batteies

StirCrazy wrote:
. . . maybe you can explain this, is why it is such a big deal to have a second stage. When I am camping in the bush the charge isn't running, so it's no big deal. With LiFePo4 everyone is so adamant about not storing them at a full charge so we shouldn't be leaving them on charge anyways when we are not using the unit. and the final category if you camp in power sites mostly, well then why did you spend money on LFP? and if you only camp with power once and a while, just turn off the charger breaker and you don't need to worry about it

StirCrazy wrote:
. . . No, not necessarily do you need 14.6v, for instance my BMS will start balancing at higher than 13.6V but for me the cell manufacture recommends charging at a constant 14.6 and then cutting the voltage when the state of charge is reached. Considering they are one of the biggest prismatic cell manufactures, I would assume they know what they're talking about and that is how I set up my system. I do play with it to see how it behaves in different situations though . . . .

Not sure if you realize it, but all this monitoring, "cutting the voltage" and "turning off the charger breaker" that you recommend doing while using a single-stage 14.6v converter would not be necessary with a 2-3 stage converter. IMO, a converter should be able to safely and efficiently charge/maintain a lifepo4 battery for weeks, months at a time . . . with ZERO user input. This is exactly what a multi-stage (2-3 stage) converter does well.

StirCrazy, here's a simple analogy that hopefully answers your question why I feel a converter with 2-3 stages is a really a "big deal" . . . and why a single stage 14.6v converter is such a bad deal.

Using a single-stage (one voltage) 14.6v converter to charge a 12v lifepo4 battery is roughly equivalent to driving a car at redline. To clarify, 14.6v subjects the cells in a 12v lifepo4 battery to 3.650v---the Maximum Rated Charge Voltage for 3.2v lifepo4 cells . . . this is roughly equivalent to driving a car with a Maximum Rated RPM (redline) of 6000---at 6000 RPM. Sure you can drive a car at redline for short periods of time. You can also charge (float) a lifepo4 battery at its maximum rated charge voltage for short periods of time, too. No immediate damage occurs in either case. However . . . common sense says . . . "redlining" a car or subjecting a battery to its maximum rated charge voltage, for extended periods of time (accidentally or otherwise), presents a much higher risk of permanent damage occuring. If you're the set-it & forget-it type, and forget to turn-off a single-stage 14.6v converter while using FHU's for a month or so, you run the risk damaging your lifepo4 battery. For folks like yourself who monitor their battery & converter closely, this risk is lower. However, I would surmise most folks would prefer not to be babysitting converters and batteries while they're on vacation---I know we'd prefer not to.

In any event, NONE of the above risks exist when charging with a 2-3 stage converter (with the proper voltages)---even if the converter and lifepo4 battery are left unattended for weeks, months at time. It negates these risks by automatically activating a completely safe, lower float voltage as soon as the lifepo4 battery is fully charged.