DC Charging of Ego Batteries?

  • 3
  • Idea
  • Updated 2 years ago
  • Under Consideration
I'd like to be able to charge Ego batteries from a DC source. My use case is an off grid solar setup, but I can imagine a similar use case for a car charger.

Would Ego consider making a DC-DC charger? Or has anybody else built one?

I realize I can go DC => AC inverter => DC but the losses are quite substantial. I'd love if Ego brought a solution to market for this.
Photo of Robby


  • 804 Points 500 badge 2x thumb

Posted 2 years ago

  • 3
Photo of Pablo


  • 180 Points 100 badge 2x thumb
Sorry. This is above my pay grade but maybe somebody out there knows. Good luck...
Photo of Blue Angel

Blue Angel, Champion

  • 180,360 Points 100k badge 2x thumb
Official Response
I would think this would need to go from a 12 V source to have as wide a market appeal as possible, so that automotive use was possible.

The issue I see with that is, the DC bus inside the charger has to run at a voltage higher than 58 V, or whatever the peak charge voltage of the batteries is. To do that you would need to step 12 V up to that voltage, which would probably require generating AC current and running it through a transformer, then rectifying it back to DC. That process wouldn’t be too different from using an external inverter from an efficiency standpoint, so I’m not sure if there would be much to gain?

Off grid DC power systems run at a much higher voltage then automotive systems do, typically. However, settling on one input voltage would suit some people and not others.
Photo of Robby


  • 804 Points 500 badge 2x thumb
@Blue Angel Yeah, I agree a 12V source makes the most sense. I believe you could step up from 12V to ~60V (or whatever the Ego batteries charge at) by way of a Boost Converter.

There are a couple advantages to this approach over an inverter. First, it should be more efficient to go from 12VDC to 60VDC via a switched supply, than to go from 12VDC to 120VAC and then down to 60VDC. Second, a DC charger could be easily designed to trickle charge with whatever current is available to it. This makes a lot of sense when you consider typical DC applications -- vehicle outlets, solar panels, off-grid, etc.

Ego crew -- any chance you would consider this? The R&D is pretty straightforward (it's entirely electrical, nothing mechanical), and it would help your tools and batteries compete with gas equivalents for off-grid accessibility.