Hi,
Recently finished a new MTB esk8 build, using 8 inch pneumatic tires and 2 x 2000 W 6354 motors. I’m pretty chocked by how much it’s draining the battery… I did a 6.5 Km ride and I got a 55 Wh/km average consumption and didn’t even ride fast.
Can someone share their own numbers with a similar setup?
Thanks, Paulo
There were a couple similar topics…
Did u ride off road? On street consumtion should be more like 20-30Wh/km, if you ride till 40kph or so, I think… Off road it could be up to 55wh/km
Yeah I am getting 25wh/mile on 6 inch and I thought that was bad
Also post this on forum
For pneumatics that seems quite ok to me, if I convert to wh/km, you get ~16 wh / km.
With these 6inch airless tires, consumption for my friends board is like 18 - 22wh/km, even when riding below 35kph (below 22mph)
I do ride offroad but these numbers were taken on a asphalt ride and I was with my dog, so not fast at all 
I think I should be getting values in the thirties, 55 wh/km is really too high… I don’t see any reasons why this is happening, the VESC configuration didn’t report any problem, it seems everything ok. How could I troubleshoot this?
From where do u take your wh/km number?
Do u have phone app using bluetooth or u got different datalogging?
55wh is too much for sure then. I would say number is doubled or there is something else going on.
U could also calculate used capacity directly, if u know how many km u rode and your charger has watthour/amp hour meter
Exactly, I’m calculating it like you do with a car
I’m using a watt meter when charging. I just read the Wh and Ah that it took to charge to the same level it was, and before I recorded my ride with a standard app in my phone so I know how many km were done.
Well, in that case I would suggest to do straight road ride, for maybe a couple of Km and then measure the energy consumption.
Also, if the outside weather is cold im sure the battery will drain faster…
I havent really looked into this by much detail, but If im right, when riding out in cold, your battery could have 20% less capacity…
So, instead of example 10ah, it would get only 8ah out of battery.
And I guess when charging you would charge more than you actually drained.
But I havent really tested this but this is something worth looking into.
So in that matter, It would be best to measure consumed energy not the one you put back while charging.
Here’s an article I found:
https://www.researchgate.net/post/How_much_energy_is_lost_when_charging_a_battery
But honestly, I would find someone who has better electronics knowledge and who can explain the Coulomb counter principle when charging. I suppose a wattmeter does count how many amps/volts goes to the battery = charged energy, but it might be that not all energy gets stored in the battery directly and some is lost in the process.
So here I dont know if wattmeter/charger can take this into an account or if the losses are bigger than 5%.
In my experience I think charged vs consumed shouldnt be more than 10% difference. But It could be more in cold weather, if what I said earlier is true. (needs more data from scientific sources)
The losses in temperature, depending on battery chemistry, can be a hell of a lot more than 20% my LiPos get maybe 40-50% of their total capacity when they’re taken into -20C for more than an hour or so, but no real degradation from the cold. LifePO4 is where you want to be if you live more than an hour from the equator.
@itsrow Hi, thanks for the input.
My 20% was a conservative amount for giving example, taking into consideration the temperature still could be +5 degrees C (~41F).
But yes, Ive heard below 0C degrees (36f) the capacity drops a lot more drastically and it is not advised to charge batteries at all, if temperature is below zero… or should be done at low c rate at best.
Good point about Lifepo. Havent seen many builds for eboards with them but they are a thing in ebike/motorbike/e-car community for sure.
My final conclusion could be that @pmouraguedes rides in cold weather, his consumed energy is less than that charged back in battery or that his gps reading is off for distance he did.
So yes @pmouraguedes give more precise data and maybe we can work this out…
Otherwise im not sure the drag / inefficiency could be that big, that you get such high energy consumption.
Hi, thanks for your replies.
I’ve been making more measurements and I’m getting around 30 Wh/km. I probably didn’t reset the power analyser on my first measurement so it gave the last two charges…
I’m currently based in Germany so the temperature has been between 0 and 10ºC.
I would say for your feedback that 30 Wh/km is a normal value, meaning I need a bigger battery!!! My current battery is a flat 10S3P Li-ion pack I built with 12 Ah capacity. It sits on an enclosure under the deck so I might get two extra 5S Lipos, put them between my feet and connect them in parallel to my current pack…
I would say average is about 25Wh/km for offroad. I started with 18Wh/km and today it’s more like 30Wh/km.
Please don’t do this, that’s dangerous. The only way would be a second Li-ion 10s3p on top made of the same cells. Maybe it’s best when you ride just with your 3p for the next time and upgrade later to bigger battery and top mount everything. Offroad is much more fun without any enclosure on the bottom.
I would say average is about 25Wh/km for offroad. I started with 18Wh/km and today it’s more like 30Wh/km.>
Then mine it's a little higher than it should. As mentioned in the other post that might has to do with some issues I'm having with the VESC.
Please don’t do this, that’s dangerous. The only way would be a second Li-ion 10s3p on top made of the same cells.
Hum, interesting... on my eyes, because they are connected in parallel they should balance themselves and it should work, as long as they have similar discharge power; at least in theory :) curious about why it's dangerous...
Maybe it’s best when you ride just with your 3p for the next time and upgrade later to bigger battery and top mount everything. Offroad is much more fun without any enclosure on the bottom.
Very interesting feedback... this is my first experience with offroad and I'm getting exactly to the same conclusion about the enclosure on the bottom.
I'm also trying to figure out whether I'll use foot straps or not. One thing that I find odd is the angle of the rear strap. When I ride my feet are approximately parallel but with the straps they are at an odd angle which I'm not sure I will like...
This happens when you're the only one riding esk8 in your town and you have to experiment everything yourself :)
So I spoke with @Tinp123 about this and as long as both pack have a bms then connecting in parallel is fine
both pack have to be same S count and at the same voltage before connecting them in parallel. it would be smart to use bms on each pack, but it is not mandatory. cell type and P number in each pack doesn’t really matter.
both pack have to be same S count and at the same voltage before connecting them in parallel. it would be smart to use bms on each pack, but it is not mandatory. cell type and P number in each pack doesn’t really matter.
Right, that is also my understanding in theory, although never tried it in practice.
About “hybrid” pack some discussion is on endless sphere forum.
But yes, they should be somewhat similar, same series count for sure.
Ive even read some people attach new cells to old pack to give it more life and discharge power
I did that, upgraded 1000km old 12s4p pack to 12s6p pack with 24 new cells. It is important here that every group is made of 4 old + 2 new cells, so capacity/discharge rate of each group is same.
I think everyone missed a big factor: @pmouraguedes, what psi are your tires? On 6X2, riding at 65PSI, I can get around 15 wh/km. Going down in PSI will drastically affect your power consumption.
But if you just added another 12s2p pack in parallel with its own bms would that be fine