Yes, the shunt has to have a separate high current path with no terminals in common with the sense leads, but also the meter power should not run on the sense wires to limit the meter reading its own power draw since the sense voltages are so small. When I looked at the diagrams for the various modes of wiring none show sharing of the sense and meter power leads.
On Sat, 11 Jun 2016 00:32:08 -0000 (UTC), John Doe Gave us:
After you re-quote and re-post them? You are a hypocrite.
You have been listening to the idiots again.
I was using precision current shunts before you knew what a nine volt against the tongue was like, little boy.
In this power meter, the shunt is inside the meter enclosure. That means you do have to run heavy gauge wires from the battery to display. I couldn't find anything with similar features and with an external shunt.
It's not too clear on the Amazon page, but is mentioned on the BangGood page as: "Bult-in shunt design, no extra needed" also:
and a drill motor is not the most intelligent solution for an electric bike either. - - -
Oh, yes we do, AlwaysWrong. You got that name for good reason.
I seem to recall its working pretty well, no?
On Fri, 10 Jun 2016 19:26:30 -0700, Jeff Liebermann Gave us:
On Fri, 10 Jun 2016 22:42:57 -0400, snipped-for-privacy@snyder.on.ca Gave us:
When I said that he called me a troll.
He is worse than Donald J. Trump in that respect.
On Fri, 10 Jun 2016 21:06:15 -0700, Gunner Asch Gave us:
Of course they do. Where have you been for the last several decades?
On Fri, 10 Jun 2016 21:08:24 -0700, Gunner Asch Gave us:
Says the retarded idiot who thinks that most handheld meters will not read DC current.
You are an idiot.
I didn't have a 3PDT switch handy to try, so the DPDT proved the concept despite the sense voltage error. A 3PDT switch would cost about as much as a second meter anyway. Separate meters for charge and discharge will totalize the energy in and out of the battery separately while a single meter with a reversing switch will add them together, which isn't very useful.
I settled on a 100A Bayite meter to monitor discharge and a 20A one to monitor charge. The 100A one is on a long cable so I can see how much battery power the inverter's loads draw as I turn them on and off, the
20A one on the charger whose constant output doesn't need watching. Both show the battery voltage. They aren't as informative as the industrial datalogger I installed on an experimental electric vehicle but they are good enough for home projects.A possible fault condition with the reversing switch is the B- contact open and the meter's operating current trying to pass through the sense leads, which might overload the input clamp diodes.
--jsw
Click on the specs tab:
DC Current Range 999.9 A Resolution 0.1 A
Choke on the price:
LOL Amazing Electrician/Electronics tech Wieber has yet to learn about the popularity of Hall Effect clamp meters.
Here, Wieber. Welcome to the 20th century.
And amateurs needn't pay Fluke prices.
It can be had for less, though:
So far the UT210E has been fine for my hobbyist use:
It won't measure car starting current but I have other ways to do that.
It -will- show the key-off drain from a car battery without disconnecting the battery and triggering the radio's anti-theft lockout.
It zeros to within a few milliamps. The main error seems to come from changing its orientation in the Earth's magnetic field between zeroing it and clamping it on the wire.
It immediately became my favorite ammeter, though the autorange-only voltage is less impressive. Uni-T makes a superb meter for voltage and you need two meters to measure both voltage and current at the same time anyway, for example checking battery or solar panel output under varying loads.
--jsw
Good find. I missed that one.
However, there's a problem. If you look at the photos of their wiring diagram, you'll notice that there's a connection between the DC Load resistor + terminal, and the power supply + terminal, while the negative wires are split between the load resistor and the power supply. In other words, this is a positive common ground system and may NOT work with a common negative ground for both the battery (power supply) and load. That's not a problem with a solar charger, floating charger, or no charger as in the electric drill, but will be a problem if you have a negative ground system.
I've run into the same problem with the LED meter modules that have both a voltmeter and ammeter in one package.
I don't have any experience with brushless motors, but have played with various brushless drills. However, that's never stopped me from offering a bad guess(tm) based on Googling and reading.
Brushless seem to have one big advantage. Thanks to tachometer feedback, they're constant RPM. This video shows it better than I can (also with some interesting drill related stuff): "Advantages of a brushless cordless drill" (7:32)
A typical brushless torque-power curve at: shows that the brushless motor is more efficient at high RPM's, and delivers an output peak in the middle of the operating range. Offhand, I would think it would not do well on hill climbs, where the RPM's might drop too low to deliver max power.
It's possible that the DeWalt drill has the same 11 step speed motor controller as shown in the video, which would make tolerable throttle control. However, that eliminated the possibility of using the drill motor as a "pedal assist" type eBike, where the motor only supplies enough power needed to keep the pedal torque (and pedaling effort) low. That won't work if the effort required is variable, such as an uneven or bumpy road. The idea is to use as little motor power as possible to extend battery life.
Offhand, I would say the motor is just fine and probably superior to a brush type DC motor, but the drill speed control might be a problem matching it to variable loads found on a bicycle.
Good luck.
I'm working with DeWalt on a related article, and I'm going to ask for their reaction to the bike. I can't wait to hear what they say about it. d8-)
They may have to limit their approval for safety reasons. We did some stunts with the lab Segways that we would never suggest to customers.
--jsw
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