Can the Maha C9000 be used to test (not charge) NiZn AAs?

[Paul_in_Maryland]

The Maha C9000 cannot charge nickel-zinc (NiZn) cells. But what about using it to get a quick reading of their voltage? Would it be accurate? repeatable? safe?

 

[TranceAddict]

i think voltage measurement shall works, but mah measurement might be inaccurate since then voltage is different. if the algorithm use integration current with respect to time then it will read correctly.

 

[Conan]

I think you can use it to discharge but not charge as NiZn requires constant current (CC) charge.

 

[357mag1]

The Maha C9000 cannot charge nickel-zinc (NiZn) cells. But what about using it to get a quick reading of their voltage? Would it be accurate? repeatable? safe?

Paul,

I used it to discharge 4 of my Nizn batteries and was watching it closely because I was worried it would discharge them too far. Of course I forgot about it while doing other things around the house. When I ran in to check it they were all done and setting at 1.54 volts. Not sure how long they were there or how much they might have sprung back to that level.

If you are interested here are the mah:

1. 1299
2. 1300
3. 1295
4. 1299

Seemed pretty consistent and that was at a 700ma discharge rate.

 

[Paul_in_Maryland]

Thanks. After reading your experience, I set my NiZn cells to discharge at 1A, the better to simulate a single-die D26 LED drop-in. Hot off the charger, each cell measured 1.72 to 1.74V. After 1 minute, each cell read 1.68V or 1.69V.

 

[357mag1]

Thanks. After reading your experience, I set my NiZn cells to discharge at 1A, the better to simulate a single-die D26 LED drop-in. Hot off the charger, each cell measured 1.72 to 1.74V. After 1 minute, each cell read 1.68V or 1.69V.

That is quite a bit different than mine read. Hot off the charger mine read 1.89 and will still be at 1.80 a couple weeks later. The ones I discharged had been setting around for two weeks.

I use them to power flashlights and a single AA battery powered tooth brush. They run the toothbrush with more energy than Energizer Lithiums.

 

[Conan]

My NiZn batteries come off the charger at 1.82-1.84 after letting it trickle charge for close to 2 hours.

 

[Paul_in_Maryland]

Ah, maybe I didn't trickle-charge them long enough on the so-called fast charger. I left them on for 5 hours and the green LED was lit, though I don't know for how long it had been lit.

Could the company have changed the fast charger's design or charging profile? The fast charger is supposed to be able to charge 1 or 3 cells at a time, but the instructions that came with mine said to charge 2 or 4 cells at a time.

Added: The low voltage reading may be a result of something I'm doing wrong in my Maha charger. Yesterday, after charging my first setof 4 NiZn cells, I immediately placed three of them into my FiveMega 3AA body, powered up my Malkoff M30WF dropin (rated 3.6 to 5V), noted the time, and slipped the flashlight into my trouser pocket. When I removed the light 15 minutes later, the Malkoff was strobing and the body was very hot. I must have been feeding it something like 5.4 volts.

 

[Conan]

Paul, is it the one hour or five hour charger that you have? I have the one hour charger. After it turns green you're supposed to leave it for an additional 90 minutes to reach full.

 

[Paul_in_Maryland]

The one-hour charger. I don't know when it turned green, but I removed the cells after 5 hours.

 

[357mag1]

Paul,

I have the white charger that will charge each channel independently. I only get the high 1.89v reading if I take them off the charger and measure the voltage just as they finish. Kind of like seeing over 1.5volts on my Eneloops right as they finish on the MD-3000 charger. If I leave them longer they come off around 1.84 like Conan mentioned. They will settle around 1.82 after a couple of hours. I took some for my tooth brush on our last underway period (Navy) and after two weeks they measured 1.8volts.

I provided the mah readings from memory in my earlier post and remembered that the battery in channel 3 read lower than the others. After checking my log I see it was 1295mah not 1277 so I'm going to edit that post.

 

[davidefromitaly]

Thanks. After reading your experience, I set my NiZn cells to discharge at 1A, the better to simulate a single-die D26 LED drop-in. Hot off the charger, each cell measured 1.72 to 1.74V. After 1 minute, each cell read 1.68V or 1.69V.

if i remember well, the C9000 read the voltage between two discharge pulses, so during the pulse the voltage is sure lower

 

[MarioJP]

Interesting thread. I have one set of these ni-zn and i use them for my electric 2 AA tooth brush. Funny thing is that I managed to get my la crosse to charge them in my la crosse charger and pull the plug when voltages peak between 1.90 to 1.95 right off the charger. I let them sit around for an hour and voltage rest around 1.84v.

They last and perform really well in my electric toothbrush.

I have done couple charge cycles already. when I discharge them at 500mA readings are 1300mAh every time. I wonder if these cells are going to get a capacity boost at least to the eneloop capacity.

 

[Conan]

^ And that is how you should NOT charge your NiZn cells.

 

[ampdude]

I have done couple charge cycles already. when I discharge them at 500mA readings are 1300mAh every time. I wonder if these cells are going to get a capacity boost at least to the eneloop capacity.

Well, 1300mAh @ 1.6v is fairly close to 2000mAh @ 1.2v already.

I'm interested in owning a Maha C9000 again, but I'm wondering if they'll release a version that can charge NiZn.