PL8 x2 on Rsp-2000-24?

[sl4ppy]

I recently got a hell of a deal on a Meanwell RSP-2000-24.

I currently run a single PL8 and would like to another one to run on this one PSU.

Am i going to run into troubles with it not being 48v? I charge 6s and 7s batteries exclusively; the majority are 5000mAH...

[realloser]

I might be wrong, the single PL8 can take only 32V. On 27V you got the full possible current: http://www.revolectrix.com/pl8_specs_tab.htm

[Gregor99]

Originally Posted by realloser

I might be wrong, the single PL8 can take only 32V. On 27V you got the full possible current: http://www.revolectrix.com/pl8_specs_tab.htm

Correct. There are two issues to be aware of. The first is the buck boost transitions. Lowering the supply voltage about 1v would address that. Increasing it likely won't allow the transitions to clear the 7s packs.

The second issue is that if you are running from generator, as you approach the maximum output of the generator, the pulsing nature of the chargers will cause AC supply stability issues. The chargers may trigger an unstable supply safety code when you are pulling between 1300 and 1400 watts from the generator.

Be sure to set the current limit on both chargers so total current does not exceed 80 amps. Also I would run separate wires from the supply to each charger.

[sl4ppy]

Originally Posted by realloser

I might be wrong, the single PL8 can take only 32V. On 27V you got the full possible current: http://www.revolectrix.com/pl8_specs_tab.htm

I guess I lucked out getting a 24v one then.

Originally Posted by Gregor99

Correct. There are two issues to be aware of. The first is the buck boost transitions. Lowering the supply voltage about 1v would address that. Increasing it likely won't allow the transitions to clear the 7s packs.

I see in the manual that it mentions voltage trimming... Is that how you suggest I lower the supply voltage? I don't have the PSU here in front of me, but it doesn't look super obvious how that is achieved.. lol

Originally Posted by Gregor99

The second issue is that if you are running from generator, as you approach the maximum output of the generator, the pulsing nature of the chargers will cause AC supply stability issues. The chargers may trigger an unstable supply safety code when you are pulling between 1300 and 1400 watts from the generator.

Be sure to set the current limit on both chargers so total current does not exceed 80 amps. Also I would run separate wires from the supply to each charger.

Im running a Yamaha ef2000i; it "claims" a stable output of 1600 watts.. Might that still trigger the safety code?

I assume limiting the max current to 40 amps is pretty easy to do via the standard interface.. (ie, I don't need to connect to a computer?)

(fwiw, I am currently running the single PL8 on a RSP-1000-24 which I max out pretty regularly..)

Thanks Gregor!

edit: this answered most of my questions. :0 Search rules.

https://www.helifreak.com/showthread.php?t=569144

[Gregor99]

I'd first try a 6s pack at low and high currents. If you are getting the buck boost transitions lower the supply voltage. The Meanwell manual describes how this is done.

The generator is rated for constant load. The chargers put pulsing load on the supply. This makes its way up stream to the generator. The generator will attempt accommodate the pulsing load. Near the limit of the generator it becomes quite difficult for the generator and the result is an unstable AC supply.

This makes its way back down to the chargers and if its bad enough the chargers trigger an unstable supply safety code. When running two chargers, typically only one charger triggers the code aborts the charge. The load is lifted by one charger aborting and the other charger continues on.

This only happens at the upper limit of the generator. Not quite to 1600 watts. Tests were done on several Honda EU2000. Although I have not tested a Yahama, I expect to get similar results. Give it a shot and report your findings. I had posted a theory in another thread that a couple large capacitors or bank of capacitors connected to the DC side of the supply might help smooth the load on the supply and reduce the pulsing effect on the generator. I do plan on testing it, but wanted to get scope first so I can more definitely quantify the affects of different capacitors on the supply voltage.

[hemp]

Originally Posted by Gregor99

a couple large capacitors or bank of capacitors connected to the DC side of the supply might help smooth the load on the supply and reduce the pulsing effect on the generator.

I love this idea!