Tesota
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Not too bad, there's a 140mm fan underneath the resistors to provide some forced airflow and the whole thing is mounted to a much larger rack that sinks a good bit of heat as well.
Anybody knows about electronic loads?
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- Thread starter
- #22
Well, I bit the bullet a bit back and bought an electronic load, primarily to test batteries and solar panels. After some debate, I decided to go inexpensive and more bare bones rather than more comprehensive since I wasn't going to do fancy dynamic testing of power supplies and the like. Read a bunch of reviews and settled on the Kunkin KP184 which had some good reviews, and was relatively inexpensive ($200) for the size (400W). It does not have a bunch of the features that better chinese units like the Rigols and Siglents have, and of course like lab-grade US brands. And notably does not have OEM software to run it remotely (but the hardware is set up for that, so there are ways around). It does have remote voltage sensing for 4-wires testing, which is critical IMO. And the measured values seem very good.
So far, it has worked very well. The main drawback I see is the user interface which is really bad, just 3 lines of LCD menu shortcuts on the display that are basically unreadable and incomprehensible without the manual. I knew that going in and I can live with it.
Now, as to usefulness, so far I am very glad I have one of those things. For example, I just bought 2 clone 18V batteries for my Makita tools, hoping for the best (against my better judgement). Well, I tested them on receipt and they proved dreadfully bad, so returned them right away. That alone saved me 1/4 of the cost of the unit. Another time, I had to decide what battery to return to Costco for core fee. I had several, so I was able to figure out the worst one and turned that one in and kept the good ones. Yet, again, bought some inexpensive 12V 100Ah LFP batteries and was able to confirm right away that they met the stated specs so I happily kept them. Another time, I wanted to check if a solar panel I have is losing its oomph. So I quickly did an IV curve for it, the load worked great for that too, and sure enough the panel is on its way out. Good to know. I have even tested 18650s with it.
So, a nice added tool to my arsenal, I think! YMMV.
So far, it has worked very well. The main drawback I see is the user interface which is really bad, just 3 lines of LCD menu shortcuts on the display that are basically unreadable and incomprehensible without the manual. I knew that going in and I can live with it.
Now, as to usefulness, so far I am very glad I have one of those things. For example, I just bought 2 clone 18V batteries for my Makita tools, hoping for the best (against my better judgement). Well, I tested them on receipt and they proved dreadfully bad, so returned them right away. That alone saved me 1/4 of the cost of the unit. Another time, I had to decide what battery to return to Costco for core fee. I had several, so I was able to figure out the worst one and turned that one in and kept the good ones. Yet, again, bought some inexpensive 12V 100Ah LFP batteries and was able to confirm right away that they met the stated specs so I happily kept them. Another time, I wanted to check if a solar panel I have is losing its oomph. So I quickly did an IV curve for it, the load worked great for that too, and sure enough the panel is on its way out. Good to know. I have even tested 18650s with it.
So, a nice added tool to my arsenal, I think! YMMV.
ntsqd
technerd
So can I order one of those 100AH LFP batteries thru you so that I KNOW that it's good?
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We use Ecoworthy 100AH lifepo4 batteries where I work (as well as the 50AH units) and have discharged fully and recharged and discharged and.... And they provide rated capacity +/- a couple of AH. They are field installed and sit in hot CA central valley conditions (that also get pretty cold in winter - well, not this winter...) and perform well.
I have one installed now for about 8 months in my 80 series with a 25A DC DC charger (with lifepo4 profile).
Pretty decent batteries. Their new series also have Bluetooth now, that can be used to read various info wirelessly.
How they do over the long haul we'll find out, but so far (1.5yrs +) they are working well with solar and above CA conditions.
cheers,
george.
I have one installed now for about 8 months in my 80 series with a 25A DC DC charger (with lifepo4 profile).
Pretty decent batteries. Their new series also have Bluetooth now, that can be used to read various info wirelessly.
How they do over the long haul we'll find out, but so far (1.5yrs +) they are working well with solar and above CA conditions.
cheers,
george.
8-1/2 years so far since purchasing a 200Ah LFP drop in style battery from ElectricCarParts...and it just keeps on working. Haven't load tested it so no clue on that spec. Originally it was in my then TrailTailor trailer but its been in the bed of my Silverado since 2017. Its been in single F digit temps for a few days/nights every winter and over 110F on numerous summer days up here. FYI/FWIW/4Grins.
- Thread starter
- #26
Ironically enough, I used to do capacity testing with a bank of incandescent light bulbs I put together. Well, turns out that thanks to the great state of California, I can no longer get bulbs to replace any bad ones, or at least not locally. So much for that. Yea! (And not many small engines any more either....)
NT, the one I just tested is a Cyclenbatt Mini. Rated at 100Ah. I measured 102 at a moderate current. Consistent with some tests I saw on YT.
NT, the one I just tested is a Cyclenbatt Mini. Rated at 100Ah. I measured 102 at a moderate current. Consistent with some tests I saw on YT.
ntsqd
technerd
Grandad had a similar load tester built into his shop. He could switch each load/light-bulb individually. The highest wattage was actually a heating coil on a ceramic cone shaped holder that screwed in like a light-bulb.
Which gives me an idea, can buy Ni-Chro wire & ribbon. Work uses it to build our load testing banks. I've yet to see an electronic tester that can handle 5 MW......
Which gives me an idea, can buy Ni-Chro wire & ribbon. Work uses it to build our load testing banks. I've yet to see an electronic tester that can handle 5 MW......
- Thread starter
- #28
I had been using some Nichrome wires occasionally too, but not too keen on starting a fire in the shop, so not using those much any more.
OTOH, easy enough to use an inverter and some electronics or appliance too as a load if the voltages are suitable. Like a fan or something. Put that power to good use!
I will say, though, that one great benefit of the electronic load IMO is that I can program it and walk away. It shuts down and records the numbers automatically. Whereas with the light bulbs bank, I always had to schedule the timing of the tests so they would not end during the night or when I'm busy when the low voltage was reached. And I had to go check periodically in order to stop at the right time. And, of course, some of the time I had no idea how long it would take. That was a pain...
OTOH, easy enough to use an inverter and some electronics or appliance too as a load if the voltages are suitable. Like a fan or something. Put that power to good use!
I will say, though, that one great benefit of the electronic load IMO is that I can program it and walk away. It shuts down and records the numbers automatically. Whereas with the light bulbs bank, I always had to schedule the timing of the tests so they would not end during the night or when I'm busy when the low voltage was reached. And I had to go check periodically in order to stop at the right time. And, of course, some of the time I had no idea how long it would take. That was a pain...
The filament of a light bulb is a terrible load resistor.
1 it burns out
2 the resistance (cold) of the filament is not uniform sample to sample
3 the hot resistance is drastically different than the cold resistance.
A better choice would be load resistors ordered from MOuser for the purpose.
You could then set up a microcontroller to do the calculations and the assumptions it would need to make would be accurate because you used resistors of known value vs a light bulb, which is a moving target.
Capice?
ntsqd
technerd
For what grandad used the light-bulbs for they worked fine.
- Thread starter
- #31
(Regarding ^^, I also can't help but note that the resistance of all resistors change with temperature, not just light bulb filaments. And don't get me started on how nominally identical resistors actually show different resistances if you look close enough. That is one more reason why you need a feedback loop control to keep things really constant when needed.)
One issue with the light bank was that as the battery voltage decreases the current decreases too. And therefore the resistance varies as well. So no fixed electrical parameter at all. Frustrating for us nerds. But, yes, it worked well enough for rough capacity testing, at least on a relative basis.
That's one reason the electronic load gives me the fuzzies, cuz i can see the current holding steady within 1 mA (per the display at least). Makes life all good again!
One issue with the light bank was that as the battery voltage decreases the current decreases too. And therefore the resistance varies as well. So no fixed electrical parameter at all. Frustrating for us nerds. But, yes, it worked well enough for rough capacity testing, at least on a relative basis.
That's one reason the electronic load gives me the fuzzies, cuz i can see the current holding steady within 1 mA (per the display at least). Makes life all good again!
I've bought two old Dynaloads off eBay. My current one is a DLVP 300-50-3000, I think. 300 Amp, 3000W.
I only really use the fixed amperage mode, but it has pulse modes and stuff.
I was doing data logging via the Agilent multimeter app and Bluetooth adaptors for their multimeters.
My Dynaload was surplus from a L3 Harris owned aircraft power supply testing rack based on the labels that were on it.
