Replacing dead NiCads tools with mains power supply?

[Man at B&Q]

e:

Yes, but at 3.3V or 5V.

MBQ

[Man at B&Q]

Which bit if the voltage difference are you struggling with?

MBQ

[Clive George]

I think you need to explain this a bit more.

[Tabby]

Which part of putting 3 psus in series are you not comprehending? That's why the grounding needs altering on 2 of them.

NT

[The Natural Philosopher]

assuming the output is grounded, at all.

[Tabby]

I've not yet seen one that isnt.

NT

[H. Neary]

SMPS's in series?

You cannot be series about this?

I'm not saying it wont work, but regulated supplies with no common reference sounds a bit iffy.

If you can get 3* 6V lead acids, go for it. Charging identical batteries is simple enough. Just ensure that they are returnable.

Why not adopt this solution in the first place?

HN

[Tabby]

Maybe electronic engineering isnt your thing

NT

[H. Neary]

What has electronic engineering got to do with batteries?

Do you not think that batteries are more akin to chemical engineering?

HN

[The Natural Philosopher]

Indeed. the amount of lab power supplies we used to connect in series..they all had three terminals. Plus, minus and ground.

[Tabby]

I was referring to your comments on the pc psu option - no batteries involved.

NT

[H. Neary]

I wasn't implying that it wouldn't work, personally I would not go out and buy three supplies expecting them to work together trouble free.

As none of the supplies are going to be exactly the rated output, one will think it has to supply more or less current than the others to maintain the Voltage. The current cannot alter in one PSU alone as they are in series, so at some point PSU number two tries to back off the current as it sees the output Voltage increase.

I have not tried this, so I do not know what would happen practically. I have seen power supplies used in parallel though, and this usualyy ends in disaster.

HN