# Iota 55 voltage



## Tesseract (Sep 27, 2008)

If the Iota was meant to run on 220VAC then even 168VDC was too low for it. It either blew up or UnderVoltage LockOut (UVLO) is preventing it from running.

The reason why is the 220VAC line is rectified to produce a nominal 310-340VDC bus. Typically, the "low line" voltage will be 200VAC (or 95VAC for a 120VAC nominal device). 200 * 1.41.4 = 283V, so... you ain't even close.

Either buy a dc/dc converter that covers your input voltage range (including sag!) or find a 13.8V switching power supply with a so-called "universal" input. PFC won't be necessary,.


----------



## spdas (Nov 28, 2009)

Thanks, and i understood a little more than 1/2 of what you said. Here is a cheap one on ebay and although it has a lower wattage, is it the type i need? Or since it has 2 voltage settings 110/220 (90-132 180-254) do I need one that says 110~220? Here it is:

http://www.ebay.com/itm/12V-30A-DC-...&otn=3&po=LVI&ps=63&clkid=5172777874747733128


thanks
francis


----------



## Coulomb (Apr 22, 2009)

spdas said:


> ... is it the type i need? Or since it has 2 voltage settings 110/220 (90-132 180-254) do I need one that says 110~220?


No! If it has a 110/240 switch, it is probably using a "voltage doubler" arrangement, which won't work on DC. It will still get power in the 110 V position, but it will get less than your pack voltage, when it is expecting at least half of about 300 V.

One that says 110~240 will work on higher or lower voltages automatically, so these are the ones that you want.

See also DC to DC converters (AEVA) (for how the voltage doubler switch works).

See also iota 55 low volt cutout.

See also Keeping an Iota DLS-55 alive.


----------



## Tesseract (Sep 27, 2008)

Yeah, what Coulomb said. If it has a 110/220 switch then you can't use it (well, you could if you had a ~300V battery pack and set the switch to the 220V setting).


----------



## spdas (Nov 28, 2009)

Ok, trying to get my education here.... 
I have a large IBM printer P/S that has 100~240v input and [email protected]~3.2Amp output to play with. 

My 145vdc from my car pack would not "light it up" and so had no DC out.



Why?


----------



## Coulomb (Apr 22, 2009)

spdas said:


> What is the minimum voltage that you have experienced that it would take to get it to run?


No experience, but this page:

http://www.solarseller.com/12_volt_...5_amazon_pumps_in_stock__teel_pumps_bilge.htm

seems to say 136 VDC for full output. But that's if you have the "dual voltage jack" installed, and I don't know what that is and if you are likely to have it.

[ Edit: this seems to be for the 120 VAC input version; the 220 VAC input versions seem to want a minimum of 260 VDC. If yours is a 220 VAC input model, it seems a miracle that it worked at all at 168 V nominal. ]

Note that the new Iotas don't handle DC input at all, so replacing your present Iota with a new one is not an option (unless you can find old stock [ edit: of the 120 V input versions] ).



> is there a way to lower the input voltage requirement a bit?


Alas, no, unless you can retro-fit this "dual voltage jack" somehow. I suspect if you don't have it, you can't easily add it.




> suggestions?


Sounds like you will need a "real" DC/DC, one intended for the purpose, or a power supply that happens to work well on the pack voltage that you now have. There are plenty of power supplies out there; MeanWell make some suitable ones (note: but many that are not suitable, for example any that use the "crowbar" or "disconnect" current limiting technique will not be suitable).

So there are three main things to check: input voltage (including suitability for DC), output voltage and power (e.g. is the output voltage adjustable; 12 V output may not be able to be adjusted to 13.8 V), and protection technique. Usually those that say "constant current limiting" are suitable, but beware of one like the one I just found that says this:



MeanWell said:


> Protection type : Constant current limiting, unit will shut down o/p voltage after about 5sec. Re-power on to recover


Obviously, you don't want the supply shutting down after 5 seconds of current limiting.

TCCharger (formerly Elcon) make a range of DC-DC converters, e.g. in the 400 W range:

http://www.tccharger.com/english/Product/T16/38.html

I don't know what their DC/DCs are like, but their chargers seem to be well regarded. You might even find a USA-based agent / supplier, e.g.

http://www.elconchargers.com/converters.html


----------



## Coulomb (Apr 22, 2009)

Here is a MeanWell unit from Mouser:

http://www.mouser.com/ProductDetail/Mean-Well/SP-500-135/?qs=w38MntJnY9MxduBvskPjOw%3d%3d

Unfortunately only 36 A output; there is a 600 W model (44.5 A output) but Mouser don't seem to stock it, or I didn't find it if they did. The Australian Mouser site lists the 600 W unit (actually 600.75 W, so it might list as 601 W, and a filter for 600 W might miss it), but it's non-stocked and it may take something like 11 weeks to get delivered. Someone else (Digikey etc) might have them in stock.

Edit: here is the 600 W model on the USA site: http://www.mouser.com/ProductDetail/Mean-Well/PSP-600-135/?qs=/bfygUuxYr4CD/kje6PnRg==


----------



## Coulomb (Apr 22, 2009)

spdas said:


> I have a large IBM printer P/S that has 100~240v input and [email protected]~3.2Amp output to play with.
> 
> My 145vdc from my car pack would not "light it up" and so had no DC out.
> 
> Why?


It's a little surprising that it would just sit there quietly and do nothing. If it has a transformer input, I'd expect it to just blow a fuse (probably spectacularly). Does it still work on AC input?

You say it's "large"... if it's heavy, it probably has a mains frequency transformer in there, which won't work at DC.

It might have a PFC (Power Factor Correction) stage that insists on a certain frequency range; the PFC stage has to "lock on" to the input frequency to achieve near-unity power factor. Most PFC stages handle DC fine, but for some, the frequency (0 Hz) is outside their expected range.

Being that small, it might have a capacitor in series with the mains input, used to drop the voltage down to something easier to work with. DC just won't get through a capacitor (after an initial brief surge). I've seen small power supplies that essentially have an X2 rated capacitor in series with a zener diode, with an electrolytic capacitor across the zener. The unisolated output is across the zener/electrolytic. But that probably won't supply more than several tens of milliamps.


----------



## spdas (Nov 28, 2009)

Now I am even more confused. 

I plugged in my Iota to the house a/c that is running at 100 volts at the moment (off grid solar with inverter) and the Iota puts out 13.6vdc fine.

It is labeled 220v, so why is it working at 100v?

hmmmm?
Francis


----------



## Coulomb (Apr 22, 2009)

spdas said:


> It is labeled 220v, so why is it working at 100v?


It may be working (outputting a voltage), but may not be working well. Try putting a 12 V battery across the output, preferably one at a low SOC, and see if it outputs much current.

According to one of the pages I linked to, it may be capable of only 1/2 to 1 amp output at low input voltages. They don't seem to say how low the 220 V input model will work down to.

It's not unusual for switch mode power supplies to work down to about half the designed input voltage. So 110 VAC input might be just on the threshold of where it will work at all.


----------



## Lordwacky (Jan 28, 2009)

Just get the 120 Vac version of the DLS 55 and you should be fine. EVparts.com and other suppliers say that they will work down to 130VDC, so Unless you are saggin a bunch (which you shouldn't be with Li) it work fine. I just read that Iota redesigned there supplies recently and the new ones will not work with DC input, so make sure you are getting an older model.

I run a DLS 55 with my ~150-160 V pack with no problems.


----------

