Same here, started from Li Po’s - I’m very happy with them and I wanted to move into glorified Li-ons. After reading a lot I’m considering staying with Li Pos for longer 
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Actually I think different chemistries waste differing amouts of energy under heavy loads. I think its related to internal resistance and voltage sag.
Personally it seems very apparent to me when my pack is nearing empty. I bet I could pull out the last 20 wh at .5C loads, but can’t do it going uphill on my board.
Your pulling very little amps. If my math is right your at 12.87 wh/mi.
I pull 23 wh/mi average on flat land. I think how much power you consume has a lot to do with rider weight, riding style and board setup. I’m over 200lbs and hit 30mph on my normal route. I estimate if I go slow I can get 15 wh/mi but once I go fast it can double the wh consumption.
So if your lipo pack is 185wh/12.87=14.37mi range. Which is close to the range you said
If I were to ride my board with your battery I would in theory get 185/23=8.04mi range
Granted with a 18650 pack you can’t get the full wh because of voltage sag.
Agreed, going 30 mph will create a lot of wind resistance that can greatly reduce mileage even more so than weight. I’m currently 195 lbs which isn’t far from your weight. However, I did not have much wind resistance riding at moderate speeds on a relatively calm day.
Under normal conditions the cell drift may be minor but in case something goes wrong like welds failing and separating cells in a cell group which could cause that cell group to discharge much faster than other groups. There have been reports of weld failures just recently. This is just one reason why it is so much better to use a BMS and not bypass it during discharge so that the BMS can’t shut the system down if such a situation occurs.
Vesc as primary voltage control BMS as emergency backup control
There is a much higher chance the BMS fails than that the battery fails. And when you have it included in the discharge cycle it can shut the system down during braking. And there were already many people who had issues with their BMS who did exactly that. Also people who used the BMS you sell.
So if you ask me i think they should only be used for charging. But that’s personal preference.
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First allow me to make clear that I have no affiliation with Bestech and I am not in the business of selling bms’s. The few extras that I have sold, I sold only to help others and I sold them at my cost + shipping so my promoting of them is not motivated by monetary gain.
As far as them failing, I can only give my account which is that I have been using them for over a year now with no problems. Often times I have rode my brakes down steep hills with a full battery and the bms did not shut down but rather took control of the regen charging not allowing it to exceed the overcharge setting of the bms and once I stopped braking, the bms proceeded to trim the cells back down as it does during the balancing process.
Maybe I missed some posts but I have not heard of this particular bms failing lately although I have heard of the cheap bms’s from eBay failing.
Ah I think I see it now. Speed as you say. Your top speed / avg speed are 26kph,12kph. In our backwards miles units that is 16mph,7.5mph.
I’m running 29mph top speed 13-14mph avg. Sounds like totoxd10001 is in the same ballpark.
I should try a slower ride to see if the number shift dramatically. But if feels safer in front of the cab then behind it…
Adding to the BMS conversation, my beef is that I don’t know what they’re doing. I’d like some kind of error indicator and a way to access individual cell voltage. I suppose we have 2 open source BMS projects going for that now.
With no BMS I’m forced to check regularly, but I feel like I’d need to do that anyway. I live in fear like lowguido and his distaste for solid state switches.
Yes going fast reduces range by a lot. It’s kind of funny that some claim you can get max efficiency by going close to top speed
so at full charge (49v roughly) max sag is about 4v, usually less than 3v. which makes sense, higher voltage, less amp draw.
so…i’ll just keep the pack charged up, this should mitigate the ridiculous sag issue.
a good bms can. A bad BMS is worse than no BMS. I try and charge to 41 volts using samsung 30q’s checking voltages manually from time to time. seems fine. edit - the bestech BMS shipped here is about 1/4 the costs of the cells. that’s a big factor why I don’t use them
This is why I try to discourage people from buying cheap bms’s on eBay
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