I’ve stumbled upon a neat trick for charging our SP140 batteries and thought it would be cool to share it here. I still run the original BMS which doesnt have an app etc. It’s all about making our pre-flight preparations a bit easier and keeping our batteries in top shape!
Here’s the setup: I use a ($10) Kasa smart plug with energy monitoring to manage my battery charging. It might sound a bit techy, but it’s super simple and effective.
Smart Plug Magic: I keep my battery plugged into the charger, which is hooked up to the smart plug. This setup lets me turn the power on or off directly from my phone. So, I can leave the charger off and only power it up when I need to charge my battery. Neat, right?
Charge on Demand: If I check the weather and it looks promising for an evening flight, I can start charging from work and have the battery ready to go when I get home.
Monitoring Made Easy: The cool part about the special Kasa plug is the energy monitoring feature.
I have it connected to Home Assistant on my Raspberry Pi, which lets me see energy usage over time. This shows me exactly when the battery is almost full or totally charged based on how much power it’s drawing – less power means it’s just about done.
4. Control from Anywhere: With a VPN, I can tap into my Home Assistant from anywhere in the world, which is pretty handy with their app to monitor the charging rate etc.
I know this might sound like a bit much, but trust me, it’s been a game changer for making sure I’m ready to fly without putting extra wear on my battery.
Here are some screenshots from my Home Assistant that show how the power usage drops off as the battery charges up.
It would be nice if there was a charging solution that could turn off the charging and draw the levels down until it got to safe storage level, and then remotely let you charge it back up when you are preparing to take it out… I really don’t like having to throw it on my back in the middle of my neighborhood to run it until it gets to storage levels, it doesn’t feel like the safe choice with other houses only 100ft away. Last thing I want is a piece of prop stuck in the house next door or in some child’s forehead.
Would highly recommend looking into purchasing an inverter to be able to draw down the charge levels. Phil posted about one on this forum a few months back / maybe late last year. I picked up the same one off eBay and it works great for the task – Plus it allows me to take advantage of having ~8kwh of battery storage available for things like a trip or emergency use around the house.
Just the other week we lost power for most of the day due to a storm. I was still able to work since I could keep my phone charged to use as a hotspot, and keep my work laptop (with a bad internal battery) online all day long and barely touched the capacity. Think I went from ~87v → 84v.
That being said, I would absolutely love a better charging/discharging/monitoring option for our batteries. They are very significant investments, and while there are a large number of pro’s to the electric option, we still currently have to deal with some pain points – Long charge times (compared to filling up a tank) combined with the need to keep it at storage levels, plus the concern with unattended charging. I know the risk of a battery event is extremely low (especially with quality components/cells like in ours), but there is a risk. I take some basic precautions, with one being that I do not charge any lithium batteries without being present.
I might still try using something like a smart plug to make it more convenient to kick the chargers on though. But I would gladly throw some money at something that I could plug my batteries into and remotely charge/discharge to preset levels as needed.
Agreed… I really want an easy to use solution to drain the battery. I had crash landed during my first SP140 training flight last year and had to wait for a new frame and prop. I didn’t expect it to take so long, so I had it charged up waiting to go… after several months the parts came and it was mid-winter… now with a very busy and wet spring, I haven’t gotten back together with my instructor and the battery has still been sitting with full charge.
I found the post you were referring to. I’ve asked Phil what he used for an inverter as it didn’t look like any model information was listed or where he got it. I’m assuming the inverters I have on hand which expect automotive voltages would burnout.
