# Electric Snowmobile Conversion



## remy_martian (Feb 4, 2019)

I'd put the generator/augmented-battery in a Ski-doo Caboose, or one of the more recent variants of it. I wouldn't add anything more to the sled, as you don't want to add weight for both handling and flotation (in powder) considerations. 

I'd also go battery swap (via contactors or cable connectors) instead of generator.


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## Passedyouby (Dec 5, 2020)

remy_martian said:


> I'd put the generator/augmented-battery in a Ski-doo Caboose, or one of the more recent variants of it. I wouldn't add anything more to the sled, as you don't want to add weight for both handling and flotation (in powder) considerations.
> 
> I'd also go battery swap (via contactors or cable connectors) instead of generator.



Thank you remy for the reply!

I have flirted with the 'caboose' thought. And yes, I agree more batteries is the most logical solution, we are extremely isolated and I worry that a gasoline option needs to be implemented, even if small. (Range anxiety am I right? Haha).

Let's say I did do a caboose. How would I get that power from the genny to the batteries other than an onboard charger? Is my rectifier option valid? I worry about my inability to regulate a load, and wish I could find some sort of solar controller that works at these voltages. 

I'm open to ideas


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## Passedyouby (Dec 5, 2020)

remy_martian said:


> I'd put the generator/augmented-battery in a Ski-doo Caboose, or one of the more recent variants of it. I wouldn't add anything more to the sled, as you don't want to add weight for both handling and flotation (in powder) considerations.
> 
> I'd also go battery swap (via contactors or cable connectors) instead of generator.



Also good call on the handling. It's been a heavy concern of mine. The good news is there at almost 100 sleds on this ride and the trail is well packed for the event, so powder isn't too likely


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## remy_martian (Feb 4, 2019)

Lithium is a current charged device, so simply applying a voltage source is a very bad idea. 

Yes, you'll need a charger. I'd just go with a small Honda 2kW and use a 120V lithium charger.

Been a few decades since I've run sleds...I do remember how awful the heavier machines were, even on packed trails and what a joy the lightweight aluminum machines were. Especially if minimally powered (no offense, but 20hp...).


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## Passedyouby (Dec 5, 2020)

remy_martian said:


> Lithium is a current charged device, so simply applying a voltage source is a very bad idea.
> 
> Yes, you'll need a charger. I'd just go with a small Honda 2kW and use a 120V lithium charger.
> 
> Been a few decades since I've run sleds...I do remember how awful the heavier machines were, even on packed trails and what a joy the lightweight aluminum machines were. Especially if minimally powered (no offense, but 20hp...).



Ha! Yes, the modern sleds have come A LONG WAY in the past couple of decades. This old school sled conversion is for fun, not practical uses. The good news is the motor and parts removed from this SOB weighed about 114lbs, so I have some wiggle room to add stuff..

Hmm on the lithium charging comment. I've been charging a 12s pack of mine via a bench top power supply, but may need to revisit that.

Back to this project. I'm struggling to find a lithium charger with adjustable output (100.4v is my target). Do you have suggestions? So many knockoffs out there


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## remy_martian (Feb 4, 2019)

Be patient - there are others on here who play in the range you are who can make expert recommendations and share war stories and will chime in during the next while


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## wjbitner (Apr 5, 2010)

This guy in the norwegian area of the world can probably give you some ideas on the snowmobile conversion. He's done lots of electric vehicles and adapts to each type of vehicle.


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## Passedyouby (Dec 5, 2020)

wjbitner said:


> This guy in the norwegian area of the world can probably give you some ideas on the snowmobile conversion. He's done lots of electric vehicles and adapts to each type of vehicle.



Good morning!

Yes!! He is actively building one right now and I am constantly checking his page for the latest updates etc. Ironically he also choose the ME1115 for his build!

Good eye wjbitner.


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## green caveman (Oct 2, 2009)

Passedyouby said:


> Ha! Yes, the modern sleds have come A LONG WAY in the past couple of decades. This old school sled conversion is for fun, not practical uses. The good news is the motor and parts removed from this SOB weighed about 114lbs, so I have some wiggle room to add stuff..
> 
> Hmm on the lithium charging comment. I've been charging a 12s pack of mine via a bench top power supply, but may need to revisit that.
> 
> Back to this project. I'm struggling to find a lithium charger with adjustable output (100.4v is my target). Do you have suggestions? So many knockoffs out there


Check the threads on hacking the Zivan NG1/NG3. There are a couple of resistor you can change out that control the final voltage. Some thought that the lead acid charging will work for you as long as the BMS is going to kill the charging. (Pretty much all charging is constant current/constant voltage - charging is not the problem it's knowing when to stop!).


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## Electric Forklift Guy (Dec 13, 2012)

Passedyouby said:


> Good morning everyone!
> 
> I know this is an odd, and potentially unrealistic, conversion and I figure I should lay down some basic expectations. My friends and I all have 2018-2019, high performance, sleds so I am not looking to break any land speed records, or reach unattainable ranges. In fact one weekend per year we all bring circa 1970s machines up for a 20mile ride, and that is the purpose of this build.
> 
> ...


The numbers for electric car range is going to be vastly different than a snowmobile (the rolling resistance is much higher)

Fortunately


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## Electric Forklift Guy (Dec 13, 2012)

Electric Forklift Guy said:


> The numbers for electric car range is going to be vastly different than a snowmobile (the rolling resistance is much higher)
> 
> Fortunately


Oops....continuing
Fortunately there's an easy way to get a semi-accurate estimate 

1 gal of gasoline= 33 Kilowatt hours.

So just drive a regular snow mobile 20 miles at 30 mile per hour and see how much fuel it uses.

Its rough , but it will show you if what you want is feasible.


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## remy_martian (Feb 4, 2019)

What about a 2 stroke engine 😂


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## brian_ (Feb 7, 2017)

remy_martian said:


> What about a 2 stroke engine 😂


I doubt that there's enough difference in efficiency between 2-stroke and 4-stroke engines in a modern production snowmobile to matter to this rough estimation, but I suppose one could pick a different value for 2-strokes (such as 1 gal of gasoline = 30 kilowatt-hours).


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## Passedyouby (Dec 5, 2020)

brian_ said:


> I doubt that there's enough difference in efficiency between 2-stroke and 4-stroke engines in a modern production snowmobile to matter to this rough estimation.



I worry about this calculation because on any of our sleds (2008-2020) we get between 11-13mpg. This would mean that I would need approx 150kw of power for a casual 55miles or so. There is a sled called Tiaga, released this year, that offers a 45kw battery pack and offers an 80mile range. That would equate to what, 50mpg? Doesnt quite add up. 

Did my best to calculate the friction of snow on the skis, track friction, etc and used that data to calculate how many NM of force would be needed to maintain speed at 35mph
Fount the needed amps for my motor to produce that output and estimate I will need 8-9kw for a 20mile trip.


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## Passedyouby (Dec 5, 2020)

Additionally. Has anyone here disassembled an old EV battery and found a heating element internally? I have found it twice now, but and confused because the heating element is doing something odd. If anyone has seen this let me know. Would love to discuss!


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## brian_ (Feb 7, 2017)

Passedyouby said:


> I worry about this calculation because on any of our sleds (2008-2020) we get between 11-13mpg. This would mean that I would need approx 150kw of power for a casual 55miles or so.


That's 150 kWh (of energy), not 150 kW (which would be power)...
but yes, snowmobiles are horribly energy-hungry for their size.



Passedyouby said:


> There is a sled called Tiaga, released this year, that offers a 45kw battery pack and offers an 80mile range. That would equate to what, 50mpg? Doesnt quite add up.


The claimed consumption for the Tiaga suggests that it is for ideal operating conditions on well-groomed trails. You probably ride in the real world instead.



Passedyouby said:


> Did my best to calculate the friction of snow on the skis, track friction, etc and used that data to calculate how many NM of force would be needed to maintain speed at 35mph
> Fount the needed amps for my motor to produce that output and estimate I will need 8-9kw for a 20mile trip.


Excellent approach, but you really need to be clear about whether you are talking about power (kW) or energy (kWh). Did you calculate the power (in watts) by multiplying the force (in newtons, N, not Nm) by the speed (in metres per second), or did you calculate the energy (in watt-hours) by multiplying the force (in newtons, N, not Nm) by the distance (in metres) and dividing by the 3600 seconds in an hour? I don't know if you estimated 8-9 kW (of power) to maintain 35 mph, or 8-9 kWh (of energy) to travel 20 miles.


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## brian_ (Feb 7, 2017)

Passedyouby said:


> Additionally. Has anyone here disassembled an old EV battery and found a heating element internally? I have found it twice now, but and confused because the heating element is doing something odd. If anyone has seen this let me know. Would love to discuss!


I haven't disassembled an EV battery, but some do have a heating element internally. That would typically be in a battery without liquid thermal management (cooling), such as a Leaf. It is there to keep temperature during storage from getting low enough to damage the battery, and getting temperature up enough to allow charging... both typically while plugged into a charging station, but the Leaf can run the heaters to protect the battery while parked and unplugged.


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## Passedyouby (Dec 5, 2020)

brian_ said:


> That's 150 kWh (of energy), not 150 kW (which would be power)...
> but yes, snowmobiles are horribly energy-hungry for their size.
> 
> The claimed consumption for the Tiaga suggests that it is for ideal operating conditions on well-groomed trails. You probably ride in the real world instead.
> ...



Doh. Good call. My appologies on the poor description with kW and kWh. Trying to reply on the forum without getting busted for not paying attention to this horrible movie with the Wifey.


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## remy_martian (Feb 4, 2019)

brian_ said:


> I doubt that there's enough difference in efficiency between 2-stroke and 4-stroke engines in a modern production snowmobile to matter to this rough estimation, but I suppose one could pick a different value for 2-strokes (such as 1 gal of gasoline = 30 kilowatt-hours).


You're probably right, Brian, though the 2 stroke will run at much higher rpm making for a much better power/weight ratio and...coming closer to an electric motor in terms of what's between the track and crankshaft for gear ratios.

Can you find the engine torque curve? Back in my day they used to publish the drive ratios, top speeds etc in snowmobile mags


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## brian_ (Feb 7, 2017)

remy_martian said:


> You're probably right, Brian, though the 2 stroke will run at much higher rpm making for a much better power/weight ratio and...coming closer to an electric motor in terms of what's between the track and crankshaft for gear ratios.


Yes, if we're talking about gearing rather than energy consumption, I agree that a two-stroke is a better match to a typical electric motor than a four-stroke... although if snowmobiles are like sport motorcycles, even the four-strokes run at electric motor speeds.


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## Passedyouby (Dec 5, 2020)

I FIGURED IT OUT!!!!! (The wierd heating element in that battery) its Actually a ThermoElectric cooler!!! It will either heat or cool the battery depending on the direction you send electricity!!! So excited to find this built into all of my packs!!!!


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## remy_martian (Feb 4, 2019)

Don't get too excited - they are horribly inefficient and eat a lot of current. 

Might be ok for charge cooling, but ick if you need to warm the pack during running, which you likely need to do, especially in a snowmobile - don't forget that to heat, it has to pump heat from the ambient environment to the battery.


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## Passedyouby (Dec 5, 2020)

remy_martian said:


> Don't get too excited - they are horribly inefficient and eat a lot of current.
> 
> Might be ok for charge cooling, but ick if you need to warm the pack during running, which you likely need to do, especially in a snowmobile - don't forget that to heat, it has to pump heat from the ambient environment to the battery.


Good points! I think I will still plan to run fluid from the motor to the packs to divert heat where its needed.

Maybe for now will put the pack in the freezer for a few hours and see if the heater can keep up while monitoring power draw! Haah


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## green caveman (Oct 2, 2009)

Won't help the battery cost, but it did occur to me that a series DC motor is going to be about as efficient as anything else and likely the lowest cost. AC (and Sepex) get you regen and so, in a car, a little extra mileage. Without wishing to start an argument about regen in cars, I suspect that possible regen in snowmobiles is about zero. On anything other than an ideal surface I imagine you pretty much have to power them - even downhill. (I have no experience riding snowmobiles so I'm open to correction here).

I started casually thinking about a snowmobile conversion when I noticed an old snowmobile down the street that I could probably get free or nearly so. Looks to be a super-heavy-weight with space under the seat for batteries and enough space up front for a motor but I have way too many projects and not enough time, energy or money to pursue it.


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## Passedyouby (Dec 5, 2020)

green caveman said:


> Won't help the battery cost, but it did occur to me that a series DC motor is going to be about as efficient as anything else and likely the lowest cost. AC (and Sepex) get you regen and so, in a car, a little extra mileage. Without wishing to start an argument about regen in cars, I suspect that possible regen in snowmobiles is about zero. On anything other than an ideal surface I imagine you pretty much have to power them - even downhill. (I have no experience riding snowmobiles so I'm open to correction here).
> 
> I started casually thinking about a snowmobile conversion when I noticed an old snowmobile down the street that I could probably get free or nearly so. Looks to be a super-heavy-weight with space under the seat for batteries and enough space up front for a motor but I have way too many projects and not enough time, energy or money to pursue it.



Well, funny you should say that, because I called last week to cancel my order for the motor and controller, and switched over to AC. Haha. Ordered a kelly controller and ME1507. Played around with fitment today and tore down the other 5 battery packs.

Agree with your statement about regen. There is sooo much drag already it will be very minimal, but since I had to tear apart the existing braking system I think I will try and set the regenerative settings to max and use that for deceleration. Will add in a secondary system probably, but for now this is the plan. Haha.

Do you see a reason I will regret an AC build other than cost? Honestly this is the first time I've ventured into the AC realm.

Heres a picture just to make this read more fun


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## green caveman (Oct 2, 2009)

Nice setup. The only reason to choose DC over AC is cost, once you get over that, AC should be a great build. And , if I understand correctly, regen with AC is almost unavoidable. You just have to avoid the temptation to seek out the death-defying downhills what would be the only place you'd really be able to get any regen.


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## Passedyouby (Dec 5, 2020)

green caveman said:


> Nice setup. The only reason to choose DC over AC is cost, once you get over that, AC should be a great build. And , if I understand correctly, regen with AC is almost unavoidable. You just have to avoid the temptation to seek out the death-defying downhills what would be the only place you'd really be able to get any regen.


😂😂


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## Electric Forklift Guy (Dec 13, 2012)

The 11 mpg sounds about right.
The track wastes a lot of power.

The range will improve at 30 MPH vs 45 MPH.
But you won't be pushing through deep snow with an electric.

You could probably have a usable range at 25 mph on a packed trail , but where's the fun in that?

I read some literature on a sled thats supposed to have a 45 mile range but I'm guessing they are driving very slowly on packed snow.


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## remy_martian (Feb 4, 2019)

I'm not so sure it's the track vs the viscous fluid it runs in (snow). Energy has to be consumed compressing the snow under the machine (including the front skis), not to mention the mere drag of running in it.


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## Passedyouby (Dec 5, 2020)

The good news is that there will be 100 other sleds on the same ride as me, and a groomer will go ahead and pack the trail down for us that morning at 5am, so conditions should be perfect 

Will keep you updated on the build! The event is Feb 14th, so I have a hard deadline. 

Waiting on my 3, daly, 24s BMSs to arrive


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## brian_ (Feb 7, 2017)

remy_martian said:


> I'm not so sure it's the track vs the viscous fluid it runs in (snow). Energy has to be consumed compressing the snow under the machine (including the front skis), not to mention the mere drag of running in it.


I think it's both. Snow is bad for drag, but even on a hard surface the rubber track consumes energy as it is flexed. In addition, while there are idler (support) wheels in most cases, even then on any soft surface the track bends up between idler wheels, so the track rides on the slide runners - that alone is a huge drag.


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## Passedyouby (Dec 5, 2020)

Morning all! Fyi I scrapped the genny. Updated motors, and increased battery capacity. Sled officially runs! Build thread link below.









So I built an Electric Snowmobile.


Starting this post to showcase an electric snowmobile I am building from an old 1980s donor. I am 2 months into the build and finally took my first test ride this evening! From building the lithium 96v packs, choosing an AC motor, designing a heating system for the batteries while sitting...




www.diyelectriccar.com


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