C9000 wish list.

[fireguy]

What features would you like to see if MAHA came out with the MH-C9001?
Personally, I think the following would be ideal:


Easy Upgrades

(1) Display the discharge capacity earlier. For example, after the discharge during a break-in cycle, there is a 2-hour rest followed by a 16 hour charge. At this point the discharge capacity is known. If you happen to be near the charger during the rest period, you can read it from the display. Once it starts to charge, however, you have to wait until the cycle completes.

(2) A keypad with numbers used to enter values. All values are entered as a percentage of C, not chosen from a list.. For "CHARGE", you would enter the battery capacity and the charge rate ( .1C, .25C, etc.) The C9000 has the ability to vary the charge/discharge rate much more than it currently gives you the option. For a break-in, you enter the capacity and it calculates .1C and .2C. A 2700 mAh battery has a discharge rate of 540 mAh. You can't normally select this rate but the C9000 will for a break-in.


(3) Use a dot-matrix LCD display instead of the current one. This would allow greater flexibility in displaying information. You could have all values displayed for all channels at one time this way. Also, you could 'zoom' into one channel and display graphs showing voltage or capacity over time. Google crystalfontz for an example of this type of LCD.

(4) 6 charging channels - great compromise between 4 and 8.

(5) Support for C, D, 9V. (not big on my list, but it would be nice)

Wish List

(1) USB port allowing access to data in real-time.




I think this charger is great the way it is, but there's always a couple of extra features that could be squeezed in! :thinking:

 

[problemchild200]

ahhh make it a lithium charger

 

[Glock27]

It would be cool if it retained status if a power failure occurs.
G27

 

[rizky_p]

it's probably better to get a hobby charger if you want that sort of information and flexibility, a C9000 with that features will cost considerably more. IMO

 

[coppertrail]

ahhh make it a lithium charger

My thought is that this will be Maha's next move as we've not seen a new NiMH charger since the C9000. I asked them about this and they simply replied "Check our web site for new product releases". I wouldn't be surprised if they have a Li-Ion charger in the works.

 

[crofty]

Good idea this wish list, especially if maha are listening and will implement some of the suggestions. Although I think you thinking too big. Your wish list imo deviates from the C9000`s aim/purpose, like rizky_p said, it`s more suited to a hobby charger and will bump the price up a fair bit. Good idea but lets be realistic

One thing I`d like to see tweaked: The up/down arrows can be used in cycle mode to see the cycle history, I don`t see why they can`t be used in other modes too.
Using the slot button to move to each cell is great but then haveing to wait for it to rotate through the info on each cell and haveing it change before you can write it down and then haveing to wait for it to come round again, is annoying.

For me, being able to use the up/down arrows to rotate through cell info and haveing your selection stay there for say 8-10 seconds before going back to auto rotate would be a very very welcome tweak. I don`t see why it couldn`t be done either, surely it would just require a firmware revision, unless a design flaw ment it would be too costly or too much hassle.

While waiting for the info to come around I glance at my BC700 then back at the C9000 then at the arrows and think, bah. I`ve even pressed them a few times even though I know they won`t do anything out of frustration The BC700 might have dodgy buttons but at least they control the display. :naughty:

C9000 I love you, but this strange quirk has to go

 

[RA40]

I like that dot matrix display thought. A steady reading of stats for each channel opposed to the scrolling and the zoom for a bar-graph.

Maybe a way to option the display lighting for on-off during charge. Along with an LED to indicate it is powered up and working if there is this display lighting option.

 

[Elliot]

How about a fan. I would really like this in my BC-900.

 

[crofty]

How about a fan. I would really like this in my BC-900.

I put my BC700 on top of a 2.5kg dumb bell weight, at 500mA the batteries stay just warm to the touch, you might need a couple stacked on top of each other for the higher rates on the BC900. I suppose anything metal that`s big enough to absorb the heat would do.

Doesn`t work as well with the C9000 though. Seems there is a considerable heat source directly underneeth the middle 2 cells unlike the BC700 where the only heat source from the charger is at the front under the LCD.

 

[jirik_cz]

ahhh make it a lithium charger

+ 1

C9000 or BC-900 are very good chargers. Now we need a good quality li-ion charger!

 

[NiOOH]

In terms of user interface/features, the only think I could wish for is the addition of backlit on/off switch.
My major disapointment with the c9000 is its charge termination. For a charger of this sophistication, I'd expect to use something better than maxV of 1.47 V. IMO the construction of the charger permits the use of dT/dt. For slower charge rates the maxV can be kept. Also, the top-off charge for AA cells could be made 200 mA for one hour instead of 100 mA for two hours. It will be faster and also the charging efficiency will be a bit better. For AAA cells the top-off rate should be kept at 100 mA but for one hour.

 

[FrontRanger]

One thing I`d like to see tweaked: The up/down arrows can be used in cycle mode to see the cycle history, I don`t see why they can`t be used in other modes too.
Using the slot button to move to each cell is great but then haveing to wait for it to rotate through the info on each cell and haveing it change before you can write it down and then haveing to wait for it to come round again, is annoying.

For me, being able to use the up/down arrows to rotate through cell info and haveing your selection stay there for say 8-10 seconds before going back to auto rotate would be a very very welcome tweak.

Spot on, crofty. This is my only serious complaint with the MH-C9000. Your proposed alteration is also reasonable if it is firmware-only. But...

... surely it would just require a firmware revision, unless a design flaw ment it would be too costly or too much hassle.

... it wouldn't quite be fair to call it a "design flaw" if it's not just a firmware change. Making everything firmware-configurable is ideal, but you never know what tradeoffs their engineers were told to make with respect to cost, schedule, etc. I don't mean to pick nits with you, so much as give them a break on the off-chance that they read this!

 

[Turbo DV8]

Redesign the negative AAA contacts. The negative contacts for the AAA cell just barely nips the end of the cell, which has caused me some charging problems no matter how hard I try to make sure the cell is pushed all the way down.


If the display just must rotate the info... The two figures I need most from the display are mAh and voltage. I hate having to wait for each cell to cycle mAh-current-time to eventually show the voltage in the last display.

My wish list for the reordering of the display sequence:

mAh
Voltage
Current
Time

I actually find more need of time than current, but I place current before time to separate mAh from mA in the cycle, to better avoid inadvertently mistaking mA for mAh.

 

[clintb]

1. USB port for charge / discharge analysis.
2. Charge /discharge rates up to 3000 mAh
3. Smaller increments on charge / discharge rates.

 

[crofty]

... it wouldn't quite be fair to call it a "design flaw" if it's not just a firmware change. Making everything firmware-configurable is ideal, but you never know what tradeoffs their engineers were told to make with respect to cost, schedule, etc. I don't mean to pick nits with you, so much as give them a break on the off-chance that they read this!

Yes that shouldn`t be taken as a digg. You can`t plan for everything so when you start changing things later on your product is bound to "develop" "design flaws"

I second reordering the display sequence, my preference though is:

mAh
Time
Voltage
Current

Also second the higher rates and smaller rate increments. In this case the arrows should scroll through the rates faster than they do now when holding the arrows down, maybe starting of slow and speeding up the longer the button is held down.

Some of these small things really would make all the difference.

 

[Turbo DV8]

Just a small quirk that can be gotten used to (usually) but should be able to correct...

When using the arrow buttons to hold-and-scroll, unless you let off the button the nanosecond you land on your desired setting, it jumps to the next subsequent setting. It would be nice if, when you let off the arrow button, it would stay stopped on whatever setting is on the display the instant you let off the button. This was one of the first annoyances I noted within seconds of first use.

 

[PeAK]

What features would you like to see if MAHA came out with the MH-C9001?
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...I think this charger is great the way it is, but there's always a couple of extra features that could be squeezed in! :thinking:

After perusing another thread, I came across a feature on the Schulze charger that Tom posted. I'll call this the Schulze Feature:

Hello Fred,

I borrowed some "abused" cells from my neighbor and charged them up on the BC-900 at 200 mA. These were AA and AAA cells. 6 of 8 cells missed termination.

I take very good care of my cells and always charge AA cells at 1000 mA and AAA cells at 500 mA when I use the BC-900. At these charge rates, and with vibrant cells, I haven't had any problems with missed terminations.

I picked up some AAA cells that had open circuit voltages in the 0.2 - 0.8 volt range. The first charge on the BC-900 at 200 mA has all cells missing the end of charge termination.

I took some of these same AAA cells and tried them on my Schulze charger at 250 mA. All the cells I tried terminated early at that rate, but when I charged them at 500 mA they terminated properly.
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Tom

By terminating early, the Schulze charger protects the cell from a destructive cycle which allows the "Refresh" mode a chance to work its magic. But why (and how) does the Schulze Charger with this Schulze Feature figure out that the charge should end early with too low a current for a cell that is not "vibrant" ? I did some experiments (still ongoing) looking at the rate at which the charger voltage changes with well behaved (vibrant) batteries and batteries that tend to miss termination.

The basis for this early termination is the identification of a longer term "zero slope" region (gradual rise and then a sudden drop). The next time the sudden drop occurs, the signal is interpreted as the "negative delta-V" signal. Manufacturers will have to determinte the "interval" over which to make the slope assessement and also need to determine the levels of voltages involved. I think this is a more flexible scheme than just terminating on 1.47 Volts but I could be wrong and welcome your thoughts.

PeAK

 

[SilverFox]

Hello PeAK,

The Schulze is actually geared toward faster charging. In order to keep from doing damage to the cells, it uses a sensitive 3 mv/cell for the -dV value.

If you spend some time looking at charging graphs, you will find that at low charging (and discharging) rates, the voltage can bounce around a little. With crap cells, it bounces around more than "a little." The premature termination is one of the early signs that the cell or pack is loosing its vibrancy.

There are some trade offs using a sensitive termination value. Most of the bouncing around occurs early in the charge, so the hobby chargers will shut off termination detection for the first part of the charge. The trade off in this is that if the cell, or pack, is already fully charged, you can overcharge because the termination is shut off.

In "normal" use, this is not a problem, but people often seem to find ways to work "outside the box" when it comes to charging batteries.

Tom

 

[PeAK]

Well put, Tom.

The interesting thing I learned when I was twelve from my woodworking class/teacher was that the simplest design is best. When complexity is thrown in and not managed (or mastered) sufficiently. It becomes a liability and an overhead...maybe even a burden. My history with chargers in probably typical:

Around 2002, I bought my first quality charger from Radio Shack in the form of the 23-425. It's done a good job of keeping batteries vibrant for the most part. One thing that always impressed me is how quickly it would shut down after you put in a fully charged battery (a case of working "outside the box"...as you say).

2 years, ago, I looked hard and long at the $40 Maha C401FS as my next charger and came to this forum to find out (from you) that it has some issues with the fast charge (looks like undercharging from overheating shutdown. Two strikes!!!).

My next charger looked a lot like the Maha for about a third of the price (C401FS was introduced about 2003) and is not surprising given the 5 year gap. But because it is a "no-name" brand, I've been running a lot of tests.
​

A lot of my recent experiments are basically to assess the limitation of chargers (especially new one) with the hope that they do not move "vibrant" batteries into the "non -vibrat" bin. So these postings on the "initial charge" show that there are a lot of people with similar feelings....probably the same ones who charge batteries at 200mA in hopes of prolonging their life but actually do the opposite, unwittingly.

PeAK