EEVblog #865 - How To Increase Alkaline Battery Capacity

[SeanB]

I'm trying to imagine a scenario where you'd want to use a sledgehammer right next to a live MRI machine. 

Getting the table unstuck after the chair has been slammed into it.

[Len]

I'm trying to imagine a scenario where you'd want to use a sledgehammer right next to a live MRI machine. 

It's a precision instrument, sometimes it needs a little adjustment.   

[Brumby]

I'm getting nervous chills just picturing this scenario ..... 

[Barny]

I've seen an old information movie for kids, where the MRI was explained.
(I think it was "Sendung mit der Maus" - broadcast with the mouse)
There the moderator held a pice of thick steel chain next to an retired, switched on MRI.
It was pulled straight to the center of the scan-chamber, not to the ring itself.

They explained they had to search a long time to find an retired one which is still workeing, because the fuleing around with the chain could damage the MRI, even when the chain dont touch it.

[station240]

Non-Magnetic for use near highly sensitive magnetic equipment; MRI and Clean Room environments; Corrosion Resistant even in the most severe environments

I'm trying to imagine a scenario where you'd want to use a sledgehammer right next to a live MRI machine. 

The super conductive magnet is on 24/7/365 as turning it off requires draining the liquid cooling it.
Hence even doing work on the floor below requires the special hammer.

[BigClive]

A normal charger will apply far too much current.

I wonder if a special slow charger could be made for alkalines. It might be worth it even if you could only recharge them to 50% a couple of times, that's still double the battery life.

I built an experimental charger that trickle charged alkaline cells continuously at very low current in the region of 10mA.  It was just a plug-in power supply and a diode, resistor and LED in series with each cell holder.

Since alkaline cells lack the chemistry to recombine the gas vented upon charge completion (or possibly even during it) the cells tended to pressurise internally and would sit in the charger and vent randomly with sharp "TCH!" noises.  At first I didn't realise what was making the noise until I was next to it and a cell vented.  This could also explain why any attempts to recharge alkaline cells often results in them leaking.  It's probable that the pressure is violating the seal and pushing electrolyte out.