Battle Born Charging
This might answer some recent questions. The table is not accurate wrt to the BB comments--don't go by it by the table itself. Wade through the questions and answers to get the true picture. Tak...
Forum Discussion
I was out, but lurking-- one last rant:
"Exactly , charge to the end of bulk stage/ start of absorption and then they say charge another 20 thru 30 minutes and you'd be full 100% soc and amps would've tapered to around 4 amps ."
BB did not say that, which is what I was complaining about.
I repeat for the umpteenth time, that all they said was, to get to fully charged, do the 20-30 minutes past the end of Bulk.
They didn't even say that, but I inferred that from what they did say--starting from when you reach 14.4--except you can't go by that--you can only tell you just got to 14.4 by seeing the amps start to taper.
You only get to 14.4 at the battery when amps fall to zero and no voltage drop. You don't want to do that with an Li AFAIK, because "they" keep saying full is back when amps were still at 4-5%, so you might be going too far by waiting until amps fall to zero. I don't know. Not my battery money at risk, so try it if you like! :)
The missing part is that you don't know if that 20-30 minutes is when amps get down to 4-5%, which came from the batt uni site, not the BB site. AND you don't know the SOC at the end of BB's 20-30 minutes either.
You keep ASSuming the battery is 100AH, and putting the cart before the horse. The battery capacity is a variable, so first you need to know what the capacity really is (within reason) so you don't overcharge it. Luckily, with Li you don't have to get to full except on special occasions, so you can play it safe and undercharge it.
The actual measurement you did with times and amps is the way to do it. Watch the amps.
The monitor cannot be trusted to tell you the percentage capacity since you don't know the actual capacity. It has to be zeroed--but not the bogus way mentioned where you ASSume it is 100AH before you even start! This is true of all monitors and all types of batteries not just Li.
AND you don't have a way (AFAIK so far) to tell when the Li really is at 100%=true full.(no "marker") AND that would be "100% of what?" so you need to find that out.
--By doing some sort of capacity test like a 10 hour discharge from 100% at the 20 hr rate (5 amps for a 100AH batt at 77F) BUT to do that you need another "marker" for when you are at 50%--which you don't have either.
(With Wets it is the SG spec for 50% so you do have a marker there, plus your AH count, plus later on when it is resting you can confirm that SG marker by another marker using the OCV for 50% like 12.1v for a Trojan.) You can "match" your SG, AH count(knowing the AH count is a WAG), and the resting voltage to be confident that you are at 50% close enough for your test.
So you can use the monitor while camping, but you have to use it within its limits.
It can tell you AH while discharging. It can tell you AH while charging--BUT you have to know the monitor's allowance for heat loss when it is charging wrt the correct allowance for your type of Li-ion.
It can tell you amps and volts. It cannot tell you SOC except if it has been recently reset (which is where we came in--how do you know when you are at 100% so you can reset it? People keep entering a capacity number they got from somewhere and then believe their monitors' %SOC. What a farce! You can get an SOC estimate by the AH count and your own est of AH capacity allowing for temperature and what it was the last time you did the test at the 20 hr rate.
So you can plan to operate within 25-75% but where are you getting those percentages from??? That's the trouble.
You can do it with your Li as long as you know what a WAG it all is and the one thing you can see correctly is the amps while recharging to stay above 4%.
Itinerant1, ISTR, said he has been operating for four years, but does not know what his battery capacity is. That makes sense. It will be lower with age/use as he has said. I wondered in that case where he got that 99% from, but he got mad when I asked that. Apparently his BMS is not the same as a BB's BMS so he can use his for that somehow. I got lost with the BMS business.
"Exactly , charge to the end of bulk stage/ start of absorption and then they say charge another 20 thru 30 minutes and you'd be full 100% soc and amps would've tapered to around 4 amps ."
BB did not say that, which is what I was complaining about.
I repeat for the umpteenth time, that all they said was, to get to fully charged, do the 20-30 minutes past the end of Bulk.
They didn't even say that, but I inferred that from what they did say--starting from when you reach 14.4--except you can't go by that--you can only tell you just got to 14.4 by seeing the amps start to taper.
You only get to 14.4 at the battery when amps fall to zero and no voltage drop. You don't want to do that with an Li AFAIK, because "they" keep saying full is back when amps were still at 4-5%, so you might be going too far by waiting until amps fall to zero. I don't know. Not my battery money at risk, so try it if you like! :)
The missing part is that you don't know if that 20-30 minutes is when amps get down to 4-5%, which came from the batt uni site, not the BB site. AND you don't know the SOC at the end of BB's 20-30 minutes either.
You keep ASSuming the battery is 100AH, and putting the cart before the horse. The battery capacity is a variable, so first you need to know what the capacity really is (within reason) so you don't overcharge it. Luckily, with Li you don't have to get to full except on special occasions, so you can play it safe and undercharge it.
The actual measurement you did with times and amps is the way to do it. Watch the amps.
The monitor cannot be trusted to tell you the percentage capacity since you don't know the actual capacity. It has to be zeroed--but not the bogus way mentioned where you ASSume it is 100AH before you even start! This is true of all monitors and all types of batteries not just Li.
AND you don't have a way (AFAIK so far) to tell when the Li really is at 100%=true full.(no "marker") AND that would be "100% of what?" so you need to find that out.
--By doing some sort of capacity test like a 10 hour discharge from 100% at the 20 hr rate (5 amps for a 100AH batt at 77F) BUT to do that you need another "marker" for when you are at 50%--which you don't have either.
(With Wets it is the SG spec for 50% so you do have a marker there, plus your AH count, plus later on when it is resting you can confirm that SG marker by another marker using the OCV for 50% like 12.1v for a Trojan.) You can "match" your SG, AH count(knowing the AH count is a WAG), and the resting voltage to be confident that you are at 50% close enough for your test.
So you can use the monitor while camping, but you have to use it within its limits.
It can tell you AH while discharging. It can tell you AH while charging--BUT you have to know the monitor's allowance for heat loss when it is charging wrt the correct allowance for your type of Li-ion.
It can tell you amps and volts. It cannot tell you SOC except if it has been recently reset (which is where we came in--how do you know when you are at 100% so you can reset it? People keep entering a capacity number they got from somewhere and then believe their monitors' %SOC. What a farce! You can get an SOC estimate by the AH count and your own est of AH capacity allowing for temperature and what it was the last time you did the test at the 20 hr rate.
So you can plan to operate within 25-75% but where are you getting those percentages from??? That's the trouble.
You can do it with your Li as long as you know what a WAG it all is and the one thing you can see correctly is the amps while recharging to stay above 4%.
Itinerant1, ISTR, said he has been operating for four years, but does not know what his battery capacity is. That makes sense. It will be lower with age/use as he has said. I wondered in that case where he got that 99% from, but he got mad when I asked that. Apparently his BMS is not the same as a BB's BMS so he can use his for that somehow. I got lost with the BMS business.
