wptski
Flashlight Enthusiast
We are running into the same problem with the C9000's as the BC-900's! Two different versions out there! I'll have my two replacements on Monday, I hope that I get the newer ones.
Improved Maha C9000…
- Thread starter SilverFox
- Start date
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SilverFox
Flashaholic
Hello Webfors,
One more thing...
When you insert a cell and select a charge rate, the display will show the charge rate, then it shows a higher voltage. This is the internal resistance check on the cell. This voltage ranges somewhere between 1.45 - 2.50 volts.
What voltage are you seeing with these "problem" cells?
Tom
One more thing...
When you insert a cell and select a charge rate, the display will show the charge rate, then it shows a higher voltage. This is the internal resistance check on the cell. This voltage ranges somewhere between 1.45 - 2.50 volts.
What voltage are you seeing with these "problem" cells?
Tom
Anders
Enlightened
Hello Tom.
I have always wanted to know what that numbers mean.
I inserted some of my AAA cells now, the highest number i got was 1,97 V, i think it is the cell with the highest internal resistance, right?
Anders
I have always wanted to know what that numbers mean.
I inserted some of my AAA cells now, the highest number i got was 1,97 V, i think it is the cell with the highest internal resistance, right?
Anders
SilverFox
Flashaholic
Hello Anders,
I am not sure just what it means, but it seems that HIGH displays when that value is over 2.00 volts.
The Energizer 15 minute charger won't charge cells that have over 0.100 ohms of internal resistance. I just happen to have a couple of cells that are very close to that and when I stick them in the C9000 they show 1.7 volts.
I have some Titanium Power Max 1800 mAh cells that have an internal resistance of 0.014 ohms. When I go to charge those cells I get a value of 1.45 volts.
A lot of my cells have 0.030 ohms of resistance and they show 1.62 volts. Others coming in at 0.044 ohms show 1.59 volts.
I may be so bold to suggest that, based on limited preliminary observations, you may want to choose lower charging rates with cells that show 1.7 volts or over during the internal resistance check on the C9000.
This may also enable us to judge the condition of our cells...
Tom
I am not sure just what it means, but it seems that HIGH displays when that value is over 2.00 volts.
The Energizer 15 minute charger won't charge cells that have over 0.100 ohms of internal resistance. I just happen to have a couple of cells that are very close to that and when I stick them in the C9000 they show 1.7 volts.
I have some Titanium Power Max 1800 mAh cells that have an internal resistance of 0.014 ohms. When I go to charge those cells I get a value of 1.45 volts.
A lot of my cells have 0.030 ohms of resistance and they show 1.62 volts. Others coming in at 0.044 ohms show 1.59 volts.
I may be so bold to suggest that, based on limited preliminary observations, you may want to choose lower charging rates with cells that show 1.7 volts or over during the internal resistance check on the C9000.
This may also enable us to judge the condition of our cells...
Tom
Anders
Enlightened
Thankyou Silverfox for your fast reply.
Interesting..., with "lower charging rates" I suppose you mean around 0,5 C?
I have the oldest version of the charger and i think i get more safe charging terminations with a little more than 0,5 C, i usually prefer 0,7-0,9 C. Do you suggest me to lower the mAh with cells with higher V readings to avoid the cells to get hot and still be over 0,5 C?
Anders
Interesting..., with "lower charging rates" I suppose you mean around 0,5 C?
I have the oldest version of the charger and i think i get more safe charging terminations with a little more than 0,5 C, i usually prefer 0,7-0,9 C. Do you suggest me to lower the mAh with cells with higher V readings to avoid the cells to get hot and still be over 0,5 C?
Anders
SilverFox
Flashaholic
Hello Anders,
I don't know for sure, but yes, I think so...
When charging at 2 amps, the charger gets hot and the cells pick up some of that heat. If the cells have higher internal resistance (what I am calling "unhealthy" cells), they will they will heat up more than cells with lower internal resistance.
At lower charge rates, the internal resistance effects is less significant.
I hope that makes sense...
Tom
I don't know for sure, but yes, I think so...
When charging at 2 amps, the charger gets hot and the cells pick up some of that heat. If the cells have higher internal resistance (what I am calling "unhealthy" cells), they will they will heat up more than cells with lower internal resistance.
At lower charge rates, the internal resistance effects is less significant.
I hope that makes sense...
Tom
Anders
Enlightened
For sure it does Tom, thanks.
Anders
Anders
More good information, Tom. Hey a somewhat unrelated question, without paying a fortune, do you have a recommendation on a good resistance tester. Right now, I'm just using this Radio Shack $20 model to at least get voltages.
Got my 0G0B01 today. Put in 4 AAA Powerex 1000's and it recognized them right away. My 0FAB01 would take 20 seconds or more.
Also you know I had some termination issues with AAA batteries. I'm hoping this is all better.
The only strange thing is that it's harder to put in AAA batteries, especially in slot #4. I think the terminals drift downward left to right. I'll have to keep an eye on this.
Cheers to Thomas Distributing and MAHA Energy.
Also you know I had some termination issues with AAA batteries. I'm hoping this is all better.
The only strange thing is that it's harder to put in AAA batteries, especially in slot #4. I think the terminals drift downward left to right. I'll have to keep an eye on this.
Cheers to Thomas Distributing and MAHA Energy.
I was hoping to get mine today, but no luck yet.
Bear
Newly Enlightened
Hi everyone!
This is my first post. I had been lurking around here for about a year and I finally decided to join. Thanks to this site I have learned a lot about flashlights, batteries, and chargers. Thanks to everyone - and especially SilverFox for his thoughtful commentaries!
I bought a C9000 late December and I have had no problems with it except that it doesn't acknowledge the presence of certain batteries, and of course the 2A charge does warm 'em up a bit when all 4 are going. Oddly enough, I found out why certain batteries don't "take" by accident. When inserting a battery more horizontally than at an angle, it "took." I couldn't repeat this but I did find the reason for it. There are two prongs that stick out of the positive terminal contacts of the C9000. On certain batteries these prongs can straddle the positive electrode of the battery. I took a little bit of tin foil and put it over the batteries' positive electrodes and then carefully inserted them into the charger and voila! - they then registered on the C9000.
I don't think there is an issue with the prongs though. Probably with just a little bit of use their sharp points will wear down enough to mate with any battery.
One data pont for Silverfox: I did notice once that an initially displayed voltage surpassed 2.00, actually 2.02, and the charger "took it" and did not display HIGH. I agree that the 2V is probably a good number though, I am just noting that there is a little wiggle room there.
One other thing about the 2A charge. This doesn't apply to the improved version as much as the initial version of the C9000. When I want to charge 4 cells at 2A I just put them into the charger in sets of 2 each staggered by about 5 minutes or so and I also put them in non-adjacent bays. Most of the temperature rise at 2A seems to be in the last minute or two. For cycling I suppose one could vary the discharge rates a bit so that the cells won't all heat up at the same time. FYI.
Good day!!
This is my first post. I had been lurking around here for about a year and I finally decided to join. Thanks to this site I have learned a lot about flashlights, batteries, and chargers. Thanks to everyone - and especially SilverFox for his thoughtful commentaries!
I bought a C9000 late December and I have had no problems with it except that it doesn't acknowledge the presence of certain batteries, and of course the 2A charge does warm 'em up a bit when all 4 are going. Oddly enough, I found out why certain batteries don't "take" by accident. When inserting a battery more horizontally than at an angle, it "took." I couldn't repeat this but I did find the reason for it. There are two prongs that stick out of the positive terminal contacts of the C9000. On certain batteries these prongs can straddle the positive electrode of the battery. I took a little bit of tin foil and put it over the batteries' positive electrodes and then carefully inserted them into the charger and voila! - they then registered on the C9000.
I don't think there is an issue with the prongs though. Probably with just a little bit of use their sharp points will wear down enough to mate with any battery.
One data pont for Silverfox: I did notice once that an initially displayed voltage surpassed 2.00, actually 2.02, and the charger "took it" and did not display HIGH. I agree that the 2V is probably a good number though, I am just noting that there is a little wiggle room there.
One other thing about the 2A charge. This doesn't apply to the improved version as much as the initial version of the C9000. When I want to charge 4 cells at 2A I just put them into the charger in sets of 2 each staggered by about 5 minutes or so and I also put them in non-adjacent bays. Most of the temperature rise at 2A seems to be in the last minute or two. For cycling I suppose one could vary the discharge rates a bit so that the cells won't all heat up at the same time. FYI.
Good day!!
SilverFox
Flashaholic
Hello Bear,
Welcome to CPF.
Thanks for adding to our database of voltages. The highest I have seen has been 2.45 volts. That cell just kept reseting and did not even display HIGH. Any idea what that voltage means?
Another data point... I just stuck an Alkaline Duracell AA cell in. It came in at 1.95 volts, charged for 3 mAh, then indicated DONE.
Good tip on staggering the cells when charging at 2 amps. That should help a lot.
I took my original unit apart and put a small square of black electrical tape on the back side of the + posts. This pushed them a little bit forward and I eliminated any problems with cells not being recognized when inserted.
Tom
Welcome to CPF.
Thanks for adding to our database of voltages. The highest I have seen has been 2.45 volts. That cell just kept reseting and did not even display HIGH. Any idea what that voltage means?
Another data point... I just stuck an Alkaline Duracell AA cell in. It came in at 1.95 volts, charged for 3 mAh, then indicated DONE.
Good tip on staggering the cells when charging at 2 amps. That should help a lot.
I took my original unit apart and put a small square of black electrical tape on the back side of the + posts. This pushed them a little bit forward and I eliminated any problems with cells not being recognized when inserted.
Tom
wptski
Flashlight Enthusiast
Tom:SilverFox said:
The higher the impedance the hiigher the required charging voltage. Maybe it compares the required voltage to produce the set current?
coppertrail
Enlightened
- Joined
- May 21, 2006
- Messages
- 920
The following are results for a set of 4 Sony 2700 mAh cells that came with a Sony charger I purchased in Mid Jan. I've not charged these cells prior to receiving my replacement Maha charger. Here are the results from a break in mode followed by a 1 cycle mode:
Break-In Mode 2/28/07
1. 2633 mAh 1.40V
2. 2611 mAh 1.39V
3. 2620 mAh 1.40V
4. 2651 mAh 1.41V
Cycle Mode (1 Cycle) 3/3/07
Charge rate: 1400 mA
Discharge Rate: 500 mA
1. 2646 mAh 1.43V
2. 2619 mAh 1.43V
3. 2629 mAh 1.43V
4. 2667 mAh 1.43V
Break-In Mode 2/28/07
1. 2633 mAh 1.40V
2. 2611 mAh 1.39V
3. 2620 mAh 1.40V
4. 2651 mAh 1.41V
Cycle Mode (1 Cycle) 3/3/07
Charge rate: 1400 mA
Discharge Rate: 500 mA
1. 2646 mAh 1.43V
2. 2619 mAh 1.43V
3. 2629 mAh 1.43V
4. 2667 mAh 1.43V
Hello friends,
Though I have just signed in as a new member, I have been regularly reading the CP Forums.
My C9000 is from the very first lot shipped by TD. Though I have not extensively tested the charger, it does have termination issues on AAA and sometimes on AA cells too. It is rather strange for a company like Maha to release a advanced charger without extensively testing it. Though they may exchange it with this new 'revised' model, this certainly increases the headache, not only for them but also for us.
Again, who knows, this one too maybe 'imperfect' so to say. Maybe Maha have quickly done a few software mods due to the heat generated in this forum. Now this 'revised' charger, if it misses termination, will stop charging after pumping in 4 amps into any cell. It is quite possible that we may soon have AA cells that are more than 4AH. Then what do we do? Remove the cells and put them back again to charge, or possibly get another charger !!
Some members have mentioned that the new version shows 'Done' on almost all the cells. We will have to ensure that 'Done' definitely means the cells are 100% charged, and not 80 or 85%.
VJ
Though I have just signed in as a new member, I have been regularly reading the CP Forums.
My C9000 is from the very first lot shipped by TD. Though I have not extensively tested the charger, it does have termination issues on AAA and sometimes on AA cells too. It is rather strange for a company like Maha to release a advanced charger without extensively testing it. Though they may exchange it with this new 'revised' model, this certainly increases the headache, not only for them but also for us.
Again, who knows, this one too maybe 'imperfect' so to say. Maybe Maha have quickly done a few software mods due to the heat generated in this forum. Now this 'revised' charger, if it misses termination, will stop charging after pumping in 4 amps into any cell. It is quite possible that we may soon have AA cells that are more than 4AH. Then what do we do? Remove the cells and put them back again to charge, or possibly get another charger !!
Some members have mentioned that the new version shows 'Done' on almost all the cells. We will have to ensure that 'Done' definitely means the cells are 100% charged, and not 80 or 85%.
VJ
Last edited:
SilverFox
Flashaholic
Hello VJ,
Welcome to CPF.
The original C9000 has issues of missed terminations when charging at lower charge rates. It seems that some cells do not exhibit the voltage drop that the original C9000 is looking for to terminate the charge. Maha noticed this during their testing, but I think they wanted to present a charger that charged cells to their fullest.
My personal opinion is that if you are charging at 0.5C and the cell does not give a good end of charge termination signal, your cell is unhealthy and should be replaced, even if there is more life left in it.
However, charging to a fuller charge also increases cell temperatures, and the C9000 when charging at 2 amps heats up as well.
The improved C9000 does not charge as full as the original unit did. Our guess is that it is using a very similar termination algorithm as what is used on the C808M charger. The result of this is that the cells don't get quite a full, but every cell terminates, and the temperatures have come down a little.
I believe the 4000 mAh AA cell is a long way into the future, and will just point out that all of the other chargers have a lower time limit than that. For example, the BC-900 has a 3000 mAh limit.
We are just receiving the improved C9000 units. You may want to hold off doing anything until we see if any other issues surface.
One way to check part of the health of your cells is to pay attention to the voltage displayed as soon as you insert the cell for charging. We have noticed that cells with higher internal resistance show higher voltages during that test, get hotter during the charge, and can have issues with termination. Cells that show around 1.7 volts are rejected on the 15 minute chargers and that value seems to be around 0.100 ohms.
If you don't mind, could you share what values you are getting with your cells that are not terminating?
Tom
Welcome to CPF.
The original C9000 has issues of missed terminations when charging at lower charge rates. It seems that some cells do not exhibit the voltage drop that the original C9000 is looking for to terminate the charge. Maha noticed this during their testing, but I think they wanted to present a charger that charged cells to their fullest.
My personal opinion is that if you are charging at 0.5C and the cell does not give a good end of charge termination signal, your cell is unhealthy and should be replaced, even if there is more life left in it.
However, charging to a fuller charge also increases cell temperatures, and the C9000 when charging at 2 amps heats up as well.
The improved C9000 does not charge as full as the original unit did. Our guess is that it is using a very similar termination algorithm as what is used on the C808M charger. The result of this is that the cells don't get quite a full, but every cell terminates, and the temperatures have come down a little.
I believe the 4000 mAh AA cell is a long way into the future, and will just point out that all of the other chargers have a lower time limit than that. For example, the BC-900 has a 3000 mAh limit.
We are just receiving the improved C9000 units. You may want to hold off doing anything until we see if any other issues surface.
One way to check part of the health of your cells is to pay attention to the voltage displayed as soon as you insert the cell for charging. We have noticed that cells with higher internal resistance show higher voltages during that test, get hotter during the charge, and can have issues with termination. Cells that show around 1.7 volts are rejected on the 15 minute chargers and that value seems to be around 0.100 ohms.
If you don't mind, could you share what values you are getting with your cells that are not terminating?
Tom
dekelsey61
Newly Enlightened
Tom,
If you are right about Maha knowing about this problem during testing then why would a company that produces fantastic products release a product that will not work properly and put there reputation on the line? If a battery does not charge as full I can care less at least you will not be damaging your batteries by alot of heat by the missed terminations. I believe you ran into this problem with the shrink wrapper melting because the batteries did not terminate. Maha did replace your batteries. I would rather have a charger that does not fill as full of a charge than a charger that gets a full charge but you have to worry about if the battery will terminate or even get really hot.
Dan
If you are right about Maha knowing about this problem during testing then why would a company that produces fantastic products release a product that will not work properly and put there reputation on the line? If a battery does not charge as full I can care less at least you will not be damaging your batteries by alot of heat by the missed terminations. I believe you ran into this problem with the shrink wrapper melting because the batteries did not terminate. Maha did replace your batteries. I would rather have a charger that does not fill as full of a charge than a charger that gets a full charge but you have to worry about if the battery will terminate or even get really hot.
Dan
SilverFox said:
Anders
Enlightened
Hello.
It seems that i also soon will have the new improved version of the C9000.
I bought my C9000 from thomas-distributing and a CPF-member was so kind that he sent it to me.
I had a few termination issues and finally yesterday the charger doesn't work at all, the third slot always are marked as it already have one cell in it and is waiting for my command.
Here in sweden i read in a forum that MAHA have a new agency so i contacted them and told them that i bought my charger in US and i asked them if i could send it to them to get a replacement.
They told me that it is a 3 year warranty on chargers here and they are happy to help me, they also told me that they have the new improwed model, that is what i call goodwill
Anders
It seems that i also soon will have the new improved version of the C9000.
I bought my C9000 from thomas-distributing and a CPF-member was so kind that he sent it to me.
I had a few termination issues and finally yesterday the charger doesn't work at all, the third slot always are marked as it already have one cell in it and is waiting for my command.
Here in sweden i read in a forum that MAHA have a new agency so i contacted them and told them that i bought my charger in US and i asked them if i could send it to them to get a replacement.
They told me that it is a 3 year warranty on chargers here and they are happy to help me, they also told me that they have the new improwed model, that is what i call goodwill
Anders
