Even though intended for motorcycle LFP at-rest SOC voltage measurements, I use this often, even moreso than my Fluke multimeter and wall-charts with other 4S nominal 12v banks when lab-accuracy is not vital:
Tecmate-Optimate TS-271 SOC meter.
Around the outside edge are red led's. The green bar is for LFP. You'll note that for bike purposes, 12.7v is considered zero, since you won't have enough to start the bike. So slightly different application, HOWEVER, this might be ok for those people who like to stay out of the discharge knee.
Meant to be measured after a 12 hour rest for most accuracy - well as much as the resolution as a ring of red leds can provide. Small triangles inside the green bar seem to try and indicate 25% and 75% respectively.
So no, it will not allow you to store at 37.5%, but makes for at least a decent ballpark check of rested SOC values. If it's easier than a Fluke and chart that somehow never seem to be together, it might help save you from an incident.
And as much as I loathe SAE connectors, as far as they go, Tecmate-Optimate seem to be a bit better than most.
Tecmate-Optimate TS-271 SOC meter.
Around the outside edge are red led's. The green bar is for LFP. You'll note that for bike purposes, 12.7v is considered zero, since you won't have enough to start the bike. So slightly different application, HOWEVER, this might be ok for those people who like to stay out of the discharge knee.
Meant to be measured after a 12 hour rest for most accuracy - well as much as the resolution as a ring of red leds can provide. Small triangles inside the green bar seem to try and indicate 25% and 75% respectively.
So no, it will not allow you to store at 37.5%, but makes for at least a decent ballpark check of rested SOC values. If it's easier than a Fluke and chart that somehow never seem to be together, it might help save you from an incident.
And as much as I loathe SAE connectors, as far as they go, Tecmate-Optimate seem to be a bit better than most.