Cheap Chinese shaver & Ni-Mh cell.

Well I don't know, and I would be very disappointed in 4 shaves on a charge. I have a Norelco (Philips) Aquatec, I have never tested it to find out, but I be very surprised if I didn't get more than 10 shaves before needing a charge. I remember commenting to someone 25 years ago that I thought rechargeable batteries were a great match for shavers. He didn't agree, but I think he was a blade man. Mikek

On Thu, 22 May 2014 17:38:43 +0100, "Ian Field"

I would check first to see if the battery is being adeqautely charged by the Chinese charger. Charge the battery in situ, and then remove it, and do a discharge test, and see how many mAh it supplies.

Peter

wrote:

Might also want to measure the current draw of the razor under load. Typical brand-name razor has two AA cells. That's more than twice the capacity given the high load. Twice 4 is 8. You're in the ball park.

How did you connect to the cell? If you soldered on it, that might be your problem.

"Peter"

That charger is meant to bring a 500mAh cell up to full capacity in about 12 to 24 hours and hold there it will a trickle of about 30mA.

If used with a 2300mAh NiMh cell, it will never become fully charged.

.... Phil

I would think the Chinese charger sense the voltage of the cell, not counting the number of mAh put into it.

So the charger would still be able to charge the cell, it just takes longer. Like about a week give or take.

Depending on shaving frequency and beard properties, the charger may not be able to keep up with the usage.

I wouldn't know, I trim my beard every fortnight or so :-)=

Leif

"Leif Neland" Phil Allison:

2300mAh NiMH cells will not charge at all at 30mA.

.... Phil

Phil Allison har bragt dette til verden:

What do you suggest happens with the 30mA, if it is not uset to charge the NiMH? Does it just turn into heat?

Leif

The 2300mAh battery was charged for 24h in a regular charger before I fitted it.

If I leave the shaver charging for more than the recommended 8h it gets fairly warm.

If I get much more pissed off with it, I might tweak a 3.3V switcher down to the right voltage and wire it for mains only operation.

It'd be a shame to give up on it just yet - it came with a spare foil & cutter block.

As far as I know, any current will reverse the cell's chemical state, however slowly. Is there a lower limit for NiMH cells I don't know about?

I have plenty of NiMH cells and a charger that can go as low as 100mA. Is that high enough to charge the cell?

My guess would be current regulating - there's no chip to sense voltage change.

The old battery got pretty warm if left charging more than the recommended

As I mentioned in an earlier post, I've tried replacing Ni-Cd shaver batteries with Ni-Mh before - they just can't handle the current draw.

The original battery in this one was a single AA cell marked Ni-Mh 500mAh, I tried a low self discharge 2300mAh cell but it didn't work very well.

Its got a 600mAh Ni-Cd in it now - it works OK, but I've yet to find out haw many shaves per charge.

Why do people need to sha where there ain't electricity /? ''''''''''nuts or something /?

The TO92 package might be an LM317 playing NiCd charger.

I wouldn't try using an NiMH cell with such a crude charger. Without proper EOC (end of charge) circuitry, you run a good chance of overcharging and kill the NiMH battery.

Jeff Liebermann har bragt dette til verden:

It's probably not designed to last more than the 14 days return warranty from the chinese website.

Leif

When the cheap Chinese one lets me down, I can fall back on the antique Ronson 55 which has a mains frequency reciprocating armature.

Having to plug it in while I'm using it is a trivial hassle compared to the weight of it - I have to keep changing hands when my arms ache!

I'm quite happy to use a wet shaver when I have to, and when odd whiskers get missed by the trimmer and won't catch the foil.

An option that still hasn't been dismissed out of hand, is to modify a 3.3V switcher down to 1.2V and have a "power brick" arrangement leaded shaver.

The instructions say to take it off charge after 8h - it gets quite warm if you don't!

The one occasionally on "weekly offers" in Lidl cost 3x as much, and aren't without their problems.

The problem with properly priced shavers is the foil doesn't last any longer than cheap ones - and genuine replacements cost nearly as much as a complete new shaver.

The cheap Chinese one came with a spare foil and cutter block - I'd like to bodge it up for at least long enough to use up those consumables.

ch

-3

se

'd

I have an old Norelco three head model that originally came equipped with t wo 500mah cells. I found this thing at the town recycling center about 15 y ears ago. And it was old back then. The present incarnation of batteries ar e 750mah cells. Last year the internal charger crapped out and I couldn't i dentify or get the parts anymore.

I removed the dead charger,(which afforded more room inside) and as suggest ed by someone on this group I built into the shaver a little 20ma constant current supply using an LM317. I installed a standard female power jack in the shaver case and found a cord with a male on one end and a cigarette lig hter plug on the other. This was easier than trying to come up with a small enough 120V power supply that would all be able to stuff into the little v inyl pouch that holds the shaver and accessories. This arrangement will cha rge the batteries enough to give me a few good shaves and works fine.

I have on occasion left this thing plugged in for several days without any problems. But I no longer shave, or use the truck for that matter every day anymore so this is not really an inconvenience. Of course like Jurb said when you think about it there's probably no need to shave at all, but it d oes keep the old lady happy. Lenny

Chances are I might go for a leaded shaver with a power brick style.

Several shavers that would have cost as much for a new foil as replace the whole thing are still in the bottom of the drawer.

Maybe strip the guts out of one of those and wire the battery compartment to the cheap Chinese shaver with a length of flex.