Wow!! What a wonderful video!! Thank you so much for such a detailed review of how it works! I bought that Electronic Load Tester over 3 months ago and after trying to understand those instructions I said to myself..... I have a $60 dollar paper weight. Thanks again! You just got another subscriber for life! Take care! Aaron from Ocala,Florida
back in the early 1990's I had a hand in designing a 4 channel electronic load that could handle 500w per channel in a 5"high rackmount chassis. You could parallel channels and they would power share for higher power ratings. I think we sold those for about $1,000 back in 1991. That Chinese load is a steal for the price.
Very interesting, I bet with a little effort one could retrofit a microcontroller on that unit to increase its capabilities. Come to think of it Scullcom Hobby Electronics channel built a electronic load as one of his projects not too long ago, one could probably leverage his work quite easily. Any ways nice job and thanks for sharing, keep up the great work!!!
If you want to see the electronics under the heatsinks, watch the video at: th-cam.com/video/3eOLWtMfjSk/w-d-xo.html You can also see the 150W and 180W boards are virtually electrically identical except for the heatsinks, and I believe they are. He also went through a problem I had and demonstrates some more functionality, and shows that the two semiconductors adjacent to the power MOSFET run VERY hot at higher test loads. After quite a bit of use, his PCBs were both discolored on the PCB backside under their locations. I recommend watching it at 1.5x speed. It's perfectly understandable. (note: I also watched THIS video at 1.5x speed without any problems.)
Thanks for the great review. I got one of these and trying to calibrate a DC DC step up converter to run 18v 10A. On the other end I have the bench power supply sending 12v 10A. Any idea why the amperage on the load tester only goes up to 5A while my bench supply and the dc dc converter reads 10A?
Is the white connector that is in between the two current adjustment knobs for an unloaded voltage measurement at the battery's terminals (in other words 4-wire measurement)? It would make this unit a lot more accurate and useful to me, but I imagine that would require a jumper or some provision for the device to know to use that measurement and not the measurement taken onboard at the loaded end of the power wires.
Good review. I wonder why the voltage reading dropped 50mV shortly after you connected it. There should be zero voltage drop across the cable with the current set to 0.00A, regardless of the wire resistance. Have you checked the actual voltage at both ends with a multimeter? I find the voltmeter on many power supplies (even an expensive Farnell unit I have) are pretty inaccurate..
Thought I'd point out a MOSFET THERMAL FAILURE EXPOSURE WITH THE HEATSINK MOUNTING SYSTEM. On the unit I received, the 4 cheap plastic pins that hold the heatsink round/circular base to the PCB do not hold it tight against the PCB. There is vertical slop in the fasteners that allows almost 0.5mm of vertical movement between the mounting base and the PCB. This means when the heatsink is mounted to the base the thermal compound that is supposed to ensure efficient conduction of the heat from the MOSFET to the heatsink is under stress, especially whenever the unit is moved around. That means that over time it's possible an air gap can develop between the MOSFET/thermal compound and the heatsink, which could lead to failure of the MOSFET due to insufficient cooling. Any gap will also allow the thermal compound to dry out faster than if there were a tight seal...again leading to earlier failure of the MOSFET. Also, in a second unit I received, 2 of the 4 pins had detached completely from the PCB and were just rolling around in the plastic clam-shell packaging. They were NOT damaged...they had just fallen out during shipment. So, upon receiving your unit I recommend at least checking all 4 pins are securely attached to the PCB. However, I highly recommend replacing these cheap plastic pins with quality non-conductive screw fasteners. (note: on my particular units I verified I could use metal machine screws without risk based on PCB design of both units, but I still used plastic washers to isolate the lock washer and nut for each screw from the bottom side of the PCB's lands.) Whatever method you use, occasionally check that the mounting base is still securely held tight by the fasteners. Note: both units I have are the 180W units with the massive vertical heatsink with two 92mm fans attached, so the heatsinks weigh a lot more AND have a higher moment-arm from the top of the heatsink to the base which can add significantly more force to the mount than the 150W unit with it's low-profile single-fan heatsink.
Hi !! Have you tried connecting a constant current source? like those used to feed LEDs, with mine I could not do it, only with resistive load. Sorry for errors in the translation, my language is Spanish.
Since it has no preset max current draw, it should have a fuse to avoid calamities. You do not want to draw max current, close to a short, because of setting the dials the wrong way by mistake. On the other hand, a fuse, let's say 20 A, will not protect any gear only capable of delivering lower current values. So I am not sure what think about this.
Well I made the mistake of buying one a wile back and really had it stuck to me. I paid like $80.00 or 85.00 for the one I got. Another mistake I made was getting it for testing 18650 batters. A power wall person suggested it and boy what a bad mistake that was also. I set it so it will stop at 3 volts low side and all it does is pop up (3 volts?) the whole time when in use. It can be used if you don't mind having to scroll through fast enough to see what's going on with the other settings. Even if I had gotten a better price it is worthless for testing batters.
If you serious want to test 18650 (eg. other type battery cells) go for this: www.ebay.com/itm/QC2-0-3-0-MTK-PE-Trigger-35W-20V-EBD-USB-Tester-Current-Load-Battery-Capacity-I/173129018123?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
The energy is dumped into a power MOSFET. The MOSFET can IN THEORY handle 300W at 25C with the proper heatsinking to keep junction temperature requirements in check. With the high-profile 2-fan heatsink that's limited to about 180W, and with the low-profile 1-fan heatsink that's limited to about 150W. It's possible with higher airflow-volume fans and/or a different heatsink, and/or a superior thermal compound you could obtain higher power operation. Could likely get quite a bit higher Watts with a water-cooled system...I don't know what kind of software protection is built-into the firmware IF ANY that might put additional limits on maximum power dissipation. The MOSFET is underneath the heatsink. DO NOT REMOVE THE HEATSINK unless you know what you're doing.
Good video and was to give a thumbs up and subscribe but I see he has never replied to any of the questions from the comments section,time to move on to someone else more active.
From what I've seen, I believe it will. There are cheaper alternatives if ALL you want to do is discharge a 2.9Vnom cell with auto-cut-off at 2.4V. I discharged a LiPo cell charged to 3.20V with a cut-off V setpoint=2.40V and it took it down to 2.70V WITHOUT shutting down the discharge process (I didn't want to damage the cell in test so I manually terminated at that point.) However, the tester did let me set the cut-off voltage (I call it Vcutoff or Vterm or Vt) to 2.40V and everything else worked as expected so I see no reason it wouldn't work for you and cut-off at below 2.40V as one would expect. However, please read my comment above in this same video at: th-cam.com/video/ed9iEQlH5t4/w-d-xo.html&lc=UgwMnO_kKMcJVbJn0LJ4AaABAg.90G32s73b9G96pRHzwBjnT for more information on my experiences with this unit (or a comparable one as there are different versions out there). As best I can tell mine is very close in appearance in every way to xraytonyb's in this video except mine is the 180W heatsinked unit. Yeah...I know Bigkato's question was a year old, but someone else might be interested with the various different voltage cells that are out there.
Check out the dummy load made by “five fish audio”. They are located near me… I think he’s in Nashville somewhere. The pcb is available on his website and eBay, and you have to assemble it as a kit. From everything I’ve seen and from the board I got, top quality, great design, and will make an incredibly good device. I’ll be putting it in an old fluke Benchtop multimeter enclosure… looks like it will make a really high-quality load. Thanks for the video. The ones for me but I do seem very good for the money.
I think US$23 is a bit steep for JUST the PCB. The detailed and Digi-key auto-ordering parts list is great but that's still added cost to the project. I input the inquiry to Digi-key and there are two parts that are "in error" (obsolete, an IC and an LED) so you have to find an equivalent part) and the order won't process unless those items are removed from the auto-order. In addition, Digikey wants 2x $7= $14 for the MOSFETs alone. That's quite pricey...and I like Digi-Key. As far as I can tell his board doesn't have a built-in display. You need to use external equipment to read the data and provide your own power supply, so that's even more cost. But one can buy this decent 180W unit fully tested and assembled for about US$40-$45 on eBay, including power supply, and a couple test leads. Less than $40 if you're willing to wait for shipment from China. Seems a more logical choice. I was quite shocked that mine arrived from China only 8 days after the order. The order was placed March 19. If I need more than 180W I can change the MOSFET and the cooling on a cheaper 150W unit for fairly little money and perhaps an hour of work, and probably easily increase it to have over 200W of power handling...if the firmware allows it. Otherwise, I'd have to hack that bit.
Hi, I just bought one but I can't set the amps. It's always at maximum no matter where the knobs are set. If I press the button 7 times it shows 0 A and the fan stops but it keeps drawing current. Do you have any idea of what's wrong? Thank you.
Hello friend I buy 1 if that, last night I empty 5 pcs 14v lifepo4 battery pack, works very well, but when I plug it out and thus morning plug it again, device will turn on but when I connect any cell or battery, shows voltage of it but not work volume controls and current not change from zero and also cooling fan not work, do you know what's problem of it?
Hello, my Load Tester nothing happens, I turn the potentiometers and nothing. I've already changed Mosfet 2 times, nothing happens. Can you tell what might be happening?
You need to see and test the voltage across the mosfet drain and source . And you need to check the gate voltage too . And test the 2. SMD transistors rectifier beside the mosfet . Try to do a reverse engineering electronic test item's. For me to fix this stuff is easy cake
The 1-page spec sheet that came with the unit says it does...sort of. Unfortunately, it looks like the ONLY Quick Charge test is on the standard-sized USB connector to the left of the coaxial connector (spec says="by qualcomm quick charge QC2.0/3.0 trigger, etc"). To test USB-C quick charge or other type it looks like one needs an special adapter for that connector. While it has C, micro, and mini USB connectors, the 1-page spec does NOT explicity show them supporting Quick Charge of any kind.
LOL, The Chines sure do like screwing with us. I figured out the Low Voltage Cut Off . DAMN, A lot of rig o ma roe that is. If you miss your mark you get the Reset the thing and I'm still not quite sure how I do it but I can do it. The Two Quick Press to increment the values works strait away . Not So if you wait too long. You have to have your chit together witch I don't. LOL Took me 30 minutes to set up to test some A123 cells . Limit discharge to 2.0V and what not. Sure would have been nice if they just had a damn Increment button ?
Put it twice and goes in One Direction click it three times it goes in the other direction and if you hold it it just Scrolls so you don't have to reset it which I did the first time but not the second time
Low-Voltage cut-off issue? KainkaLabs in the video at th-cam.com/video/KcGBHZEOt5s/w-d-xo.html claims there is no Minimum voltage cut-off and he had to add a custom circuit to what appears to be the same product in order to get the device to stop drawing power from for instance a battery when the battery's voltage dropped below a specific value. He claims this is to keep the device from draining the battery once it dropped below a voltage he sets on his special added circuit (his circuit provides 3 discrete cut-off choices at 1V, 2V, and 10V). But, you seem to say that the device already has a minimum voltage setpoint (you call it a "trip-point") function and will stop draining a connected battery when it falls below your entered minimum voltage trip-point. The text at the bottom of the video claims both Min and Max setpoints are available for volts, amps, and watts...or, am I misunderstanding what you said and showed on the display at 10:24? Also, is there a link to an online copy of the user manual/pamphlet you can point us to to help clarify this issue? My entire reason for getting something like this product is to be able to automatically test batteries without having to worry about over-discharging them during a test.
I would have to check to be sure, but I think there were several versions of this unit for sale out there. The biggest problem I have with this unit is that it is a pain to program, with all the multiple button -push menus and such. I think I might have a PDF version of the instructions. If you e-mail me, I'll try to send you a copy. Thanks for watching!
Wow!! What a wonderful video!! Thank you so much for such a detailed review of how it works! I bought that Electronic Load Tester over 3 months ago and after trying to understand those instructions I said to myself..... I have a $60 dollar paper weight.
Thanks again! You just got another subscriber for life! Take care!
Aaron from Ocala,Florida
back in the early 1990's I had a hand in designing a 4 channel electronic load that could handle 500w per channel in a 5"high rackmount chassis. You could parallel channels and they would power share for higher power ratings. I think we sold those for about $1,000 back in 1991.
That Chinese load is a steal for the price.
Well done. Very goog explanations! Thank you sir!
I made some modifications in my DC load as the one you have . It reach 25A / 330W .
If you want some picture of what I did I can do that .
Very interesting, I bet with a little effort one could retrofit a microcontroller on that unit to increase its capabilities. Come to think of it Scullcom Hobby Electronics channel built a electronic load as one of his projects not too long ago, one could probably leverage his work quite easily. Any ways nice job and thanks for sharing, keep up the great work!!!
Nice video, very interesting.
So doing capacity testing on a LiFePo4 cells I can set the Low Voltage shut down using the
If you want to see the electronics under the heatsinks, watch the video at:
th-cam.com/video/3eOLWtMfjSk/w-d-xo.html
You can also see the 150W and 180W boards are virtually electrically identical except for the heatsinks, and I believe they are.
He also went through a problem I had and demonstrates some more functionality, and shows that the two semiconductors adjacent to the power MOSFET run VERY hot at higher test loads. After quite a bit of use, his PCBs were both discolored on the PCB backside under their locations.
I recommend watching it at 1.5x speed. It's perfectly understandable.
(note: I also watched THIS video at 1.5x speed without any problems.)
Thanks for the great review. I got one of these and trying to calibrate a DC DC step up converter to run 18v 10A. On the other end I have the bench power supply sending 12v 10A. Any idea why the amperage on the load tester only goes up to 5A while my bench supply and the dc dc converter reads 10A?
Is the white connector that is in between the two current adjustment knobs for an unloaded voltage measurement at the battery's terminals (in other words 4-wire measurement)? It would make this unit a lot more accurate and useful to me, but I imagine that would require a jumper or some provision for the device to know to use that measurement and not the measurement taken onboard at the loaded end of the power wires.
Well done, thanks.
Good review. I wonder why the voltage reading dropped 50mV shortly after you connected it. There should be zero voltage drop across the cable with the current set to 0.00A, regardless of the wire resistance. Have you checked the actual voltage at both ends with a multimeter? I find the voltmeter on many power supplies (even an expensive Farnell unit I have) are pretty inaccurate..
Thought I'd point out a MOSFET THERMAL FAILURE EXPOSURE WITH THE HEATSINK MOUNTING SYSTEM.
On the unit I received, the 4 cheap plastic pins that hold the heatsink round/circular base to the PCB do not hold it tight against the PCB. There is vertical slop in the fasteners that allows almost 0.5mm of vertical movement between the mounting base and the PCB. This means when the heatsink is mounted to the base the thermal compound that is supposed to ensure efficient conduction of the heat from the MOSFET to the heatsink is under stress, especially whenever the unit is moved around. That means that over time it's possible an air gap can develop between the MOSFET/thermal compound and the heatsink, which could lead to failure of the MOSFET due to insufficient cooling.
Any gap will also allow the thermal compound to dry out faster than if there were a tight seal...again leading to earlier failure of the MOSFET.
Also, in a second unit I received, 2 of the 4 pins had detached completely from the PCB and were just rolling around in the plastic clam-shell packaging. They were NOT damaged...they had just fallen out during shipment. So, upon receiving your unit I recommend at least checking all 4 pins are securely attached to the PCB.
However, I highly recommend replacing these cheap plastic pins with quality non-conductive screw fasteners. (note: on my particular units I verified I could use metal machine screws without risk based on PCB design of both units, but I still used plastic washers to isolate the lock washer and nut for each screw from the bottom side of the PCB's lands.)
Whatever method you use, occasionally check that the mounting base is still securely held tight by the fasteners.
Note: both units I have are the 180W units with the massive vertical heatsink with two 92mm fans attached, so the heatsinks weigh a lot more AND have a higher moment-arm from the top of the heatsink to the base which can add significantly more force to the mount than the 150W unit with it's low-profile single-fan heatsink.
Good information thanks!!!!
how accurate is the internal resistance measurements if you have one of those meters to compare it to
No current, no voltage drop. If it shows less voltage w/o current it's just a wrong measurement.
Hi great video but am i missing how to do cut off voltage !,Having problem setting mine
Nice!!
Hi !! Have you tried connecting a constant current source? like those used to feed LEDs, with mine I could not do it, only with resistive load. Sorry for errors in the translation, my language is Spanish.
Since it has no preset max current draw, it should have a fuse to avoid calamities. You do not want to draw max current, close to a short, because of setting the dials the wrong way by mistake. On the other hand, a fuse, let's say 20 A, will not protect any gear only capable of delivering lower current values. So I am not sure what think about this.
Well I made the mistake of buying one a wile back and really had it stuck to me. I paid like $80.00 or 85.00 for the one I got. Another mistake I made was getting it for testing 18650 batters. A power wall person suggested it and boy what a bad mistake that was also. I set it so it will stop at 3 volts low side and all it does is pop up (3 volts?) the whole time when in use. It can be used if you don't mind having to scroll through fast enough to see what's going on with the other settings. Even if I had gotten a better price it is worthless for testing batters.
If you serious want to test 18650 (eg. other type battery cells) go for this: www.ebay.com/itm/QC2-0-3-0-MTK-PE-Trigger-35W-20V-EBD-USB-Tester-Current-Load-Battery-Capacity-I/173129018123?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
So, what actually uses the current in these? Is there a heating element that's fed via PWM or something?
The energy is dumped into a power MOSFET. The MOSFET can IN THEORY handle 300W at 25C with the proper heatsinking to keep junction temperature requirements in check. With the high-profile 2-fan heatsink that's limited to about 180W, and with the low-profile 1-fan heatsink that's limited to about 150W. It's possible with higher airflow-volume fans and/or a different heatsink, and/or a superior thermal compound you could obtain higher power operation. Could likely get quite a bit higher Watts with a water-cooled system...I don't know what kind of software protection is built-into the firmware IF ANY that might put additional limits on maximum power dissipation.
The MOSFET is underneath the heatsink. DO NOT REMOVE THE HEATSINK unless you know what you're doing.
I just needed 10 seconds to hit the "like" button.
Good video and was to give a thumbs up and subscribe but I see he has never replied to any of the questions from the comments section,time to move on to someone else more active.
I have LTO Lithium batteries 40ah cells resting voltage is at 2.9 I need to discharge to 2.4 will this device work
From what I've seen, I believe it will. There are cheaper alternatives if ALL you want to do is discharge a 2.9Vnom cell with auto-cut-off at 2.4V.
I discharged a LiPo cell charged to 3.20V with a cut-off V setpoint=2.40V and it took it down to 2.70V WITHOUT shutting down the discharge process (I didn't want to damage the cell in test so I manually terminated at that point.)
However, the tester did let me set the cut-off voltage (I call it Vcutoff or Vterm or Vt) to 2.40V and everything else worked as expected so I see no reason it wouldn't work for you and cut-off at below 2.40V as one would expect.
However, please read my comment above in this same video at:
th-cam.com/video/ed9iEQlH5t4/w-d-xo.html&lc=UgwMnO_kKMcJVbJn0LJ4AaABAg.90G32s73b9G96pRHzwBjnT
for more information on my experiences with this unit (or a comparable one as there are different versions out there). As best I can tell mine is very close in appearance in every way to xraytonyb's in this video except mine is the 180W heatsinked unit.
Yeah...I know Bigkato's question was a year old, but someone else might be interested with the various different voltage cells that are out there.
Check out the dummy load made by “five fish audio”. They are located near me… I think he’s in Nashville somewhere. The pcb is available on his website and eBay, and you have to assemble it as a kit. From everything I’ve seen and from the board I got, top quality, great design, and will make an incredibly good device. I’ll be putting it in an old fluke Benchtop multimeter enclosure… looks like it will make a really high-quality load. Thanks for the video. The ones for me but I do seem very good for the money.
I think US$23 is a bit steep for JUST the PCB.
The detailed and Digi-key auto-ordering parts list is great but that's still added cost to the project. I input the inquiry to Digi-key and there are two parts that are "in error" (obsolete, an IC and an LED) so you have to find an equivalent part) and the order won't process unless those items are removed from the auto-order. In addition, Digikey wants 2x $7= $14 for the MOSFETs alone. That's quite pricey...and I like Digi-Key.
As far as I can tell his board doesn't have a built-in display. You need to use external equipment to read the data and provide your own power supply, so that's even more cost.
But one can buy this decent 180W unit fully tested and assembled for about US$40-$45 on eBay, including power supply, and a couple test leads. Less than $40 if you're willing to wait for shipment from China. Seems a more logical choice.
I was quite shocked that mine arrived from China only 8 days after the order. The order was placed March 19.
If I need more than 180W I can change the MOSFET and the cooling on a cheaper 150W unit for fairly little money and perhaps an hour of work, and probably easily increase it to have over 200W of power handling...if the firmware allows it. Otherwise, I'd have to hack that bit.
Send me the link for that PCB .
And for this 180w I can modefid the mosfet to reach 300w / 25a .
But I think I can do more modefication to reach 400W
got it for less than 30 boxes from ali ...
Please put a search link
worked 4 u, junk 4 me
Is this unit still alive? sometimes i wonder how long these units last.
Still works, but I don't use it a lot. The user interface is a bit clunky to navugate.
Hi, I just bought one but I can't set the amps. It's always at maximum no matter where the knobs are set. If I press the button 7 times it shows 0 A and the fan stops but it keeps drawing current. Do you have any idea of what's wrong? Thank you.
I have just bought one and the same problem. Could you solve it?
@@yelsing1 I had to replace the main MOSFET, the original was shorted, that's why it was always on.
@@NelioSmix Thanks for your help. I will desolder the MOSFET just to make sure it is damaged.
Hello friend I buy 1 if that, last night I empty 5 pcs 14v lifepo4 battery pack, works very well, but when I plug it out and thus morning plug it again, device will turn on but when I connect any cell or battery, shows voltage of it but not work volume controls and current not change from zero and also cooling fan not work, do you know what's problem of it?
yes the MOS is broken, it happened to me yesterday, so i changed for another one (irfc 640), 'till waiting for the right spare part
Hello, my Load Tester nothing happens, I turn the potentiometers and nothing.
I've already changed Mosfet 2 times, nothing happens.
Can you tell what might be happening?
You need to see and test the voltage across the mosfet drain and source .
And you need to check the gate voltage too .
And test the 2. SMD transistors rectifier beside the mosfet .
Try to do a reverse engineering electronic test item's.
For me to fix this stuff is easy cake
I never see anybody test these with micro USB or USB-C... Can this even test USB-C QC or PD power supplies??
The 1-page spec sheet that came with the unit says it does...sort of.
Unfortunately, it looks like the ONLY Quick Charge test is on the standard-sized USB connector to the left of the coaxial connector (spec says="by qualcomm quick charge QC2.0/3.0 trigger, etc"). To test USB-C quick charge or other type it looks like one needs an special adapter for that connector.
While it has C, micro, and mini USB connectors, the 1-page spec does NOT explicity show them supporting Quick Charge of any kind.
didn't work for me. I can not set the current. Always draining max current possible
me too, always full load, cant put less
Most interested is what must I do to destroy this thing. Because to evoid it!
LOL, The Chines sure do like screwing with us. I figured out the Low Voltage Cut Off . DAMN, A lot of rig o ma roe that is. If you miss your mark you get the Reset the thing and I'm still not quite sure how I do it but I can do it. The Two Quick Press to increment the values works strait away . Not So if you wait too long. You have to have your chit together witch I don't. LOL Took me 30 minutes to set up to test some A123 cells . Limit discharge to 2.0V and what not. Sure would have been nice if they just had a damn Increment button ?
Put it twice and goes in One Direction click it three times it goes in the other direction and if you hold it it just Scrolls so you don't have to reset it which I did the first time but not the second time
...and wifey can use it to dry her finger nails.
Low-Voltage cut-off issue?
KainkaLabs in the video at th-cam.com/video/KcGBHZEOt5s/w-d-xo.html claims there is no Minimum voltage cut-off and he had to add a custom circuit to what appears to be the same product in order to get the device to stop drawing power from for instance a battery when the battery's voltage dropped below a specific value. He claims this is to keep the device from draining the battery once it dropped below a voltage he sets on his special added circuit (his circuit provides 3 discrete cut-off choices at 1V, 2V, and 10V).
But, you seem to say that the device already has a minimum voltage setpoint (you call it a "trip-point") function and will stop draining a connected battery when it falls below your entered minimum voltage trip-point.
The text at the bottom of the video claims both Min and Max setpoints are available for volts, amps, and watts...or, am I misunderstanding what you said and showed on the display at 10:24?
Also, is there a link to an online copy of the user manual/pamphlet you can point us to to help clarify this issue?
My entire reason for getting something like this product is to be able to automatically test batteries without having to worry about over-discharging them during a test.
I would have to check to be sure, but I think there were several versions of this unit for sale out there. The biggest problem I have with this unit is that it is a pain to program, with all the multiple button -push menus and such. I think I might have a PDF version of the instructions. If you e-mail me, I'll try to send you a copy. Thanks for watching!
The units I received both accepted setting a low-cutoff voltage.
Example, it defaults to