My bad. I meant a facepalm reaction.?
Claims to be a facepalm but sure doesn't show up very well.
Not getting in this discussion just pointing out we do have one![]()
My bad. I meant a facepalm reaction.?
Claims to be a facepalm but sure doesn't show up very well.
Not getting in this discussion just pointing out we do have one![]()
Something like this ?My bad. I meant a facepalm reaction.
Thanks for that....certain discussions/posters should just be ignored cause they are only here to cause trouble. Some call them trolls.?
Claims to be a facepalm but sure doesn't show up very well.
Not getting in this discussion just pointing out we do have one![]()
I vote for #2!Something like this ?
or maybe this ?![]()
To find the same for a battery with multiple cells in series, discharge with rated constant current, until one of the Cell hits 2.5 V. Then note the voltage of that cell after recovery. That in theory, represents the absolute minimum cut-off voltage for LFP.
I don't have the money and equipment to test it with factory new cells, but I suppose it is somewhere around the ~2.8V mark.
Look,Claim:
What theory? Yours?
Cite source or confirm you just made it up.
I might come across as incredibly dumb, but how do I use them for reacting to other's posts?
Its : then fp together and : with fp2 for the other one.I might come across as incredibly dumb, but how do I use them for reacting to other's posts?
You have to top balance them then insert into current thread.I might come across as incredibly dumb, but how do I use them for reacting to other's posts?
But on a rainy, cloudy day, I’m down to 0.02C which exceeds chart parameters for even the low setting of 3.5V.
Already explained in post #51 in this thread.So I pose this question to the hive: using the given pieces of the puzzle, 920ah, 1200w, 0.1C to 0.02C, what’s a proper charge-to voltage, or is this a case where I need to add another control function to the mix?
if (id(current).state > 0) { // Current can't be negative for calculation of 'charging' cut-off voltage
float cutoff_current = (id(battery_ah).state * 0.05 * (cell_bulk_v - 3.375) / (3.625 - 3.375));
float cutoff_voltage = (3.375 + 5 * (id(current).state / id(battery_ah).state));
// Stop Charging
if ((id(current).state < cutoff_current) & (id(max_cell_voltage).state > cutoff_voltage)) {
// End Of Charge
id(charge_status) = "Cutoff";
}
// Start Charging
else {
// With the "Auto Charge Current Control", the current is reduced automatically if "max_cell_voltage" approaches BMS OVPR
// Absorption : Max Cell V. > Cell Absorption V.
else if (id(max_cell_voltage).state > (cell_bulk_v - 0.005)) id(charge_status) = "Absorption";
// Bulk
else id(charge_status) = "Bulk";
}
}
Okay, then let’s change the parameters so my question becomes valid.But your loads will take that power, no? If you don't have loads, turn off at 3.45V or so.
I have never had a full battery, no loads, and 0.02C coming in. You just go back to float once you hit 3.5V per cell, and only charge again once the battery drops below the float value.
Isnt 3.45 the magic number for 100% with slow charging and zero detriment? I am pretty sure you are right!but the slow charging is what sneaks past the guard and ruins the cells.
That’s the question, and we really won’t know if our batteries last 30 years but could have made it 35, or if we added 5 years to them. I guess nobody really knows.Isnt 3.45 the magic number for 100% with slow charging and zero detriment? I am pretty sure you are right!
I usually charge to 3.45 and once every 5-6 months charge to 3.55 for balancing.
That is totally normal and exactly why we dont need to go that high. Simply put, there isnt much energy there so not a big point to do it.I get a big hockey stick when the charge voltage gets above 13.6. It climbs rapidly to 14V or 14.2V, whatever I have set.
I would charge to 13.8 and not think about it. Thats what I do.If the batteries can be charged to 3.5V (14V) no matter what charge rate is being allowed, then I’ll set the chargers to 14V
I dont believe there is any need for this. The idea is to charge to a voltage that the BMS starts balancing that is in the hockey stick curve of the charging process. If you dont have that info or its not available, dont worry too much. Even balancing at 3.5 yields very limited gains. If you can get and keep all your cells at 3.45 you will be just fine.If it is beneficial to charge them every 6 months until the BMS shuts them down
What makes you think it doesn't?I went and reread #51 which addresses charging at various C levels, but doesn’t address charging at all those varying C levels during one day. While it’s possible to follow a charging protocol based on a C rate, I have an infinite number of C rates going all day long, from 0.25C down to 0.00000001C.
You said you've a victron unit?I’m looking for someone to tell me how to set my solar chargers and let them work.
My BMS units are sealed within the batteries and not accessible in any way.What makes you think it doesn't?
It is valid for instantaneous values of current. You can poll the value of current 10 times a second or 10 times a minute for this loop. It is up to you. It will not fail.
You said you've a victron unit?
Does it supports CANBus? Have you got a JK BMS?
If yes, you can put together $10 in parts (ESP32 + SN65HVD30 + 4 Pin 1.25mm pitch JST XH connector) that will solve this problem forever.
It will automatically handle the charging for you.
As it has for me for last two weeks.
You can utilize the tail-current feature of your Victron hardware. Set a voltage like 3.475 V/Cell for bulk and 3.37 V/cell for float and corresponding tail current. It is better than any absorption timer.I’m looking for the voltage or combination of voltage and absorption time that will do a pretty good job of keeping my batteries healthy at charge rates between 0.25C and 0.00001C.