Yet even another Eneloop charger thread

[ChrisGarrett]

Is there a voltage at which the NiMH battery is too drained to recharge as with li ion batteries? What is the best voltage at which to recharge?

The Maha C-9000 discharges down .90v as a rule and that level seems safe and healthy for the batteries.

Some chargers won't charge a NiMH battery unless it's above a certain voltage, but usually a dumb charger will charge them up.

Whether getting down to say .50v will damage a battery, I can't really say, but you should be able to charge them back up.

Unlike some situations with lithium-cobalt cells getting discharged down to below 2.50v and left that way for weeks and months, I don't think NiMH will explode when charged back up.

Chris

 

[recDNA]

Thanks Chris. I usually just use them until light gets dim but didn't know at what point I had over discharged them. I will try to recharge by .9 volts now that I know.

 

[KeepingItLight]

I will try to recharge by .9 volts now that I know.

It's also okay to recharge sooner. CPF member Power Me Up concludes from his cycle testing that Eneloops last longer when they are not fully-discharged. In this post, Power Me Up reports getting almost 5000 cycles from his Japan-made Eneloops. Charging was limited to 1.44 volts. Discharge, to 1.1 volts.

 

[recDNA]

Thanks. Great tip.

 

[MidnightDistortions]

It's also okay to recharge sooner. CPF member Power Me Up concludes from his cycle testing that Eneloops last longer when they are not fully-discharged. In this post, Power Me Up reports getting almost 5000 cycles from his Japan-made Eneloops. Charging was limited to 1.44 volts. Discharge, to 1.1 volts.

Usually i'll recharge the cells when they get around 50%. Every once in awhile i'll cycle them down to 0.9 volts in a charger but Eneloops seem robust and the C9000 charges them nicely enough to ensure they are not overcharged at all.

 

[roadwarrior]

One other caveat: after the Maha MH-C9000 shows "Done," you still have to leave your batteries on the charger for an additional 2-hour top-off. Otherwise, you won't get fully charged batteries. Total charging time is about 4 hours.

If you record the start time, and then note how long charging took (as reported by the C9000), you can determine when the "Done" message first appeared. From that, you can add 2 hours, and figure out the earliest time at which charging will be finished.

With the C9000, the top-off uses a tiny current. You don't have to be overly precise about charging times. You can let it run for as much as 12-24 hours after it reports "Done" without damaging your batteries.

I read this Maha MH C9000/Eneloop "caveat" in numerous threads on here and in various reviews.....do you or any of the members on here consider this a con, versus other chargers that do not require the 2 hour trickle charge after the display reads done?

I am trying to make the best informed decision before I purchase a charger. Be interested to hear some opinions from knowledgeable members here.


P.S. I was confused on whether not to ask this question here or start my own thread. The rules stated they preferred folks to use the search function prior to starting new threads with questions. I by no means want to hi-jack the OP's thread. If need be I can create a separate thread, just did not want to violate rules. I apologize in advance if I messed up.

 

[KeepingItLight]

I read this Maha MH C9000/Eneloop "caveat" in numerous threads on here and in various reviews.....do you or any of the members on here consider this a con, versus other chargers that do not require the 2 hour trickle charge after the display reads done?

It's not a con at all. It's just the way the Maha MH-C9000 works. My only complaint is that this makes a poor user interface. "Done" should mean done. I would like to see a second message, perhaps "Done 2," after the trickle charge finishes. It's a hassle to have to figure it out yourself.

I bought the Opus BT-C700. It was cheaper than the C9000, but it is also less capable. It's biggest shortcoming is probably that it does not have a "break-in" mode like the C9000. When the C700 says "done," it means it.

 

[roadwarrior]

It's not a con at all. It's just the way the Maha MH-C9000 works. My only complaint is that this makes a poor user interface. "Done" should mean done. I would like to see a second message, perhaps "Done 2," after the trickle charge finishes. It's a hassle to have to figure it out yourself.

I bought the Opus BT-C700. It was cheaper than the C9000, but it is also less capable. It's biggest shortcoming is probably that it does not have a "break-in" mode like the C9000. When the C700 says "done," it means it.

I agree. Since you mentioned the Opus, I have begun to now to look at the new Opus BT C2000 v 2.2. Too bad there are not any reviews I have been able to find on the V2.2. I read the 2.1 review on here and it was rated "a very good charger", so I will be taking a closer look.

Thanks for the feedback!

 

[WalkIntoTheLight]

Thanks Chris. I usually just use them until light gets dim but didn't know at what point I had over discharged them. I will try to recharge by .9 volts now that I know.

It's really hard to get Eneloops below 0.9v, unless you have mismatched cells in a multi-cell light. But Eneloops are very well matched if similar age, so even that's unlikely. At 0.9v, there's just no more power in them, and the light will shut down.

 

[onthebeam]

I agree. Since you mentioned the Opus, I have begun to now to look at the new Opus BT C2000 v 2.2. Too bad there are not any reviews I have been able to find on the V2.2. I read the 2.1 review on here and it was rated "a very good charger", so I will be taking a closer look.

Thanks for the feedback!

It's the same as 2.1 with the addition of flexibility for lighting up the readouts for a longer time. No difference in performance. I'm in the market for this one too and hoping for a better price. Can be found on eBay for $30.

 

[LedTed]

(REDACTED) Nothing wrong with the 808 charger ... Chris

But you can't use an 808 Drum!

 

[roadwarrior]

It's the same as 2.1 with the addition of flexibility for lighting up the readouts for a longer time. No difference in performance. I'm in the market for this one too and hoping for a better price. Can be found on eBay for $30.

I am actually leaning towards the Maha MH C9000 now.

DL Portable Power is the only place I have been able to find that is shipping V 2.2. Good luck!