Vic Harder said:
Here's the link -
Batteries Tested! What Is The Best RV Battery For The Money? | Mortons on the Move
This felt like a more honest test, frankly. And yet the results are still shockingly bad for AGM batteries.
They note that a key to battery life is good monitoring and protection circuits, with voltage cutoff relays for example. Not many FWC/ATC have these, so I wonder if folks are maybe getting more apparent power out of their AGM batteries, because they are abusing them?
I've used AGM's and Gel cells before LiFePO4 batteries for the house bank, for over 20 years. And that's full time, on a boat, as a liveaboard. I also never plugged into shorepower for 10 of those years while cruising, relying completely on solar and wind power. I always monitored the batteries and tried hard to never discharge more than 50% of the capacity of my Trojan AGM 400 AH battery bank (at the time, Lithium batteries were not yet a practical option). On occasion I would need to discharge past the recommended 50% level, and went as far as to 80%, probably more times than I should have - but in the real world sometimes that's what it takes to get by. I could tell without looking at my meters where the battery capacity was by the dimness of the lights in the cabin, something I can't do with a LiFePO4 . I can tell you that even with careful monitoring and tweaking the parameters of the AGMs through a smart charger/controller, a new set of qualityAGMs would begin to degrade within months of full-time, no-shorepower useage, after installation. And for the most part I'm not even talking about cold-weather performance. It's frustrating to see that kind of degradation for a battery that is supposed to give good performance for 5-10 years. And it is not inexpensive to replace a 400 AH AGM battery bank every 2-3 years with quality batteries. The batteries would still work if I held on to them for longer, say 7 years or so, but the performance would have gotten progressively worse after the first couple of years, sometimes sooner. Along comes LED lights, efficient fridges, and better solar arrays. And followed up later with smart chargers that make LiFePO4 batteries with integrated BMS and now self heaters a stellar, practical, and highly efficient solution, in retrospect. I think it's increasingly clear (at least after 1-2 years - okay, we haven't yet seen real-world results after 8-10 years, but I'll take that chance) that our LiFePO4 house bank will surpass our AGMs in all around performance, including cold -weather performance down to 90% of capacity (~ 10% SOC). We can read all the test analysis we can stand, and draw conclusions all we want, but in the end if you are getting a quick charge and the lights are bright and you can discharge capacity to 0-10% SOC, without harm to the chemistry and you're going farther between charges cycles, and premature replacement of your battery bank isn't necessary, then you've got something to write home about.
Rich
