ouR escaPOD mods

Time for another modification. No pictures yet, but I am going to start this write-up.

After thinking about it and realizing that the travel we have done with dual 6V GC2 batteries puts a lot of stress on the A frame (The batteries together weigh about 120 lbs.), and seeing that prices on LiFePO4 batteries are coming down from the stratosphere, I decided that it was time to convert from the GC2 batteries to an LiFePO4 battery. The two batteries I have are 215AH batteries. Since they are flooded cell, I effectively have a little over 100AH of usable power. I was researching batteries, thinking I would purchase a Battle Born 100AH LiFePO4 battery, but they are still over $900. (Battle Born will give a military discount if anyone wants to purchase from them.). I came across a listing on Amazon for an Expert Power battery. https://smile.amazon.com/gp/product/B07X4Z8FML/ This battery has some pretty good specs and like the Battle Born battery, has an expected 10 year lifetime. The current price is $789.99. I happened to hit it when a coupon code was available, so I paid less.

It isn't just a simple switch though. Along with this comes the need to have a charger that can properly charge the LiFePO4 battery. The charging profile is not the same as for Lead-Acid batteries. So, the stock WFCO 8955 converter will not properly charge it. WFCO does make a replacement converter section that is a drop-in replacement for the 8955 Main Board. It is the WF-8950L2-MBA. It is a 2 stage charger which does not have a float charge. This is because the LiFePO4 batteries have a very low (@3%/month) self-discharge rate. This, coupled with the battery's built-in Battery Management System (BMS) should work to keep the battery charged and ready.

The third piece of this puzzle is a way to monitor the battery. Simple voltage won't work since the discharge profile of LiFePO4 is almost flat until it is almost fully discharged. If you have ever used Lithium AA batteries, you can see this. Things work great and just suddenly die when the battery is drained. The BMS will shut down the battery before the battery is discharged so much that it would be damaged as well as stopping it from being overcharged, but it still does not inform of the state-of-charge. So, I looked and got sticker shock at the prices of the Victron equipment. Fortunately, I found a more reasonable solution again. It is an AiLi Voltmeter/Ammeter/Voltage Current Meter and claims to be a kind of "fuel gauge" for the battery.

The battery and meter should be arriving this week. The converter has already arrived and has been installed. It isn't any different in appearance than the previous board, so I will only post a picture to illustrate some of the wiring changes. Part of the modification is removing the batteries from the tongue and relocating the new battery to the compartment I constructed in one of my early mods (see:  http:////www.rpod-owners.com/forum_posts.asp?TID=7712&PID=72849&title=our-escapod-mods#72849 ). The smaller compartment next to the wardrobe is where the new battery will reside. Since LiFePO4 does not require ventilation and since it does better at more even temperatures, that looked like a better location than outside.

Of course, the relocation means new wiring. I purchased some AWG 4 gauge wire, only to realize that it was rated for 90C. The other wiring in the RPod is rated for 105C. Plus, I wanted to differentiate between the positive and negative wires, so i drove down to Raleigh to the AutoZone next to their distribution center and purchased 10 feet of Red AWG 4 Gauge 105C wire and 10 feet of black wire (white was not available).

After removing the power center (power disconnected and batteries also disconnected, I fished the wires under the bath and wardrobe along the space where the other wires and water lines were run. I can't connect the battery or meter until they arrive, but I did install the new main board. The existing positive cable to the original battery needs to stay connected so I will have power at the tongue to operate the jack. Otherwise, I would have disconnected it and left it in case I reverted the system back some day. The new negative wire runs to the block where all the other negative and the ground wire from the converter are connected. All other wiring remains the same. After connecting the jack's wire and the Zamp wire to the battery cable up front, I wrapped all of them with lots of electrical tape to keep the connection from shorting. I will tie it to the framing to keep it attractive and keep it from falling and scraping along the road.

I ordered one more item. I needed a way to put terminals on the battery cable so I ordered a TEMCo Hammer Lug Crimper, which arrived and has been put to use to attach a terminal lug to the negative terminal (had to test it). I still need to put one on the positive cable, but I am waiting until the battery arrives. I also need to figure out where to mount my battery cut-off switch.

That is what I have done so far. Pictures will follow when I get the battery installed. The meter will be temporarily installed next to the battery as I have an extension data cable on order that won't arrive for 2 or 3 weeks (coming from South Korea). Then it will get mounted next to the current monitor panel in place of the voltmeter I currently have there.