All four batteries will charge at least 30 minutes earlier than the normal hour and a half with the 24 V set up. That is the current setup I use. , several friends at our flying club are using the same set up, but they’re buying commercial power supplies that they can turn down to 35 V 60 amps. The aircraft that I fly require two batteries per plane. I have 12 of these packs. By using the set up, I will always have batteries ready to go throughout the day. I’m simply following others leads, however, I don’t want to spend $400 on a commercial power supply when I know this can be done with these server supplies. Again, I’m a tinker, and I like solving problems for less money while exploring, and learning.

 

OK, and now that I understand the application, some of the advice still holds, which is to separate those three supplies to allow adequate cooling air flow, since they will be operating near their maximum rating. Using a slightly undersized wire (possibly #16 AWG.) for the inter-connections will lead to a slight voltage drop, with reduced efficiency. In this case, maximum efficiency is not the target.
BUT if the voltage drop in the interconnections is enough to allow the charger to accept the voltage then the goal is achieved.

And with the voltage drop and heating spread out there should not be any problems. AND with the adequate air circulations your power supplies should be happy and live longer, and I am aware that purchased new, those H.P. supplies are not cheap.

 

Thank you, wonderful advice. I should have mentioned earlier that I have those set up as a test bed. My intention is to put them in a pelican case with a 1 inch space between the three power supplies and a cooling fan administering airflow through the three power supplies in and out of the case. There’s so much information. It’s hard to put it all in one post. But I have it set as a test stand just to understand the voltage and try to achieve my goals. Thank you so much for your advice. I will give that a try.