Nice work!

I notice that Nickel-Zinc batteries are rarely mentioned in this sort of 
discussion; they do require somewhat different charging parameters but 
otherwise are pretty similar to NiCds, but with a 1.6V voltage instead of 1.2.

When it comes to rechargeable 1.5V alkalines my experience has been pretty 
disappointing but that may just be the brand I used; experience with NiCds and 
NiMHs has also been mixed.

m

----- Original Message ----- 
From: "Kurt McCullum" <[email protected]>
To: <[email protected]>
Sent: Tuesday, June 26, 2018 12:06 PM
Subject: [M100] NEC Low battery light update


A couple weeks ago I was asking about the low battery light on my NEC when 
using rechargeable batteries. The problem was that after about 45 minutes the 
low battery light would come on because the voltage difference (1.2 vs 1.5) of 
Alkaline vs NiMh batteries. Originally I was going to look at the power supply 
itself to see if I could replace a resistor so that the light would come on at 
a lower voltage. I opted to leave the power supply alone and focus on the 
battery.

I bought ten 1/3AA NiMh batteries and built a battery pack. There are two banks 
of five 1/3AA batteries and two spacers(S1 & S2). The ending battery pack looks 
like this:
+                -
|   S1 S2   |
|     |     |     |
|     |     |     |
 ---        ---

S1 has a wire that goes to ground, and S2 has a wire going to positive.  The 
two 5 battery banks are in parallel and each bank has a capacity of 300mah, 
giving a total capacity of 600mah. The batteries that I took our of the 
original NiCd back were 500mah so it's very similar to the original which was 
rated to give 5.5 hours. I'm still testing but so far the battery light issue 
has gone away. I need to see how much time I have left once the low battery 
light comes on because rechargeable batteries fall off rather quickly.  Voltage 
on the pack is 6.4v when charged. Very similar to what new Alkaline batteries 
would give.

A Regular 4 battery NiMh battery pack has a much longer run time but the 
problem is that you never know when you are almost out of power. The low 
battery light is on almost the entire life of the battery.

I'll keep you posted on my testing results.

Kurt

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