mc-3000 discharge rate

hahoo

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for lithium batteries
awesome charger, unreal fast charge rate at 3amps per slot
so why did they cripple it, at a horribly slow 1 amp discharge rate?
it will do eneloops faster than a massive 5000 mah 26650 for petes sake.
why ??
my lil opus 3200, will do all 4 channels on lithium batteries as fast as this machine at 1 amp x4, discharge
i dont get it, somebody explain it to me:confused:
 

ChrisGarrett

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for lithium batteries awesome charger, unreal fast charge rate at 3amps per slot so why did they cripple it, at a horribly slow 1 amp discharge rate? it will do eneloops faster than a massive 5000 mah 26650 for petes sake. why ?? my lil opus 3200, will do all 4 channels on lithium batteries as fast as this machine at 1 amp x4, discharge i dont get it, somebody explain it to me:confused:

Heat mitigation?

Chris
 

sbj

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What most buyers of battery chargers with discharge function do not understand is the fact, that during a discharge all the power in the charger has to be converted into heat.

The discharge power is limited to 15W. You can discharge a single LiIo battery with 2 A.
4 pieces at 2A for example, would be 34Watt of wasted heat. The housing, the built-in heat sink and the 30mm fan are simply too small for this.

If you look at typical RC Hobby charger, you will find that their discharge performance is usually only 1/10 of their charging capacity. The smaller 50W chargers, all have only 5W discharging power.
 

Gauss163

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If you look at typical RC Hobby charger, you will find that their discharge performance is usually only 1/10 of their charging capacity. The smaller 50W chargers, all have only 5W discharging power.

There are in fact some hobby chargers of similar form factor as the MC3000 that can discharge up to 200W or more. These were especially common in the old days for conditioning NiCd packs.

However, achieving the same in the MC3000 would have required very careful design to ensure that the added heat does not have any negative impact.

Some chargers can achieve high rate discharges by using external loads, e.g. iChargers have a regenerative discharge mode that uses charging another battery as the load.
 
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Tachead

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Yep, you need somewhere for all that energy/heat to go. As Gauss said, regenerative discharge is a good option if you have a spare partially discharged lead acid battery handy(preferably deep cycle). Revolectrix has been doing this for years and iCharger started including this option more recently but, they are in a whole other league compared to the MC3000 and other consumer cylindrical chargers on the market. My Revolectrix Powerlab 8 V2 can discharge batteries up to 40 amps, 1344W in regenerative discharge mode for instance. It is nice if you need to pull down one or a bunch of batteries to storage because the weather turned and you couldn't use it/them. Hopefully in the future some consumer cylindrical battery chargers will include this feature or another remote add on that can dissipate/burn the heat/energy.
 

hahoo

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ok tx...
just seems if this lil opus, a toy by size and build comparison, can do a 1 amp discharge x 4 , then this tank of a charger, should at least be able to pull off a 2 amp discharge x 4
i still say they could of done better than a wimpy 1 amp discharge
but what do i know.....
 
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sbj

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Certainly the charger could have been optimized to a slightly higher discharge capacity. Thus, the arrangement of the cooling ribs and the air duct have not been optimally achieved.

...Some chargers can achieve high rate discharges by using external loads, e.g. iChargers have a regenerative discharge mode that uses charging another battery as the load.
I know that. Have a few myself. :)
 

hahoo

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Certainly the charger could have been optimized to a slightly higher discharge capacity. Thus, the arrangement of the cooling ribs and the air duct have not been optimally achieved.


I know that. Have a few myself. :)


yeah, for 100 bucks they could of done way better on it for sure
you can buy 4 decent chargers for what this one cost
 

tatasal

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yeah, for 100 bucks they could of done way better on it for sure
you can buy 4 decent chargers for what this one cost

Yeah, you can say that again... expensive over-hyped product.
 

tatasal

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Maybe, but still the best you can get.

If the best can at the same time mean having to buy an extra housing to prepare the almost certain breaking of the pins that hold the springs, the shutting down of the discharging of 4 cells simultaneously to prevent over-heating due to incorrect air cooling, etc. etc., then, it is.

On the other hand if you are saying that it is more accurate than the others, well, it SHOULD be, as it costs 3 times more, but is it accurate 3 times as much?
 

HKJ

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If the best can at the same time mean having to buy an extra housing to prepare the almost certain breaking of the pins that hold the springs, the shutting down of the discharging of 4 cells simultaneously to prevent over-heating due to incorrect air cooling, etc. etc., then, it is.

All that was fixed long time ago and a lot of people got a free housing to fix their charger.

On the other hand if you are saying that it is more accurate than the others, well, it SHOULD be, as it costs 3 times more, but is it accurate 3 times as much?

Probably much better than 3 times.
And it also have a couple more functions.
 

tatasal

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All that was fixed long time ago and a lot of people got a free housing to fix their charger.



Probably much better than 3 times.
And it also have a couple more functions.

While some issues are fixed in the succeeding model, what about those hundreds of people like me who got the early ones?

A much more expensive product should have much more functions.

Is SkyRC willing to replace us with that 'fixed' one, freight at their expense?

And, can you please enlighten me the "Probably much better than 3 times" more specifically?
 

HKJ

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While some issues are fixed in the succeeding model, what about those hundreds of people like me who got the early ones?
Is SkyRC willing to replace us with that 'fixed' one, freight at their expense?

They have the warranty to get replacement or they can buy new plastic or they can fix it them self.
That is about the same as other chargers.

A much more expensive product should have much more functions.
It has a lot more functionality, that alone can be enough to justify the higher price.


And, can you please enlighten me the "Probably much better than 3 times" more specifically?
As standard it is "only" about 1.5% tolerance, but you can calibrate to less than 1%
Other chargers can be above 10% in tolerance (They are not always calibrated, but just depends on the component tolerances).
Non-pulsing discharge and adjustable lower limit will also secure much better precision than other chargers, if you know how to use it.
 

tatasal

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They have the warranty to get replacement or they can buy new plastic or they can fix it them self.
That is about the same as other chargers.


It has a lot more functionality, that alone can be enough to justify the higher price.



As standard it is "only" about 1.5% tolerance, but you can calibrate to less than 1%
Other chargers can be above 10% in tolerance (They are not always calibrated, but just depends on the component tolerances).
Non-pulsing discharge and adjustable lower limit will also secure much better precision than other chargers, if you know how to use it.

Oh well, l also have used my MC3000, those 'tolerances' are perhaps only seen in your lab precision rigs and l can't find real life usage and performance differences compared to my other chargers and imo, can't really justify the additional $75 price difference.
 

ChrisGarrett

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Oh well, l also have used my MC3000, those 'tolerances' are perhaps only seen in your lab precision rigs and l can't find real life usage and performance differences compared to my other chargers and imo, can't really justify the additional $75 price difference.

Why did you buy it then? What was your thought process as you clicked on the 'submit' button?

The MC3000 is a NERD charger for people who like to write code, review this stuff as a hobby, anal-ize over Nth degree numbers and plot this stuff out on their computers.

There's a 20,000,000 post thread on it, going back to before it was even available, so you had to have had some idea of what you were getting into, no? At least regarding the various features and capabilities, right?

I like the latest and greatest, as much as the next guy and I said here that I really didn't 'need' an analyzing charger for li-ions, like my Maha C9000, but then I bought an Opus BT-3400 and this charger is fine for my analytical needs.

Right now, $100 bucks is more than I want to spend on another charger, but I'm glad the bugs have been worked out and I certainly wouldn't rag on the product if I didn't really use all of the features.

I'm sure if you wanted to sell it for $50-$60, somebody would take it off of your hands.

Chris
 

tatasal

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Why did you buy it then? What was your thought process as you clicked on the 'submit' button?



There's a 20,000,000 post thread on it, going back to before it was even available, so you had to have had some idea of what you were getting into, no?

Well, because of the hype and the promises in 'that' thread of the initial model, I was already sold out even before it came out, that was my thought process.
 
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