@Friskies Nope, sag isn’t affected by changing from 12s5p to 10s6p (for the sake of apples-to-apples, both have 60 cells.) Either way you’re losing 0.5v (*20A=10W) per cell, and it’s the same percentage either way: 50.4v -6v sag is the same percentage of speed loss as 42v - 5v sag. Same wattage lost, same percentage of speed lost, same same.
The only things that affect sage are temperature (warmer batteries sag less), number of cells total (more cells = less load per cell), the cells themselves (higher-discharge cells sag less), and loading (the less you draw, the less it sags).
But going from 10s4p to 12s4p adds 8 cells, as well, so you have more available power, thus more overhead, thus less sag. For a real apples-to-apples, you have to consider packs with the same number of cells.
vtc5a 12s6p is like 2-4max Volts for me when Iam going to the max (about 60a max in the config) with a dual6374 emtb. Iam curious how much it is when my vesc6s are here and Iam able to drain the pack a bit more.
Does someone get the effect with lower voltages lets say 30% left dont sag as much like with a full charged battery?
Yeah, the initial sag from 4.2 down to whatever working voltage is is always more severe. Also your 30% battery is probably warm, which improves performance.
One important variable is that the internal resistance is variable and depends from cell to cell, when almost empty the IR rises a lot, that’s why you experience a lot of sag when near zero
I don’t agree with what you are saying here. The thing you are forgetting is the speed at which the user wishes to travel at. Increasing the voltage input to a VESC will increase the speed of the board correct? Regardless of which way you look at it, if you were comparing the 12s at 10% charge to a 10s at 10% which board will be travelling faster?
Our VESCs do not compensate throttle value based on voltage input so as the battery voltage drops, so does the top speed and overall performance of the board.
The sad thing is, at the end of the day you are always better off with 12S if you want performace; even at its lowest it will still be rivaling the 10S at full capacity.
My vtc5a’s have been great. Compared to my 25r pack, 10S4P, those sagged like 9-10v under 80A load… The vtc5a pack, 10S5P sags maybe 3-4v under 120A load. Does sag really affect range? I feel like it does, I rode 14 miles today and got down to 60% charge by the end of the ride. The absolute most I could squeeze out of my 25r 10S4P pack was maybe 15-18 miles, running low amp limits, or 10 miles just cruising hard.
I agree with everything you said here, but none of that addresses your earlier comment of “to avoid sag, go 12s.”, or my response to that.
Yes, a 12s pack will produce more voltage than a 10s pack. BUT, a 12s pack of X cells (For equal values of X) will still sag just as much as a 10s pack of X cells at the same discharge power, because math is commutative. Doesn’t matter if 12s at 10% is faster than 10s at 10%, your 12s board will still lose Y percent power/speed/voltage at a given load, and that number will be identical to a 10s pack with the same number of cells. Yes 12s is faster. No, faster does not equal less sag.
Sagging is real. Thus why I went to a 12s 25ah lipo. I no longer know what sagging is lol. I drop less than .2v under full acceleration (pulling about 200a at 12s). And charging? What’s that? lol
I agree with the 12s vs 10s that’s not what will change the sag, it’s the number of cells in parallel that your spreading the amperage across to lower sag. That is of course if you are not changing the battery amps in relation to the number of cells.
Example 10s4p pulling 60 amps will sag more then a 10s6p pulling the same amps. But if you adjust your amp to maximize your power per cell if each cell can take 20 amps, 120 amps on a 6p then you’ll see the same amount of sag, at least in my mind.
I understand and agree with what your saying here. What I’m trying to get at is that if you are not pushing your cells hard and just cruising up to 35kmh on a pack with low voltage. The sag should be less noticeable in terms of speed on the equivalent pack vs the 10s as the rider would still be able to achieve the desired speed. Under steep acceleration you would still hit sag or a steep hill you would feel the equivalent performance loss but I would prefer to be sagging and at 44 kmh on 12s 30% than riding at a top speed of 40kmh and sagging under load and at low voltage to 32/34kmh on the 10s equivalent pack. Thats just my preference. 12S5P>>10S6P
While I get your point, that’s the point at which I would just decrease the gear ratio by 20% for the same effect. 10s6p with E.G. 2.4:1 would perform identically to 12s5p with 2:1. (I like 10s, can you tell? More overhead to avoid ESC problems.)
Haha each to their own my friend. I also prefer hubs and DD (I own both) so gearing is not an option for me. I don’t think that any of the high end vescs have problems with 12S though; the real trouble is finding stock…
Did some monitoring on my ride today, from a full charge at 41.5v, at full throttle I hit 32v that’s a massive sag. Other parameters, 42a motor, 23.6a battery, top speed was 23mph (I weigh 200lbs) while cruising at top speed my voltage went back up to 36v. I guess I’ll be building a battery sooner then I expected, for now I changed my soft cutoff to 31v and full cutoff to 29. Should get me an extra trip to work and back before charging. Not too worried about killing these batteries.
