in person instead of messing around with shipping like in the SOK warranty process.

In the end, we paid $1363.34 for 460Ah where the SOK batteries would have been ~$1225.00 for 412Ah and a 7 year warranty.

We considered each of the batteries of equal quality, history of service and online reputation. It really came down to which company would be easier to deal with if a warranty claim was required over the next decade or so.

We are confident this 460Ah EPOCH will suit our application much better than the 4x 6v Trojan T-105 batteries and at a significant weight savings. The 4x Trojan batteries weigh in at a slim 248 lbs and the 1x EPOCH weighs in at 84 lbs for a savings of 164 lbs.

We like the idea of having 2x SOK batteries for redundancy in the event of a failure, but picking up a cheap 12v deep cycle battery for emergency use can be done at thousands of places across the country.

Now I am on the hunt for a replacement converter charger and thank Denny for the recommendation of Progressive Dynamics. They were already near the top of our list for sources.

 

1 hour and 14 minutes after placing the order with EPOCH, the battery has been marked as shipped via UPS ground and is expected to be delivered tomorrow by 2000 hours.

 

One thing I have found is the lithium batteries when charging will take everything the converter will deliver until they get close to full charge. I can monitor it with my remote read from my Progressive Dynamics EMS system. Sure makes the run time on the generator shorter and takes less fuel. Another thing I started doing because lithium don't like to be held at full charge I turn the batteries off and run off the converter when running on shore power for long periods of time.

Denny

 

I plan to break the circuit from the panels and battery when the camper is parked at our home on 30A service. This way the batteries can sit idle with zero load.

 

yes keep the lithium between 20-80 and they are as happy as a pig in you know what...they do nto have a memory and can sit at partial charge pretty much forever without losing capacity, you might need to top balance them occasionally so make sure the battery you buy has BT access so you can adjust balancing voltages.

BTW current connected (Dexter) is about the straightest shooter I have encountered int he current solar game. not a bad guy to deal with at all. he remnds me of RiffRaff in how he operates.., just on the solar vice diesel scene

 

A phone call to Current Connected was our first yesterday. I was planning to order the EPOCH through them, but since EPOCH is 2 hours away and I had a 15% off coupon, I went straight to the manufacturer.

Battery is out for delivery.

 

Order for the EPOCH battery placed at 11:55 AM through the EPOCH website. At 2:31 PM the next day, 26 hours and 36 minutes later UPS was at the end of my driveway to meet me with my riding mower and dump trailer. Battery tested good with a multimeter and is in the basement waiting for the converter charger to be selected and purchased.

I am still deep in the weeds on which model to go with, but so far I am leaning toward the EPOCH 12v/50A since the service has been nothing but stellar from EPOCH.

Converter charger link: https://www.epochbatteries.com/produ...poch-batteries

 

I've got an Epoch 300Ah battery "12300A-V2 12V 300Ah V2 | Heated & Bluetooth & Victron Comms | LiFePO4 Battery". Replaced 2 lead acid batteries. Lead acid were only a year or 2 old, but were dying. They got low over the winter when I forgot to plug in the trailer or had an outlet issue. I forget why, but I recall walking by the trailer & hearing the low battery alarm going off & realizing I'd probably toasted the batteries in the cold. They still worked, but with noticeably reduced capacity. 300Ah is a little light, but we have solar & a generator if needed, so it has yet to be a limitation worth throwing more money at.

The Bluetooth range isn't great. Batteries are in the front compartment & I can get signal half way down the trailer only half the time. App isn't great, but gets the job done. I was planning on using my Victron BMV-712 to connect directly to the battery, but despite the name containing "Victron Comms" they told me that I should still use a shunt & that the Victron stuff was only for inverters or something. So I have both & they generally are within a few percent of each other. The Victron has better range, so I tend to look at it more. I had the Victron monitor before, so no huge loss, but it would have been nice to get rid of the shunt wiring.

Battery terminals scare the hell out of me. I live in perpetual fear I'm going to drop a wrench on them or something. Having an on-off switch on the battery itself is really nice when you are fiddling with things & don't want to accidentally start arc welding.

My 2022 or 2023 trailer was new enough the stock converter had a lithium profile, as did the Go Power solar charge controller. The previous owner wanted a Go Power inverter & had purchased a 2kw inverter with an integrated converter to install. I was going to install it, but in tracing out the wiring & digging into the basement I found a 2kw inverter that was installed from the factory. Wired up a bit funky, but I cleaned things up & have yet to install the Go Power. It would match up with the solar charge controller though & I keep thinking about re-wiring things & moving the battery towards the middle of the trailer instead of the front. I have yet to rationalize enough benefit for me to get to that project though.

 

Why did you consider the 300 ah battery to be a little small?

just curious how you are using them such that they are potentially a limiting factor.

 

To be honest, we expected more out of the 4x 6v Trojan batteries, but I am cursed when it comes to FLA batteries. I have swapped all other FLA batteries in our vehicles and even riding mower out for AGM. Not a big deal as when we bought those 6v batteries years ago, we knew they were there only to get us to lithium one day.

As mentioned earlier, we have 400w of solar on the roof and a 2400w dual fuel generator on board. This setup has worked well for us for many years and we could easily put another 200w of solar on the roof, but the cost vs benefit is not there. We have a portable 100w panel that we carry as a just in case too, and have never used it.

I have found the BT range on the Victron components to be fairly limited as well. The BMV-712 is toward the rear of the 5th wheel and the MPPT controller is toward the front. If I am logging into the MPPT, I sit on the bed or am outside near the garage space. If I log into the BMV, I sit on the couch or near the dinette. This works well for me since I generally only check them a few days prior to departing for a trip. I consider these devices a set up and let them do their thing. In the coming days, I will connect to the EPOCH 460Ah battery via BT and familiarize myself with the app. I have already read the manual and watched a few videos on the functions and features of the app. I am now noting and researching all of the specific settings for the Victron MPPT controller and BMV that need to be set and changed from the FLA settings.

I don't have the fancy Victron communication devices, so administration of the two Victron devices is only a burden during initial setup and then they just do their thing. I don't mind checking on the Victron devices from time to time and I will likely check the EPOCH SOC vs the BMV once a year just to make sure they are still on the same sheet of music. I too run the shunt with the BMV, but prefer this method since I took the time to plan the system around the MPPT controller and BMV.

As for the battery terminals, I will be securing the EPOCH battery in the same storage space in the front of the 5th wheel as the 4x 6v Trojan batteries currently occupy. I will build/create a non-conductive cover for the terminals and ensure there are no metal surfaces exposed or have the possibility of arching during travel or maintenance in the storage space. I have a strong background in IT and electronics and though a large battery like this makes me triple check what I am doing regarding positive, negative and the dangers of an unintended discharge, I have done well thus far.

Thank you for your insight and I appreciate your words of advice and caution as I venture into the wonderful world of lithium batteries.