Travato Lithium Battery Project
My Travato came stock with one Group 31 AGM battery from NAPA. This is a good battery, 110 AH. I could make it a couple days running lights, fantastic vent fan, entertainment systems and the water p...
Forum Discussion
Having a meter for voltage at the battery is quite important. We wind up with duplication with the TriStar MPPT, Magnum inverter, and Battery Management System (BMS) giving the battery voltage from different viewpoints. Happily, they all give the value(s) for total voltage. The BMS also gives the individual voltages of all 16 cells.
The conventional wisdom is a maximum of 3.4 V at "float" (80%) which is 13.6 V at "float" for the four cell battery. As OP noted, LFP systems are set to charge at 3.6 V per cell or 14.4 V for a 4-cell battery (the cells are continuously balanced by BMS and the cells never go over 3.4 V. Since our system is set up with four batteries in series (16 cells total), we are looking at 54.4 V at "float".
Chris of Technomadia did great work when he was first in US (as far as we can tell) to an LFP system in their motorhome. He made mistakes on which he has candidly written. These mistakes along with the correct decisions he made are lessons to all who came after him.
As noted in previous posts, we have only hooked into line power once in two years (for two days when it was over 103 and in the shade at an RV park) so we do not have the problem that Chris had with keeping LFP battery bank at to high a state of charge. We generally start the day at -2 to -4 kW-hrs deficit when we are in high usage mode (sunny skies) and are far more circumspect when we are forced to park in heavy shade. We turn off inverter in these cases since it has a parasitic draw of about 100 W.
Reed and Elaine
The conventional wisdom is a maximum of 3.4 V at "float" (80%) which is 13.6 V at "float" for the four cell battery. As OP noted, LFP systems are set to charge at 3.6 V per cell or 14.4 V for a 4-cell battery (the cells are continuously balanced by BMS and the cells never go over 3.4 V. Since our system is set up with four batteries in series (16 cells total), we are looking at 54.4 V at "float".
Chris of Technomadia did great work when he was first in US (as far as we can tell) to an LFP system in their motorhome. He made mistakes on which he has candidly written. These mistakes along with the correct decisions he made are lessons to all who came after him.
As noted in previous posts, we have only hooked into line power once in two years (for two days when it was over 103 and in the shade at an RV park) so we do not have the problem that Chris had with keeping LFP battery bank at to high a state of charge. We generally start the day at -2 to -4 kW-hrs deficit when we are in high usage mode (sunny skies) and are far more circumspect when we are forced to park in heavy shade. We turn off inverter in these cases since it has a parasitic draw of about 100 W.
Reed and Elaine
