I have seen, when it gets to final balance mode, if there is a power glitch, the 'charging status' can lock up what it shows you,but it's still working in the back ground properly. I have seen that occasionally too, it'll 'hang' at 96 ill say good enough, unplug, cycle power, everything is 'reset' and talking again and it's now at 100. Especially if it hangs but been sitting there for a while at 96 and you just didn't realize it.
I have also seen where it's at like 96 or 98 then decides, ok it's balanced and then just goes right into, ok im charged. You turned it off, it finished settling out overnight you turn it back on, it looks at batteries, and their temp (which may have cooled down a bit, and NOW their voltage shows they ARE charged all the way)
I still can't see how the balancing is not just done in the background, it's a simple wheatstone bridge really, nothing more. I think the 'cell balancing' is just giving it a bit of time for that process to just complete happening, and even if you turn it off, it can still balance in the background anyways.
I 'rescue' lithium batteries, for my own personal use, re string them, and then use them for my own storage applications. It's in a shed out back, if one goes nuclear and the halon don't snuff it, ok BFD i just burn down a 10 x 10 shed, not the entire house, anyways... the balancers I use are really friggin simple
https://www.ebay.com/itm/114731606093 is a great example. Basically when it's balanced, it sucks flea power, if one cell goes high or low during cycling, it starts slushing from the others to balance it all out, and it's all pretty much passive.
You charge everything up hot, then give it a little bit for everything to settle out, see where it's at, then trickle top it off as needed.
Finally and I'll say this again, SOC, can get 'complicated'. To get a true SOC you need to know temps, life span of battery, draw rates, etc etc, it gets messy. You really can't just go by voltage, although most people DO because it's just easier, and columb counting has it's own set of issues.
Also, going by voltage, the power density at the ends of the spectrum are very low, so that final 2 percent by voltage is almost nothing.
Here: lets try an example to hopefully show a bit better how it works..
Lets take a battery bank that has a 100 KW capacity.
Lets say at 0 percent SOC the voltage is 0 volts
Lets say at 100 percent SOC the voltage is 100 volts.
NO these are not real numbers, im just trying to keep the math simple so that some folks don't get more confused.
If you go by voltage, every volt is 1 percent and in an ideal world it'd take 1kw of power put into the battery to bring it up that 1 percent. The entire charge / discharge would be nice and linear..... good luck with that !!
In the real world now it's a different matter.
in the real world, when you pay say 5 kw into that battery, it's voltage is right around 45 volts or so. But wait, shouldn't 5kw input make it only 5 volts? Not in the chemistries mind !!
Now you can throw another 60 kw into it and that brings your voltage up to maybe 80 volts... but wait shouldn't it be more like 65 volts? nope, not in chemistry's mind
throw another 30 kw into it, that's 95 kw in and your voltage is more like 85 volts.
now, from 85 volts to 100 volts you'd expect 15 kw of power needed to do that, but in reality you'll get it with about 5 kw max.
The power curve is pretty linear in the middle but at the ends it falls off a cliff on the low end or hits the moon on the high end.
So at the end of the day, that final 2 or 3 percent of 'charge' is not a kw or so, it may only be 150 watt hour, which in the world of multi KW capacities ... is flea power.
I have not taken apart an Energica Battery but would imagine, it might be a 6 modules of 48 volts each, in series to give you your baseline 300 volt, full charge 330 volt pack. Your standard 48v75aH pack, times 6 for your 300v 21.5kw cap, with a little wiggle room. They may 'cheat' a bit and add a cell or two to each bank to give it a little 'reserve capacity' to account for aging, etc etc.
That balancer I shown you, you can string those together endlessly in theory. So instead of a 4 channel, they plug in a 6 channel one. it's good for up to 5 amps of 'power transfer' between cells, not bad really. It's balancing continuously as the battery charges, AND discharges to be honest, only 'topping off' at the very ends. Unless you got a bad cell, the unbalance of a battery really should be almost negligible, and even if you did have a weak cell, with the balancer it's going to continually try to 'correct' that.
Maybe someone from Energica may chime in, if they are allowed to, but at the end of the day. A final 2 or 3 percent charge display variation, Id not worry too horribly about. If their determination of SOC IS more complicated then just voltage division, then yes, the battery sitting over night and the temps changing SIGNIFICANTLY can very well alter it's charge state.
Just my postulations and theories, again, I have NOT dissected one of their batteries (yet) so can't speak with any authority on them (yet)
Psstt... hey!! any of you dealers have a shit battery you need to dispose of.. wink wink. I got all my permits so YES it IS a legal transfer to me to dispose it
Aaron
Author
Topic: Ripley's - Energica Believe it or not (Read 426 times)