Charging four devices with one DC supply

Thread Starter

8bitAndy

Joined Jul 8, 2021
2
Hi, I have four battery powered roller shades. Each has an 8.4v 1000ma DC charger.
The battery life is not very good and hooking up the DC chargers is a hassle. So is trying to raise or lower the blinds only to find out the batteries are dead.

I was thinking of hard wiring them by running a single DC wire to the top of one window, then splitting it into four lines, each with a barrel connector to connect to the blinds.

I have a couple of questions about this:

1. Do I need to worry about current being drawn out of one shade and going into another, or other issues with running them off one split cable? Is there a simple circuit I can use to eliminate any issues?

2. Would it be OK to have them permanently charging with DC, or would it be better to put the chargers on a timer so they only provide current for a few hours every few weeks (just enough to keep the batteries always charged)?

3. How should I approach the DC amperage? Should I measure the actual amp draw of the blinds, get a 4 amp charger, or use resistors to limit the draw of each to 250ma and use one of the current chargers?

Thanks
 

LowQCab

Joined Nov 6, 2012
1,343
Unless You have a Schematic of the Internal-Circuitry,
You should not connect any individual Shade to another one, by any means.

The Chargers are designed to specifically handle just one Battery,
You need to keep it that way,
and use the Factory Chargers only.

You can certainly situate the Chargers anywhere You like,
and then simply extend their wiring.
All Chargers could be plugged into a "Power-Strip",
and then the Power-Strip could be plugged into a 24-Hour Timer
that turns them all on for a couple of hours each day.

Don't leave them plugged-in continuously,
it's very likely to reduce the Battery's Life-expectancy.

Use caution, and protect the Wires well, from Cats, Mice, and potential Physical-damage.
They are attached to a Battery, and could easily start a FIRE if shorted-out.

Installing a ~1-Amp, In-line Fuse very close to the Battery is a really good idea.
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Thread Starter

8bitAndy

Joined Jul 8, 2021
2
Use caution, and protect the Wires well, from Cats, Mice, and potential Physical-damage.
They are attached to a Battery, and could easily start a FIRE if shorted-out.

Installing a ~1-Amp, In-line Fuse very close to the Battery is a really good idea.
Thank you for the feedback. I disassembled one of the motors and disconnected the battery from the RF/Charger PCB. The shade still works when plugged into the DC charger, without the battery attached.

Would there be a concern running it like this through a DC splitter?
 

LowQCab

Joined Nov 6, 2012
1,343
What is a "DC-Splitter" ?

If You intend to actually remove the Batteries,
and the Shades work Fine with just the Charger Powering them,
then you can connect all of the Shades to one Charger, all at the same time,
as long as You only operate one Shade at a time.
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