the problem with using those 2880w psu's to run the A2's is the A2 controller board requires a 24 pin PSU connection so those would be a no go.
the problem with bronze is it gets no efficiency from 240 V unlike gold and platinum , yes bronze is cheaper up front but remember you are running miners like servers which is why server hardware requires 90+ platinum ratings since they are running 24-7 at maximum output unlike a regular pc/desktop.
Have you looked in detail at their power distribution board? I haven't but I suspect they're not doing anything too fancy with it, so if they're only pulling the 12V lines from the PSU and jumpering the PWR ON, then you could just hack together an adapter to do it. Then again, they could also be using the 5V for driving the Pi, in which case I don't think there's a 5v line on the IBM's.
If you haven't, I'm planning on pulling it apart in the next few weeks to add a connector for PWR ON, so I can hook it up to the same ethernet relays I used on my S5's to do remote rebooting. The damn PDU's I ended up buying a bunch of (Tripplite) only shut off 1/2 of the 240v circuit, so sometimes the PSU's shut down, and sometimes they just dynamically switch to 110v and continue on like nothing happened - pretty annoying.
I love this stuff though, that's half the fun of fiddling with these miners - tweaking with the config, writing apps to run them, building hardware, etc. Although I'm not making enough mining to cover my hourly rate...
Great link, I hadn't seen that chart before - so even at Titanium you're only looking at a 1-2% gain to 240v... I'll be interested to see if in practice that's what I'm also seeing with the supplies.
Yeah i have the same issue , working with these boxes on my offtime is fun but its not worth the time taken away from my other projects .
Not had a chance to look at the PDU board but i think you are right an adapter would be fine if you could build one, The PI's seem to be powered through the 32 port gpio cable so i think 12v to the board should do it. I dont have any spare boards for my six machines so i cant try it right now.
I missed your post about the triplite PDU's that reminds me i have 2 of those POS pdus i bought that and 20amp units same issue you have. I ended up just saying screw it an instaled 4 30amp circiuts and bought used 24apmp /208v PDUs instead and have had no power down issues since then
You should do that its a better option than modifying the boards , I found an electricin on criaglists to do the circut upgrades for around $300 all i had to do was buy the 30amp rated cables and the lp-30 twist lock power receptacles ($19 each)
In fact im having him come in this weekend and upgrade me from a 100amp panel to 200 amp so i can power up 3 machines sitting here gathering dust since my main breaker is filled up.