Meanwell PS creates a load?

brulaz wrote:
Recently realized that my solar systems daily output had increased by ~50Wh per day when in storage with no shorepower.

It was hard to believe that the parasitic loads or the battery self-discharge had increased by that much as the only change I had made was to install a Meanwell 27V 500W adjustable power supply to charge up my 24V battery bank when on shorepower. I assumed that when it's unplugged from 120VAC the Meanwell would have no load on the batteries, so I hard-wired the DC output through a fuse block to the 24V battery bank.

But after pulling the DC fuses in the Meanwell's output, that new 50wh per day load has disappeared. (Someday I'll have to measure its actual current draw with my clamp-on.)

Do other PS/charger/converters do this? I don't recall such behaviour with the WFCO or Prog. Dyn. when boondocking, but never really looked at it closely.

Anyway, it's not that big an issue as I don't need the Meanwell that much. Usually solar supplies everything we need, so I'll just leave the fuses out until it's needed. But it is unexpected.

I would consider this to be normal for most any power supply that was never designed or intentioned to have a voltage on the output terminals when the supply is off (IE battery or solar).

To get around that issue, I use a simple diode in series with the power supplies output. This way the power supply output section never gets back fed from the other power sources.

I have used that trick to connect multiple power supplies together in parallel..

Works great when you have power supplies with an adjustable output voltage.. Add diode then adjust the output voltage up to cover the insertion voltage drop of the diode.