Hi All,

I am looking at a Qualcast Cordless Trimmer charger
For a friend.

After a quick shufti it looks as though the 21V 550 milliamp wall wart has shuffled off its mortal coil.

I didnt think I had anything around that voltage in my spares bin, but it occurs to me I have some old laptop psus that are rated at 19V (and probably at least an amp)

The hedge trimmer is an 18V model.

Does the team think the laptop PSU will be man enough (but not OTT) for the job?

TIA

Chris

On Saturday, 16 May 2020 22:48:43 UTC+1, wrote:
Hi All,

I am looking at a Qualcast Cordless Trimmer charger
For a friend.

After a quick shufti it looks as though the 21V 550 milliamp wall wart has shuffled off its mortal coil.

I didnt think I had anything around that voltage in my spares bin, but it occurs to me I have some old laptop psus that are rated at 19V (and probably at least an amp)

The hedge trimmer is an 18V model.

Does the team think the laptop PSU will be man enough (but not OTT) for the job?

TIA

Chris

If the battery holder has separate charging control, the laptop psu /might/ work, though 19v is likely too low. If no separate charge control it might or might not be a bad idea to try it.


NT

On 17/05/2020 20:48, Paul wrote:


The purpose of writing a long explanation like this,
is precisely to keep people out of trouble. If you
don't understand all the limit conditions, you should
not be doing this stuff. There's no way to know
what could happen to that battery pack next. These
can catch fire an hour after you walk away from them.
They're fickle.

My hedge trimmer has a cord. Full disclosure.

Â*Â* Paul

Great post. Being rather of the "hack it and see" tendency, it's posts
like this that have convinced me not to mess with Lithium Ion. Nice to
have the "diagnostic options" so well explained.

Hmmm.........

Most of these replies came in after the horse had bolted.

The battery is LiOn, the 19V laptop charger was nobbled by its manufacturer to only put out put a decent amount of milliamps if it can €œsee€� a Dell laptop.

Nearest I could get was a wall wart marked 12V which put out 16 and a bit volts both on and off load (battery has just 2 connectors). (The wall wart is a big beast and I suspect has a transformer, rectifier and a smoothing cap inside, the original was tiny).

I charged it for its 4 hours maximum charge, checking regularly that neither the wall wart nor battery were getting hot.

At the end of that, the battery output was nearly 17V (up from 15 and a bit..

The user reports that the hedge trimmer is working fine.

I suppose it might shorten the battery life, but hopefully nothing will go bang.