The M102 service manual says the trickle charge is at 1.2mA, and some batteries may not be as tolerant.
On Mon, Mar 12, 2018 at 3:54 PM, Fugu ME100 <[email protected]> wrote: > I swapped to NiMH for my replacements mainly because NiCd was hard to > find. Before doing so I did some research on manufacturer > recommendations. This doc is pretty good http://data.energizer. > com/pdfs/nickelmetalhydride_appman.pdf If you look at the Recommended > Charging Rates section (pg 11) it gives this recommendation on trickle > charging: > > '*Finally a maintenance (or trickle) charge rate of less than > 0.025C (C/40) is recommended. The use of very small trickle charges is > preferred to reduce the negative effects **overcharging*.’ > > The NiMH and NiCd self-discharge very badly so if the trickle charge < > self discharge rate things should be fine. > > Looking at the charge circuit on the M100 it is basically a series diode, > resistor (1.8K) and the battery. If the battery is at 0V the max current > is ~2mA, at full charge (3.7V) the current is ~300uA. Based on the > recommendations of Energizer the charge should be <C/40 for a trickle > charge. The battery is ~60mAh, which gives ~1.5mA trickle or maintenance > charge well above that produced in the M100, in fact the NiMH might sell > discharge at that rate. So I went ahead and updated the batteries. > > If you trickle charge at very high rates then NiMH might fail earlier but > so too would NiCd. The initial charge might be slower for NiMH compared > to NiCd but that is not really an issue in this application it is merely > acting as a backup battery. > > > > From: M100 <[email protected]> on behalf of George > Michael Rimakis <[email protected]> > Reply-To: <[email protected]> > Date: Monday, March 12, 2018 at 10:10 AM > To: <[email protected]> > Subject: Re: [M100] batteries... > > The thing about NiMH, is the level of trickle charge that they can > tolerate is a bit less than NiCD. Might not be good in the long run. > > On Fri, Mar 9, 2018 at 5:00 PM, Jim Anderson <[email protected]> wrote: > >> > -----Original Message----- >> > >> > This brings up an interesting point. Having just replaced my NiCad I >> > think I'm going to use my label maker to leave a note about when it was >> > replaced under the battery door. >> >> I like to do this anyway (and not just with m100s), because I find myself >> struggling to remember later which machines have which things replaced, and >> when they were done... >> >> >> >> >> >> >> >> jim >> > >
