What's a good battery level monitor?
What's a good monitor that I can install in my Casita to see the battery level throughout the day? Ideally a monitor that draws minimal power since we boondock frequently. When we're camping in an...
Forum Discussion
I get it now, I think! Does the ali show the amps still going in and tapering while the AH counter is frozen at zero when it thinks you are at 100%? When it gets dark and amps go negative, does the 100 start to go down then too? (kind of an auto reset?)
What about charging efficiency? The Trimetric has default setting for that (which you can adjust) ISTR 94% ? Anyway, that means it records the correct amps but adjusts the AH by that amount when charging-but not when discharging-, so that if the charging efficiency (allowance for heat loss) happens to be correct, AH back in will equal AH out. Since that allowance for heat loss will be off by whatever amount, your counter will "drift" and need to be reset.
The capacity entry that is "full" needs to be corrected for temperature and battery condition, so the %SOC will be wrong just from that. An AGM loses 15% capacity at 32F compared with its rating at 77F, eg. Do you re-enter your capacity according to average ambients when camping? Battery age and usage matter too. Say your battery loses 5% a year and you have 3 year old batteries (down 15%) at 35F (down 15% from that.) So what is your capacity for 100% that your monitor is using?
I prefer to have the actual approx capacity at the time worked out and figure out the SOC myself from the AH count. I just can't see how the monitor showing a percentage SOC can be believed, so I don't even have that displayed.
That is also where voltage /SOC is misleading--- the capacity can be down but the voltage per SOC is still close to valid. You can be at near full voltage with a smaller capacity. So the AH counter is valuable as a cross-reference to see if they "match" for SOC.
"Percentage of what?" has to be asked.
What about charging efficiency? The Trimetric has default setting for that (which you can adjust) ISTR 94% ? Anyway, that means it records the correct amps but adjusts the AH by that amount when charging-but not when discharging-, so that if the charging efficiency (allowance for heat loss) happens to be correct, AH back in will equal AH out. Since that allowance for heat loss will be off by whatever amount, your counter will "drift" and need to be reset.
The capacity entry that is "full" needs to be corrected for temperature and battery condition, so the %SOC will be wrong just from that. An AGM loses 15% capacity at 32F compared with its rating at 77F, eg. Do you re-enter your capacity according to average ambients when camping? Battery age and usage matter too. Say your battery loses 5% a year and you have 3 year old batteries (down 15%) at 35F (down 15% from that.) So what is your capacity for 100% that your monitor is using?
I prefer to have the actual approx capacity at the time worked out and figure out the SOC myself from the AH count. I just can't see how the monitor showing a percentage SOC can be believed, so I don't even have that displayed.
That is also where voltage /SOC is misleading--- the capacity can be down but the voltage per SOC is still close to valid. You can be at near full voltage with a smaller capacity. So the AH counter is valuable as a cross-reference to see if they "match" for SOC.
"Percentage of what?" has to be asked.
