[time-nuts] Re: Backup DC power with current battery technology?

[Stephen C. Menasian]

Actually, you can monitor voltage to determine when to start charging. I
have a 36V, 80AH LiFePO4 battery for a 600 Watt solar panel setup. When
the voltage is 39.7 or more, the battery will reliably hold up overnight.
Below that, I put it (and the load) on the charger (an 8 Amp, max unit
supplied with the battery). At 36.5 Volts and below, immediate charge 
is advised and at 36.0 Volts, it is necessary (under 3 hours left).

I have added a 36 Volt DC power distribution system to the house. 5 Volt DC-DC
converters at the endpoints and a centralized 12 Volt DC-DC
converter (with its output also distributed with the 36 Volts to the
various endpoints) complete the system.

On Tue,28 May 2024 11:01:01 +0200 Wilko Bulte
via time-nuts <time-nuts at lists.febo.com> wrote:

> LiFePO4 batteries have a very steep cliff: a very flat voltage curve
> during discharge, followed by a sudden switch off performed by the BMS.
> So you cannot monitor battery state based on voltage. 
> 
> I own a couple I use for /P hamradio. Experiences have been excellent. 
> 
> Wilko
> 
> To unsubscribe send an email to time-nuts-leave at lists.febo.com