• Have you tried out dark mode?! Scroll to the bottom of any page to find a sun or moon icon to turn dark mode on or off!

diy solar

diy solar

9 years so far....

Sojourner1

Itinerant
Joined
Sep 30, 2019
Messages
791
Location
USA
It has been 9 years now that we began our full-time "boondocking" or "off grid" or "dry glamping" adventure. Any one of these fits the description, I guess. 😉

Reviewing some #s from 9 years of record keeping of the solar/ lfp system. Yes..that's 9 years of daily recordings mainly for my personal review. It started just for when the batteries crapped out I could go back and possibly pin point the time period. It hasn't happened yet.

Remember LiFePO4 (LFP) back then was a new and unknown "tested" chemistry in the boat/ rv world. There were many failures along the way when using the manufacturer voltage setting for charging of 15.0v (3.75 vpc). After reading many thread in the boat forums and seeing failures of packs. Decided to charge to 14.2v (for a couple years) and now bounce between 14.1v late spring to late fall. Then I'll increase back to 14.2v during winter only because of long partail SOC use during the shorter daylight hours in winter. Thought the little extra couldn't hurt.

My battery manufacturer with their CPU (bms) will reset the capacity to 100% whenever the pack voltage reaches 3.49 to 3.52 V/cell on average.

Balancing starts when individual vpc reach 3.55v.
From the manual...
"In a battery system with many cells in series, one or more cells can be charged more than others. The capacity of the battery system is limited by the cell that holds the least charge. The Elite Power Solutions battery balancer is a small, sealed module that attaches to each cell in a series string of lithium batteries to assure that they are all charged the same amount.Lithium battery chargers are designed to charge the cells to 3.60V per cell. The battery balancer will apply a small load (0.5A) as long as the cell voltage is above 3.55V. In this way, when the charger stops charging, the cells that are above 3.55V will be discharged until they all reach the same voltage point of 3.55V. Thus, they will all have the same charge. Because of the low discharge rate, it may take some number of hours to accomplish the discharging and multiple balancing cycles may be required. This low discharge rate prevents excessive heating in a sealed battery box.OperationThere are two LEDs on the balancer. The green LED indicates that the battery is properly connected. It will light when the cell voltage is above about 2.5V. The red LED will light to indicate that the load is applied. It lights when the battery voltage is above 3.55V. The load is a constant current and does not vary with battery voltage. When not discharging, the balancer draws about .001A (1mA) of current which is not appreciably more than the self discharge rate of the battery."

I've actually never let it run a full balancing event this entire period. Once absorbs (14.1v or 14.2v) starts it goes for 6 minutes and switches to float. That's just the way I have my settings since day 1 experimenting. The cells aren't perfectly match and haven't been since day one. Didn't know back then it was a must or your pack won't last a longlife.....LOL. They're within. 04v highest to lowest vpc between the 5 100ah batteries in parallel. Never had an over voltage or under voltage event when charging or using high draw appliances at low SOC.

System components:

• 12v 500ah lithium batteries (Elite Power Solution GBS LFMP battery system).
• 8 CTI 160w panels (1,280w), 2 in series, 4 sets. Each set goes to the combiner box where all sets are in parallel. Panels lay flat on the roof.
• Magnum PT100 controller
• Magnum 3012 hybrid inverter/ charger.
• 7" display monitor and the ME-ARC 50 display to read the performance of the system.
• Subpanel was added so everything in the 5th wheel except the water heater is running through the inverter.

After this period of time I've yet to notice any lose in either solar production or battery use in any SOC. I was hoping for 8 years of pack use and have reached that. Now exceeding it, the question is for how long??? This was truly a set it and forget it system. Yes, I still look at it everyday just because.... well, it's there. 😆

One regret is that I didn't buy a "Cellpro Powerlab 8" years ago, it seems that this piticular animal isn't made anymore. I figured I could do different tests and recording to see how these battery cells have held up over the years.

This video actually shows GBS cells and how he tested them using it.

He had a couple other videos with the Cellpro. Maybe someone stumbling across this post knows of unit like this?

Recorded end of year #s... traveling through midwest/ western US states. Late Spring/ Summer/ early fall "northern" late fall/ winter/ early spring "southern".



Screenshot_20250409_072649_Excel.jpg
Screenshot_20250409_072746_Excel.jpg
Screenshot_20250409_072835_Excel.jpg
Screenshot_20250409_072930_Excel.jpg
Screenshot_20250409_073158_Excel.jpg

This month's...
Screenshot_20250419_105142_Excel.jpg

Happy travels and hope everyone's system operates as well as mine has over the years.
 
Last edited:
Great summary and results! Should I start using the camper more I probably should start pulling statistics, but I deal with numbers/data so much in my job that by the end of the day I tend to not care.
 
I keep thinking I'm going to stop recording data but it just doesn't seem right to stop after 9 years. 😕

Plus a system can run nicely in the background without henpecking the :poop: out of it once you have the parameters set that help you sleep at night and move on to another endeavor. 😉
 
Last edited:

diy solar

diy solar
Back
Top