Upgrading two Lead Acid 80AH batteries to two 100AH LifePo4 SOK batteries.
Why:
-
My current two and a half year old batteries were dying.
-
The SOK batteries were approximately 100lbs lighter than the lead acid batteries they replace.
-
The SOK batteries have 120Ah more usable power.
Items purchased:
-
2 x SOK 100Ah replacement batteries 2 x $600. They were discounted from $650 to $600. At the time I am writing this, they are $570.
-
Cabling kit - $51.64 – Included 2/0 welding cable (probably overkill). It is a lot more flexible. Cable connectors and heat shrink.
-
Bus Bars - $39.99, I only needed one.
-
Progressive Dynamics 60 Amp Replacement Converter Section for PD4060 - $272.00
-
3’ Aluminum angle iron - $6 - Lowes
-
Wire protectors split wrap $8 - AutoZone
I had to replace the batteries in my 2018 Forest River 3271S. If I try to add a 7A load to the old batteries they would only last 20 minutes before they would drop below 12V. It was time to replace them.
To replace them with what I already had would have cost ~$200 and probably only last 2.5yrs.
To upgrade cost me lest than $1470, but I should get 2.5x more usable power and they are guaranteed for 7yrs. They are truly maintenance free and I don’t have to worry about draining them below 50%.
Saving 100lbs of weight is an added bonus.
One of the negatives is, the SOK batteries are not the same size as the lead acid batteries. They are around 1.5 inches taller. They do not fit in my steps like the lead acid batteries. This is the reason for the added expense of $92 for the cabling kit and bus-bars. I needed to place the SOK batteries in a storage compartment next to the stairs.
One of my other choices would have been two Battleborn 100Ah batteries. These would have been direct replacement but would have cost $700 more for the two.
Before you start:
Turn your battery disconnect switch to “OFF” and disconnect from shore power.
Step 1:
Take pictures of the old battery lay out, draw up a wiring diagram, and label all the wires.
Step 2:
Remove the batteries and clean out the battery compartment. My lead acid batteries left sulfuric residue in the bottom and were beginning to corrode the metal box. I used baking soda and water to neutralize the acid.
Step 3:
Mount your bus-bars.
Step 3:
Place the new batteries in their new position in the storage area and measure the wire needed.
Step 4:
Create your cables. I used my bench vice to crimp the cable connectors. There are hammer crimpers and other types that will work. It is important you make good crimps.
Step 5:
Put on your wire protecting split wrap.
Step 6:
Connect your cables.
Step 7.
Turn your battery disconnect to “On” and make sure your rig’s 12V systems are working. Then turn it off.
Step 8:
Replace the charge controller. Since mine was a direct replacement It was very simple. Some newer Progressive charge controllers have a jumper to move so it will charge LifePo4 batteries. Alas, I was not so lucky.
Step 9:
Connect to shore power and turn your battery disconnect to “ON”. T urn shore power on.
This should be it. Your charge controller should be charging your batteries. After around 10min, you will probably hear the fan on the charge controller kick on. The batteries suck a lot of current.
I have an inexpensive battery monitor. I saw it begin charging and supplying 58Amp to the batteries.
It is very important
you check the temperature of your battery cables during this first
charge. I had one cable connection that was getting very hot. It
appears the original connection to the 60A breaker had a less than
ideal crimp. The added resistance was generating heat. I needed to
re-crimp it. This was one of the cables that was installed on the rig
at the factory. This would not have been an issue with lead acid
batteries since they do not draw as much current.
At the
beginning of the charge cycle, I was seeing 58As being supplied to
the batteries. After an hour or more, it began to drop. Eventually it
went to near 0.
Once you have
everything working the way you want, secure the batteries. I used
some angle iron. You can use wood or whatever you have laying around.
You don’t want the batteries bouncing around.
Make
sure you recycle your old lead acid batteries safely.
Links:
Video
https://www.youtube.com/watch?v=gCmwBfIk9Gs&ab_channel=LoveYourRVLoveYourRV
SOK Battery
https://www.sokbattery.com/100ah-12v-lifepo4-deep-cycle-battery.html
Cable Kit
https://www.amazon.com/gp/product/B07K4W2PX3/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
Power Converter
https://battlebornbatteries.com/product/progressive-dynamics-60-amp-replacement-converter-section-for-pd4060li-lithium-series-electronic-power-center/
Bus Bar
https://www.amazon.com/gp/product/B07C5SC7TB/ref=ppx_yo_dt_b_asin_title_o04_s01?ie=UTF8&psc=1
Battery Monitor
https://www.amazon.com/gp/product/B07CTKYFTG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Pictures:
Batteries new home
Here is the old converter/charger. The new one looks exactly the same.
