BM200 Charger information.

[StyXSIS]

The functions of the BM200 are great that’s not in doubt for me, it’s probably one of the best i’ve seen, But!, the fact it heats up so Very quickly and gets so hot as it charges has completely put me right off. It’s already been said that it heats up so much it transfers that heat to the batteries as it charges. So basicly it is just burning it’s own circuitry up everytime it’s used heating the batteries with it and killing them and the charger in the process, so why would anyone buy something that’s going to burn out quicker than the other chargers and kill our batteries. You’ve said it’s being worked on but i don’t get why you’d show this one that’s clearly not that good and not just tell us that it’s being updated, so until you’ve got the BM200 updated, I’ll just keep my technoline BL700 charger, it’s served me very well after quite afew years, and it’s saved myself, friends and alot of family members a hell of Alot! of batts from being binned and it hasn’t burnt out or killed any batts, it just works.

[danaco]

@StyXSIS

The functions of the BM200 are great that’s not in doubt for me, it’s probably one of the best i’ve seen, But!, the fact it heats up so Very quickly and gets so hot as it charges has completely put me right off. It’s already been said that it heats up so much it transfers that heat to the batteries as it charges. So basicly it is just burning it’s own circuitry up everytime it’s used heating the batteries with it and killing them and the charger in the process, so why would anyone buy something that’s going to burn out quicker than the other chargers and kill our batteries. You’ve said it’s being worked on but i don’t get why you’d show this one that’s clearly not that good and not just tell us that it’s being updated, so until you’ve got the BM200 updated, I’ll just keep my technoline BL700 charger, it’s served me very well after quite afew years, and it’s saved myself, friends and alot of family members a hell of Alot! of batts from being binned and it hasn’t burnt out or killed any batts, it just works.

Hello Simon,
Yes, I understand your points and they are valid. You are quite correct that heat kills batteries.

One thing I would like to point out is that your Technoline 700 is limited to 700 mA charge current. If you use the BM200 under the same conditions it is as cool as the Technoline or La Crosse BC-700. So it is really not a direct comparison to a 1000 mA charger.

It is only when you try to push higher currents that heating issues occur on all the chargers (La Crosse BC-1000, AccuPower IQ328 etc., except the PowerEx C9000. The BM200 actually performs better in the configuration that I ship than the BC-1000 and IQ328 as far as thermal cycle due to battery heat.

But you are quite correct the Technoline 700 and La Crosse BC-700 and other clones never have heat issues. That is due more to current restrictions than brilliant design. I own those chargers as well and they perform well without even thinking about it. I recommend them all the time.

This brings me to my original design goal with the BM200 that I ship. It can test C and D cells out of the box. The adapters to do that ship in the box. None of the other chargers can do that.

And for full disclosure I sell all of the chargers mentioned.

Thanks for your comments,

[veer (vēer)]

Hey, danaco, nice work, I hope you can optimize this charger up to the level where it becomes viable budget alternative to C9000 :D!

One question - will those BM200 C/D adapters fit C9000 or not?

Ive seen them on sale so I was wondering whether I should buy them or not, Chinese sellers list them as compatible with lots of chargers, C9000 as well, but you never know, just like with Chinese lumens :D!

[danaco]

@vēer

Hey, danaco, nice work, I hope you can optimize this charger up to the level where it becomes viable budget alternative to C9000 :D!

One question - will those BM200 C/D adapters fit C9000 or not?

Ive seen them on sale so I was wondering whether I should buy them or not, Chinese sellers list them as compatible with lots of chargers, C9000 as well, but you never know, just like with Chinese lumens :D!

Yes, the adapters that ship with the BM200 are the same sold separately for the C9000. They are my adapters. That development process had it’s issue also but fixed now and all adapters fit both chargers well. Sold on Amazon and ebay if you want some.

Also beware, there are other BM200 chargers on the market that do not ship with C&D adapters. I have no idea the configuration of these chargers. I can only vouch for the ones that I supply. That will change with the next model, it will be a new model number. In fact there will be a series of chargers with the new model number scheme. I have another surprise charger on the way, the likes of which no one has seen before.

Thanks,

[Jinx]

@danaco

@Jeansy

How accurate is it at termination at various charge rates? What parameters terminate charge?

Hi Jeansy,
Full charge event is -dV like all NiMH chargers. There is a secondary 0dV condition that is checked as well. Depending on either one of those the full condition is set. The 0dV is a backup event, the -dV condition is primary for full charge termination.

I have never seen it miss the termination point on good quality cells, or any cells I tested for that matter. I have tested at all available rates from 200 to 1400 mA. Of course the concern is that at lower rates of charge it is harder for the charger to detect the -dV condition. This charger seems to be very good at determining that event. I suspect the addition of the 0dV algorithm backup may help with that. I have not gotten any reports from testers or customers about the charger missing charge termination. That does not mean it has not happened since not everyone would communicate that to me.

Hope that answered your question.

There are some other conditions that will terminate charge as well which are being added to the new model. They are backup events in case of defective cells or other abnormal conditions. However those are not in the current shipping charger. They will be in the new model. I should have some of those pre-production units for testing within the next week or two.

Thanks,

Thanks for the reply, so the charger doesn’t monitor dT or have a timer (say 16hrs) as back-up termination?

[picrthis]

Hello there Danaco……good to see you post on here, enjoy your stay here it’s a nice place to openly post info and share; Thanks for the thermo pics as you know I’ve got a few of these myself.

[danaco]

@Jeansy

@danaco

@Jeansy

How accurate is it at termination at various charge rates? What parameters terminate charge?

Hi Jeansy,
Full charge event is -dV like all NiMH chargers. There is a secondary 0dV condition that is checked as well. Depending on either one of those the full condition is set. The 0dV is a backup event, the -dV condition is primary for full charge termination.

I have never seen it miss the termination point on good quality cells, or any cells I tested for that matter. I have tested at all available rates from 200 to 1400 mA. Of course the concern is that at lower rates of charge it is harder for the charger to detect the -dV condition. This charger seems to be very good at determining that event. I suspect the addition of the 0dV algorithm backup may help with that. I have not gotten any reports from testers or customers about the charger missing charge termination. That does not mean it has not happened since not everyone would communicate that to me.

Hope that answered your question.

There are some other conditions that will terminate charge as well which are being added to the new model. They are backup events in case of defective cells or other abnormal conditions. However those are not in the current shipping charger. They will be in the new model. I should have some of those pre-production units for testing within the next week or two.

Thanks,

Thanks for the reply, so the charger doesn’t monitor dT or have a timer (say 16hrs) as back-up termination?

Not sure what you mean about monitor dT. If T is temperature then no, that is not a full charge termination event. However over temperature limit does suspend charging on the affected channels only, charging resumes with all parameters stored when temp below limits on the affected channel. All four channels monitored for temperature individually. dV (delta Voltage) is monitored for full charge event, both -dV and 0dV algorithms. No timer since charging a high capacity D cell could take quite a while. 20,000 mAh of charge is a terminating condition. I think that is everything but I will double check it. There may be a high V termination to catch high impedance cells but I am not sure if that is in the current version. I am working on the new unit and things are starting to run together in my head.

In the new model there will be other backups to better deal with defective cells and such. But they are not in the current shipping model and so I am not ready to discuss them as they may change before production.

Thanks,

[danaco]

@picrthis

Hello there Danaco……good to see you post on here, enjoy your stay here it’s a nice place to openly post info and share; Thanks for the thermo pics as you know I’ve got a few of these myself.

Thanks for the welcome. Lots of insightful questions so far. It is good.

[Jinx]

@danaco

@Jeansy

@danaco

@Jeansy

How accurate is it at termination at various charge rates? What parameters terminate charge?

Hi Jeansy,
Full charge event is -dV like all NiMH chargers. There is a secondary 0dV condition that is checked as well. Depending on either one of those the full condition is set. The 0dV is a backup event, the -dV condition is primary for full charge termination.

I have never seen it miss the termination point on good quality cells, or any cells I tested for that matter. I have tested at all available rates from 200 to 1400 mA. Of course the concern is that at lower rates of charge it is harder for the charger to detect the -dV condition. This charger seems to be very good at determining that event. I suspect the addition of the 0dV algorithm backup may help with that. I have not gotten any reports from testers or customers about the charger missing charge termination. That does not mean it has not happened since not everyone would communicate that to me.

Hope that answered your question.

There are some other conditions that will terminate charge as well which are being added to the new model. They are backup events in case of defective cells or other abnormal conditions. However those are not in the current shipping charger. They will be in the new model. I should have some of those pre-production units for testing within the next week or two.

Thanks,

Thanks for the reply, so the charger doesn’t monitor dT or have a timer (say 16hrs) as back-up termination?

Not sure what you mean about monitor dT. If T is temperature then no, that is not a full charge termination event. However over temperature limit does suspend charging on the affected channels only, charging resumes with all parameters stored when temp below limits on the affected channel. All four channels monitored for temperature individually. dV (delta Voltage) is monitored for full charge event, both -dV and 0dV algorithms. No timer since charging a high capacity D cell could take quite a while. 20,000 mAh of charge is a terminating condition. I think that is everything but I will double check it. There may be a high V termination to catch high impedance cells but I am not sure if that is in the current version. I am working on the new unit and things are starting to run together in my head.

In the new model there will be other backups to better deal with defective cells and such. But they are not in the current shipping model and so I am not ready to discuss them as they may change before production.

Thanks,

Ok thanks for expanding, I hope you don’t think I’m being an ass asking all these questions, I’m genuinely interested and learning.

As for what I was referring to, I’ll allow Wikipedia to explain better than I can;

ΔT temperature charging method[edit source]
The ΔT temperature change method is similar in principle to the ΔV method. Because the charging voltage is nearly constant, constant-current charging delivers energy at a near-constant rate. When the cell is not fully charged, most of this energy is converted to chemical energy. However, when the cell reaches full charge, most of the charging energy is converted to heat. This increases the rate of change of battery temperature, which can be detected by a sensor such as a thermistor. Both Panasonic and Duracell suggest a maximum rate of temperature increase of 1 °C per minute. Using a temperature sensor also allows an absolute temperature cutoff, which Duracell suggests at 60 °C.[15]
With both the ΔT and the ΔV charging methods, both manufacturers recommend a further period of trickle charging to follow the initial rapid charge.

Do you also continue to trickle charge? Will the charger kick back in fully at a certain trigger point?

[danaco]

@Jeansy

@danaco

@Jeansy

@danaco

@Jeansy

How accurate is it at termination at various charge rates? What parameters terminate charge?

Hi Jeansy,
Full charge event is -dV like all NiMH chargers. There is a secondary 0dV condition that is checked as well. Depending on either one of those the full condition is set. The 0dV is a backup event, the -dV condition is primary for full charge termination.

I have never seen it miss the termination point on good quality cells, or any cells I tested for that matter. I have tested at all available rates from 200 to 1400 mA. Of course the concern is that at lower rates of charge it is harder for the charger to detect the -dV condition. This charger seems to be very good at determining that event. I suspect the addition of the 0dV algorithm backup may help with that. I have not gotten any reports from testers or customers about the charger missing charge termination. That does not mean it has not happened since not everyone would communicate that to me.

Hope that answered your question.

There are some other conditions that will terminate charge as well which are being added to the new model. They are backup events in case of defective cells or other abnormal conditions. However those are not in the current shipping charger. They will be in the new model. I should have some of those pre-production units for testing within the next week or two.

Thanks,

Thanks for the reply, so the charger doesn’t monitor dT or have a timer (say 16hrs) as back-up termination?

Not sure what you mean about monitor dT. If T is temperature then no, that is not a full charge termination event. However over temperature limit does suspend charging on the affected channels only, charging resumes with all parameters stored when temp below limits on the affected channel. All four channels monitored for temperature individually. dV (delta Voltage) is monitored for full charge event, both -dV and 0dV algorithms. No timer since charging a high capacity D cell could take quite a while. 20,000 mAh of charge is a terminating condition. I think that is everything but I will double check it. There may be a high V termination to catch high impedance cells but I am not sure if that is in the current version. I am working on the new unit and things are starting to run together in my head.

In the new model there will be other backups to better deal with defective cells and such. But they are not in the current shipping model and so I am not ready to discuss them as they may change before production.

Thanks,

Ok thanks for expanding, I hope you don’t think I’m being an ass asking all these questions, I’m genuinely interested and learning.

As for what I was referring to, I’ll allow Wikipedia to explain better than I can;

ΔT temperature charging method[edit source]
The ΔT temperature change method is similar in principle to the ΔV method. Because the charging voltage is nearly constant, constant-current charging delivers energy at a near-constant rate. When the cell is not fully charged, most of this energy is converted to chemical energy. However, when the cell reaches full charge, most of the charging energy is converted to heat. This increases the rate of change of battery temperature, which can be detected by a sensor such as a thermistor. Both Panasonic and Duracell suggest a maximum rate of temperature increase of 1 °C per minute. Using a temperature sensor also allows an absolute temperature cutoff, which Duracell suggests at 60 °C.[15]
With both the ΔT and the ΔV charging methods, both manufacturers recommend a further period of trickle charging to follow the initial rapid charge.

Do you also continue to trickle charge? Will the charger kick back in fully at a certain trigger point?

Oh no, the questions are why I am here in the forum.

Yes, now I understand. That is be a viable method of detecting full charge if the cells were isolated from other thermal sources. As they state little heat is generated by the battery until the cell reaches full charge, after that the charging energy is converted to heat. In it’s present form the BM200 is not capable of that full charge detection method due to thermal contamination from the charge circuits, as is the case with most low cost chargers. In the new model thermal isolation will be improved and there will be thermal measurements used but not the exact method stated above.

The charger is a constant current charger until full charge is detected then charge is terminated and maintenance trickle charge is applied.

I do not have the exact number handy but it is somewhere around 10 or 20 mA. I will get that number for you.

After full charge termination event and trickle charge applied the charger will not reset into any other mode without user intervention.

[Chloe]

In event of power failure during charge cycle, how does the charger behave? Does it have default charging settings?

What happens when you put in already charged cells? How long does it take to detect if they are fully charged and (presumably) enter trickle charge?

[danaco]

@Chloe

In event of power failure during charge cycle, how does the charger behave? Does it have default charging settings?

What happens when you put in already charged cells? How long does it take to detect if they are fully charged and (presumably) enter trickle charge?

In the event of a power failure the charger will default to charge mode at 200 mA upon power up.

Charging fully charged cells terminates usually within a few minutes after start of charge. However this depends on the cells being charged more than the charger. Poor cells with high internal resistance may take longer.

In answer to a previous question about trickle charge rate. The rate depends on the cells internal resistance. It is between approximately 5 - 20 mA. Trickle charge is accomplished by setting the PWM to minimum.

[danaco]

@HKJ

It is very interesting to see these pictures of chargers.

@kreisler

however Japcell, a Denmark company from the Skandinavias, licensed it and is redistributing it as BC4001 model.

japcell has placed its webserver in Denmark, but is not registered as a company in Denmark.

I see the Japcell charger. That is not the same charger even though they look the same. This BM200 has different charge circuits and firmware so that it can do cells up to 20 Ah. Comes with C&D adapters for charging and testing high capacity C & D cells. That is the old version that they had Opus print their name on for retail. It can only do cells up to 3000 mAh. Confusing yes. I will fix that shortly. Sorry to be adding to the confusion.

[Chloe]

Danaco, do you have any other chargers you can test (even lower current Ni-MH)? I started a thread recently about charging temps and your thermal imaging would be a great contribution there!

[danaco]

@Chloe

Danaco, do you have any other chargers you can test (even lower current Ni-MH)? I started a thread recently about charging temps and your thermal imaging would be a great contribution there!

Yes, I have lots of chargers. All the PowerEx chargers. Some Tenergy chargers. The La Crosse chargers. Tell me what you would like to see and I will take some thermals of it. I assume everyone is most interested in AA chargers??

[Chloe]

Hi Danaco, yes I think AA and AAA are the most popular Ni-MH sizes. Although hobby charger data would be nice I would prefer to focus on the kind with built-in charging bay (preferably using the internal power supply for fairness of comparison). Do you have any Nitecore/Jetbeam i4 intellicharger too?

[picrthis]

@Chloe

Hi Danaco, yes I think AA and AAA are the most popular Ni-MH sizes. Although hobby charger data would be nice I would prefer to focus on the kind with built-in charging bay (preferably using the internal power supply for fairness of comparison). Do you have any Nitecore/Jetbeam i4 intellicharger too?

@ Danaco………if you don’t have one let me know and I’ll ship one out to you.

[danaco]

@picrthis

@Chloe

Hi Danaco, yes I think AA and AAA are the most popular Ni-MH sizes. Although hobby charger data would be nice I would prefer to focus on the kind with built-in charging bay (preferably using the internal power supply for fairness of comparison). Do you have any Nitecore/Jetbeam i4 intellicharger too?

@ Danaco………if you don’t have one let me know and I’ll ship one out to you.

Nope, don’t have any of the Nitecore chargers. When I get it I will do a full thermal workup on it.
BTW picrthis I should have a charger to send to you for testing by Thursday.

I just started an AccuPower Accumanager 10 charger with 4 AA cells. I will post those thermal pics soon.

[picrthis]

@danaco

@picrthis

@Chloe

Hi Danaco, yes I think AA and AAA are the most popular Ni-MH sizes. Although hobby charger data would be nice I would prefer to focus on the kind with built-in charging bay (preferably using the internal power supply for fairness of comparison). Do you have any Nitecore/Jetbeam i4 intellicharger too?

@ Danaco………if you don’t have one let me know and I’ll ship one out to you.

Nope, don’t have any of the Nitecore chargers. When I get it I will do a full thermal workup on it.
BTW picrthis I should have a charger to send to you for testing by Thursday.

I just started an AccuPower Accumanager 10 charger with 4 AA cells. I will post those thermal pics soon.

OK, don’t waste your money on one because for AA they run too hot (my person opinion) I’ll get a new one out to you, I have more than I need, keep for your collection to compare against. :bigsmile:

PS: for 18650’s they are OK

[veer (vēer)]

Hehe, I like this thread :D!