Some e-bike bloggers spend their time writing about bikes they’ve never ridden. This is not that kind of blog, instead I spend my time using batteries, motors and inverters for things I really shouldn’t be doing. In the process, I try not to get electrocuted or cause any permanent damage (I cut off the end of my index finger last week because the sauerkraut god demanded a sacrifice). One of the things I’ve been wanting to do for the past 2 years is to buy a cheap AC inverter from Alibaba and use it to run large high current tools like pressure washers, log splitters and rotary tillers. At first glance this might seem like a crazy idea, but I have to admit, it is. The reality is that many large e-bike batteries work very well as a portable 120V AC power source if you’re not too concerned about batteries and are willing to take the risk.
My wife has gone crazy buying hundreds of trees this winter along with 600 strawberries and 1000 asparagus crowns. I don’t even ask questions anymore, I’m essentially a free slave laborer, I’ve accepted my life. Asparagus crowns are especially problematic because they need to be planted in trenches about 6 inches deep. My wife shoveled by hand and planted about 25 canopies in an hour. I begged her not to do this, but she insisted on planting 100 plants like this. Maybe it’s best to let her suffer a little to help her clicker fingers learn a little restraint in their insatiable appetite for the “buy now” button.
I came to the rescue with a very cheap AC powered rotary tiller from Amazon (can be purchased) here)Previous year. Initially I thought I’d power it directly from the e-bike battery, but having an AC motor running on DC current is a royal PITA, so instead I just bought a high powered DC->AC inverter, from the 48V standard Said DC to 120V AC, rated power is 5000W. 120V service should never exceed 1800W at 15 amps, but the wattage ratings on these inverters are ridiculously overstated, I think buying a 5000W inverter and running 1800W is fair game. I ran the rototiller for over 4 hours with barely any drop in capacity on the 60Ah battery.
I bought a DC 48v inverter from AliExpress for $115 shipping (although it’s $125 now) here) and appear after a few days.I used XT90 connectors with pigtails and crimped some solid copper ring connectors like These 10 on eBay for $7. Using solid copper is probably overkill, but I don’t want to lose any conductivity on the connector. Connecting my e-bike battery to the inverter was literally a 5 minute job, crimping the ring connectors, putting them on and done. Note that the inverter draws power from the battery when turned on, even when there is no load. It is also wise to keep an eye on the temperature of the XT90 connectors and wires, if they get too hot then you may need higher amperage connectors or thicker wires. Also keep an eye on the battery temperature to make sure you don’t stress the battery. The battery may be warm to the touch, but never.
If I had to do this again, instead of connecting the inverter to a homemade electric tractor battery rated 48V, I would buy an inverter rated 60V and connect it to my Sur-Ron battery. The battery has an inline BMS that protects against low battery or short circuits. It also has a shockproof and somewhat waterproof case, while my battery comes in a crappy cardboard box with a Thermarest pad and a trash bag on the outside. I wonder which setup is more likely to blow up?
I can’t say enough good things about my Sur Ron and its battery.You can buy an extra 60v 32Ah Sur-Ron pack for about $1600 here Or you could take a battery pack from a scrapped EV (I think the Volt is the best) and use it as a larger battery pack that can last for days instead of hours. I’ve gotten to the point where I’m going to start doing this myself.
A lot of people use a 12V inverter hooked up to the 12V bus in a 2nd gen Prius, and if you leave the car on, the main hybrid battery will automatically replenish the 12V battery when it dies. If the main battery gets too low, the car will start itself and recharge the hybrid battery while in the driveway.Lots of people use them as backup generators when the power goes out for a few days (link to forum here). Note that if you’re doing this with 12V DC, you’ll have to use better connectors and thicker wires, as you’ll be pulling more current than your e-bike setup.
One of the biggest issues with cordless tools is cost and durability. My wife and I bought an Ego 56v 16″ chainsaw for nearly $300 and we’ve now destroyed a second one. The first saw lost its controls and the windings on the second saw were completely melted. Ego keeps sending us new equipment, but you can buy a 120V AC chainsaw which is much lighter and costs about 1/6 the cost. The same goes for hedge trimmers, lawn mowers, pole saws, etc. Cordless tools cost more, have shorter battery life, and are heavier. You can put a 20Ah+ e-bike battery and inverter in a small backpack and use your AC chainsaw or hedge trimmer all day (not just under an hour). Make sure the inverter has a way to “breathe” (it has a small fan), otherwise it could get too hot and burn out.
Now you’ve mastered a method for creating a piggyback generator to run AC electric hand tools throughout the day. Whether you’re a farmer, construction worker or homesteader, or just preparing for a zombie apocalypse, anything that can be plugged into an outlet, you can use cheap Chinese inverters.
whether you or not should It’s a different question entirely.
For more information on inverters please see This article on overlandsite.com