Maha MH-C9000 SUPPORT / FAQ - continuation

[mactavish]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

I'm not having the issue, but I understand some might have a slight issue which is easily resolved with no cutting on the plastic on your Charger which I would never do. The positive contact can be 20 mil too high, crimp the rounded top off of that and all is well. In the enclosed pic the one on the right has been reworked, it may be hard to see because it's only 20 mils difference.

http://i832.photobucket.com/albums/zz245/electronman5/CDadapters.jpg

I hope that helps.

Your images are oversize, when you post an image please remember Rule #3

Rule #3 If you post an image in your post, please downsize the image to no larger than 800 x 800 pixels.

Please resize and repost. - Thanks Norm

Thanks for the very detailed photo. I thought I might have to do this "mod", or the one mentioned earlier in this thread of removing some plastic on the MH-C9000 charger itself. But before doing anything, I took the two "D" adapters that came with the BM200 (not the aftermarket ones available on ebay, though they may be the same?), and placed them into the Maha charger, they clicked in just fine, and the charger recognized the 2 Tenergy 8000 mAh LSD batteries. Comparing my two adapters to the photo in your post, it seems there is NO extra metal to even bend in. Perhaps they made an improvement or the ones included with the BM200 are different, though one might assume there is only one factory making these adapters in the first place? So far, working fine. I would still assume, that using these adapters, still bypasses any over temp sensors the C9000 has, as these adapters ride higher up on the charger, so one must rely on the timer and voltage cutoffs when charging "D" batteries in a charger that does not officially support this. I only have 4 "D" batteries I need to keep in an emergency LED "Coleman" light, I would use in power blackouts. The rest of my batteries are AA/AAA.

 

[mactavish]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

[/LIST]

Haven't seen you post in a while TakeTheActive! It's good to see you active!

The 2.5 and 3X is referring to the number of regular charge cycles needed to fully charge a completely depleted D cell. During the normal charge cycle, the MH-C9000 has a charge capacity limit of something like 4000 mAh. So, the charger would have to be restarted a couple or three times to completely charge an 8000 mAh to 10000 mAh D cell. Of course, that is not the case when using the break in mode. I only use the MH-C9000 for testing and running D cell through a break in cycle. I use a MH-C808M to charge them. The MH-C808M charges at a pulsed 2000 mA charge current, and the Accuevolution D cell that I have recommend charging at 2000 mA. So far my old D cells have been working very well.

Read everything I could find on using the "D" Adapters with my new MH-C9000, trying to charge the only 4 "D" batteries I own, the Tenergy LSD 8000 mAh. While the general consensus is to use the "Break-In Mode", I just didn't want to wait the 4 days it would take to do both sets of (2). So just for fun, and as a test I put the C9000 on the basic "Charge Mode".

(Charge Rate = 2000 mA = .25C) 1st Charge = 2:15 min. stops at 4,000 mAh - 2nd Charge 2:15 mins, 1.4.0 Volts. - 3rd Charge 30 mins. 1.4.0 Volts, - 600 mAh, then DONE! 5 hours total.

Downside, the resting voltage on the charger, these batteries never show more then 1.40 volts, as opposed to the 1.46-1.48 resting voltages I get when using the R&A mode on all my AA/AAA Eneloops. The other downside is when using the regular "charge mode", you don't get to see the total mAh's, since there is NO discharge cycle. While I only bought these 4 "D" batteries to keep in a Coleman LED emergency light, so I did not want to buy another charger just for these 4 "D" bats, they may be fine at the 1.40 voltage, but I guess I'm going to have to break down, and put them on the "Break-In Mode", if I really want to know their capacity and hopefully get more voltage into them at the end. I'm new to both NiMH batteries and chargers.

Let me take a second to thank ALL the members for their posts, I went back to posts from 2007 regarding usage of the MH-C9000 charger. While there of course are some conflicting comments, I saved many posts in a document to refer to, and just have to weed out, some of the older data that may no longer apply, no easy task for a newbie!

Does this make sense?

 

[Russel]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

[...]
(Charge Rate = 2000 mA = .25C) 1st Charge = 2:15 min. stops at 4,000 mAh - 2nd Charge 2:15 mins, 1.4.0 Volts. - 3rd Charge 30 mins. 1.4.0 Volts, - 600 mAh, then DONE! 5 hours total.[...]

That looks about right, given the 4 Ah limit that the C9000 has in standard charge mode. Keep in mind that you can top off a little more by leaving the cells for a couple hours after "done."

If you really want to get a reasonably accurate capacity reading for your D cells you do need to use the break in mode. Be sure to set up your charging station in a safe manner, especially because of the long time it will take. I like to set up on an old kitchen counter remnant that's about 2' by 3' of stone.

 

[mactavish]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

That looks about right, given the 4 Ah limit that the C9000 has in standard charge mode. Keep in mind that you can top off a little more by leaving the cells for a couple hours after "done."

If you really want to get a reasonably accurate capacity reading for your D cells you do need to use the break in mode. Be sure to set up your charging station in a safe manner, especially because of the long time it will take. I like to set up on an old kitchen counter remnant that's about 2' by 3' of stone.

Thanks "Russel".

I've been following the general advice of leaving all my Eneloops AA/AAA on the charger for an additional 2 hours after "DONE" appears "trickle mode", as it's been mentioned the cutoff on the later model C9000's is about 1.47 volts. Didn't realize that might apply to the Tenergy D's after 3 "charge" cycles. I keep the charger on a fireproof surface with a smoke detector above it, but the approx. 39 hours for "break-in" mode is a bummer, as I prefer to be around when charging bats. I am happy however that I returned the BM200 for "overheating batteries", and got this C9000, have not noticed the batteries getting anything more then warm in all my charging so far.

Using the AA to "D" adapters is a slight concern as I assume they way they ride high up in the charger, negates any built-in charger high temperature sensor cutoffs, and all that's left for the charger brain, is the voltage cutoff point.

Thanks again, I've saved many of your posts regarding charging for my "notes"!

 

[mactavish]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

Not sure what's going on with my charging of the Tenergy LSD 8000 mAh "D" batteries. I decided to put them on "Break-in Mode" on the MH-C9000. 2 "D's", one in each adapter. I think I messed up on the one in slot 2, so I began a discharge on it, and then a manual charge, basically had to bail out on the 39 hour BI mode. But the one is slot 1, was going through it's cycles, and at 15 hours from start of BI mode, it was on it's "charge" cycle, but looking at the charger, it stated 12.4 mAh's, that's 12,400 and the battery felt HOT, so I removed it. I'm beginning to wonder if using these adapters on a charger that is not designed specifically for "D" charging is a perhaps a bad idea in the first place. After all the reading I did, it seemed safe to try the BI mode, but this battery felt very hot, and that number way too high.

Any thoughts?

 

[Russel]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

The break in mode charges the cells at 0.1C for a fixed time of 16 hours. That is 1.6 times the capacity of the cell. NiMH cells at the 0.1C charge rate can tolerate this over charge because it is at a low rate, with respect to capacity, and the charge efficiency is lower at such a low rate. (Charge efficiency at low rates is still a debated subject.) So, it is normal for the cell to be warm after 15 hours of the 16 hour charge.

 

[mactavish]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

The break in mode charges the cells at 0.1C for a fixed time of 16 hours. That is 1.6 times the capacity of the cell. NiMH cells at the 0.1C charge rate can tolerate this over charge because it is at a low rate, with respect to capacity, and the charge efficiency is lower at such a low rate. (Charge efficiency at low rates is still a debated subject.) So, it is normal for the cell to be warm after 15 hours of the 16 hour charge.

Thanks! I guess I panicked when I saw that HUGE mAh number. The manual mentions what you said as well, but since the battery felt more then "warm", as in HOT, I stopped. I wonder how high the mAh figure will go if I left it on the charger. I guess I'm going to have to discharge and try again, though the temperature of the battery can't be good for it for long periods. When I used the Break-In mode on the AAA's then never got hot.

Then again, maybe I should just use the normal "charge" mode, and put all 4 in the LED Coleman light, and see how long it runs, then charge em again, and put it away.

Thanks Russel!

 

[Mr Happy]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

Thanks! I guess I panicked when I saw that HUGE mAh number. The manual mentions what you said as well, but since the battery felt more then "warm", as in HOT, I stopped. I wonder how high the mAh figure will go if I left it on the charger. I guess I'm going to have to discharge and try again, though the temperature of the battery can't be good for it for long periods. When I used the Break-In mode on the AAA's then never got hot.

If you run a break-in cycle on the D cell and enter 8000 mAh as the capacity, then the charger will try to charge the cell at 800 mA for 16 hours (nothing wrong with this, it is what the break-in cycle is supposed to do).

However, 800 mA is rather a large charging current compared to the, say, 200 mA that an AA cell would get. It is often recommended to limit the maximum charging current on a D cell to 1 A or 2 A or so, and 800 mA is a significant portion of this. The D cell is also rather larger than an AA cell with a smaller surface area to volume ratio, so it is harder for the heat to escape.

So it does not surprise me that the D cell would get hot during the break-in cycle. I have not tested D cells myself this way, so I have no direct comparison to make. This is just an estimate.

If you try running a break-in cycle again, you might try entering a capacity of 6000 mAh instead of 8000 mAh and see if the batteries stay cooler.

Also bear in mind there is nothing to stop you running a discharge on the C9000 to measure the capacity of your D cells. I don't think there is a limit on the maximum capacity for discharge.

Lastly, you can use the break-in cycle to run a "manual charge" on a battery. For example, proceed as for a break-in cycle, but enter a battery capacity of 20,000 mAh. This will cause the charger to charge at a rate of 2000 mA for 16 hours. However, you don't have to let it run for this long. Let it run for 4 hours and watch the battery carefully. When the voltage on the display stops climbing and when the battery starts to get very warm, manually stop the charge. Do not leave this to run unattended or bad things will happen if you miss the stop time!

 

[mactavish]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

Thanks "Mr. Happy", I save many of your posts as well, in my home made "Battery Info Manual". More great info, and I like the extra option, for "manual charge" using BI mode, I'll be careful. I feel better reading your post about the HEAT now, at first it was alarming, reminded me of why I returned the BM200 charger, it overheated AA batteries, this C9000 never gets those hot at all.

In your opinion, does keeping these Tenergy "D" batteries on "trickle charge", they way you have to with the "Eneloop" brand, after the C9000 says "DONE", to get from 90% to 100% charged, advice APPLY? That "note" seemed to apply mostly to Eneloops on the C9000 charger. Or since they are so dense, it would take forever, and be a waste of time? They seem to top out at 1.40 volts, where you can get the Eneloops to about 1.47 volts if left on the charger for the extra 2 hours after "DONE", but the AA/AAA are so much smaller.

Thanks again guys/gals for the EDUCATION!

 

[Mr Happy]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

The question of 1.40 volts or 1.47 volts depends on the battery technology. Some of the "older" battery technologies such as you might find in those Tenergy cells will top out at lower voltages than the new batteries like Eneloops. Eneloops in particular go to much higher voltages than some other NiMH cells.

So it may be that the Tenergy cells will never go to 1.47 volts no matter how much you charge them.

 

[mactavish]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

OK, I get it. Right now, with of a bit of a discharge already, I'm just putting them in the standard charge mode, until they say DONE. I'll let them sit and then read the voltage with a meter. I've played with almost every charging mode at this point, and have learned a lot. In 6 months I'll take them out of the emergency LED Coleman lantern and re-evaluate them. It's certainly shown me that AA/AAA charging is a lot simpler, then again that's what the C9000 is really designed to do in the first place. If I had more "D" batteries I would buy a separate charger for them. Thanks again for taking your time to help a newbie!

 

[SilverFox]

Thank you for your answer.
I have this problem with some AA and AAA.
And I have some AA and AAA this problem dosn't exist.

What is strange, o few of them, just passed brake-in process and was full charged.
I expect "done" after a moment of charging such akus rather then "select mode dead cycle", am I right?

Best regards
Paweł

Hello Pawel,

I just ran into this myself.

I have a solar light that rarely gets used. I happen to put a crap battery in it just to see how crappy it would get. I used it a couple of times and ran the battery down. When I put it into the C-9000 charger it would reset again and again.

I moved the battery to a different charger that would allow me to monitor voltage under a low current charge. What I found was that as soon as any charging current is applied, the voltage ramped up to around 3.4 volts.

I believe the Maha charger has a high voltage cut off of around 2.0 volts, so as soon as it applied some current to check the condition of the battery the voltage ran up beyond its cut off and it shut down. As soon as the current is stopped, the voltage of my battery dropped to about 1.4 volts. The Maha charger sees this voltage and recognizes it as a cell that can be charged.

As this cycle repeats you continue to get the reset condition that you experienced.

The bottom line is that my crap cell got crappier and is now in the recycle bin.

Tom

 

[picrthis]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

Thanks! I guess I panicked when I saw that HUGE mAh number. The manual mentions what you said as well, but since the battery felt more then "warm", as in HOT, I stopped. I wonder how high the mAh figure will go if I left it on the charger. I guess I'm going to have to discharge and try again, though the temperature of the battery can't be good for it for long periods. When I used the Break-In mode on the AAA's then never got hot.

Then again, maybe I should just use the normal "charge" mode, and put all 4 in the LED Coleman light, and see how long it runs, then charge em again, and put it away.

Thanks Russel!

Funny how you complained about heat problems with the BM200 too and now the C9000, looks like you have a lot of learning to do yet. It's a shame you are doing the "learning" at the expense of the Seller of the BM200 danaco, because you returned the BM200 for "heat issues" and You kept the C & D adapters and are now using them on the C9000 and having a few issues too; I really hope danaco goes to Amazon and shows them this post as further proof and gets his money back from your fraud. You received a full refund including overnight shipping and kept the C & D adapters with the full intent of using them on the C9000, that's no mistake, it's clearly fraud.

 

[mactavish]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

I still own a BM200, since it's one I can't return, you are welcome to it. Continue on, you amuse me.

 

[picrthis]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

Here's the REAL story;

http://www.danaco.net/BM200.html

 

[mactavish]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

Yes, spelling aside, it's a fantastic "story", nice work.

 

[Illumination]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

How hot should a cell being charged. I charged 4 2650 MAH Duracells last night at 700; woke up surprised they were still charging and touched them. They were really hot so I pulled them. Is this normal? It has been a while since I have used my charger but don't ever remember getting cells hot to the touch. Thanks.

 

[bbb74]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

How hot should a cell being charged. I charged 4 2650 MAH Duracells last night at 700; woke up surprised they were still charging and touched them. They were really hot so I pulled them. Is this normal? It has been a while since I have used my charger but don't ever remember getting cells hot to the touch. Thanks.

That's called a missed termination and you've damaged or killed the batteries. Why did you charge at 700mAh? Its too low for cells of that capacity and it increases the risk of a missed termination. I'd be charging those cells at 1000mAh *minimum*, more like 1200 if you are having termination issues with them.

 

[He's Dead Jim]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

if i make my own battery adapters, do i have to jump out the temperature sensors as well?

i have 6 different size batteries and none of them are AA or AAA.

 

[SilverFox]

Re: SOMETHING COMPLETELY NEW For the Maha MH-C9000: Custom C/D Adapters!

Hello He's Dead Jim,

Welcome to CPF.

I don't think anyone worries about the temperature sensors. You are moving the cells away from the charging circuit so that source of heat is not a concern. If your cells get hot enough to melt the adapters with the maximum charge rate of 2 amps you most likely need some new cells.

Tom