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[flynnstig82r]

https://www.bluetti.com/products/bluetti-ac30s-300wh-300w-portable-power-station-1

I looked at the listing for this portable power station and thought maybe it could prevent getting stranded if I were limping home or to a charge station and didn't quite make it. The 300 Wh would provide another few miles and might be preferable to pushing the bike.

However, with only a 300w output, would the OBC or charge tank w/ turbo cord just trip this thing's breaker immediately? Or would one of those 2 chargers know to only pull 300w?

Is there a better small, lightweight solution than this portable power station that could add another ~2 miles range in a pinch?

[staples]

Would the cost (in energy used) to carry this battery, possibly all the time, be worth the charge you could get from it? How many times have you actually drained your battery to 0 range available and had to push / tow your way to the next charger? I've had the same range anxiety on a gas bike that I've had on my Zero. Running on fumes trying to get to the next gas station after I switched the petcock to reserve, feels the same as watching the SOC tick down from 5.. 4.. 3.. 2.. 0. All the while knowing my distance to the next station. Both situations are a result of poor planning on my part. Ultimately I think if you need the extra range to get between chargers, you need a bigger battery, not an 300W accessory.

[Crissa]

You need a 2000W supply to charge using an S-platform charger.  That won't do it.  A 1200W supply might do for an X-platform charger.

-Crissa

PS - I have tried a 1500W supply on my S and it tripped immediately ;

[flynnstig82r]

Would the cost (in energy used) to carry this battery, possibly all the time, be worth the charge you could get from it? How many times have you actually drained your battery to 0 range available and had to push / tow your way to the next charger?

Twice in seven days, but I'm a new owner so those were rookie miscalculations.

I've had the same range anxiety on a gas bike that I've had on my Zero. Running on fumes trying to get to the next gas station after I switched the petcock to reserve, feels the same as watching the SOC tick down from 5.. 4.. 3.. 2.. 0. All the while knowing my distance to the next station. Both situations are a result of poor planning on my part. Ultimately I think if you need the extra range to get between chargers, you need a bigger battery, not an 300W accessory.

All very true, but I doubt I'm going to stop planning poorly any time soon.

Also thanks to Crissa for the info!

I can see those small power stations aren't going to cut it, but I'm still attracted to the idea of a limp-home battery, something equivalent to carrying a pint of gasoline to make it to the next station on a traditional motorcycle. A quick perusal of IMRbatteries shows Molicell 21700 4000mah 45A cells going for $5.50 each. A 28S1P pack would have equivalent voltage to Zero's monolith and 1/25th of the capacity, enough to make it an extra couple of miles. The cells would weigh just over 4 lbs and could be arranged in a relatively flat pack that could sit on the inside of a top case lid or maybe a cylindrical pack that could slot into the "bonus storage" on the SR's swingarm.

The tricky parts would be inverting the power so the charge tank or OBC would accept the charge (unless they can take 116v DC, I'm assuming they can't) and designing an enclosure safe enough for >60 volts as a hobbyist. If I were to add Diginow SC's, that would solve the first problem.

[flynnstig82r]

Related question: Is it possible to charge while riding?

If I could see that I probably wasn't going to make it to the next charger, I'd probably rather hook up the hypothetical auxiliary battery and continue riding than lose power unexpectedly and possibly get rear-ended before pulling over to hook it up.

[staples]

Related question: Is it possible to charge while riding?

This could be probably be done through the auxiliary port, but you'd need 116V or whatever to push into it. Then it's the same as "get a bigger battery" like a power tank.

[flynnstig82r]

Interesting! I would assume that using the aux port in this way would require a DigiNow SC or other charger that can accept DC input?

The power tank doesn't solve the problem. I might still miscalculate and need the small boost once in a blue moon. Of course, in an ideal world I'd never miscalculate but I've already done it twice so it would be nice to have a bailout solution other than pushing a bike along a highway or waiting hours for a tow truck.

[Crissa]

You could probably store that many batteries in the wings of the plastic.

But lithium doesn't like sitting around full.

-Crissa

[T.S. Zarathustra]

Would the cost (in energy used) to carry this battery, possibly all the time, be worth the charge you could get from it? How many times have you actually drained your battery to 0 range available and had to push / tow your way to the next charger?

Twice in seven days, but I'm a new owner so those were rookie miscalculations.

I've had the same range anxiety on a gas bike that I've had on my Zero. Running on fumes trying to get to the next gas station after I switched the petcock to reserve, feels the same as watching the SOC tick down from 5.. 4.. 3.. 2.. 0. All the while knowing my distance to the next station. Both situations are a result of poor planning on my part. Ultimately I think if you need the extra range to get between chargers, you need a bigger battery, not an 300W accessory.

All very true, but I doubt I'm going to stop planning poorly any time soon.

Also thanks to Crissa for the info!

I can see those small power stations aren't going to cut it, but I'm still attracted to the idea of a limp-home battery, something equivalent to carrying a pint of gasoline to make it to the next station on a traditional motorcycle. A quick perusal of IMRbatteries shows Molicell 21700 4000mah 45A cells going for $5.50 each. A 28S1P pack would have equivalent voltage to Zero's monolith and 1/25th of the capacity, enough to make it an extra couple of miles. The cells would weigh just over 4 lbs and could be arranged in a relatively flat pack that could sit on the inside of a top case lid or maybe a cylindrical pack that could slot into the "bonus storage" on the SR's swingarm.

The tricky parts would be inverting the power so the charge tank or OBC would accept the charge (unless they can take 116v DC, I'm assuming they can't) and designing an enclosure safe enough for >60 volts as a hobbyist. If I were to add Diginow SC's, that would solve the first problem.

In the old days motorcycles had limp home mode. You had a petcock that could be switched to "reserve" when you ran out of fuel. With more accurate modern fuel gauges these became unnecessary.
To get extra range there are tricks like "halving the speed gives you twice the range", run with the bike, put more pressure in the tires, go on that diet  .
Here is an idea. Instead of carrying extra batteries, modify your BMS to keep 10% in reserve. Then, when you run out, you can push a button to activate the last 10%.

What I'm trying to say is that the weight of the extra battery will have negative effect on range. It is IMHO better to try to be more conservative when estimating range.

[peterwarm]

The great thing about running out on my SR/F is that in practice it never actually happens!

My experience is that i missed a service station ( not paying attention) and kept going hoping i would make the next one, 25 miles away.  I was cruising at 70 mph to start with, watching the caudated range drop faster than the mileage signs.  So I slowed down, 60, 10 mins later 50, then quite quickly as I realised I was in trouble to 50, 40. At this point I was in danger of being rear ended on the highway, so I cut the speed to 30 mph and drove on the hard shoulder, cars wizzing past.  I got to 1% left and saw an early exit which I took, thinking its better to be rescued off the high way.  Then I realized that my early speed/load reduction had worked, but not enough and the bikes own restrictions started to cut in.  I actually travelled about a mile on the pavement (unoccupied!) with zero on the SOC, doing 6-8mph to the service station.

This was freaky, but I learnt that the BMS has in fact got a limp home feature built in, which was kinda reassuring. However, I note I went home and paid £86 for a years motorbike recovery, as the other lesson I got quite clearly is that there is no way I can push this thing for a mile on the level, let along any slight hill/bump.

Hope this helps.
pete

[valnar]

I think the additional weight and inconvenience of carrying a second battery large (heavy) enough to charge the bike will be a problem.  This may sound flippant, but the right answer is to not run out of power.

I would choose an ICE bike before doing what you suggest.

[princec]

or indeed... the power tank.

Cas

[flynnstig82r]

The backup battery that I envision would weigh just over 4 lbs in cells. Not large or heavy, just enough to eke out another mile or two of range and avoid calling the tow truck.

The power tank is not a solution to this problem. The point of the battery is not that I need an extra mile or two of total range, it's to bail me out after I've already miscalculated and can't make it to the next charger. I can just as easily miscalculate and run to nothing with a power tank as without.

For instance, when I had to push the last 3 blocks to make it home, it was because I didn't spend enough time at the charging stop in Oakland prior to attempting the last leg of the trip over the Bay Bridge. I tried to give myself an extra 5% reserve and thought that my SR could cover a similar ~5 extra miles after running to 0% like the SR/S I had rented the previous week. The strong headwind made me run out a lot sooner than expected but I was already on the Bay Bridge with no option to exit or to go slower without risking a rear-end collision. If the bike had started cutting power even a 1/2 mile sooner, I would have been forced to call a tow truck, as there would have been no way to make it the rest of the way across the bridge safely.

Not screwing up in the first place would of course be preferable, but I'd rather have the extra safety net and not need it than need it and not have it. Keeping a reserve is an interesting idea, but I'd hate to lose the last 10% range, and modifying the OEM BMS sounds like a much bigger project than building what amounts to a small e-bike battery.

The first order of business will be to increase charge rate. 3.8 kW is just not cutting it, and I would have spent the extra time adding another 10% if it didn't mean standing around in a sketchy Walgreens parking lot for another 20 minutes. If I can add range much more quickly at charging stops, I might not need the limp-home battery, but it would still be nice to know it's there.

[flynnstig82r]

The great thing about running out on my SR/F is that in practice it never actually happens!

My experience is that i missed a service station ( not paying attention) and kept going hoping i would make the next one, 25 miles away.  I was cruising at 70 mph to start with, watching the caudated range drop faster than the mileage signs.  So I slowed down, 60, 10 mins later 50, then quite quickly as I realised I was in trouble to 50, 40. At this point I was in danger of being rear ended on the highway, so I cut the speed to 30 mph and drove on the hard shoulder, cars wizzing past.  I got to 1% left and saw an early exit which I took, thinking its better to be rescued off the high way.  Then I realized that my early speed/load reduction had worked, but not enough and the bikes own restrictions started to cut in.  I actually travelled about a mile on the pavement (unoccupied!) with zero on the SOC, doing 6-8mph to the service station.

This was freaky, but I learnt that the BMS has in fact got a limp home feature built in, which was kinda reassuring. However, I note I went home and paid £86 for a years motorbike recovery, as the other lesson I got quite clearly is that there is no way I can push this thing for a mile on the level, let along any slight hill/bump.

Hope this helps.
pete

That's how the SR/S was. I didn't quite get to the 6-8 MPH level that you did, but I got to the point where it the top speed was about 35 MPH, which reminded me of the Scoot mopeds at my old job. My 2017 SR was much more abrupt. It started severely limiting top speed soon after hitting 0% SoC and giving too much throttle would shut down the whole bike and it would need to be power cycled with the ignition key. I was able to make it most of the way back through the city in the bike lane by being extremely gentle with the throttle in eco mode, but once the top speed dropped below about 20 MPH, it shut off for the last time and refused to start again until I pushed it home and plugged in.

[Richard230]

My 2018 S with PT was good for over 3 miles at 25mph while climbing a 12% grade after the SOC display read "00". I don't know how much further it would have gone, but I heard someone in the past mention 10 miles on level ground was in the pot after SOC read empty.    However, no doubt that depends upon the overall condition of your battery pack.