I have an 18" wide electric plug-in snowblower that I got for about $100 (normally $200) last year during a sale that went on about this time last year. Worked great but plugging it in and dragging the cord behind me is annoying and it is a bit of a pain trying to keep the electric cord out of the wet slush at the end of the driveway to avoid getting zapped. This summer I completed converting my plug-in 120v black and decker mower to battery power using 9 spare Honda hybrid NiMh sticks(54 cells series) and it does the job although higher voltage would be ideal.
Now that the same ad was in the newspaper just last week, I went to the garage and stared at it a bit thinking about the colder weather and snow coming soon enough and put two and two together that this electric snowblower might also be a good candidate to convert to battery power. Figuring that both were possibly universal brushed motors I tested it out by tossing my hobby charger into NiMh mode at 5 amps and it sprung to life under constant current, of course 150 watts isn't getting it to max speed but it worked. I grabbed my 54 NiMh cells, low on charge but a moment of overdischarge doesn't hurt NiMh cells much if any are completely empty, it fired up and I was satisfied but it isn't quite up to full speed and to throw snow I need full power.
What would the average voltage be going through a bridge rectifier into the motor of something like this? In the mower threads most people were powering theirs by 80v packs and I remember most people who did it say that it is slightly underpowered from the original power source but plenty good to do the job. With a single-stage snowblower, the performance is directly related to how fast the paddle is spinning and I want to have this as close to peak power as I can get so I'm aiming for the voltage that the motor ends up seeing as an average after bridge rectification but I'm not sure what that would be. I'm looking to go with the Turnigy 5Ah 4S 20c hardpacks that are going for $23 right now from the HobbyKing USA warehouse and put enough in series to get a decent voltage. I was thinking that either 6 or 7 of those for 24(88.8v nom-100.8v charged) or 28 cells(103.6v nom - 117.6v hot). If I put more voltage through the motor than usual the brushes will arc over and if I'm buying more voltage than I need than I'm spending more money than I need. I'll also plan to use this same pack for the electric mower and possibly share it with an ebike for the summer months. If the pack was only for the snowblower I'd probably skip the idea entirely based on the cost of the cells but if I share these cells with other purposes it makes more sense.
I know not to charge HobbyKing LiPo cells in freezing temperatures so I'll either need to use a heated box or charge them away from flammables in the basement using as many precautions as I can, but what I'm more interested in is that I never hear about their discharge performance when they are cold, can I pull 15 amps from these cells if they are -10f?
Now that the same ad was in the newspaper just last week, I went to the garage and stared at it a bit thinking about the colder weather and snow coming soon enough and put two and two together that this electric snowblower might also be a good candidate to convert to battery power. Figuring that both were possibly universal brushed motors I tested it out by tossing my hobby charger into NiMh mode at 5 amps and it sprung to life under constant current, of course 150 watts isn't getting it to max speed but it worked. I grabbed my 54 NiMh cells, low on charge but a moment of overdischarge doesn't hurt NiMh cells much if any are completely empty, it fired up and I was satisfied but it isn't quite up to full speed and to throw snow I need full power.
What would the average voltage be going through a bridge rectifier into the motor of something like this? In the mower threads most people were powering theirs by 80v packs and I remember most people who did it say that it is slightly underpowered from the original power source but plenty good to do the job. With a single-stage snowblower, the performance is directly related to how fast the paddle is spinning and I want to have this as close to peak power as I can get so I'm aiming for the voltage that the motor ends up seeing as an average after bridge rectification but I'm not sure what that would be. I'm looking to go with the Turnigy 5Ah 4S 20c hardpacks that are going for $23 right now from the HobbyKing USA warehouse and put enough in series to get a decent voltage. I was thinking that either 6 or 7 of those for 24(88.8v nom-100.8v charged) or 28 cells(103.6v nom - 117.6v hot). If I put more voltage through the motor than usual the brushes will arc over and if I'm buying more voltage than I need than I'm spending more money than I need. I'll also plan to use this same pack for the electric mower and possibly share it with an ebike for the summer months. If the pack was only for the snowblower I'd probably skip the idea entirely based on the cost of the cells but if I share these cells with other purposes it makes more sense.
I know not to charge HobbyKing LiPo cells in freezing temperatures so I'll either need to use a heated box or charge them away from flammables in the basement using as many precautions as I can, but what I'm more interested in is that I never hear about their discharge performance when they are cold, can I pull 15 amps from these cells if they are -10f?