I’ve been riding an average of 90 minutes a day almost every day this season in the snow. Most of the time it is in powder that is 4-6″ deep. The snow at my wife’s house is over 2.5 feet deep now and impossible to ride on. I can still ride on snowmobile tracks and XC ski tracks that have been frequented. The only problem riding XC ski trails is that they are a lot like riding skinnies, as soon as you fall off the packed down trail which is often less than a foot wide your front wheel drops down a foot in the powder and you are stuck. Often you tip over in slow motion and fall into 2 feet of powder. Using the bike to push against the snow you slowly wiggle your way out and try to stand again in the powder to do it all over again. Ride\Fall\Getup\Repeat.
The biggest problem I’ve been having is one of power consumption. When plowing through a lot of snow you tend to have to peg the throttle all the time. If you’re not running chains or a massive tread rear tire like the Surly Lou then often times your tire will just spin out and dig down in the snow. It’s a fine balance between unweighting the back tire enough to not dig in and weighting it enough to get traction. I spend most of my time riding with one leg on a pedal and the other leg keeping balance by dragging out behind the bike and catching myself as I start to fall. It must look very strange. Sometimes I take both legs off the pedals and drag them behind the bike in the snow to get the maximum weight I can on the rear tire which probably looks even stranger, but it works.
My usual battery is a 16lb 20Ah 16S LifePo4 ‘duct-tape’ pack which without snow on the ground gives me over 3 hours of singletrack riding. Depending on the depth and heaviness of the snow that time can be cut down to under an hour. It is not uncommon to run the BBS02 and keep it pegged all the time at >1000 watts. As long as the motor keeps spinning fast it doesn’t seem to ever overheat. Since my gearing is so low (often I use a 32T front and 22-24 T on the rear) the motor is always spinning very fast, fast enough that it is useless to pedal except on very steep hills over 15 degrees of incline.
So how do you deal with these power levels? One thing I’ve found is really helpful is to find hills with snowmobile tracks going up and then XC ski trails going back down. Trying to go uphill in deep powder is really hard on the equipment, but going downhill through 6″ of powder is much easier.
Another thing that really helps is using a watt meter or bringing along a spare battery in case you kill yours. You can use a 12S1P pack built out of two of these in series which will only cost <$60 and weigh 974g. This pack won’t generate that much power, but it will be good to get back to your car without having to walk for miles. A 3000ah pack should get you about 2 miles or so if there is not a lot of snow on the trail. Make sure to charge your Lipos in the oven (but don’t turn it on!) like I do so if they blowup they won’t take your house with them.