E-Bike Battery Powered Sump Pump with Z-Wave Controller and Monitor
This IS a good one, but after you see it, you’re just going to ask yourself, why? And if you ask me that, all I’m gonna do is smile and say, why the h not? Cuz this is one bad*** sump pump with features you will find on none other!
Here’s the other thing, if you need to rely on on a sump pump during the rainy season or else, then if there’s ONE thing you need for local natural disaster preparedness in these new and never seen before climate changing days of 7 inch downpours in 2 or 3 hours, which hasn’t happened here in my hood yet, but it has twice in the last two years elsewhere in the Chicagoland area, so it’s a big concern, and a RELIABLE and POWERFUL battery powered and Z-Wave controlled and monitored backup sump pump like this is what you all may need, too!
Another reason I’m putting this out here is to show off some fun stuff that can be done with z-wave. And get you thinkin’, about what you can do with stuff like this.
For decades, I had been relying on the Basement Watchdog brand of battery backup units but their primary pumps didn’t last so I ditched those years ago but kept the controller, deep cycle battery and their 12v DC backup pump, which is a good pump. But the controller always drove me nuts too with its alarms for power outages and battery water. Dealing with those big lead acid batteries every few years is no fun either. Which in the end is what led me to ditch that thing completely last fall when it wouldn’t stop beeping every night unless I went out and bought yet another one of their batteries. Nope, I have a better idea.
I just so happened to have a 48v 17ah rack mount e-bike battery that I bought by mistake and had no other use for other than short duration emergency 120v through an inverter (tip: don’t use rack mounted e-bike batteries unless you want to pop wheelies or tip over like the guy on his trike on laugh in). Which reminds me, I need to put my DIY e-bike out here, too.
So anyway, all I had to do was get that down to 12v (easy enough) to power the heavy duty 15amp pump with some kind of relay for the float switches to trip, which would then power the pump, with the additional requirement to keep the pump running for several seconds after the water drops and the float switches open. That means we need the float switches to trigger a “Off Delay Relay” that will trigger the power relay to the pump and provide additional run time after the float switches open. Got it? You will soon.
The other major concern is amperage. The relay that powers the pump needs to be rated at 15amp or higher, which is what the pump draws at start up. No problem there. A cheap standard 12v 30 amp automotive relay will do the trick.
As for the “Off Delay Relay”, that took some digging, but I finally found what I needed on Grainger, buried deep in the archives. I sure do miss their catalog (like so many others). Always seemed to have one of those sitting around last century. Not anymore.
One more thing, very important. Low voltage protection for the battery, like a golf cart or e-bike would have. No problem there, either.
For the Z-wave components, we’ll be using a Zooz 15amp relay and switch to control battery power to the controller, along with two relays and contact sensors to monitor and report on battery power and pump power.
So now that we have all the pieces, let’s connect them together with some 12 or 14 gauge wire and see how it works.
SAFETY FIRST!
E-bike batteries pack a punch so be darn sure its OFF before wiring it up, and that’s the last thing you will do.
Now Build It
Here’s how it works:
- Turn Battery Power on using Zooz Relay switch in HE
- Battery Monitor reports Closed
- Water or your finger rises and first Float Switch closes
- Off Delay Relay closes its NO switch across Pins 8 & 9, triggering the Pump Relay and Pump Monitor
- Pump Monitor reports Open
- Pump Relay closes and Pump starts running
- Water drains and Float Switches Open
- Off Delay Relay starts timer, configurable in seconds 1-60
- Timer expires
- Off Delay Relay opens circuit to Pump Relay and Power Sensor
- Pump Relay opens circuit to Pump and Pump stops running
- Pump Monitor reports Closed
- Rise and repeat
- Storms are over. Turn battery power off.
- Battery Monitor reports Open
Wiring Made Easy
Wiring the contact sensors is easy, too. Polarity is not important on the two ports inside. Use BELL WIRE (24ga).
Other Nuances and Improvements
There is one more thing I want to add to this: A water sensor in the sump pit just above the level of the primary pump and just below the backup floats so I can have HE power up the controller when it looks like its going to be needed, plus I’ll get an alert on that.
The thing that is sure to bite ME with this is not leaving the external battery switch on. Doh!
Not sure how long a fully charged battery of this size will last and haven’t done the math either. The pump draws 6-7amps under load for 15-20 seconds with a 10 ft lift and empties nearly as fast as my primary. Maybe I’ll test it for a few days and see how long it goes under steady heavy load, every 30-60 minutes right now as the snow melts.
Charging is done offline with the charger that came with the battery. Takes several hours to get up to 53-54 volts from 41-42.
The low voltage cut-off IC can manage charging too but I’m not going to bother with that.
So that just about covers it for now. Thanks for stopping by and checking this out. Perhaps it got ya thinkin’, and that’s a good thing. Something like this might be useful for a pond circulation pump, or some variation thereof.
So until next time… take care, be safe and have fun!