Originally Posted by davedutah
Sure, but some of the lithium batteries come with integrated battery management systems in each battery, like the Battle Born 100Ah which are designed as a drop in replacements for Group 31 AGM sized batteries (though I would install them inside for temperature protection). The Battle Borns have twice the usable amp hours for half the weight (and are rated for many times the number of charge cycles of AGM).
However, the existing charger still usually needs to be reprogrammed for the different voltage thresholds used by the lithium batteries. I'm mainly wondering if anyone has done so with the existing one in the Trend or Viva 23L, and if so, how easy was it?
As always, I will say that you have to be careful with the claims of the "drop in" lithium batteries. Unless they have fixed it lately, the Battleborn site is full of technical errors and erroneous claims to make themselves look better and AGM batteries worse. They appear to be made by Dragonfly which has been around for quite a while but didn't get much market. The BMS in drop ins is usually very basic and not all that protective, from what we have been able to find, and has no output so you don't have any way to see what is going on, even for state of charge. There is also the waste of buying multiple BMS systems that aren't centrally controlled/
Several manufacturers have tried using drop-in lithium in their RVs and have quickly gone away from them. Some people have used them and had good luck, though.
If I were considering a lithium system, I would first look at a system line the Elite kit that is mentioned further up on this thread.
There are lots of things to consider with lithium as you need to have the charging sources disconnect when the batteries are full for all of them but still reactivate when charging is needed or to recover from a low voltage or low temp shutdown. You can't charge under freezing, but can use down to about -4F per the latest we have heard but some dispute. You have to have heaters, of course, for the batteries, and the power to run them if the batteries are offline.
Basically, this is not a "drop in some batteries and reprogram the charger" installation IMO.
There are lots of discussions of systems on this forum, both factory and home built, which will give you lots of information.