# Kelly DC-DC converter glitch



## jondoh (Sep 8, 2008)

I had a similar situation where the lights would dim and the radio would momentarily turn off when the vacuum pump started. I put in a capacitor used for car audio systems. They're about 2 farad. It mostly solved the problem but the lights still dim a little.


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## BradQuick (May 10, 2008)

Great. Thanks for the info. I'll see if I can find one today.

- Brad


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## Tesseract (Sep 27, 2008)

BradQuick said:


> Great. Thanks for the info. I'll see if I can find one today.
> 
> - Brad


Going out on a limb, here, but I'm guessing the cost of a 2F cap + the Kelly DC-DC converter, is more expensive than simply buying a _good_ converter. Why throw good money after bad, here?

Get an Iota and quit screwing around with the Kelly.

http://www.iotaengineering.com/dls30.htm


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## BradQuick (May 10, 2008)

First of all, I already have the Kelly, so subtract that from your equation. 

Radio Shack sells a 1 F capacitor for less than $5 and I can probably get a scrap one from my dad who has collected years of electronic parts for free.

Other than the slow response to sudden increases in load, the Kelly is working fine.

- Brad


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## Tesseract (Sep 27, 2008)

BradQuick said:


> ...
> Radio Shack sells a 1 F capacitor for less than $5 and I can probably get a scrap one from my dad who has collected years of electronic parts for free.


Hmmm... I stand corrected - just found it on their site.


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## Guest (Sep 13, 2009)

My Kelly DC DC seems to be working just fine even with the headlights on. Largest voltage drop was from 13.5 volts to 12.9 when all my components are operating. With just the headlights it is 13.1 volts. My DC is a 25 amp model. Works fine and is isolated. Are your DC DC from Kelly the older models?

Pete


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## BradQuick (May 10, 2008)

No, mine is fairly new. The voltage only seems to dip briefly when a load is applied.

- Brad


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## Guest (Sep 13, 2009)

Then why worry. Your voltage dips when you apply your throttle too but we all know batteries will dip when a load is applied. Mine dips too. So do all the others. 

It is a minor voltage. If it really affects your system then just go get a better one. I like mine. Works like a charm even with it's tiny voltage drop. Works far better than just a 12 volt battery. 

I have no way to install an alternator. I do not have a dual shaft motor. 

Pete


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## BradQuick (May 10, 2008)

The problem is that the voltage dips low enough to affect the throttle and the car lurches.

I ordered a capacitor off of ebay. We'll see what that does for me.

- Brad


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## TheSGC (Nov 15, 2007)

Do you still have a car battery to help with the loads?

I have a Curtis 1400E DC/DC that is 20 AMPs, but I also left my old car battery in there to help the loads when the lights were on and the brake pump kicked it. I actually tried it without the DC/DC but the voltage go low enough that my Contactor shut off at one point, so I added the DC/DC to keep the battery up and so far so good.


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## tj4fa (May 25, 2008)

What model DC-DC controller do you have? Is the voltage output user adjustable? 

If so, couldn't you just adjust the output another .5V or so?


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## BradQuick (May 10, 2008)

The converter has a 13.8V output.

I hooked up my .5f capacitor that I got off of ebay. The one I got is made by Monster Cables.

It works great! No more glitches when I turn the headlights on.

Thanks for the brilliant help, guys.

- Brad


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## brainzel (Jun 15, 2009)

I got a Melcher K2000 DC/DC converter with a printed output voltage of 12 Volts. (2 outputchannels with 6A each channel) I haven't measured the voltage so far (five batteries left to install).
Should I put the converter directly parallel to the onboardbattery?
Will this configuration charge the battery or is it just an assistance to it and I still have to charge the battery separately?


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## tj4fa (May 25, 2008)

brainzel said:


> I got a Melcher K2000 DC/DC converter with a printed output voltage of 12 Volts. (2 outputchannels with 6A each channel) I haven't measured the voltage so far (five batteries left to install).
> Should I put the converter directly parallel to the onboardbattery?
> Will this configuration charge the battery or is it just an assistance to it and I still have to charge the battery separately?


Your product manual:

http://server.oersted.dtu.dk/ftp/database/Data_CDs/Component_data/Melcher_Power_Supplies_1996/dat/inha/inha_11.pdf

I don't have a Melcher unit but I have my Astrodyne DC/DC connected in parallel across the entire battery pack for the high voltage input to the converter. In my case that is >144V.

I have it wired through relays that when the Key-Switch (Ignition) KSI is energized, the high voltage from the battery pack goes through the converter and then the converter puts out the low voltage to both the vehicle 12V system and recharges the accessory battery at the same time.

My DC/DC has an adjustable output that I currently have set to about 13.8V to do the battery charging and run the rest of the vehicle's 12V system components.

The accessory battery provides the initial 12V required to activate the primary contactor, and once it closes, the accessory battery is there for emergency in case the DC/DC converter fails and perhaps provides extra back-up if the voltage from the DC/DC dips down under heavy loads.

Because I have it connected through relays, the accessory battery is not charged during vehicle main pack charging so that the accessory battery does not mess with the charger algorhythm set for the main battery pack. The converter is also not "on" when the vehicle ignition switch is off.

Hope this helps some.


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## brainzel (Jun 15, 2009)

Thank you so far. I have to read the manual you gave to me precisely, but it seems that I can't adjust the outgoing voltage :-/


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## BradQuick (May 10, 2008)

I don't have an accessory battery. My DC-DC converter runs all the time unless I turn off an emergency cutoff switch in the driver's compartment. I put the capacitor directly on the output of the DC-DC converter, so it's also always charged. 

The only thing I'm lacking is backup power in the case that my converter fails. Otherwise, it works great as it is.

- Brad


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## Guest (Oct 16, 2009)

I'm testing DC-DC converters right now. I'm guessing the comment about going to an IOTA was a joke. We've played with two of these and they are simply junk. 

On the low cost end I like the Sure Power 71030i and the Kelly HZ series. The Sure Power is used on the GEM and the Zenn and a couple of others. It regulates quite well. It's rated at 30 amps and very good for low voltage systems. IT's nominally 96 v but will go 130 and down as low as 56 volts. We got ours for $211.

The one problem with the Sure Power is that it craters at 35 amps. Hard to fault it when the spec reads 30 amps.

But the Kelly HZ is outstanding. Very good voltage regulation and we tested it to 38 amps without a hiccup. IT's rated at 25 amp. 38 amps is the most I can test right now in a constant current load at these voltages. Ours cost $149. It's very small. Comes with an inline fuse and confusing color coding.

The IOTA drops below 12vdc at about 15 amps with ANY DC input, including 120 vdc. At the rated 55 amps, it's about 8 vdc. This is useless for any purpose I can think of. So if you want to quit fooling around and get a REAL DC-DC converter, avoid this one with all due haste. It's not sealed, the components are bare, and it may not even be isolated as best I can tell. We tried one in the Speedster and it just didn't do anything worthwhile.

I like the idea of a bare converter. But the affordable ones seem to be in this 25-30 amp range. Most cars today have a 75 or 90 amp alternator. I have bult a 120 amp converter out of Vicor bricks from eBay for the Mini, and it works pretty well but was kind of expensive by the time I put it all on a heat sink etc.

A small motorcycle battery can do 200-300 amp surges. These little 25 amp converters have no difficulty keeping them charged (as long as they will maintain 13 volts that is), and the batteries are simply cheaper than the converters. A Dekka EXT30L sealed AGM runs about $75. 

The 108 volt we got does NOT like lower voltages - ours craters at 96 volts which is higher than their spec. But their line is kind of voltage specific and you can get them for a bunch of different voltages. You didn't mention which Kelly you had, nor what your pack voltage was. But it sounds like you had a low pack voltage input.

Both the Kelly and the SurePower are HALF the size of an Iota, although about the same weight. Both are in finned aluminum enclosures and quite sealed against the weather.

The SurePower has a bit of an advantage for your application. It has both switched and unswitched outputs. So you can wire it up to your pack and route the unswitched to the ignition. Run the ignition back to the ignition input on the SurePower and that will turn on the SWITCHED outputs. It's clearly designed to eliminate the battery altogether. And it's used on GEM's and Zenn's and so forth. It features a very nice finned case. I don't particularly like the Deutsch connector because its a bit of work, but it's also weatherized.

The Kelly comes with an inline fuse and holder. It's very simple to wire, but just has a two wire 13.5 vdc output. Like I said, I ran ours at 38 amps for 10 amp hours and it held 12.84 vdc flawlessly. That's pretty good for a 25 amp rated unit at $149.

Once again, the Chinese version with the CHinglish instructions exceeded the advertised specs, outperformed the American versions, and did so at less cost. And you get them in about a week. This is getting to be a theme. I guess I better get a copy of Rosetta Stone for Mandarin.


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## Overlander23 (Jun 15, 2009)

Any inexpensive options for higher voltage systems (200v)? Is there a way to use two Kelly or Surepower's with inputs ganged in series somehow?


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## Tesseract (Sep 27, 2008)

jrickard said:


> I'm testing DC-DC converters right now. I'm guessing the comment about going to an IOTA was a joke. We've played with two of these and they are simply junk.
> ....
> The IOTA drops below 12vdc at about 15 amps with ANY DC input, including 120 vdc. At the rated 55 amps, it's about 8 vdc. This is useless for any purpose I can think of. ...


Well, we've had exactly the opposite experience as you, so no, my comment about going with IOTA, at least, wasn't a "joke". 

You seem to either not realize, or else have forgotten, that the IOTAs are line-operated battery chargers, not "dc-dc converters", per se and so the input voltage range spec of 108-132V is for RMS AC volts, not DC volts. To convert full wave rectified DC back to sinusoidal AC multiply by 0.707. Thus, when you tried to power the converter with 120VDC that was the equivalent of the AC line being at 85VAC. Gee, no wonder they didn't work so well for you .


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## Otmar (Dec 4, 2008)

Thanks Jack for the test results. I sure appreciate the reporting that you provide the EV community. 

My favorite test for converters is to load them at current limit (say, with a load that holds the output down to 12V or so) and then adjust the input voltage to determine the useful input voltage range. It's good to keep in mind that maximum power comes from a battery at just over 1/2 of nominal voltage rating and this mean that most of us rely on a backup 12V battery if we are severely pushing the power limits of batteries. 

I suspect you may have had a bad Iota, and also at 120 VDC you are well below the low end of its rating. Since it is rated 108-132 VAC you should not expect full power below 1.4 times that the minimum. This since the converter normally harvests the peak of the AC waveform and the 108V rating is RMS. So 151 VDC is the true minimum but I am pretty sure it will put out full power well below that. Beware about taking it above 180V though since I suspect it has 180V capacitors in the input. I usually only use the 120V IOTA in 144V systems.

I'm sorry that I have lost the test data I had on a 220V IOTA converter. I know it ran full power down to about 170V and then dropped off gracefully to 140V input or so. I have never had anything but good luck with them. 

As to the Kelly putting out 38 Amps I'd be very afraid! If it's built for 25 Amps as it's rated then it will blow if you run it at 38A for long. The efficiency curve seems to indicate that it is not built for the higher current that you ran it at. The current limit is the most important part of such a device and I'd test it for at least half an hour at full load (as limited by the current limit) to insure that it protects itself from overheating before I put it in any car. If it does survive several full load runs and does not get too hot to touch then there is a chance that it really is overbuilt and that would be great. From what I've seen inside other Kelly products I would not hold my breath. 

Thanks again for the research,
________
drug test kit


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## Guest (Oct 25, 2009)

Otmar:

I like the same test. And in fact ran it first. I've found myself repeatedly painted into a little lower voltage than is traditional between 100 and 120vdc. This is too high for the 72 vdc solutions and not quite there for the more traditional 144 vdc. So the input range IS the issue for me generally.

My mark is Vicor for DC-DC converters. I just don't see the output curve you reference. They'll do full power at the top of the range, and full power at the bottom of the range as well. There's a point at which they simply shut down on both ends. But no particularly discernable "curve" here within the range. And the range is usually just a bit wider than the advertised limits. I don't find any products to exceed Vicor on any point. They're the DC-DC guys, but very proud of their products in a very decimal denominated sense.

I have TWO Iotas. And I've duplicated this test at 150vdc. Anything over about 35 amps the output voltage regulation was just horrible on both - one of them diving to 8.5 vdc at 50 amps. So either I'm part of a bad "batch" or they're just awful. I don't have to really discern the cause. I've taken one apart and looked at it, and it looks like something I might have cobbled together with my shakey hands WITHOUT my nice Weller station. I don't like them.

The two under test did pretty well on the range issue with the Smart having a much wider input range and again no real curve on the output against input voltage. It will put out just as much at 65 volts as it will at 112.

The Kelly was a little more range bound. But it's hard to fault. They have them in unusually small input voltage increments. Pick the right one. Within its range, again, I found no real output curve. But the range was slightly narrower than advertised.

It is true I'm not quite as elegant and carefully measured in my testing as you would normally be. I both admire and envy you that, but it isn't me. Even on my OWN circuits, I normally design them, build them, and test them for what I want them to do. Then I crank it up to 150 or 200% and see if it bursts into flame. Unfortunately, it often does.

And that's what I did here. The Sure Power is rated at 30 amps. The Kelly at 25. The highest I can test with an ACCURATE constant current source right now is about 500 watts and that works out to 38/39 amps. I'm going to order another addon load that will gang me up to 1000 watts but I don't have it yet. I would have preferred to put them at 45 amps for 30 minutes. If one burst into flames at 25 minutes and one simply did an orderly shut down in 15, I would put the latter into the car.

So I'm a little more ham handed on the testing. But as a result of a phase out of Halogen allowed in my hangar, I've wound up with some GREAT but obsolete fire extinguishers here in the garage. (Somebody told me you fly?) So slam it. If it doesn't burst into flames, we'll put it on a car.

You're quite correct, the Iota runs cool. But it won't do the voltage. And part of the cool is it's wide open. I can spill a cup of coffee on this thing and kill it.

The Sure Power advertises 30 amps and does 30 amps at full load for a half hour. It gets hot. But it does it. I can do 35 but after a few minutes it goes into a wierd collapse/recover/collapse/recover oscillation that's a little frightening to watch.

The Kelly ran about 30 minutes at 38 amps. It got quite hot. And it kept pumping power. And it kept the voltage rock solid. 

In a car, there's actually some stuff I can do with mounting plates and air stream locations if I need to and know about it.

There's some kind of big bias in the community against Kelly that I don't understand. I've used their controllers. I've gotten quick replies to support questions. And their stuff seems to work - normally in excess of their claims. I hear you. But I cannot connect with what I've seen with my own eyes with these products. 

It's true, I may not be testing them correctly. But I am intentionally abusing them and they seem to hold up. And I have to tell you that if I do have a talent it is in breaking things. It's just a gift is the only way I can explain it. God saw fit to bless me with an uncanny ability to start fires and as my Chinglish friends note "cause rapid disassembly to avoid".

I would really like to be able to disseminate this type of information, the questions I've had to struggle with, to those wishing to do these conversions. But I don't have a religion as to methodology. I'll grab any adult supervision I can beg or steal on any topic.

My ambitions in this area know no bounds, and unfortunately likewise my needs. I've been struggling this week with a kind of shocking concept that I would be very interested in. And that is in testing electric motor and controller combinations. I talked with the main guys in the field, who supply to Oak Ridge National Labs, and I was a little set back. An electric motor dynomometer capable of doing about 450 hp and 6000 rpm with an eddy current load would be REAL cool (if I could find space for it) with a bench battery bank. They'd really like about $83,000 for just the dyno/table/plumbing/data out port. And you know, while I like the idea, I'd have to like it a LOT more to spend $83K on it.

Do you guys have any idea, other than trying to build one from dirt like Martha Stewart, on how to put together such a system for something more in the $30-$40K range? 

It is a MARVELOUS time to be in this field with very suddenly a LOT of new action in controllers and motors, as well as batteries. But I'm struggling with these performance data that seem to me incomparable - particularly on the motor front. But an accurate load that won't burn down the building would be a big plus....

Jack Rickard
http://evtv.me


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## Guest (Oct 25, 2009)

Tesseract said:


> Well, we've had exactly the opposite experience as you, so no, my comment about going with IOTA, at least, wasn't a "joke".
> 
> You seem to either not realize, or else have forgotten, that the IOTAs are line-operated battery chargers, not "dc-dc converters", per se and so the input voltage range spec of 108-132V is for RMS AC volts, not DC volts. To convert full wave rectified DC back to sinusoidal AC multiply by 0.707. Thus, when you tried to power the converter with 120VDC that was the equivalent of the AC line being at 85VAC. Gee, no wonder they didn't work so well for you .



YOU seem to be pretty full of yourself. What I might realize or have forgotten is pretty ad hominom and pretty much my business. They ADVERTISE the thing at a DC input voltage range, and it won't do the duty. I don't have to do an idiotic RMS calculation. It's printed in the sheet that comes with it.

I know what the thing was originally designed for. But it's being sold by EV suppliers with a DC input voltage range that it won't do. And I have tested them at 150 vdc, and they don't do it there either. I don't BELIEVE you have tested them at all or you wouldn't see it that way, or else we're testing different devices. Whether it's a design shortcoming or a quality control issue disinterests me intensely. THEY'RE JUNK EITHER WAY. Don't put em in a car on purpose. I tested TWO of them, received at different times. And I'm not guessing. I have no interest in 50 amps at 10 or 11 volts. It's worse than useless.

But if I ever DO need to relearn Basic Electronics and Electricity I for Dummies from a real expert, I'll be certain to e-mail you first....

Jack Rickard
http://evtv.me


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## JRP3 (Mar 7, 2008)

jrickard said:


> There's some kind of big bias in the community against Kelly that I don't understand. I've used their controllers. I've gotten quick replies to support questions. And their stuff seems to work - normally in excess of their claims. I hear you. But I cannot connect with what I've seen with my own eyes with these products.


There were a number of problems with their early models and not everyone was happy with their "support". If they've fixed their problems, great, but it seems as if part of the "fix" was simply to de-rate existing products. Maybe that was the proper solution if the only real problem with the units was over ambitious operating specs. 
Your experiences with the Iota's does seem to fly in the face of years of use in the EV community. Maybe most people just pair them with a battery and don't see the effects you describe.


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## Guest (Oct 25, 2009)

Tesseract said:


> Well, we've had exactly the opposite experience as you, so no, my comment about going with IOTA, at least, wasn't a "joke".
> 
> You seem to either not realize, or else have forgotten, that the IOTAs are line-operated battery chargers, not "dc-dc converters", per se and so the input voltage range spec of 108-132V is for RMS AC volts, not DC volts. To convert full wave rectified DC back to sinusoidal AC multiply by 0.707. Thus, when you tried to power the converter with 120VDC that was the equivalent of the AC line being at 85VAC. Gee, no wonder they didn't work so well for you .



I wasn't going to do this, but ok, I'll try once. 120VAC electrical power IS RMS. That IS .707 of the AC peak. It IS equivalent to the DC rectified voltage already. If you want to convert dc to peak AC, I guess to avoid blowing up a cap or something, the value you want is simply the inverted 1.414 x DC for peak AC. But without specifying peak, any reference to AC power normally ASSUMES the RMS value, and that is .707 peak. 

The iota takes advantage of the fact that in applying a DC voltage, you're already there. But it has the advantage of not caring about polarity. You can connect the input at either polarity, and the output will retain the same polarity either way. You certainly don't need 1.414 x 120 to power it, though that's a crude way of estimating the maximum safe DC voltage for the components.

If you're going to offer a course in Basic Electronics and Electricity, you ought to make a sincere effort at becoming familiar with parts of it. There are a lot of people very enthusiastically trying to convert their cars to electric drive that are not afforded the luxury of taking the time to get a graduate degree from Rensselaer Polytechnic before making a decision on a DC-DC converter. This kind of input just muddies the waters hopelessly for those seeking information on forums such as this.

This may sound harsh. I don't mean to. I don't have another way of addressing this without just leaving the misinformation lay to confuse others.



Jack Rickard
http://evtv.me


_*



*_


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## Guest (Oct 25, 2009)

JRP3 said:


> There were a number of problems with their early models and not everyone was happy with their "support". If they've fixed their problems, great, but it seems as if part of the "fix" was simply to de-rate existing products. Maybe that was the proper solution if the only real problem with the units was over ambitious operating specs.
> Your experiences with the Iota's does seem to fly in the face of years of use in the EV community. Maybe most people just pair them with a battery and don't see the effects you describe.



Perhaps. Actually, I WAS paired with a battery and it didn't work. I did order another one and tested it before I put it on the car. I hooked it up to a very NON precision dummy load resistor and it DID do 58 amps - at 8.5 volts. I took the one out of the car and got the same result.

They were laying around when I tested the Kelly and the Sure Power, so I threw them on. They do a little better at 112 vdc than 100 vdc, but the 100v graph tells the tale well enough. At 112 and about 30 amps they go below 12 vdc. So to me, same difference. I want a dependable 12.8 vdc so I don't mess up my battery.

I don't know how to deal with the many years and many users issue. I believe you. I just can't make it work in front of my eyes. I lucked into two bad ones? Ok. What's with the QC? Either way, I have to say save your money.

In MY admittedly crude tests, on MY shamelessly littered and untidy bench, the Iota is not in the same LEAGUE with either of these less expensive units. It doesn't even belong in the comparison, and only showed up there because it was on the shelf at the time.

Testing aside, I wasted over $400 on them and they just didn't do the trick on a car that has all LED bulbs except the headlights, and a stereo. It's not a gadget wagon and really has little load to present to a DC-DC converter.

If you have one and its working for you, don't fix it on my account. If you're shopping for one, go with the Kelly at $149.

Jack Rickard

http://evtv.me


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## JRP3 (Mar 7, 2008)

jrickard said:


> They were laying around when I tested the Kelly and the Sure Power, so I threw them on. They do a little better at 112 vdc than 100 vdc, but the 100v graph tells the tale well enough. At 112 and about 30 amps they go below 12 vdc.


They may perform well enough at 120 and above when paired with a battery that most people don't have problems. I don't doubt what you've observed, just trying to make sense of it in comparison with others.


> If you're shopping for one, go with the Kelly at $149.


Most likely what I will do since I'm running a lower voltage system, 115v, and don't want to buy and test them all out myself. I appreciate you spending the money so I don't have to


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## Otmar (Dec 4, 2008)

jrickard said:


> Otmar
> I like the same test. And in fact ran it first. I've found myself repeatedly painted into a little lower voltage than is traditional between 100 and 120vdc. This is too high for the 72 vdc solutions and not quite there for the more traditional 144 vdc. So the input range IS the issue for me generally.


I think you may be undervaluing that the IOTA runs on the peaks of the AC wave, not the RMS. Therefore it wants to run under 180V but not too low either. But you do say that the paperwork with the unit quoted a DC Range, and you tested it at high voltage as well. I don't see that DC rating in the online installation manual, but I believe that your test was valid and there certainly is a problem. 

When I looked these up I was reminded that IOTA changed the design recently. The ones I used and liked looked like this: 









And the new ones that I have never used look like this: 








Maybe that accounts for our variance in performance since they changed the design.



> My mark is Vicor for DC-DC converters. I just don't see the output curve you reference. They'll do full power at the top of the range, and full power at the bottom of the range as well. There's a point at which they simply shut down on both ends. But no particularly discernable "curve" here within the range. And the range is usually just a bit wider than the advertised limits. I don't find any products to exceed Vicor on any point. They're the DC-DC guys, but very proud of their products in a very decimal denominated sense.


Vicors are certainly of a different class. They have data sheets and actually are expected to meet the spec. You do have to be careful since an industrial DC-DC is usually not a battery charger like we need (unless you are using the Vicor Batt-Mods) and so may not have the protections we expect. The land of low cost EV DC-DC's is a different world. Many people are trying to get away with minimal cost, and the requirements are different. For instance, in a EV it is preferred to have a wider input voltage range even if it means putting out less current at the lower input voltage, while in a industrial DC-DC it is usually preferable that the unit shuts down instead of browning out. EV's must have high temperature cutback while many Vicors just fail if not cooled correctly. 



> The Kelly was a little more range bound. But it's hard to fault. They have them in unusually small input voltage increments. Pick the right one. Within its range, again, I found no real output curve. But the range was slightly narrower than advertised.


Narrower input and output ranges are easier to design for and less expensive. But harder for the distributor to stock. It's all a trade off. 


> It is true I'm not quite as elegant and carefully measured in my testing as you would normally be. I both admire and envy you that, but it isn't me. Even on my OWN circuits, I normally design them, build them, and test them for what I want them to do. Then I crank it up to 150 or 200% and see if it bursts into flame. Unfortunately, it often does.


Oh I do plenty of quick and dirty tests myself. I have some train braking resistors that I got years ago from C&H for $25 each, perfect for high current testing. Documenting and publishing my tests is where I lack. Occasionally I'll spend a couple days on a forum like today, but often I'm not as vocal. Hopefully soon I will have more time to do tests. My Garage Mahal is almost built. 



> You're quite correct, the Iota runs cool. ... I can spill a cup of coffee on this thing and kill it.


No argument there, I have some that got wet in my junk pile. 
True of my Zilla too, don't get it wet. Fortunately only a few have been damaged that way that I know of. 



> Do you guys have any idea, other than trying to build one from dirt like Martha Stewart, on how to put together such a system for something more in the $30-$40K range?


I've been involved with a number of dyno builds, the most famous was Teslas first dyno. You can do expensive and you can do cheap. It's all a question of how much scrounging and work you want to do yourself. I'd probably come in at $2K-$6K if I built one for peak testing our DC motors, and I have been tempted to build another. 
You need some way to measure and record a few temperatures, amps, volts, rpm and torque. Plus a video of the brushes. Do it simple with gauges and mirrors and the video becomes the data recorder. That's what I did on my 240V S-10 truck in the mid 1990s. Simple cheap and effective. 
Beyond that you need an adjustable load. This could be a heavy vehicle (so values change slowly) the http://www.gtechpro.com/ calculates HP from acceleration, or some disk brakes running red hot, or a water brake etc. Just beware that unlike ICEs the EV's want to be loaded with full torque at very low rpm. 


> It is a MARVELOUS time to be in this field with very suddenly a LOT of new action in controllers and motors, as well as batteries. But I'm struggling with these performance data that seem to me incomparable - particularly on the motor front. But an accurate load that won't burn down the building would be a big plus....
> 
> Jack Rickard
> http://evtv.me


Agreed, it's a great time. I've been waiting for lithium for so many years, I read a 1981 article that claimed we'd have LiPo cells in a few years. Now lithium is the key to huge potentials and it makes building the support components all the better.


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## kittydog42 (Sep 18, 2007)

I am also a fan of using the Iota DLS series of battery chargers as DC/DC converters. I use the DLS-55. They are inexpensive and consistently work the best. I have had the same luck with both the new and old models, installing or selling at least 10 without any problems. I don't like the fact that they are so susceptible to water damage, but I take that into account when I locate it. If they were water resistant or built to be installed in an EV, they would cost a lot more. I tried using Astrodyne SD series DC/DC converters a few times, and they work great standalone, but they did not work well for me with an accessory battery installed in parallel with the output. They shutdown on overload, but will reset when the input power is cycled. I am guessing that this is because they are not true battery chargers. I have not tried the Kelly or Sure Power, but it is good to know that they may be a viable option if I can work with a 25A or 30A output. How do they work with an accessory battery installed?


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## major (Apr 4, 2008)

jrickard said:


> 120VAC electrical power IS RMS. That IS .707 of the AC peak. It IS equivalent to the DC rectified voltage already.





Tesseract said:


> so the input voltage range spec of 108-132V is for RMS AC volts, not DC volts. To convert full wave rectified DC back to sinusoidal AC multiply by 0.707. Thus, when you tried to power the converter with 120VDC that was the equivalent of the AC line being at 85VAC.





Otmar said:


> at 120 VDC you are well below the low end of its rating. Since it is rated 108-132 VAC you should not expect full power below 1.4 times that the minimum. This since the converter normally harvests the peak of the AC waveform and the 108V rating is RMS. So 151 VDC is the true minimum


Hmmm,

Score is 2 to 1.


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## Guest (Oct 26, 2009)

major said:


> Hmmm,
> 
> Score is 2 to 1.



Yes, and that seems to be how these forums operate, by ballot.....

Here's the data included with the unit, the ONLY documentation it came with.

Electric Vehicle use with the 120 volt AC input DLS battery chargers.
Many EV (electric vehicle) owners have been looking for a way to charge 12 volt DC batteries from their high voltage vehicle battery bank as well as to power 12 volt DC loads.
The following is from IOTA Engineering regarding using the DLS battery chargers from a high voltage direct current source.
From: Jeff Young [mailto:[email protected]] Sent: Wednesday, January 17, 2007 2:26 PM Subject: Re: question [DC operation of DLS units]
The DLS-45 and DLS-55 will not produce full output power with less than 130Vdc on the input and will be limited to an output voltage of 13.6VDC; an increase of the input voltage (to 136VDC) would be required to attain full output power with the DV (dual voltage) jack installed. The DLS-45 and DLS-55 will operate at less than 130VDC, but at a limited capability. At 96VDC, the output will remain in regulation up to ~1⁄2 ADC. Above ~1⁄2 ADC load, the output voltage will decrease linearly until the load current reaches ~1ADC (Vout = ~10VDC). Above 1ADC, the output should maintain an output voltage of 9 -10VDC. The DLS-30 (Series M) also has limited operation at lower input voltages. At 96VDC, the Series M can sustain normal float voltages out to ~20ADC. Above 20ADC, the output voltage decreases linearly to ~10VDC at 30A output.
Jeff Young - Power Products Engineer
[email protected]
IOTA Engineering, L.L.C. Tel - 520-294-3292 Fax - 520-573-2934
In a later correspondence, 1/24/07, John Kehm specified that the highest DC input voltage for the DLS-30M, DLS-45 and DLS-55 is 190VDC.
IOTA DOES NOT RECOMMEND SERIES CONNECTION OF EITHER INPUTS OR OUTPUTS OF THE DLS SERIES POWER SUPPLIES.
Paralleling inputs and outputs is acceptable.


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## Guest (Oct 26, 2009)

Here is a link to the perhaps more readable PDF

http://www.evsource.com/datasheets/iota/IOTA_DC_operation_120VAC_unit.pdf


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## major (Apr 4, 2008)

jrickard said:


> Here's the data included with the unit, the ONLY documentation it came with.
> 
> The DLS-45 and DLS-55 will not produce full output power with less than 130Vdc on the input .....The DLS-45 and DLS-55 will operate at less than 130VDC, but at a limited capability. At 96VDC, the output will remain in regulation up to ~1⁄2 ADC. Above ~1⁄2 ADC load, the output voltage will decrease linearly until the load current reaches ~1ADC (Vout = ~10VDC). Above 1ADC, the output should maintain an output voltage of 9 -10VDC.


Hi jrickard,

It looks like to me that your test pretty much confirmed what they told you. Thanks for clearing that up.

And I do appreciate your testing of products and posting results. But please don't take it personally if some question those tests, results or conclusions. That is the nature of science, isn't it?

The way I see these forums is that people post opinions. Those that read the opinions can choose to take them on face value, check them out further, challenge them or simply dismiss them. This is just exchange of ideas and nothing personal.

Keep the ideas coming.

major


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## Otmar (Dec 4, 2008)

major said:


> Hmmm,
> 
> Score is 2 to 1.


No need to rub it in. 
We're all on the steep part of the learning curve here. This stuff is not simple until you already know it.


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## brainzel (Jun 15, 2009)

major said:


> The way I see these forums is that people post opinions. Those that read the opinions can choose to take them on face value, check them out further, challenge them or simply dismiss them. This is just exchange of ideas and nothing personal.


Sometimes I wish there were more people (like jack) out there who make it easyer to distinguish between there opinion and there established experience.
That could save me some money ;-)

A constructional discussion is the base of every forum i think.
So carry on


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## Tesseract (Sep 27, 2008)

jrickard said:


> The IOTA drops below 12vdc at about 15 amps with ANY DC input, including 120 vdc.


Just for reference I'm including your original faux pas.




jrickard said:


> I wasn't going to do this, but ok, I'll try once. 120VAC electrical power IS RMS. That IS .707 of the AC peak. It IS equivalent to the DC rectified voltage already. If you want to convert dc to peak AC, I guess to avoid blowing up a cap or something, the value you want is simply the inverted 1.414 x DC for peak AC. *But without specifying peak, any reference to AC power normally ASSUMES the RMS value, and that is .707 peak.*


The text in bold is correct; the rest is not.

If you HALF WAVE rectify AC _then_ the output voltage will be approximately equal to the input RMS value, but no one half-wave rectifies the AC line unless they are powering an LED or something.

The more common process of FULL WAVE rectification results in an output voltage that is ~1.414x higher than the stated/measured RMS value. Thus, 120VAC becomes ~165VDC (assuming, of course, there is enough filter capacitance to reduce ripple to below, say, 10%).

Thus, when you ran the IOTA at 120VDC that was the equivalent of the AC line being at 120 x 0.707 or ~85VAC, but you yourself stated that the input range is _108-132VAC_ so it's no wonder the IOTA fell out of regulation. 

As far as the rest of your post goes, well.... how's that foot taste?


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## Guest (Oct 29, 2009)

Tesseract said:


> Just for reference I'm including your original faux pas.
> 
> 
> 
> ...



I just don't know how to respond Tesseract, or whatever your real name is. I have thrown away two messages already that are simply abusive. Instead of calling you a copy and paste engineer and my usual diatribe about typing yourself smart, I'm going to actually attempt an explanation. You clearly believe what you believe, but you're regurgitating rules of thumb, not calculations.

I SAID i didn't want to get into this, and its because of these misunderstandings and correcting them takes too much time and effort.

The DC voltage output of an ideal full wave bridge rectifier is NOT give by what you think it is. A very SUMMARY calculation for an UNLOADED circuit, can be given, for SINUSOIDAL waveforms, at a FIXED frequency, as follows:

Vdc=(2Vpk/pi). 

Now that's as FAR as this can be reduced without devolving to total nonsense. 

The peak voltage is about 170 for a 120 vac rms circuit. 

Vdc = 340/3.14159
Vdc = 108 vdc.

If you replace the 120 vac RMS value, and the full wave bridge, 108 vdc will do well enough. 

It is of course true that if you go measure the DC output of a full wave bridge at a filter capacitor, with no load, it will charge to the peak value. And you can measure it. But if you put a load on it, none of that happens that way.

Now if someone read your postings, and went and designed a DC power supply from what you know, it would explain why it doesn't put out 12.8 vdc at 55 amps. So in this particular case, you and the design engineer are probably pretty well in the same boat, and all of this clears up for me real quickly.

But you are totally focused on feet and "looking cool" in your forum.

For those using an IOTA DSL 55 in a car and it working, DON'T FIX IT. I'm simply reporting bench results. Not only will your mileage vary, but your needs as well. My experience has been that most people doing E cars don't KNOW how much current they need, or at what voltage. If your headlights and tail lights and turn signals work, and your radio plays - you're already good to go. Don't fix it to get a better one you don't need.

If you are shopping for one, Iota ain't it guys. Not at ANY input voltage. 

Both the Sure Power and the Kelly have much better regulated output, and do in fact delivery that regulated output at the advertised spec current levels. And Otmar is quite right, if you exceed them, they shut down and save themselves gracefully and can be used another day.

The Vicors I prefer are very good DC-DC converters. But if you take them over or under voltage, or overload the outputs, they generally shut down, but never to awaken again. They become their nickname, a brick. I've bricked several. If you want protection circuitry, Vicor Corporation will not interfere in any way in your design, construction, and full ownership of it.

I SHOULD have a followup video on higher voltage (375 vdc) DC-DC converters posted tomorrow. It is in the middle of a 17 hour render as I type. The air is even thinner up there.

Jack Rickard
http://evtv.me


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## Tesseract (Sep 27, 2008)

Any particular reason you resorted to rudeness and name calling to make your point, jrickard?

First off, yes the 1.414 multiplier is a rule of thumb. It became one because it works - funny how that tends to happen so often in engineering. Another example of such a rule is the time it takes for the capacitor in a simple integrator to fully charge is 5RC. Knowing them is a convenient shortcut and proves not much about my knowledge level; screwing them up or misunderstanding them is another issue altogether...

That said, I agree that the voltage the capacitor in a full wave rectifier circuit charges to will depend on the harmonic content of the AC waveform as well as the total source impedance, which for the AC line is considered negligible for loads under a kVA. The average voltage (ie - as read by a multimeter, particularly an analog one) will also depend on the amount of ripple present, which if the capacitance value is made arbitrarily large (and ESR is inversely proportional) then ripple can be made arbitrarily small.

The fact remains, though, that running a DC-DC converter spec'ed for 108-132VAC on 120VDC clearly violates the input voltage range.

Therefore, calling the IOTAs junk strictly because they needed a minimum of 150VDC and you gave them 120VDC is, to be charitable, a bit premature. Your other complaints are valid, but, to be fair, the IOTAs are technically being misused when installed in an EV.


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## Qer (May 7, 2008)

jrickard said:


> Now if someone read your postings, and went and designed a DC power supply from what you know, it would explain why it doesn't put out 12.8 vdc at 55 amps.





jrickard said:


> But you are totally focused on feet and "looking cool" in your forum.


Anyone else but me that find these accusations hilarious considering they're directed at Tesseract? 

*brings the pop-corn*


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## rbgrn (Jul 24, 2007)

Hey guys, let's take it easy. No need to resort to name calling to make a point. Just cite your sources and stick to the facts.

jrickard - You're clearly experienced. We've seen the EV Porsche. 
tesseract - You've been around the block as well and are a very active forum contributor. 

You both know what you're talking about. Please resolve the issue without letting this get out of hand!

I know you can do it.

Thanks guys.


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## Guest (Oct 29, 2009)

Tesseract said:


> The fact remains, though, that running a DC-DC converter spec'ed for 108-132VAC on 120VDC clearly violates the input voltage range.
> 
> Therefore, calling the IOTAs junk strictly because they needed a minimum of 150VDC and you gave them 120VDC is, to be charitable, a bit premature. Your other complaints are valid, but, to be fair, the IOTAs are technically being misused when installed in an EV.


I should lunge at the bait as to who started RUDE here. Rather, let me offer a sincere apology for anything I've said that could even be construed as "rude". I'm kind of a rude provincial kinda guy, and I have to work on this ALL the time.

I agree that the Iotas are technically being misused when installed in an EV, and in fairness, they were designed as a charger, not a DC to DC converter.

But the same is true of the Zivan's and while I haven't looked at one myself, I've had several people tell me they work great as a DC-DC converter.

Now see HERE http://www.evsource.com/tls_dcdc.php at 108 vdc listed or HERE http://www.grassrootsev.com/dcdc.htm at 96 vdc listed. Do you want more? I'm not selling ANY of these. But they are on the street, they're inexpensive, and they don't do what they are presented to do. And this leads people to of course buy them, and then be disappointed. 

After looking inside, looking outside, and running some basic tests, I think these are junk. And the response appeared to be that I don't know what I'm talking about then because they are just great. Well, I disagree. THey're not great at ANY voltage. But they're certainly and demonstrably not great at:

100 vdc
112 vdc
150 vdc.

I've tested them there, and they aren't great. They're not even adequate.

Jack Rickard


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## JRP3 (Mar 7, 2008)

If resellers mis label the Iota products I'm not sure that's Iota's fault. I don't see anywhere on Iota's site where they mention DC input. On the other hand a quick search on the EValbum shows 168 Iota's, far and away the most common DC/DC. My guess is most of them are used in 144 volt and above setups, and must be working adequately. Hardware that fails tends not to become popular. Maybe most EV setups don't pull many amps from them most of the time so the voltage remains acceptable. 
As to the personality clashes, I doubt Tesseract cares any more about popularity here than you or I, just the facts. Don't take it personally.


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## kittydog42 (Sep 18, 2007)

I have successfully used Iota DLS-45 and DLS-55, both new and old style, on systems with 120VDC (twice), 144VDC (twice), and 156VDC (twice), and sold about 10 more to others. On every occasion, it has worked great, with no failures. I cover the open areas with a piece of clear Lexan, with enough room for ventilation, to keep the water out. Sure Power and Kelly are not competition for these products, as far as I am concerned, because they are not 45A or 55A rated, and I am not sure that they support an accessory battery in parallel as the Iota does. The Iota does, of course, because it is actually a battery charger, and could conceivably get connected in such a way as to allow for recharging the accessory battery on 120VAC during the charge cycle. In my opinion, if Iota marketed this as an EV product, and designed the housing and design accordingly, it would be the perfect DC/DC if it still came in at a similar price.


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## Tesseract (Sep 27, 2008)

jrickard said:


> I should lunge at the bait as to who started RUDE here.


Sigh... whatever. You called my suggestion to go with IOTA a joke so that would be you that started off with the rudeness.




jrickard said:


> ...THey're not great at ANY voltage. But they're certainly and demonstrably not great at:
> 
> 100 vdc
> 112 vdc
> 150 vdc.


150VDC is still technically a couple volts below the minimum input voltage requirement, and that is even before including the forward drops of the line rectifiers. I suggest that you either test them at a voltage within the manufacturer's recommended operating range (not what some EV parts dealers says) or retract all of your previous comments.


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## Guest (Oct 30, 2009)

Tesseract said:


> Sigh... whatever. You called my suggestion to go with IOTA a joke so that would be you that started off with the rudeness.
> 
> 
> 
> ...


I just don't have anything left. I've explained the MANUFACTURERS RECOMMENDED OPERATING RANGE and your idiotic misapplication of a rule of thumb, ENCLOSED the PDF from the manufacturer, provided actual test data, and even explained the under the curve calculus for sinusoidal waveforms at its most reduced, "even you can understand it" level. And I've provided you links to EV parts suppliers currently insisting that the device is good down to 108 vdc and even 96 vdc and advertised for sale on that basis. 

As Mr. Big Dog by virtue of posting 26 times a day, you win. I don't have time to provide further information to people who are pathologically determined to seize on their own thoughts. You cannot TYPE YOURSELF SMART, even if you get a LOT of people to type "yeah, yeah" in the forum with you. 

If anyone DOES open a forum for information on real products that might further anyone's effort to not have to buy six of these things to find a good, one, I would be most willing to share what little I learn by actually doing things. If you want to run a forum for the self aggrandizement of some online forum engineer with a degree from Google and a lot of experience typing himself smart, and learning by reading what he's written himself, I'll have to move on to something else. I have NO respect for that. And that you've led a group of innocents who don't know any better into this miasma of misinformation is criminal.

And WHAT YOU RECOMMEND in your pompous patronizing fashion is completely of disinterest to me. Presented with ACTUAL information, you pathologically cling to a line of reasoning simply because its yours. Why would I care what YOU recommend - you pompous ass.

How does that work for RUDE. And I repeat YOU POMPOUS ASS!

Jack Rickard


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## Tesseract (Sep 27, 2008)

I guess this means your previous apology wasn't sincere, huh?


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## Guest (Oct 30, 2009)

Tesseract said:


> I guess this means your previous apology wasn't sincere, huh?


I think of it as "retracted". Pearls before swine.... a waste of time and keystrokes......

>>> Jack Rickard <<<<<<

The above is a NAME. I'm not ashamed to use it.... my dad gave it to me....


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## rbgrn (Jul 24, 2007)

Guys...

I asked nicely before but this is a real warning. Please keep the personal stuff off of the public forums!! People look to you both for advice and knowledge and you're both just losing respect by bickering like this.

Please, no more finger pointing, name calling or snide remarks. If it continues, I'll resolve this by deleting this entire thread.

If you guys need to keep talking about the personal side, exchange email addresses or phone numbers or something and just work it out.


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## Voltswagen (Nov 13, 2008)

I'm just going to wade in here and suggest that some of us have actually built operating EV's using Kelly products without incident. I don't mean to sound like an ad but.....
I installed the Kelly KDH12600B Controller, HWZ series DC/DC converter (with an accessory battery) and their KP Series 5v throttle on a 120v system. All components have performed admirably for nearly a year now.

Many choices to build or not to build come down to price and Kelly products afford those on a budget a way to get the vehicle on the road.
I think we could all agree that EV's are less expensive to operate than ICE powered vehicles. 

But sadly, it is those who would benefit most from owning an EV who struggle with the cost.

Roy


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## Otmar (Dec 4, 2008)

Otmar said:


> I'm sorry that I have lost the test data I had on a 220V IOTA converter. I know it ran full power down to about 170V and then dropped off gracefully to 140V input or so. I have never had anything but good luck with them.


If I may return to actual data and EV's, 
I just found some data I have on a old style IOTA, this is the one in the finned aluminum extrusion, not the newer folded metal case. 

IOTA DLS-220-45
On 110 VAC input, the output sags to 12V at 35A load on output. 
Note, Low voltage turn on threshold seems to rise as unit warms up. 
Input V A /Output V A
100V 0A / 1V 0A
150V 0A / 13.61V 0A 
141V 1A / 13.4V 7.3A
141V 2.5A / 12.2V 19.3A
144V 2.5A / 13.56V 21.5A
147V ?A / 13.55V 29.7A
180V 4.15A / 13.5V 44.7A

I assume this will run to at least 360VDC since it is a 220VAC model, but I did not test the upper range. 

Maybe this will be of help to someone....


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## alfu (Aug 30, 2017)

BradQuick said:


> I have a Kelly DC-DC converter in my 144V Del Sol. I notice that sometimes when I increase the 12V load (13.8 actually) the voltage will dip quite a bit.


It sounds like you don't have an accessory +12V battery in the vehicle for the converter to feed into. You should.


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## alfu (Aug 30, 2017)

<deleted>


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## JRP3 (Mar 7, 2008)

Not sure why you keep replying to a 12 year old thread.


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## alfu (Aug 30, 2017)

Yes, I was drawn to the Kelly controller by price. I'm using a KAC7250N at 80 volts, finding the hardware to be quite competent, but sadly, I can't recommend Kelly.

The documentation and downloadable software SUCK. Definitely not ready for prime time. It is up to the user to determine what effect changing parameters have on performance through direct experimentation, since parameter descriptions in the manual are incomplete. And this is difficult, because none of the parameters can be changed on the fly, and the connection to the controller has to be broken for a road test and later re-established every time a parameter is tweaked.
Parameters are named by varying cryptic abbreviations, usually without units appended, no datalogging whatsoever. When they introduce an updated version, they don't bother to increment the release number!

Their android app intentionally quits if it detects the motor rotate!

Regen was working fine for me at up to 30%, but then suddenly became very unstable, causing violent shuddering. No change in parameters could fix it, and ultimately their support suggested not to use Regen. So now I have no regen.


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