PL6 charging station

[jperkosk]

In the meantime I have finished a nice little side project: my PL6 charging station

First, got me 2 HP DPS-600PB 12V 47A server power supplies, $50 for both including shipping in the US from some surplus PC outfit selling through Amazon.



Second, a nice sturdy, and non-conductive $50 toolbox from a local Home Depot:




Third, a quarter of a full 8'x4' sheet of 3/4" thick plywood, plus some screws, washers, latches, mosquito screen, let's call it another $50.

[jperkosk]

Since there is a potential safety issue with grounding (server PSUs have negative DC terminal connected to the case) I went with the totally insulated concept and did away with the grounding altogether, same way some commercial power supplies are designed when they're missing the grounding plug.

So first, I built an inverted mounting deck for the power supplies. They are electrically insulated with 19mm thick plywood:



AC power side. Both PSUs connected in parallel through the power switch, all grounding completely removed:



DC output side. PSUs connected in series, output wires ending with EC5 connector:



It's important to keep the ends unobstructed for the cooling air flow.

[jperkosk]

Next, drilled some ventilation holes at the ends of the toolbox:



Used mosquito screen and hot glue to protect them on the outside:



On the AC side mounted a PC power supply socket:

[jperkosk]

The power switch on the deck connects to the socket on the side of the toolbox:



And the whole assembly drops into the toolbox. Please note the side handles, they are pull handles on HP PSs that I removed and installed on the sides of the deck for easy dropping-in and pulling out:




The door latches keep the deck locked in place and a couple of strategically placed bits provide for a snug fit for a PL6 charger:

[jperkosk]

Field testing yesterday:




Almost forgot: I needed another $600 bit from a local Home Depot

[ragge1]

very nice Jerry

[sutty]

Good work Jerry. Only as to be expected from you. What can you achieve with that then. Keep yourself flying at the club all day?

Cheers

Sutty

[CyprusDave]

Top notch Simple but extremely effective

[jperkosk]

Thanks, guys. I have big packs for the hexa and 6HV, and up until now every time I was flying more than 2 flights I had to wait for the packs to charge. With this station I will be able to charge 2 flight packs in parallel @2C and even 3C, meaning almost no waiting time

[copterboy]

Nice build Jerry! Inspiration to get mine finished ready for summer!

[redbird300]

Fantastic Jerry ! This is the stuff that makes me drool, but you guessed that already.

I just remember that I still have a few used 2000 Watt 12 Volt server PSU's, bought them extremely cheap a year ago or so, but they are still in the box. Waiting for a charger that would use that kind of power, and I'd need stronger circuits in the house...

[Luke Warmwater]

Nice kit....but wouldn't it be cheaper to buy more batteries?

....I'll get my coat.....

[jperkosk]

@Raf: haven't told the whole story, these PSUs give me an even 1000W @ 25.2V (25.2V*40A=1008W), as by default they generate 12.6V (adjustable from about 11.5V to 12.8V by external pot, but for 12.6V I didn't have to do a thing ). Perfect match for 1000W 40A PL6, and only very slightly underpowered for 1344W 50A PL8 (they would produce just under 1200W). Also, they have automatic power factor compensation, meaning VA=W, so no problem with running low loads or running from the generator. All for $50 a pair!!!

@Luke: +1000 Actually I'm beginning to believe it would have been much cheaper not to have done any of this, beginning with getting to know you guys, and especially Tom who sets a morally and financially destructive example

[Luke Warmwater]

Hehe.....my tongue was firmly in my cheeky Jerry. I know that buying batteries would solve the "problem", but you wouldn't have "done anything".

There's a guy on the HBFP forum, who is spending loads of time and money converting a 450 CP into a fixed pitch....because he can.

[jperkosk]

Plus there is another aspect to it: battery life. My standard procedure is to fully charge all my Lipos upon returning from the day of flying and store them in the sealed plastic containers in the fridge. That way when I decide to run out to the field I just grab a couple of containers appropriate to the birds I'm taking and I'm all set.

But there is this controversy about storing Lipos fully charged. I did some reading on it and it's still not totally clear, I feel like being back in my old country: whenever you put a 3 Polish guys together to discuss a subject you'll get minimum 4 different opinions

My latest opinion is that storing in the fridge definitely helps, as it slows all the chemical processes down, but I'm probably still having some deterioration of the packs due to storing them fully charged, albeit slower. Recently noticed that some 3s packs for a 300 felt a bit underpowered after a year of non-use. So with this charging station I'll be able to change my routine: store the batteries at storage level, then run to the field and quickly charge them there before flying. Well, I'll probably start doing it for large (and expensive) packs only . And possibly store them at 4.1V rather than 3.8-3.85V, read somewhere that most deterioration to the pack in storage is above 4.1V level.

[redbird300]

Originally Posted by redbird300

I just remember that I still have a few used 2000 Watt 12 Volt server PSU's, bought them extremely cheap a year ago or so, but they are still in the box.

I knew I still had a picture of them somewehere, they would make a nice 36 Volts PSU.

[jperkosk]

Can't see the specs due to the low pic resolution, what are they?

[redbird300]

Originally Posted by jperkosk

Can't see the specs due to the low pic resolution, what are they?

12.2V/164A each.

[jperkosk]

Wow, you'll need a wheeled 10HP engined generator for 3 of these