Can a Sorensen PS be used in series w/ Meanwell?

sailah

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Aug 13, 2010
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I apologize if this is an obvious question but I have been searching and reading threads often trying to get a definitive answer.

I am planning out my build and assembling ideas in my head about how to go about it.

I have a number of lab power supplies my largest being a Sorensen 0-40V 0-20A supply.

My battery pack I'm planning on is a 22S9P 18650 build with BMS

The sorensen won't get me there and I've been reading up on these Meanwell mods like the R33 and putting in a POT on other models. Rather than buying numerous S-350-48 and doing that mod, which honestly is beyond my understanding and soldering ability, can't I just buy 2 Meanwell say the S-350-36 and run it in series with my Sorensen? I can adjust current on Sorensen and it would be the lowest voltage of the series @19.3V

Or alternatively I could pick up another 0-60V Sorensen and use both or am I not understanding these things?

I'm trying to learn as much as possible. Mechanical things I'm very good at, electronics it's still a struggle

The goal is to build a bulk charger and learn some more about this ebike stuff while doing it. Just buying a Satiator seems too easy lol

Thanks

Peter
 
As long as the PSUs you are using are all isolated (output is not connected at all to the input, electrically; you can continuity test this with all wires disconnected from sources and loads), then you can series any PSUs you like to get up to whatever voltage you need.

One caveat is that if something fails the wrong way within one of the PSUs, then if there is no output protection on it (or the others) the entire series voltage of the pack might end up across components that can't take it, and cause smoke. ;) Doesn't happen very often but it could.

I've used my Sorensons in series with each other and various MW and other PSUs, so that I can use the Sorenson as the current limiter. Some of the Sorensons are very old heavy transformer-based units, and the biggest one is a more modern SMPS type. They all work equally well AFAICT.


Keep in mind that the lowest-current-capability PSU in the series will be the limiting factor in how much current you can draw from the whole series string--so you have to be sure to set the Sorenson (if it's doing the limiting) current limit below that point, to prevent the series string of PSUs from having any unit overloaded.



But I'll say that the Satiator is definitely "easier" to use in that you can program it via the PC for a number of separate profiles for different battery packs you might have, or different charge profiles for the same pack (quick charge, standard charge, full charge, long-life charge, etc). it's just not as high-current as you could get with other PSUs, if you need to charge a really big pack really fast. For a typical ebike pack, it's plenty.
 
Thanks. How about a NOOB question #2...

could you explain the isolating power supplies a little more? I'm not sure I understand the output not connected to the input thing.

I watched WCEC video showing him wiring up his 3 meanwell s and adjusting voltage. My plan was to buy 2 of the cheaper meanwells that are not current limiting and utilize the current limiting on my sorensen below the rating for the meanwells. Perhaps I don't understand the concept fully.

Maybe the satiator is the better option to start with. They seem highly regarded.

I just like to use what I have and gain some knowledge. My sorensen is one of the old beasts, transformer machine.

Thanks. I'm a much better machinist than I am a sparkie. :mrgreen:
 
sailah said:
could you explain the isolating power supplies a little more? I'm not sure I understand the output not connected to the input thing.
There's a few threads in here:
https://endless-sphere.com/forums/search.php?keywords=isolat*+&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search
about isolated power supplies / chargers / charging that explain it / show how to test for it, and even how to do it if it's not isolated, for certain PSUs.

Basically if they're not isolated, then the ground of the second (more positive) charger in the series would short out the first (most negative) charger in the series, possibly even damaging it.



I watched WCEC video showing him wiring up his 3 meanwell s and adjusting voltage. My plan was to buy 2 of the cheaper meanwells that are not current limiting and utilize the current limiting on my sorensen below the rating for the meanwells. Perhaps I don't understand the concept fully.
That's pretty much exactly how it works--the sorenson does the limiting for the whole string. You just have to make sure it's limit is set below the max current abilty of the other PSUs in series, if they are smaller than it is.

So if you get PSUs rated for 9A max, and the sorenson is 20A max, you can't set the sorenson for anything above 9A, or teh PSUs in series with it will be overloaded.


Maybe the satiator is the better option to start with. They seem highly regarded.
If you have the money (they're not cheap!) and don't need high-current charging for a huge pack, it's certainly easy enough to use. :) It's well-supported and comes with presets for a number of common packs, and the PC software makes it easy to change those if you like, or make your own from scratch. Just be sure to get the USB-serial cable with it for that. And make sure you get the model for the voltage you need, keeping in mind that the higher the voltage the lower the current it can output.


I just like to use what I have and gain some knowledge. My sorensen is one of the old beasts, transformer machine.
It'll work fine as long as it's isolated; it probably is, but you have to test that with the multimeter. (same with all the other PSUs you get).


Thanks. I'm a much better machinist than I am a sparkie. :mrgreen:
I do it all by guess and by gosh, for the most part, with experience building up to keep me from redoing my worst mistakes. :oops:
 
Thank you those threads provided exactly what I needed. Now thinking server power supplies. ..
 
All Meanwells I've tested were isolated.

The other thing to watch is the minimum expected pack voltage. If only one supply is current limiting, it has to cover the entire voltage range. In other words, the total of the fixed supplies needs to be less than the minimum expected pack voltage.

I'd also put reverse biased diodes across all the supplies to protect against reverse voltage being applied to the outputs. This is optional and only needed if you make multiple mistakes.
 
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