RV Lead Acid/AGM to LITHIUM

A few years ago I installed a rather involved solar system in my Forest River RR19 Toy Hauler travel trailer.

Back then, with a single Lithium battery costing over $1000 I decided to go the AGM (Absorb Glass Mat) route.

You can read all about this project on another article here on my web page:

http://rvbprecision.com/rv-projects/solar-install-grey-wolf-19rr-toy-hauler.html

This year, 2022, the price of Lithium batteries has really fallen. High quality Li batteries with all the bells and whistles can now be had for $500 and sometimes much lower.

To understand the whole Lithium world better, and before I tear into the travel trailer, I ordered a Chinese battery with all the features….but most importantly for where I live and where I camp…the battery had to have “Low Temperature Charge Protection”……(Lithium batteries should not be charged below 32 degrees F (0c)…

The battery I sourced through Amazon is the LISUATELI 12v 100Ah LifePo4. All the features I needed and at under $350 (March 2022).

I decided to build this battery into a portable power system for my roof top tent camper. Using a standard plastic battery box and adding various connections and an Aili battery monitor I ended up with a really nice, relatively low weight, portable solar generator.

I needed a way to charge this battery so I upgraded the solar charger in my truck to a Renogy Wanderer Li 30A 12V PWM charge controller. (I have a 100w panel on the roof top tent and a DC to DC charger, Inverter, Battery Monitor, Blue Tooth dongle, etc installed in the truck’s cap side box) This is a total stand alone system, independent of the camper. It is used when camping with the roof top tent and the trailer (And my wife) are staying home.

With the portable battery box complete, and the trucks charging system updated to Lithium, I needed a way of charging the battery with 120V shore power when available. Lots of internet research led me to the Victron Energy Blue Smart IP22 12-Volt 30 amp 120V charger. This is an amazing piece of kit! Offers Blue Tooth connectivity, history of charging data and more….

I charged and discharged and charged this battery a half dozen times and was always blown away by how long the battery lasted running a ICECO 45L refrigerator. With a 100ah AGM battery I could get 3 days run until the AGM was at 50%……With the Lithium I got over a week before I pulled the plug and the battery was around 25% (The Aili Monitor was not calibrated correctly so this is a SOC guess based on the time it took to recharge the Lithium battery)….Also, the AGM test was performed in the summer with ambient temperature around 80 degrees….The Lithium test was with the refrigerator in the garage at 55 degrees. So not a fair comparison…..but with the Lithium battery having roughly 80ah available compared to the AGM with 50ah available, the Lithium will be a huge improvement.

The Blue Smart Charger would bring the Lithium battery back to full in an amazingly short time, compared to the AGM battery.

So now that I understood the world of Lithium a bit better, it was time to convert the travel trailer from AGM to Lithium….

As luck would have it, about this time, (Winter 2022), Renogy was running a sale on their Blue Tooth, 100ah Lithium batteries……$499 each with free shipping. I purchased two and the arrived within a week.

More had to be done. When I installed the AGM batteries into the trailer, I upgraded the WFCO Charger/Converter with a Progressive Dynamics PD4655V module that offered four stage charging which was a better charging system for AGM batteries.

But this is not what Lithium wants. Lithium wants a two stage charging system with 14-4-14-6V on bulk and 13.5 in absorb mode…….

So I ordered a WFCO replacement module that offers this criteria. WFCO WF-8945LiS

Swapping out the AGM board in the WFCO charger/converter for this Lithium upgraded module was relatively easy. Took all of 45 minutes. (Cost = $200)

Knowing that at some point in time I would be moving to Lithium, I had recently replaced the Bogart Engineering SC-2030 PWM solar charge controller with a EPEVER MPPT Charge Controller 40A 12V/24V Tracer4210AN with the MT-50 monitor.

Along with the Bogart Engineering SC-2030 I had also installed a TriMetric TM-2030 state of the art battery monitor. I left this in place until I decided on Lithium batteries.



Once I decided on Renogy batteries, i made the decision to replace the TriMetric with the Renogy 500A battery monitor. (Cost = $80)

The TriMetric lived in a little Monitor Center I had built into the trailer.

A filler panel had to be fabricated as the Renogy 500A is smaller than the TriMetric>

Although the TriMetric offers a wealth of solar and battery information, most of it is lost when not using their solar charge controller. And to be honest, most of the info it supplied I had no idea what it really meant!

The Renogy 500A gives you exactly what info you need to maintain your solar system…..Nothing more. Very easy to install and VERY easy to interpret the results.

So now that everything is installed and operating, what is the initial verdict?

WISH I HAD DONE THIS YEARS AGO!!!!

#1) Lighter weight….Since the batteries live on the hitch frame, going lithium removed 100 pounds from my tongue weight.

#2) Much, much faster charging from the 420w of solar on the roof. The AGM batteries would take until 3-4 in the afternoon to come back from 70% to 100%……..The Lithium batteries are taking under 2 hours to come back from 70%, with New England April sun angle!

#3) Constant voltage. the Voltage stays at 13.2- 13.5v throughout the entire discharge cycle, where the AGM stated declining voltage the minute you started to discharge them. My TVs that run on 12V appreciate this as I’m sure other 12V devices in the trailer also do.

#4) When using the inverter under heavy loads, the voltage stays much more constant.

So, all in all, I’m thrilled with the conversion. Now I need to get out there and do some real boondocking to see how they respond in real life!

Here is a quick walkaround video of the system:

Total cost for this upgrade: (2022 prices)

2-Renogy 12V Lithium Batteries @$500ea $1000

1-Renogy 500a Battery Monitor $80

1-EPEVER Tracer4210AN MPPT charge controller $165

1-WFCO WF-8945LiS Lithium Upgrade module $200

TOTAL FOR UPGRADE $1445.00

ADD for entire system

3-120w Solar Panels @$130ea $390

Wire, Fuses, connectors (Estimate) $500

Complete Solar System $2335.00

THANKS FOR VISITING! Be sure to check out the whole web page for more RV articles and other “Garage Adventures”…. www.rvbprecision.com

And my YOUTUBE channel:

https://www.youtube.com/channel/UCHnX8-AC4ylVovILzLro8Vg/videos

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