Originally Posted by gregmchugh
Based on the installation instructions, the add on Ecotrek is simply wired in parallel with the existing AGMs and the two 12 volt connections on the Ecotrek are connected together with a short cable.
If you have not seen this you might find it interesting...
Interesting article, wish they had done AGMs also, though.
It seemed to do what would be expected, with the lithium doing most of the work early on. I was a bit surprised the the very initial discharge came from the wet cells, so they went down a little.
In the application they used, they have few discharges and very long times on float, so the wet cells would stand a better chance of getting back full. It would certainly change a bunch on repeated cycling every day.
They did say that both batteries need to have similar charge and float voltages, and that might be an issue as some say lithium should not be floated, and the lithium would probably be at a higher voltage than the lead acid battery at rest.
Trying to make both types see conditions to maximize their life is an interesting exercise, I am sure, especially if there is a constant voltage charger on the system that probably would be too high for lead acid batteries for long perionds.
Time will tell, though.