Use PWM to control your Jebao DCT pump using brushless motor controller from ebay

[karimwassef]

Since I'm doing multiple drives for multiple pumps, I'll use a larger plate, U tubes and a fan.

[d0ughb0y]

I was trying to find the listing for the heat sink, and it was just a sample picture of the board attached to a heat sink and not selling the actual heat sink.

and the other listing for the same board says to use a heatsink if load is > 60watts. So I incorrectly said 6A. So it makes sense now since your graph shows you are going over 60 watts, that you need to use a heat sink.

[d0ughb0y]

Can you test if the pump still operates if you power it with 12v?
I think it still should, with PWM at least 50%, or maybe closer to 100%.
The board is rated 12-36v.
The stock controller only works on 24v, so it cannot be used with 12v backup power.

I just found UPS battery on sale at a local store, like $12 for 7AH 12v battery,so I might get some and use it as backup power.

Bad news for me, I think the green board I got is defective. I will contact the ebay seller.

[karimwassef]

sorry to hear that. I just ordered three more... Hope my odds are good.

We do need to exercise the controllers to make sure they're robust.

I'll try the 12V.

I'm running a 24V backup battery, by the way, so 12V isn't necessary.

[d0ughb0y]

did you diy your backup battery?

I am looking for a simple charging switch over circuit.

[karimwassef]

No. I found a really cheap charge controller on amazon. $11

https://www.amazon.com/gp/product/B00L37KZI6



It's originally intended for solar panel charging, but it doesn't matter.

[d0ughb0y]

Good idea. I was just looking under lead acid battery chargers.
Does this power the load if there is power from solar input and charge your battery at the same time, then automatically use the battery to power the load if there is no input from solar?

Does it also know to shutdown completely if battery voltage goes down to say 10v? (or 20v if you are using 24v). As you do not want to completely drain your battery.

I tried searching online for a manual and can't find one, but based on the description, it looks like it will shut off the load at 10.8v. This is perfect.

[karimwassef]

I haven't tested it under all different conditions.

I wouldn't use a normal lead acid battery though. Also, the energy storage/$ is important to me since I would like to survive for several hours on a charge.

A deep discharge marine battery is really best here. This is the one with the best value IMO

https://www.amazon.com/gp/product/B00S1RT58C

You can stack them two deep to get to 24V.

This charger is limited to 20A though, so that's not much power throughput IMO. I was looking for a higher current bypass so the 20A only limits the charging and not the normal running current.

This is a big topic for me - you might want to start its own thread so this one can stay focused on the motor drive.

[karimwassef]

As an aside - I don't use the cheap 12V or 24V power adapters if at all possible. They're horrendously expensive and very poor quality.

I prefer refurbished power supplies, but you need to do some work to get them up and running.

I wouldn't recommend the same for everyone, but this is the best solution I've found for real DC power. I use it for 12V and 24V grids

http://www.rchelination.com/setting-...-power-supply/

[d0ughb0y]

I don't need anything that heavy duty.
That battery is a bargain compared to the icecap and vortech battery.

[karimwassef]

Yup. Two in series is 24V at 100A-hr so it would run 2400W-hrs (assuming slow discharge so the discharge penalty is minimal). So a 100W pump (or two running at 50W) can run for a day. That's enough time to get a generator primed and gased in case of a longer gap... Or it would ride through most normal outages.

[d0ughb0y]

ok, good news, my pump is now running using the green board. It was a user error. Somehow I programmed my arduino to output 25% pwm, since I don't want it to splash water out of the bucket all over the room if I start out at 100%. After I changed it to gradually increase to 100%, the pump is now running!

I tried to Gnd the Z/F direction pin, and the pump spins. I can't tell though if it is actually spinning the reverse direction or not, but the water still comes out of the top, but definitely not as strong as the forward direction. So maybe the impeller is actually spinning the opposite direction. In any case, I still believe this will work with crossflow and gyre.

I checked the signal pin, and the signal is the same as what I saw on the white board. If the pump is running, there is a signal that seems random, but probably is synchronized with each commutation. One thing for sure though, once the pump stops, the signal either stays low or stays high. So I think that can be used to detect if the pump is running or not.

[d0ughb0y]

And I just tested on 12v, the pump did not work.

[karimwassef]

Mine runs but it's very weak. Let me measure the current

[d0ughb0y]

I will try again later. I can't find another 12v power supply so I used a splitter.
The green board specs says it works with 12v. I think the pre-drivers requires 10v bias, so I think this should work with 12v. So the only reason this won't work is if the pump itself does not want to work with 12v.

[karimwassef]

Hmmm.. Ok, the results require some interpretation... I'll share the data and leave the interpretation for later.

So, first, I set up the measurement for the 24VDC first. Remember that I was seeing about 70W a couple of days ago (~3A)? Now it's only drawing ~1.8A at the same setpoint (signal = 4.5VDC). Here's a few details:

1. The pump has been running continuously for 2+ days.
2. When I first tested the pump, it hadn't been running for a couple of months after a deep cleaning. It may have had a lot of resistance to turning?

Ok. So that establishes the new baseline of 45W (at least for my old recently cleaned pump) at a signal of 4.5VDC. I have a new pump too (out of the box) - so I'll rerun the tests on that one too.


Then I ran the same setup on my 12VDC. A little detail on my 12VDC source: it's capable of driving up to 800W, so its current capability is exceptionally high. First, when I plugged it in, the current went negative ~-0.3A. The pump was actually running but with a negative current? Very weak, but it was running at about 3W. I realize that the wire is covering up the negative sign before 0.28 in the picture, but it's there if you look closely.


I decided to disconnect the other loads on my 12VDC source, and after a few seconds, the current reversed and went positive until it got to 0.75A. That's about 9W (so 20% of the 24VDC state). The flow is significantly lower than the 24VDC too.


That's the data - interpretation?

[karimwassef]

I made a video if you guys think it's worth posting to compare the flow.

[d0ughb0y]

Is your meter set to measure DC current? I take it that it is set correctly.
Your current connection may be reversed. I think the sign should not matter.

I think you need to rewire your Amp meter connection.
The power supply negative goes direct to green board negative.
The power supply positive, connects to meter + then meter - to green board +.

[karimwassef]

I'm making my measurement on the ground (-ve), not the +ve line.

The normal 24VDC measurement works fine.

The current flips without changing the connections, so it's a real flip. I repeated it several times.

It is on the 20ADC.

[karimwassef]

[d0ughb0y]

I think we can say it is not feasible to run the pump at 12v.

[karimwassef]

I agree. While it turns, it doesn't do much for flow.

Still makes me wonder about running higher though in a cyclical mode. Just not sure how high would be safe.

[karimwassef]

One more tidbit on the current measurement. I'm using modified meter wiring to reduce the resistance in the current loop. Last time, I used the standard meter wire probes. I think that could contribute to the higher current reading.

[d0ughb0y]

Can you measure power and current using stock controller?

BTW to test running at 100%, simply connect the VR pin to 5V pin with a jumper wire.

[karimwassef]

I thought of that, but I wanted to characterize over different setpoint voltages 0-5V

I'll collect a lot more content this weekend