LiFePO4 Batteries

I decided to go ahead with replacing my very dead Group 31 AGM batteries with LiFePO4 batteries of the same size. I contacted Smartbattery.com and they were very responsive to all my questions. They weren't the very cheapest I found on the Internet but they seemed to be one of the few who have a clear business and support their product. After a couple of days, I got handed off to their distributor in North Carolina who was also very responsive to all my questions and who went the extra mile in finding the correct answer for me and my specific set up. When I ordered them, I called the guy and gave him my credit card number on a Friday afternoon. I told him I didn’t need instant service and could wait until Monday. He had a different person call me for the details and I got the call back by 4pm which was too late for them to go out that day. But they went out on Monday and I got them via UPS on the following Wednesday. Very fast delivery.

In the discussion, I learned that my Parallax 3 stage charger would never deliver sufficient volts to fully charge the new Li batteries as it is capped at 13.9V or 13.6V, depending on what part you read of the documentation. The Li batteries need 14.6V to get fully charged. My alternator delivers that but not the charger as verified by my Trimetric battery monitor I installed 3 years ago. So I decided I had better upgrade the charger too. I was concerned about whether the old charger should be disconnected and if I would lose the AC-DC converter aspect of it. He didn’t know and tried to get an answer from Dodge since my Sprinter was Dodge branded (pointless as Dodge never supported the Sprinters and all this is the RV portion and not Sprinter. He gets points for trying, tho.) I did a bit of research and finally found a clear explanation. A converter is nothing more than a charger. It is a nomenclature that confuses. All chargers convert AC to DC to charge the battery. So all chargers are also converters and vice versa.

SmartBattery sells what looks like good chargers so I ordered that from them too (DeltaVolt Dual Pro can provide 15 amps to each battery). At the time of ordering, they told me that the charger would drop ship from the manufacturer and they would load it with their specific algorithm for the LiFePO4 batteries. Nice touch. He said it might take to the end of the week for delivery, which was fine for me. It came the next day. So A++ for customer service and delivery. If I was in a hurry, I’m pretty sure they would have gotten the order in that day in time for it to go out the same day.

First Charge

It was very cold (again!) so I unpacked the batteries and charger in my house. The charger has 2 connections and can charge two battery banks separately at the same time so I set them down near an outlet inside my house and connected the charger to both batteries. The batteries arrive about half charged due to hazardous materials shipment requirements. The first charge cycle took several hours and the battery charger registered them both at the 30% level. One battery charged up to full and measured at 14.4V after it was unplugged. The second one said it was fully charged but only registered at 13.56V. I unplugged the charger and plugged it back in and the second time it charged the second battery to 15.2V during it's final phase and it dropped back to 14.4V after it was all done. The first battery registered at 14.5V. I did it a third time and it again got up to 15.2V during the final phase of charging and the batteries registered at 14.5V and 14.4V in resting.

I emailed my contact again and asked if this was acting properly and he said they were behaving perfectly. The charger in its final stage should bring the battery up to 15.2 or 15.3. After charge it will float back down to around 14.4V. The capacity of the battery is between 13.5 -12.9 once that battery reaches 13v it is around 80% empty. The .1V after float does not mean much in terms of actual usage and will not have an effect on the life of the battery. After a few days of sitting, they drifted to 13.56V.

Installation

I finally got a few days of mild weather instead of the single digit lows and started installing the new batteries and charger. I first pulled the Parallax Converter/Charger and discovered the charger portion of the unit is powered by a 3 prong AC plug that is wired to the breaker in the AC box. That makes it easy.

The biggest problem was fitting the Inverter on its side so there would be room for the new charger in that cavity that already has a vent on the door for the needed ventilation. The length of the big wires required that it be positioned on the left side of the cavity. I had thought to rig an L bracket to mount the charger on the back and the inverter on the side but getting that contraption into the cavity was impossible and there was no way to screw it together inside the cavity. I ended up using galvanized L brackets to support and fasten both boards to the floor and hold them upright.

I used some 3/4” plywood I had laying around for the boards. I cut a big circle in the middle of the inverter support board because it has ventilation on the bottom and more air is better. I cut the charger support board tall enuf to fit behind the back of the shelf that is above the cavity to help support it. The charger is fairly heavy and wants to fall forward. Its weight will help to hold the board upright and not have to depend soley on the L brackets. I then painted all surfaces of both boards to protect them from moisture. Not a necessarily needed step but wood with paint on it tends to last better.

Mounting board for Inverter

Mounting board for charger

I then measured and drilled and screwed the mounting screws supplied with the charger and the L Brackets to the board. For the inverter board, I mounted the L brackets on the back side of the board and mounted the inverter to the board and used a couple of cable ties around it for extra security. I had to re-orient the wire lugs on the back to fit the space as well.

The inverter fit pretty well and I could drill and screw the forward L bracket to the floor. The rear bracket is hard to get to but it seemed very secure so I just did the one screw. The charger board felt very strong once I had drilled and screwed all 4 screws into its L brackets. The Charger slipped pretty easily onto the mounting screws in the board and I secured them tightly.

Inverter, back side mounted

Inverter mounted vertically on board. Yellow plug powers an outlet

Wiring the charger consisted of plugging the power cord into the Parallax plug (not plugged into shore power so it didn’t matter what order). I coiled the second battery cable and cable tied it to the top of the charger as it is not needed with my configuration. The first battery cable has a Y with the negative and positive ends. There is a screw in the electrical cavity for grounding and I connected the negative wire to that. It has a buss for the positive wire connections and I connected the positive wire to that. Easy peasy.

Charger Mounting board secured to the floor and the top behind the shelf
with the charger mounting screws in place.
To the right is the black water tank. Behind it is the waste vent pipe
and some electrical wiring that goes up to the ceiling.
Inverter on the left

Charger securely mounted on the board. There's still room to tuck in a few small boxes too.

New LiFePO4 batteries. One for each side of the van rear
(the tarp was to line the back for a dump run - such a versatile vehicle!)

Battery 1

Battery 2 wired in parallel to get 200AH

The old batteries were not easy to get out as they are very heavy. I managed but did have one fall and hit me on the shin. The side had a label with 11-09 on it so I think that is the date for them. That means they are less than 4 years old. About 3 years before they conked out. The new batteries have a screw connection and no post. One of the connectors used the post mount whereas the rest had ring connectors for the screw post. I got a screw on ring terminal for 4 gauge wire to replace it. One of the screws they supplied was not long enuf for the 3 wires connected to it but I had one long enuf to handle them to replace it. One of the battery holder bars won’t fit the new battery while the other one fit fine. I have to figure our a way to secure it. The one that works has a dogleg to fit into the slot in the batter box, the other one is a straight bar. Nobody has one with a dogleg so I'll have to jury-rig something.

The batteries immediately measured the same after I connected all the wires so they are one bank in parallel.  My Trimetric monitor said they are at 13.3V while my hand meter says they are at 13.4.  That's with the bits that bleed a little juice while the van is sitting.

All wired up and the van came back to life. The lights work again. Unfortunately, my errant refrigerator still does not come on. I am sending it back to the manufacturer for them to fix or replace it. No matter what I do, the compressor won't come on. Since it is under warranty, they are paying for UPS to pack it up and ship to them, so at least it won't cost me anything but the trouble to get it to the UPS store.  

And I'm getting beeping and blinking lights from both the CO and propane monitors. Oh look, one of them says to replace after 5 years. Oops. Guess I have to get new ones of those now.  Shazam! They are expensive.

I also noticed a burn mark on the neutral wire nut in the AC box. The wires were fused together - a clear sign of way too much heat.  I finally cut it off and then found some gooey stuff on the wire strands.  I think I need to replace the shore power wire. Fortunately, I found a 30amp 10 gauge wire at Lowes so it won't be hard.

And next on my list is find a recycler for the dead batteries and get the engine battery tested to be sure it is up to snuff.  Don't want to have it die on me on the road.  Plus I need a new serpentine belt for the engine.  I hear it is really ugly if it breaks while driving.