Chaconne
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I guess the only upgrade path is to buy a new bike every few years.
Stark Battery Tech Thread
- Thread starter Karinshi
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i think the overall estructure/idea of the Stark Varg its pretty complete and solid. Minor improvements can be made here and there, but overall there's little to invent or improve beyond battery technology.
If battery improvements become relevant, Stark could release enhanced models like the EX 1.2, and for us, the original EX 1.0 users, in a few years we could buy that new battery instead of a entire new bike unless you've pushed your bike to the limit and most of its components don't have much life left in them.
Nothing is perfect, and it's clear this is an expensive sport/hobby; if you want something cheap, you can always dance and sing
Can't wait to see the future
Chaconne
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Agreed. Instead of singing or dancing I could play guitar like Paco and give you some free tickets so you could afford to buy your new EX 1.2...i think the overall estructure/idea of the Stark Varg its pretty complete and solid. Minor improvements can be made here and there, but overall there's little to invent or improve beyond battery technology.
If battery improvements become relevant, Stark could release enhanced models like the EX 1.2, and for us, the original EX 1.0 users, in a few years we could buy that new battery instead of a entire new bike unless you've pushed your bike to the limit and most of its components don't have much life left in them.
Nothing is perfect, and it's clear this is an expensive sport/hobby; if you want something cheap, you can always dance and sing
Can't wait to see the future
Big news, related to Stark incoming road models but even bigger (might deserve its own thread).
And that's a surprise for me cause I was convinced Stark would not risk going there, these guys are crazy!
Stark is partnering with EVE Energy, a Chinese company leader in battery production, to produce its own cells under a new 26120 model (as in 26 mm diameter and 120 mm height).
26120 cell on the left, standard 21700 cell in the middle and iPhone for scale
Mass production should start in 2026.
These larger cells with aluminum casings are lighter so getting very high capacity (prototypes are at 330 Wh/kg) and also increased thermal conductivity meaning less thermal limitation wether that's when riding or charging thus enabling fast charging with claims of full charge in 10 min.
Current cells in 7.2 kWh battery are 5.0 Ah 21700 cells similar to Molicel P50B with 265 Wh/kg, that's 27.2 kg in cells only.
At 330 Wh/kg with the new cells, that 7.2 kWh battery weight would decrease to 21.8 kg (-5.4 kg).
Or for the same weight of 27.2 kg, capacity would increase to 9.0 kWh (+1.8 kWh).
Good times.
And that's a surprise for me cause I was convinced Stark would not risk going there, these guys are crazy!
Stark is partnering with EVE Energy, a Chinese company leader in battery production, to produce its own cells under a new 26120 model (as in 26 mm diameter and 120 mm height).
26120 cell on the left, standard 21700 cell in the middle and iPhone for scale
Mass production should start in 2026.
These larger cells with aluminum casings are lighter so getting very high capacity (prototypes are at 330 Wh/kg) and also increased thermal conductivity meaning less thermal limitation wether that's when riding or charging thus enabling fast charging with claims of full charge in 10 min.
Current cells in 7.2 kWh battery are 5.0 Ah 21700 cells similar to Molicel P50B with 265 Wh/kg, that's 27.2 kg in cells only.
At 330 Wh/kg with the new cells, that 7.2 kWh battery weight would decrease to 21.8 kg (-5.4 kg).
Or for the same weight of 27.2 kg, capacity would increase to 9.0 kWh (+1.8 kWh).
Good times.
You are the man! please make a new thread if more information becomes available and relevant
Thats very good news, density is key.
The question is how current Varg Owners like us are going to benefit from this advancement. And if Stark will manufacture new batteries with this technology for the current Varg platform. will we be able to buy them? Would it be worth paying roughly 5,000$ for a new battery with 1.8kwh more? Probably not. Only if you are out of warranty and needs a replacement.
IMO there is no doubt they MUST make update Varg models with this range, EX 1.2 in about 1.5/2 years years maybe
If mass production is planned for 2026, it means that development and quality testing are practically finished, because that requires a lot of trial and error testing and it seems to be relatively complete
Now it makes sense when Anton said in the last "road map" video, that we will be able to charge the bike in 10 minutes or in the same amount of time it takes you to drink a coffee
Now it makes sense when Anton said in the last "road map" video, that we will be able to charge the bike in 10 minutes or in the same amount of time it takes you to drink a coffee
@Beagle: IMHO it should absolutely be opened already now and I guess that you would like to be the thread opener.
Thanks for having shared this revolutionary piece of news.
Semi related, I purchased two batteries from Amorge one with Molicel P45 (4.5Ah) and the other EVE 4.0Ah cells. The EVE battery was 1/2 cost. I have been using both, the EVE battery has less continuous / max amp rating.
In the real world I am not seeing really any difference I power or range. I realize this is not very scientific, and I have no idea if the EVE cells will loose performance more quickly but for the price I will just get a new battery every couple years.
In short really impressed with the EVE cells so far.
In the real world I am not seeing really any difference I power or range. I realize this is not very scientific, and I have no idea if the EVE cells will loose performance more quickly but for the price I will just get a new battery every couple years.
In short really impressed with the EVE cells so far.
if this are the current cells which i think is VERY possible, what i see interesting here is that after 1.000 cycles it has like an 87% of retention... It supposedly had 500 cycles and 80% retention. Wich is good news
The continuous current of only 10.11A and Continuous power of 34.7W seems very low in comparison for P45B and P50B... everything else is very similar. Im not an expert so maybe is possible that the performance is still enough with that characteristics
Yeah I was actually wondering about that.
For retention we would need more data at various currents and so on. In this regard, Molicel publicly available datasheet are complete than that of EVE Energy.
Remember when we discussed about the Molicel M65A having a higher gravimetric energy density at the expense of the current?...
Talking about heat dissipation, the volume to surface ratio is higher in a 26120 cell: 5.9 vs 4.6. I am using an approach similar to the casting modulus used in foundry: the idea is that, the higher that ratio, the slower the cooling. If we exclude the two faces of the cells assuming that they are covered by connections that don't cool significantly, the ratios become 6.5 vs 5.3, still worse in the 26120. Vice versa, if we assume that only the two faces cool down siegnificantly since they are connected to the magnesium outer case, still the 26120 has a higher ratio: 60 vs 35.
This is true in general: typically when the size increases, the volume increases more than the surface since it usually depends to some dimension to the third power instead of to the second power like the surface.
On the other hand, if we consider that their thermal conductivity is far better since their cases are made up of aluminum, that, depending on the alloys, is like 10 fold more heat conductive than the steel ones, than maybe the whole battery case should work better as a heat sink and so here is one of the explanations of the choice.
EDIT from some hours later: like @Beagle has pointed out, actually currently only one side of the cells is in contact with the magnesium battery case, so the above evaluation is mistaken.
Talking about heat dissipation, the volume to surface ratio is higher in a 26120 cell: 5.9 vs 4.6. I am using an approach similar to the casting modulus used in foundry: the idea is that, the higher that ratio, the slower the cooling. If we exclude the two faces of the cells assuming that they are covered by connections that don't cool significantly, the ratios become 6.5 vs 5.3, still worse in the 26120. Vice versa, if we assume that only the two faces cool down siegnificantly since they are connected to the magnesium outer case, still the 26120 has a higher ratio: 60 vs 35.
This is true in general: typically when the size increases, the volume increases more than the surface since it usually depends to some dimension to the third power instead of to the second power like the surface.
On the other hand, if we consider that their thermal conductivity is far better since their cases are made up of aluminum, that, depending on the alloys, is like 10 fold more heat conductive than the steel ones, than maybe the whole battery case should work better as a heat sink and so here is one of the explanations of the choice.
EDIT from some hours later: like @Beagle has pointed out, actually currently only one side of the cells is in contact with the magnesium battery case, so the above evaluation is mistaken.
Good, but I'd like to know your opinions. Do you think Stark will release a better 9kWh battery for the Varg? How would you like to benefit from these advancements? Do you believe in an EX1.2 with this battery or similar?
If they do release it, I don't think it will be in less than a year, it might be possible by Q1 2027, but by then technology will have advanced and maybe a new 400Wh/kg (or more) cell will already be available. With the same weight of 27 kg, 10.8 kWh could be possible.
It's a never-ending story
If they do release it, I don't think it will be in less than a year, it might be possible by Q1 2027, but by then technology will have advanced and maybe a new 400Wh/kg (or more) cell will already be available. With the same weight of 27 kg, 10.8 kWh could be possible.
It's a never-ending story
Personally, I can't really predict whether it will be lighter with the same energy, or more energetic with the same weight or something in between. They seem to behave following logic and considering past experience, so they may even have reasons to think it's better to have more weight and even more energy or vice versa. They are pretty hard to predict.
Personally, I don't find the weight of the Varg to be too much, maybe only sometimes like in the whoops. I guess that less would be better but it's acceptable. Accepting more weight would feel frustrating, though, so I'd say keep the weight the same but, for me personally, give me more range so that I may start going to the track, never charge and just go home when the SOC is too low. I think that I use roughly 10 kWh in a trackday, so 9 kWh would still be too little if you consider that draining the battery to very low SOC systematically is detrimental and I could only use like 7 kWh out of 9. That would mean to go home having ridden significantly less than I wanted. So even 330 Wh/kg wouldn't be a breakthrough for me. It's also hard to predict what tracks are going to do: if these cells withstand higher and longer charge/discharge currents and tracks start providing fast charge for riders, than maybe lowering the weight and keeping 7 kWh would be fine.
So hard to make predictions about this.
Maybe a good thing will be to add to the bike configurator on the web the option "Battery selection", and choose for "Lightweight" or "Range" depending on the user...
Lightweight could be the same 7.2kwh as now but 5kg less, and Range will be the same weight and 9kwh. Could be 10.8kwh if they wait for 400Wh/kg to be developed. I will choose the Range option.
I agree with you, the bike shouldn't weigh more than it does; this is its maximum weight, and from here they should reduce it as much as possible with technological advances.
Fast charge damage is something that needs a lot of improvement, and I don't usually see much information about progress on it.
That's an interesting approach, you got me thinking, thanks.
You used the casting modulus to compare a single object to another single object of different dimensions.
Now let's think about the pack.
To get 7.2 kWh, that's 400 of the actual 21700 5.0 Ah cells, total cell volume is about 9700 cm3 (9.7 L).
Stark did not mention volumetric capacity for the 26120 prototype so for the sake of the discussion, let's make an assumption here. Given one of the highest capacity 21700 cells, Molicel P60B, is at 280 Wh/kg and 838-888 Wh/L, assuming same density then the 26120 at 330 Wh/kg would be 1000-ish Wh/L. That would translate to 7.2 L, about 113 larger 26120 cells.
One side of each 21700 cell is connected to the magnesium case.
So the total surface in contact with the case (itself air-cooled) is 1385 cm².
A volume of 9700 cm³ dissipating heat through a surface of 1385 cm² gives a casting modulus of 7.
Let's do the same calculation for new 26120 cells: if each 26120 cell were connected to the case on one side, a volume of 7200 cm³ would dissipate heat through a surface of 600 cm², resulting in a casting modulus of 12.
Not good!
BUT since 2 rows of 21700 are 14 cm long and 1 row of 26120 is 12 cm long, keeping the same general shape, each 26120 cell could be connected to the case on both sides, giving a casting modulus of 6.
That would be slightly better than for the 21700 cells but I'm sure Stark will be cleverer than keeping the same shape with these newer cells they've conceived themselves AND this calculation doesn't take into account the super thermally conductive aluminum casing of 26120 cells (depends on the alloys but should be at least 10 times more conductive than steel) that could be directly in contact with the magnesium case on both sides.
TLDR I think this new form factor adapted to electric motorcycles will also be used to improve packing and cooling
@Karinshi : you keep asking if Stark would sell newer batteries for older models... well, Stark did not do that for MX1.2, no more than Apple does for its Iphones.
Maybe when the market becomes more mature, with much higher sales of electric road motorcycles, we could see aftermarket companies refurbishing battery packs with newer cells. In fact there are already some actors in this space for cars and even KTM freeride so definitely possible.
I believe options for different pack capacities, like already exists for cars, could also easily happen.
However do not hold your breath to see if any OEM would offer retrofitting newer batteries to older bikes, they would much rather have you buy another brand new motorcycle altogether.
Maybe when the market becomes more mature, with much higher sales of electric road motorcycles, we could see aftermarket companies refurbishing battery packs with newer cells. In fact there are already some actors in this space for cars and even KTM freeride so definitely possible.
I believe options for different pack capacities, like already exists for cars, could also easily happen.
However do not hold your breath to see if any OEM would offer retrofitting newer batteries to older bikes, they would much rather have you buy another brand new motorcycle altogether.
@ Beagle: yes, actually in my evaluation there was a mistake: the current cells have only one side contacting the magnesium case and, considering that and considering that they wouldn't arrange 26120 cells side by side like that, the casting modulus is better for 26120 cells.