LiFePO4 Solar Controller

[Pappion]

vsheetz, thanks for the link. Battery University was little help. Battle Born recommended 1/2 hour absorption per 100AH. Very little info on bulk charge behavior prior to absorption. Seems like SOC is easier to determine by voltage while charging, but difficult while discharging.

I ordered a Victron SmartSolar 100/50 charge controller.
https://battlebornbatteries.com/prog...ge-controller/


I'm getting cold feet on the LiFeP04 batteries. I don't like how 45c (113f) can damage them. That would cause me storage issues in AZ in summer which has many 35c - 47c days. That's why I put advanced AGM with nano-carbon on my last camper. They got old, so I let them go with the camper. No longer available.

[n0arp]

Originally Posted by Pappion

I'm getting cold feet on the LiFeP04 batteries. I don't like how 45c (113f) can damage them. That would cause me storage issues in AZ in summer which has many 35c - 47c days. That's why I put advanced AGM with nano-carbon on my last camper. They got old, so I let them go with the camper. No longer available.

Most mfg datasheets I've seen for LiFePO4 are around the same. The one I pulled to double check my numbers says that you can charge them from 32° to 120° F, operate -4° to 140° F. and store from -4° to 113° F - which I assume means store at a sustained temperature for months on end - something you won't have in your application.

[astrocamper]

My Reno days are not as hot as your Arizona days. I have been logging my battery, pass-through storage and outside trailer temperatures since July with my Cerbo GX. My batteries are stored inside under a polycarbonate twin wall cover between my sit and sleep sofa and the wall adjacency to the front pass through storage. They stay at least 10 degrees cooler than the daytime highs and about 10 degrees warmer than the night time lows.

I keep one window on the east side of the trailer open and a bathroom fantastic fan on which is under a 300 watt solar panel which protects it from rain. My daytime highs are about 35-40 degrees warmer than the nighttime lows. The inside trailer temperatures are moderate compared to the outside temperatures.

In the cold months I leave the window and fan closed. The overnight lows inside the trailer keep the batteries from being too low to take a charge in the daytime when the sun is shining on the panels.

My seven 100 amp-hour BattleBornBatteries are not inexpensive but perform very well with my 1440 watts of solar on the roof and my VE Multiplus 3000VA 12 volt inverter/charger. When camping in the summer we run the air conditioner when the sun is shining using solar/battery power to the inverter. We supplement the roof top solar with 640 watts of portable panels. I have enough battery to run the air conditioner until the evening temperatures cool down after sunset.

[hclarkx]

I like having the BT from the LiFePo4 BMS. It pretty much tells me all I want to know and helps ensure my $$$$$ batteries are being treated well. It gives me important bits like battery internal temperature, SOC, balance, charge/discharge current, etc. It even tells me that my solar is working as it should by looking at the battery current and looking around at my loads and where the sun is. I check the readouts on the three solar controllers only rarely and as an occasional check to be sure they are working as they should since the battery only tells me the total of the three. As others have mentioned, battery internal temperature never gets as low as the ambient or as high as the ambient. That's very useful information with LiFePo4.

[Pappion]

OP posting... I bought the Victron Smart Solar 100/50 with bluetooth. Installed 4 days ago. Adaptive Absorption and Tail Current exit are great features for AGM (lead acid) charging. The logs are great for evaluating charge and use patterns.

I concluded that the 2x 100AH AGM batteries this TT came with won't be enough for me this winter. Furnace blower is 7.5A, Laptop is 4-7A, TV/DVD about 7A.

I am looking at a 200AH LiFeP04 to start with. No rush, they seem to get cheaper as I wait. Right now I am plugged in and simulating boon docking by shutting off the breaker to the converter.

[hclarkx]

Originally Posted by Pappion

OP posting... I bought the Victron Smart Solar 100/50 with bluetooth. Installed 4 days ago. Adaptive Absorption and Tail Current exit are great features for AGM (lead acid) charging. The logs are great for evaluating charge and use patterns.

I concluded that the 2x 100AH AGM batteries this TT came with won't be enough for me this winter. Furnace blower is 7.5A, Laptop is 4-7A, TV/DVD about 7A.

I am looking at a 200AH LiFeP04 to start with. No rush, they seem to get cheaper as I wait. Right now I am plugged in and simulating boon docking by shutting off the breaker to the converter.

Neat. I have a load calculation spreadsheet if you are interested. It will tell you how much battery you need to get through the night with a given SOC remaining as a cushion. You enter the load current and the day and night hours of use (or fraction of an hour). Below is the Winter side of the load list.

It also estimates solar required for locations you might visit using 50 years of solar data.

Did you see LoveYourRV's test and tear-down of a $620 SOK 100 AH LFP? I was impressed. It holds up considerably better than Battleborn below 15% SOC. It can be dismantled!! Cells and BMS can be replaced.