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[hotsauce]

I'm debating adding a power tank to my 2023 SR/F, and I'm trying to decide if 3.6kWh is worth the expense. Am I right in thinking that's only an additional 30 miles of range in Eco mode? I'm planning some long trips, around 600 miles/1000km each way, and I'm weighing the pros and cons. It's another 30-45 minutes of riding between charges, but also another 30 minutes of charging at 6.6kW.
I've pretty much ruled out the charge tank since there are so few chargers that go above 7kW that it's hardly worth the $3000+

[TheRan]

For a long trip like that with many charging stops I would think about it less being able to ride for longer and having to charge for longer and more having greater charging options and not having to cut it so close. If you get to a charger and it's busted you now have some extra range to make it to an alternative. And say you had 150 miles of range and a charger at 70 miles and 170 miles, instead of having to stop early and charge for a short time at the first charger to make it to the second you could go straight to the second, maybe even taking a better route.

[T.S. Zarathustra]

To me powertank is not worth it. Taking into account price, capacity and weight. Here in Europe we have good selection of 11 and 22 kW AC chargers so chargetank would make more sense in my situation. My advice is to take range and charge time into account while organising your trips. Couple of months ago I went just under 300 miles in one day. Even with few long breaks while charging it was a slog. I prefer to travel shorter distances per day. My preference is to start the day with a fully charged bike and end it at a charging station with about 20% left. Maybe do one charge during the day. This usually allows me to choose the nice curvy roads, end the day early for fresh start early next morning.
Your values might differ.   

If you want to travel longer distances Energica is probably the bike to go for.

[DonTom]

I'm debating adding a power tank to my 2023 SR/F, and I'm trying to decide if 3.6kWh is worth the expense. Am I right in thinking that's only an additional 30 miles of range in Eco mode? I'm planning some long trips, around 600 miles/1000km each way, and I'm weighing the pros and cons. It's another 30-45 minutes of riding between charges, but also another 30 minutes of charging at 6.6kW.
I've pretty much ruled out the charge tank since there are so few chargers that go above 7kW that it's hardly worth the $3000+

I use 7 miles per KWH as an average for normal riding. So expect an extra 25.2 miles with the power tank for MOST of your rides or as an average. Some rides will be a bit more and some a bit less. But I find 7 miles per KWH to be a realistic average on most electric motorcycles with one person (no passenger).


You are the only one who can decide if that extra 25 miles of range will be helpful to you. Just as with the charge tank.


On my Zero DSR/X, I like the extra storage space most of all. The 6.6 KW charging works well for me and I also do not need more range to get between charge stations.


IMO, charge station locations are a lot more important than range.  If you have a larger battery, it will also take longer to charge for the extra range.


Anything you add up there will make the bike more top-heavy. If you can get by with the bike as is, I would leave it as is.


-Don-  Auburn, CA

[MVetter]

Until someone can provide a reasonable counter-argument I am staunchly against Power Tanks. They are mixing and matching cell chemistries and pack voltages. It is a phenomenally stupid idea and unique to the gen 3 bikes that have the new Farasis P73 cells in the monolith.

For the layman: Zero switched to a new battery cell which I have no problem with. It's great. It's solid. It's awesome. It's physically really really tall. Twice the height of the previous cell so they had to change their pack design to accommodate it. Unfortunately this means it won't physically fit in the Power Tank spot. So instead they use the last generation cells in there which are a different chemistry and operate at slightly different voltage. I recommend finding a battery engineer and asking them if it's a good idea to mix and match chemistries and voltages in the same pack and watching their heads explode when you tell them a company is doing it in an EV.

[DonTom]

Until someone can provide a reasonable counter-argument I am staunchly against Power Tanks. They are mixing and matching cell chemistries and pack voltages. It is a phenomenally stupid idea and unique to the gen 3 bikes that have the new Farasis P73 cells in the monolith.

For the layman: Zero switched to a new battery cell which I have no problem with. It's great. It's solid. It's awesome. It's physically really really tall. Twice the height of the previous cell so they had to change their pack design to accommodate it. Unfortunately this means it won't physically fit in the Power Tank spot. So instead they use the last generation cells in there which are a different chemistry and operate at slightly different voltage. I recommend finding a battery engineer and asking them if it's a good idea to mix and match chemistries and voltages in the same pack and watching their heads explode when you tell them a company is doing it in an EV.

Which year did Zero start doing such?


I assume it does not apply to my 2017 SR with Power tank . . . or does it? What was the year they started to use the new cell in the main battery pack?


-Don-  Auburn, CA

[hotsauce]

they use the last generation cells in there which are a different chemistry and operate at slightly different voltage.

Are we sure about that? The 2022 model year and newer power tank is a completely different item than prior years. I would have thought that was because they use the new chemistry.

Which year did Zero start doing such?
I assume it does not apply to my 2017 SR with Power tank . . . or does it? What was the year they started to use the new cell in the main battery pack
-Don-  Auburn, CA

2022

[MVetter]

Are we sure about that? The 2022 model year and newer power tank is a completely different item than prior years. I would have thought that was because they use the new chemistry.

100% sure. The Farasis P73 cell, which is what they use in the current Monolith, is 542mm tall. Or ~21.3" in Freedom Units. That's the cell itself with no enclosures, wiring, or other components.

The Power Tank is 9.5" x 7.5" x 9.75" (HxWxL)

The Power Tank uses the previous gen cells, P32, that are 231mm or 9.09" tall.

[T.S. Zarathustra]

I fully agree that mixing and matching cells is not ideal. But as long as the Powertank has its own BMS, and the voltage range is the same for all cells, there is no reason paralleling cells with slightly different chemistries shouldn't work without issues. I am certain Zero has taken full precautions to prevent problems with slightly different form of cells.
When cells (or batteries) are in parallel, most power is drawn from the cell with the highest charge or lowest ESR (Equal Series Resistance - I know it's AC term usually applied to capacitors but it does apply to cells). As power is drawn from that cell (let's assume it has half the capacity of the others), its charge drops, it's ESR increases, so power draw from that will be reduced compared to the other cells and the other cells will contribute more of the total power. Since they are all connected in parallel one cell cannot get empty before the others while in normal use. This is assuming similar voltage range for all cells.
You're more likely to run into issues with cells in series in the battery. A weak cell in series will draw down the the voltage for the whole series connection.

[MVetter]

The voltage range is not the same for all cells.

[TheRan]

So are they actually using the older power tank cells outside of their specification? I think I remember that Zero was fairly conservative with their utilisation on older models, but also with newer models they let you "overcharge" them for extended range.

[MVetter]

Right. With the new P73 cells in the current monoliths, the "charge to 110%" feature goes above 4.157vdc which was the cap on the P32 cells. The P32 cells are still capped at 4.157vdc. While I have not been successful in finding the exact value that is the 110% charge caps out at, I have confirmed that it is above 4.157. That is a major issue in my opinion.

[TheRan]

But wasn't the upper limit on the old cells actually below what they're rated for? The spec list I found said 4.15-4.2v. I don't know whether that extra ~1.6v is enough for that extra 10% SoC though.

[MVetter]

Yes. That is what I refer to as a padded value to reduce stress and wear on the cells. Zero's LVC value for the P32 cells is ~3.39vdc, and the HVC is ~4.157vdc. You COULD take them to 3.3 and 4.2 but it will degrade the pack measurably faster. This is also why the 32 in P32 which stands for 32 Amp hours are in fact capped at 28.5 amp hours. As recognized by the bike the packs are seen as 28.5 which, in the old monoliths resulted in a total capacity of 114Ah.

This also explains the Charge Tank delivering a strange value of 57 Amps max to the pack. Because the old S and DS models were offered in a 7.2 variant, and Zero's max charge rate is 1C aka 1 hour to charge, this meant that the Charge Tank used on a 7.2 pack wouldn't exceed that. Because they're half of the 14.4 pack which was 114Ah meaning it's 57Ah. And hence why the Charge Tank delivers max 57 amps.

Should it be 32Ah instead? It's not my area of expertise so I'll defer to Bryan Cady who probably made the call when he was Zero's head battery engineer.

[TheRan]

Some interesting information. I'm a little surprised they never tried to eke out a little more capacity from the 7.2/14.4 after all those years by going higher and lower. Do you know what min and max they're using on the new ones outside of the 110%? Also is that where the extra capacity comes from with the 15.6? And also how are they also getting even more capacity with the 17.3?