OK tried registrating myself on the image gallery to send it schematics, not happening.? Im a total failure.
I used the  LEF2017 thing as a global password.... is that correct to do that.?
Anyhow it didnt work, if some kind soul can walk me through?
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Yes, with only the terminal voltage to actually gauge battery SOC, it's not very accurate.  By manually boosting each cell with a separate supply, it's possible to get them all at the same level  and then let the balancer take over. It's fascinating to watch the indicator LEDs flashing as the dumps turn on and off.  I will perservere with the resistor ladder network and comparator method to monitor cell voltage during a charge cycle ...this just compares each cell to the fixed ratio of a resistor network.... I know, schematics would help... I'm working on it..  Another scheme would be a sigma delta detector, ....DvDt.  where the rate of voltage rise is the indicator for end of charge, and not the absolute voltage itself, this method was successful in the old fast charge NiCad days. I have noticed this effect also seems true for lithium.
It's fun learning this stuff, and Bruce, I don't envy your 120 volt system when it comes to battery management. With 600amp hours in each cell, it's very slow going to see any change occurring, and time consuming too. If my electronics gets any more complicated, it may be better to just have dpdt relays  between cells to force parallel connection of all cells occasionally?
I'm still wondering if I'm over thinking this.

OK, it seems this "top balancing" is a fudge. Research tells me that under high charging currents, the cell chemistry is unstable, changing cell resistance and therefore cell voltage. This settles down after charging, but then cell voltage drops,  rendering these dissipative cell balancers useless. By cutting back the completed charge rate, keeping the cell voltage high, then these BMS systems have time to work. But not at the 100mA these things used originally.
So, I have modded a  Chinese  balancer by using the dump FETs to switch the base current of four PNP power transistors. These bang a 1 ohm resistor across that cell..... Current drain of around 3 amps differential. Now, at the time these activate, the solar controller has detected its max battery voltage at 14.6 and has shut down, supplying only the voltage required to supply the low cells and the additional shunt currents from the balancing drains. This seems to be working well, although I'm still not convinced its required, all cells are very close without. But, it will do no harm I guess. The biggest change I have noticed with lithium is the much shorter charge time , a direct result of higher chemical efficiency..... Energy not wasted producing oxygen and hydrogen gas, as you get with lead acid.

Hi Bruce.
Yes, my legacy  system is "stuck" at 12 volts. This is what I started with back in the 80s and it probably will stay that way unfortunately. All the appliances and ancillaries are 12 volt, quite a mission to change to even a 24 volt system.
The way I have understood this cell balancing is that any cell drifting high compared to its neighbours will reach the 3.65 fully charged voltage first, thereby leaving the other at a partial charge if charging stops at that point, which it must if cell damage is not to occur. Looking at the charging curve, the top most fractions of a volt represent such a very small part of the total; capacity of the cells, the loss is minimal. I have wired each battery in parallel, then ran 3 wires between cell junctions, this effectively places all cells in all batteries as one giant series parallel configuration.  As you say, this limits the problem to just 3 junctions.
These are also connected to 4 of those small Chinese digital voltage displays that are taped to the battery giving a constant display of cell condition.
I have since constructed a automatic cell monitor using 2 LM339 quad comparators. One  input is referenced to a seriesed and tapped  resistor string across the battery, the other input referenced to each cell junction. The tapped resistor voltages rise and fall with battery voltage, but remained in a fixed relationship. The cell voltages rise and fall, but are not in a fixed relationship with each other.
This allows the comparators to monitor not the absolute voltage of each cell, but the difference between what they shuld be from the fixed resistor string, and what drift has occurred in the cells,.
 By alternating between  inverting and non inverting inputs, we can have a window comparator with just a few millivolt window. The open collectors are simply paralleled through one LED to indicate a fault. The remaining two comparators detect 14.6v and 10.7v respectively.
Ill post this diagram too if its useful.
To me, this has been a better way to do this.
The other BMS issue that caused me  problems was its ability to turn the seriesed BMS FETs off as the battery voltage got near 14.5v, it would simply totally disconnectthe battery  from the "grid", giving an open circuit to the alternator, high voltage into the house wiring and killing anything that happened to be turned on at the time.  The overvoltage switch to the field works very well, and in my case, much more elegant.
The one strange thing I have noticed, the high cell is never the same one each day, it varies but so far has never exceeded 3/10ths.
To understand the balancing part of these BMS units, I removed the 100 ohm smd resistors from the dump FETs, ran wires to outboard resistor and LED combo to monitor the action. These turn on at cell voltage 3.55. Now, this is at the top of the charging curve where, at a charge rate of even a few amps, this would have little to no effect given that charging at this point is almost finished.
Still, this is my knowledge of Lithium so far.

Yes Mike,, and many thanks for the kind words......
I can honestly recommend these LiFePo batteries. I used to worry and stress over the lead acids..... how much charge I had to leave in for longevity reasons,  periodic equalising, are they sulphating, much like a woman, you are never sure you are doing the right thing, and the costs of not doing so can be crippling.
Lithium are bloody expensive, but the full capacity can be used, they cannot be damaged by long periods of partial charge, in fact, they will exceed the rated 2000 full cycles if "mistreatred" like this.

Glort, you are talking rubbish. and again becoming hysterical and dramatic.
Smallish Induction motors are designed to run at 50 and  60 cycles for a worldwide market, and a safe percentage above and below. If they are not overloaded, they will happily run on higher or lower frequencies, exactly as happens with variable speed drives.
A generator should NOT vary its voltage significantly when running above or below its stated RPM, this is the job of the AVR. Even if it did, all motors are rated within plus/minus 20 percent constant. voltage , with substantial safety margins.
What issues with the AVR? Are you saying it will burn out attempting to saturate the stator? Another myth.
The sander in question will be powered by a capacitor start motor,as it is not required to have high starting torque, therefore any centrifugal switch is not present. Increased wear on bearings???  Rubbish.
The rotor in an induction motor has shorting bars, not windings, so how can the rotor be "stressed" above and beyond?
Your suggestion of a VFD is ridiculous for such an application, its likely to cost more than the sander.
The gentlemans query was to slow run a cheap sander easily and presumeably cheaply I believe.
This  also implies intermittent use of the appliance anyway..
You  are  very quick to have an opinion on stuff you know very little about.... google does your thinking i suspect.
Yes, I can demonstrate this, I do this frequently with my drill press, but I wont....... your incessant need to be right, you will poo poo any demonstration and start a slanging match, as you have so done before, and attempting to do now.

You can do this job for free. Power the sander with your generator, and slow the generator down. Lower generator RPM equals lower mains frequency equals slower induction motor.....

you're welcome

You can speed it up like this too.