# Mean Well SP-320 dual voltage modification



## rwaudio (May 22, 2008)

And some lame video....
http://www.youtube.com/watch?v=XDLfyQoowII

more lame video...
http://www.youtube.com/watch?v=-92CJwOvHj8


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## brainzel (Jun 15, 2009)

Not the same usage but I'm searching for a MeanWell SP-320-3.3 as a powerful single cell charger (CALB).
Same technic but used for another issue 
MeanWell SP-320-3.3 Datasheet
Max. 55A @ 3.14 ~ 3.63V


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## JRP3 (Mar 7, 2008)

Nice, thanks for the writeup. Do you find that the fan is always running, even when the car is off? Mine speeds up and slows down after sitting for a while from the parasitic loads. I was thinking of wiring in a thermal switch to stop the oscillating as I can't believe it needs fan cooling when putting out a few tenths of an amp.


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## Yabert (Feb 7, 2010)

Nice!

But I'm not sure if I will need it. After some road test with headway 12v battery (13.0-13.2v) the light seem well (no vacuum pump, no power steering). So, I expect all will be perfect with 13.5-13.6v.

Just to inform you.... I buy my SP-320-13.5 from Powergatellc for only 63$ plus shipping. 
Pretty sweet deal for this nice DC/DC.


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## JRP3 (Mar 7, 2008)

My lights and accessories are also fine at 13.2V, but they would be better at 14.2.


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## rwaudio (May 22, 2008)

JRP3 said:


> Nice, thanks for the writeup. Do you find that the fan is always running, even when the car is off? Mine speeds up and slows down after sitting for a while from the parasitic loads. I was thinking of wiring in a thermal switch to stop the oscillating as I can't believe it needs fan cooling when putting out a few tenths of an amp.


At 13.6 with no load the fan is running very slowly (but still running) I believe there is already a thermal switch to speed up the fan under high loads, they just don't let it turn off completely.



Yabert said:


> Nice!
> 
> But I'm not sure if I will need it. After some road test with headway 12v battery (13.0-13.2v) the light seem well (no vacuum pump, no power steering). So, I expect all will be perfect with 13.5-13.6v.
> 
> ...


That's a good price! I've also been driving my car dc/dc converter-less with the headway pack and everything does work well however from my car stereo days I can appreciate the difference between 12-13v vs 14.4v running your lights, wipers and stuff. 



JRP3 said:


> My lights and accessories are also fine at 13.2V, but they would be better at 14.2.


yup, it's surprising how much difference a volt or two makes.


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## JRP3 (Mar 7, 2008)

Yes it does speed up at higher loads, and slows down at lower loads, which ends up oscillating in my car at lower loads. I'd like it to turn off completely at low loads to stop the oscillating.


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## rwaudio (May 22, 2008)

brainzel said:


> Not the same usage but I'm searching for a MeanWell SP-320-3.3 as a powerful single cell charger (CALB).
> Same technic but used for another issue
> MeanWell SP-320-3.3 Datasheet
> Max. 55A @ 3.14 ~ 3.63V


If you want a single cell charger don't pick the SP series, get an S or RSP or PSP, basically any version with the constant current limiting instead of the hiccup mode as overload protection. On the bench I'm using a couple PSP-225-48's with some small modifications so that I can adjust the output voltage and the current limit. They will run all day and night as a charger if you limit the current to just below it's nominal rating. And no annoying turn on/turn off issues if you are trying to charge a deeply discharged cell.


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## MN Driver (Sep 29, 2009)

My personal preference would be to wire up the system to run at the higher voltage only while the headlights were on so I'd probably wire my circuit into a relay powered when the headlights are on. My lower voltage would be at whatever the cells rest at if fully charged, I'd expect output current to be very close to zero if all other loads were off with fully charged cells if I had the cells sitting for 24 hours and then fired up the converter. 13.6v should be fine while the car is operating though but if you have a fully charged Headway cell, let it sit untouched for a few days, how much current would it initially pull if at 3.4v? I haven't tested this but am curious. Thinking more about this I'd probably set it up to run the headlight voltage with the headlights on and 13.6v with the ignition on and no headlights, maybe that voltage while charging and a lower voltage, say, 13.2v to 13.4v with the car off. Depends on the loads imposed with the car off but hopefully they aren't high. I'm probably overthinking this.


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## profal (Jun 22, 2012)

So how does one hook up the SP-320? I have a 325V main battery but the connectors on the SP-320 only show the GROUND, N, and L. The output is clearly marked so my question is simply with the DC on the input???

Thanks
The Prof


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## MN Driver (Sep 29, 2009)

profal said:


> So how does one hook up the SP-320? I have a 325V main battery but the connectors on the SP-320 only show the GROUND, N, and L. The output is clearly marked so my question is simply with the DC on the input???
> 
> Thanks
> The Prof


Ground, neutral, and line are connections from the outlet. The plus and minus should be outputs, not inputs. You should review the documentation for the SP-320 before you blow the unit up by connecting things to the wrong places.


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## rwaudio (May 22, 2008)

profal said:


> So how does one hook up the SP-320? I have a 325V main battery but the connectors on the SP-320 only show the GROUND, N, and L. The output is clearly marked so my question is simply with the DC on the input???
> 
> Thanks
> The Prof


The +/- from the pack are connected to L and N (normally AC inputs) 
This is from the FAQ section on the Mean Well site.

A9. In MEAN WELL's catalog, we see AC and DC at input, what is it all about?

Ans:
Due to different circuit designs, MEAN WELL power supply's input consists of three types as below√2VAC≒VDC) 

a.85~264VAC;120~370VDC 
b.176~264VAC;250~370VDC 
c.85~132VAC/176~264VAC by Switch; 250~370VDC 

In a and b inputs models, power supply can work properly no matter under AC or DC input. Some models need correct connection of input poles, positive pole connects to AC/L; negative pole connects to AC/N. Others may require opposite connection, positive pole to AC/N; negative pole to AC/L. If customers make a wrong connection, the power supply will not be broken. You can just reverse the input poles and power supply will still work.
In c input models, please make sure that you switch the 115/230V input correctly. If the switch is on the 115V side and the real input is 230V, the power supply will be damaged.



MN Driver said:


> Ground, neutral, and line are connections from the outlet. The plus and minus should be outputs, not inputs. You should review the documentation for the SP-320 before you blow the unit up by connecting things to the wrong places.


These power supplies can be run off of AC or DC and work well over a very wide input range. AC or DC can safely be applied to what is normally considered the AC input.


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