57w vs 100w charger

[solentlife]

If time was money I would not buy either one.
Instead I would buy something like this:

Venom Pro DJI Phantom 3 Quad Battery Charger - Standard/Advanced/Professional/4K



Sent from my iPhone using PhantomPilots

WOW .... money to burn !!

Why not have a look at this one that charges 3 flight batterys and the RC simultaneously without sequencing ...

4in1 Battery Charger Adapter Quick-Charge For DJI Phantom 3 & Remote Controller | eBay

Cost about $40 .....

I have one from Amazon .. slightly higher priced but still well under the price of the DJI single unit !

Nigel

 

[solentlife]

Slow down there, Nigel.

My 57 Watt charger that came with my P3A as well as the 100 Watt charger for the P3P both have coaxial plugs for charging the RC (split off from the heavier cable and connector for the AC batteries) and the RC for my P3A has a little rubber covered coaxial socket for that purpose.

Perhaps along with the P3S earlier versions of the other P3s were different. But I promise you the 57 Watt brick with my P3A has that RC charging lead and my RC has the socket for it.

I maintain that DJI's recommendation might have merit with the 57 W charger but not so much with the 100 W charger at least from a power point of view. Being dumb bricks, there should not be any issues with electrical noise, etc.

OK .. I stand corrected - but the 57 with RC charge lead must only be the Adv version as the Std has no such RC charge lead ... its not needed. Actually it makes sense - as the Adv basically has the same controller as the Pro.

One aspect that I am not happy with DJI chargers : They have no safety factor. They rely on the battery control board to cut out if any irregularities. It is one of the reasons I prefer to use a programmable LiPo charger.
In event of any problem such as under or over voltage, short, unusual event - the charger itself would shut off immediately. But the DJI unit will continue to try push out power ...
A LiPo charger therefore gives a double safety factor ... its own shut down and battery control board shut down.

It still remains that my previous post with a, b, c etc. stands but should be amended for RC charge lead.

Nigel

 

[Bad Andy]

Why not have a look at this one that charges 3 flight batterys and the RC simultaneously without sequencing ...

4in1 Battery Charger Adapter Quick-Charge For DJI Phantom 3 & Remote Controller | eBay
Cost about $40 .....

That one won't send to the 'States. :-( But a fairly decent deal it seems. Would be even nicer in my opinion if each battery circuit had maybe 1 Amp or so more capacity.

One aspect that I am not happy with DJI chargers : They have no safety factor. They rely on the battery control board to cut out if any irregularities. It is one of the reasons I prefer to use a programmable LiPo charger. In event of any problem such as under or over voltage, short, unusual event - the charger itself would shut off immediately. But the DJI unit will continue to try push out power ...
A LiPo charger therefore gives a double safety factor ... its own shut down and battery control board shut down.

I think it's more than bit of a leap for one to assume that what appears to be a fairly run-of-the-mill switching power supply brick supplied by DJI features no protection from over-voltage or over-current/short-circuit scenarios. If that were the case I sincerely doubt it would be able to carry the dozen or so certification logos that it has from various electrical device approval organizations around the globe.

Not sure what an "unusual event" would be. Pepsi syndrome? Fire? Will the programmable charger detect flames?

Also, for what it's worth, typical failure modes for switching supplies are low/no voltage, not over-voltage.

The responsibility for managing the charging of the cells in a battery subsequently falls upon the electronic circuitry within the battery pack, along with monitoring after charging. I don't see a huge problem with that. And that is in fact your second safety if designed correctly.

I understand you'd prefer to micro-manage each cell in the pack with a programmable charger that you have personal confidence in, rather than being forced into blind confidence of a circuit inside a turnkey pack that you can't see and put your fingers on. That's fine. But I don't think the OEM arrangement is as bad as you believe. I don't get the safety argument. Either DJI's battery control board manages things or the programmable charger's regulator/logic board manages things. Either way it's managed.

I agree there are potential benefits to individually supplying charge current to and managing each cell. You could get slightly quicker charging because the regulator circuitry would not need as much compromise for power dissipation in the beginning of charging versus declining charging current in the end of the charging phase. Although recommended charging curves tend to neatly follow the compromise anyway. And if the DJI's pack circuit doesn't individually manage each cell during charging, you have a better guarantee of getting the most out of the pack if for some reason the cells get substantially out of balance. But unless you're taking liberties with the critical battery warnings when operating the aircraft, I don't see how any of that affects safety.

I think you're being too nervous about stuff you can't see, but again, the difference in preferences is fine.

 

[N017RW]

I agree blind-faith in the DJI batt pack circuitry is one which those who do have experience with ‘typical’ LiPo chargers are not comfortable with.

For me there is no evidence of the CC-CV profile preferred for the chemistry. This was determined by monitoring the profile or pack voltage during charging.
I accept that this may not be a major issue since DJI has been very successful thus far in preventing failures during the charging of their packs.

 

[Bad Andy]

All I know about charging profiles is what the LiPo manufacturers recommend. Of course science is not always an absolute and what the manufacturers suggest tomorrow may differ from what they suggest today, but LiPo isn't all that new any more. Specialized silicon for the purpose is ubiquitous now. When millivolts count, it actually comforts me somewhat to have the silicon electrically closer to the cells.

I would not rush to judgment against what's in the packs until someone can point to better, authoritative information about that circuitry. The only real down-side I'm seeing about how the DJI packs work - based on what I can find on the Interwebz in a cursory search - is the lack of ability to charge the four cells in the pack independently. There is definitely individual cell monitoring and thermal protection in a stock P3x pack.

I wonder how much of this is blind faith in one circuit with clever advertising behind it versus blind faith in a circuit we're just expected to trust.

So far the most frequent DJI battery failure reports I'm seeing are in the form of people not sticking the darn things in securely and them falling out during flight. D'OH!

Is anyone using fancy-pants aftermarket chargers in the hopes of improving on the charging curve, cell charging or cell monitoring? No matter what you hook up to a stock pack, the batteries will still charge serially. Once one cell tops out in that configuration, the rest aren't gonna move substantially without risking thermal damage. At best you could just wind up with a slower, more gradual charging curve that may not be proven to be beneficial.

 

[N017RW]

Do a little more research. Some of your statements are incorrect.

The power supply many refer to as the ‘charger’ is just a supply. Attaching a different supply won’t change the charging profile, times, etc. Some may provide better detail such as the amount of charge delivered but won’t yield a better or different quality charge.

 

[Bad Andy]

Do a little more research. Some of your statements are incorrect.

The power supply many refer to as the ‘charger’ is just a supply. Attaching a different supply won’t change the charging profile, times, etc. Some may provide better detail such as the amount of charge delivered but won’t yield a better or different quality charge.

Tell me specifically what statement or statements you believe to be incorrect. Perhaps I have something to learn.

My initial post in this thread used the word "charger" (erroneously as you point out) multiple times but also included a paragraph at the bottom clarifying that the DJI bricks were actually just simple power supplies.

I would like to point out that technically right or wrong, even DJI refers to those bricks as "chargers". To the Great Unwashed, the distinction is largely lost.

 

[solentlife]

That one won't send to the 'States. :-( But a fairly decent deal it seems. Would be even nicer in my opinion if each battery circuit had maybe 1 Amp or so more capacity.

There are various sellers of this charge system and many sell to the States. Amazon is one.

Ramping up amp rate is actually not good as the battery control board cannot take high rates of charge. The main power contacts do not pass direct to battery - they pass through board circuitry which would reduce amp rate anyway.

I think it's more than bit of a leap for one to assume that what appears to be a fairly run-of-the-mill switching power supply brick supplied by DJI features no protection from over-voltage or over-current/short-circuit scenarios. If that were the case I sincerely doubt it would be able to carry the dozen or so certification logos that it has from various electrical device approval organizations around the globe.

Actually wrong. - Certification is based on a product meeting design specs and submitted data. Safety in electrical is usually that shorts / faults be contained within the product and unless major - should not endanger surroundings. Certification in fact is a lot less than people think. Second that leabel and warnings are part of that - which is why many items carry warning about using outdoors / damp areas etc.
I know for example a brand of Flashlight - certified for all EX use : USA, EU, in fact universal, (that's all areas subject to Petrochermicals, Explosives etc. where any electrical item must be strictly designed). The particular brand can be opened without 'key' and internals exposed. All other brands have 'key' to prevent such.

Not sure what an "unusual event" would be. Pepsi syndrome? Fire? Will the programmable charger detect flames?

Also, for what it's worth, typical failure modes for switching supplies are low/no voltage, not over-voltage.

It is not unknown for failures to have voltage pass through and in the time it takes for components to 'burn out' can do damage further on.
Ever had a charger damage a phone or other item ? I know I'm not only one.

The responsibility for managing the charging of the cells in a battery subsequently falls upon the electronic circuitry within the battery pack, along with monitoring after charging. I don't see a huge problem with that. And that is in fact your second safety if designed correctly.

Think you missed the point. With my use of a LiPo charger - I have the chargers built in safety functions which will mean that it will cut out on detection. This backs up DJI batterys own functions. When it cuts out - the charger has NO power at plug connection to battery. Its ZERO. But the DJI charger still provides 17.5V as it has no such cut-out, it relies on the battery circuit.

I understand you'd prefer to micro-manage each cell in the pack with a programmable charger that you have personal confidence in, rather than being forced into blind confidence of a circuit inside a turnkey pack that you can't see and put your fingers on. That's fine. But I don't think the OEM arrangement is as bad as you believe. I don't get the safety argument. Either DJI's battery control board manages things or the programmable charger's regulator/logic board manages things. Either way it's managed.

Again you miss the point. DJI have decided that all decisions on charge are decided by battery circuit board. You have near zero balance function, you have total voltage functions only. There is no CC / CV mode changes during charge - it is purely CV all the way.

I agree there are potential benefits to individually supplying charge current to and managing each cell. You could get slightly quicker charging because the regulator circuitry would not need as much compromise for power dissipation in the beginning of charging versus declining charging current in the end of the charging phase. Although recommended charging curves tend to neatly follow the compromise anyway. And if the DJI's pack circuit doesn't individually manage each cell during charging, you have a better guarantee of getting the most out of the pack if for some reason the cells get substantially out of balance. But unless you're taking liberties with the critical battery warnings when operating the aircraft, I don't see how any of that affects safety.

Trying to understand where you are with that one ... In fact if it was possible to access balance lead and execute programmable normal LiPo charging - you would most likely have longer charge time. Why ? Because a LiPo charger works by bulk charging till near full, then swaps to balancing cells. It will be discharging high cells and then charging low ... in cycles. It is not uncommon for this to be a significant part of the charge time. But the end result is a balanced pack.

I think you're being too nervous about stuff you can't see, but again, the difference in preferences is fine.

Nervous ? No way. I charge up and use my DJI ... I appreciate DJI making it simple. It is that I know I can charge and balance my packs better if I was given access to the packs like other LiPo's. I do not say everyone has the knowledge, but many like me who have been in RC Electrics LONGER than DJI have been providing Phantoms .... might prefer manual access and control.

Nigel

 

[solentlife]

All I know about charging profiles is what the LiPo manufacturers recommend. Of course science is not always an absolute and what the manufacturers suggest tomorrow may differ from what they suggest today, but LiPo isn't all that new any more. Specialized silicon for the purpose is ubiquitous now. When millivolts count, it actually comforts me somewhat to have the silicon electrically closer to the cells.

It is universal that LiPo charging is best based on CC / CV modes where bulk voltage is supplied until near full. Then balancing of cells is made ...

This DJI do not do. The charger just supplies bulk 17.5V and circuitry then cuts of when battery pack reaches 17.4V

I would not rush to judgment against what's in the packs until someone can point to better, authoritative information about that circuitry. The only real down-side I'm seeing about how the DJI packs work - based on what I can find on the Interwebz in a cursory search - is the lack of ability to charge the four cells in the pack independently. There is definitely individual cell monitoring and thermal protection in a stock P3x pack.

Cell and Thermal is for Telemetry and FW limits. It will initiate action if outside limits. That's it.

I wonder how much of this is blind faith in one circuit with clever advertising behind it versus blind faith in a circuit we're just expected to trust.

?? Having dismantled more than one P3 pack and others I was in communication with doing similar - we arrived at common results. The DJI system works as a good safety measure for new kids on the block to avoid errors in LiPo use. But it seriously limits experienced users access to maintain LiPo manually.

So far the most frequent DJI battery failure reports I'm seeing are in the form of people not sticking the darn things in securely and them falling out during flight. D'OH!

You sure ? Most frequent are actually cell voltage inbalance and failure to correct, batterys not charging after storage, one or more cells failing. In fact often not that different from other LiPo's when aged ... trouble is - we cannot access the DJI cells to try manual recovery.

Is anyone using fancy-pants aftermarket chargers in the hopes of improving on the charging curve, cell charging or cell monitoring? No matter what you hook up to a stock pack, the batteries will still charge serially. Once one cell tops out in that configuration, the rest aren't gonna move substantially without risking thermal damage. At best you could just wind up with a slower, more gradual charging curve that may not be proven to be beneficial.

Makes no difference in charge time unless you set lower amp than a DJI brick. The charger will still only pass voltage through the circuit board. It cannot pass into balancing stage because circuit board will shut down once total voltage is reached, and we have no balance lead connected to charger anyway.
What you do have though - lets give example of an Accucel 6 80W charger ..... you can see in the picture, you have :

Settings showing type and cell count of battery being charged
Present voltage level
Amp rate charging
mA gone in
Time on charge



So the question then is : Would you prefer just blind charging or know what is going on ?

I know for some it may be a bit OTT all this and simple charging is asked. That's fine.

Nigel

 

[N017RW]

Tell me specifically what statement or statements you believe to be incorrect. Perhaps I have something to learn.

My initial post in this thread used the word "charger" (erroneously as you point out) multiple times but also included a paragraph at the bottom clarifying that the DJI bricks were actually just simple power supplies.

I would like to point out that technically right or wrong, even DJI refers to those bricks as "chargers". To the Great Unwashed, the distinction is largely lost.

Nigel pointed out my concerns with your statements adequately above.

With something this well understood and technical in nature it’s easy for you to research the points made and accept or refute them technically.

There’s a lot of experience here and folks will point out when ANY of us are a bit off the mark.

 

[Thermographer]

It is universal that LiPo charging is best based on CC / CV modes where bulk voltage is supplied until near full. Then balancing of cells is made ...

This DJI do not do. The charger just supplies bulk 17.5V and circuitry then cuts of when battery pack reaches 17.4V



Cell and Thermal is for Telemetry and FW limits. It will initiate action if outside limits. That's it.



?? Having dismantled more than one P3 pack and others I was in communication with doing similar - we arrived at common results. The DJI system works as a good safety measure for new kids on the block to avoid errors in LiPo use. But it seriously limits experienced users access to maintain LiPo manually.



You sure ? Most frequent are actually cell voltage inbalance and failure to correct, batterys not charging after storage, one or more cells failing. In fact often not that different from other LiPo's when aged ... trouble is - we cannot access the DJI cells to try manual recovery.



Makes no difference in charge time unless you set lower amp than a DJI brick. The charger will still only pass voltage through the circuit board. It cannot pass into balancing stage because circuit board will shut down once total voltage is reached, and we have no balance lead connected to charger anyway.
What you do have though - lets give example of an Accucel 6 80W charger ..... you can see in the picture, you have :

Settings showing type and cell count of battery being charged
Present voltage level
Amp rate charging
mA gone in
Time on charge



So the question then is : Would you prefer just blind charging or know what is going on ?

I know for some it may be a bit OTT all this and simple charging is asked. That's fine.

Nigel

I am thinking about getting on of these chargers is there a specific adapter needed for the phantom 3 battery?

 

[solentlife]

Search eBay ... loads of cables ... example :

For DJI Phantom 3 2+ Battery to B6 B6AC Balance Charger Connector Charge Cable | eBay

Way to do charge :

Setting of Charger is Lithium High Voltage, 4S, 5A max, charge mode only.

Switch on battery - plug in charger lead and press start.

All stops automatically.

You can use it to read battery voltage as well ... switch on battery - set charger to battery meter ... plug in ...

Nigel

 

[Bad Andy]

Nigel pointed out my concerns with your statements adequately above.

With something this well understood and technical in nature it’s easy for you to research the points made and accept or refute them technically.

There’s a lot of experience here and folks will point out when ANY of us are a bit off the mark.

Okidoki.

I know that Nigel has a lot of experience and has done a fair amount of digging. His name is all over here, DJI and other RC groups. Just want to be clear that I'm not dismissing what he has to say.

As for the notion that I'm suggesting "ramping up amp rate", I'm well aware that the power goes through the battery control board. My comment concerning that charger on Amazon relates to simple math. DJI 57 W P3S/P3A "charger" = 3.25 A capacity. DJI 100 W P3P "charger" = 5.7 A, reduces charge time ~ 25%. Mystery Maker 4-in1 "charger" = 4 A per circuit, advertises charge times close to what most people here experience with the P3S/P3A "chargers". So it seems to me that the Chinese 4-in-1 could offer a little more capacity without being harmful. If on the other hand you're suggesting that the increased capacity may in your experience be harmful, then that means we shouldn't be using DJI's P3P chargers either.

This goes right back to the whole thing about devices only drawing as much as they are designed to. You can hook up a pack to a 17.5 Volt source capable of supplying 100 Amps but the DJI's controller should be the final arbiter of what the current consumption and power transfer rate will be. Is that not so in actuality?

Hey, does that Chinese 4-in-1 have over-voltage protection? ;-)

I know that a lot of those certifications and approvals are actually completely on the honor system, too, and at most are subject only to random testing if at all. But it's still an assumption that DJI's bricks have no protection. If on the other hand you can show me a schematic diagram of a power supply for a DJI P3 that reveals a lack of short and over-voltage protection, I'd like to see that.

I have to point out that it's also an assumption that protection mechanisms won't fail. I have seen "crowbar" protection circuits fail, along with the results.

For what it's worth, in all my years dealing with many thousands of switching mode power supplies, I've only seen one* exhibit an over-voltage condition. I put an asterisk there because of an important distinction. That one supply was one of my own - a $10 (!) no-name offshore PCI unit. I've also seen two crappy USB phone "chargers" (getting tired of the quotes yet?) fail that way. I refer to these as Canal Street Specials - a nod to the good ol' days when NYC's Canal Street was an electronic hobbyist's Mecca. But I've never seen an OEM unit from Apple or Samsung fail that way. Get where I'm going with this? ;-)

And just to be nit-picky, if your LiPo charger has a no-load cut-out, it still has to be measuring for presence of a load somehow. It may be close to zero on the output leads but it's not gonna be zero. Anyway, that just means that exposed leads aren't a danger to some dingbat with a metal key or something. But I do get the point.

I'm curious about what is being said about the charging profile. You can't assess a current condition by monitoring voltage unless you somehow have a handle on internal cell resistances. You'd need a voltmeter across the cell pack and a DC ammeter in line with the charging current to accurately determine the charging profile being used by DJI's battery controller.

I am aware that the approach being used by DJI does not appear to use any kind of balancing, thanks. Pretty sure I mentioned that.

I totally agree that a different "charger" would only offer the opportunity for a slower charging curve. I think I said that too.

Interesting that part of the balancing routine would discharge high cells. Why?

 

[N017RW]

Okidoki.

I know that Nigel has a lot of experience and has done a fair amount of digging. His name is all over here, DJI and other RC groups. Just want to be clear that I'm not dismissing what he has to say.

As for the notion that I'm suggesting "ramping up amp rate", I'm well aware that the power goes through the battery control board. My comment concerning that charger on Amazon relates to simple math. DJI 57 W P3S/P3A "charger" = 3.25 A capacity. DJI 100 W P3P "charger" = 5.7 A, reduces charge time ~ 25%. Mystery Maker 4-in1 "charger" = 4 A per circuit, advertises charge times close to what most people here experience with the P3S/P3A "chargers". So it seems to me that the Chinese 4-in-1 could offer a little more capacity without being harmful. If on the other hand you're suggesting that the increased capacity may in your experience be harmful, then that means we shouldn't be using DJI's P3P chargers either.

This goes right back to the whole thing about devices only drawing as much as they are designed to. You can hook up a pack to a 17.5 Volt source capable of supplying 100 Amps but the DJI's controller should be the final arbiter of what the current consumption and power transfer rate will be. Is that not so in actuality?

Hey, does that Chinese 4-in-1 have over-voltage protection? ;-)

I know that a lot of those certifications and approvals are actually completely on the honor system, too, and at most are subject only to random testing if at all. But it's still an assumption that DJI's bricks have no protection. If on the other hand you can show me a schematic diagram of a power supply for a DJI P3 that reveals a lack of short and over-voltage protection, I'd like to see that.

I have to point out that it's also an assumption that protection mechanisms won't fail. I have seen "crowbar" protection circuits fail, along with the results.

For what it's worth, in all my years dealing with many thousands of switching mode power supplies, I've only seen one* exhibit an over-voltage condition. I put an asterisk there because of an important distinction. That one supply was one of my own - a $10 (!) no-name offshore PCI unit. I've also seen two crappy USB phone "chargers" (getting tired of the quotes yet?) fail that way. I refer to these as Canal Street Specials - a nod to the good ol' days when NYC's Canal Street was an electronic hobbyist's Mecca. But I've never seen an OEM unit from Apple or Samsung fail that way. Get where I'm going with this? ;-)

And just to be nit-picky, if your LiPo charger has a no-load cut-out, it still has to be measuring for presence of a load somehow. It may be close to zero on the output leads but it's not gonna be zero. Anyway, that just means that exposed leads aren't a danger to some dingbat with a metal key or something. But I do get the point.

I'm curious about what is being said about the charging profile. You can't assess a current condition by monitoring voltage unless you somehow have a handle on internal cell resistances. You'd need a voltmeter across the cell pack and a DC ammeter in line with the charging current to accurately determine the charging profile being used by DJI's battery controller.

I am aware that the approach being used by DJI does not appear to use any kind of balancing, thanks. Pretty sure I mentioned that.

I totally agree that a different "charger" would only offer the opportunity for a slower charging curve. I think I said that too.

Interesting that part of the balancing routine would discharge high cells. Why?

Your post is too long for my patience.
But that's not your problem. I'm old.

I will not address each point you make 1-1 because some of the foundations of your assertions are not correct. This makes further assertion also incorrect.

I've made no claims with respect to any specific aftermarket or 3rd party charger other than to say that to the batt. pack... a supply is a supply, period.
I never said any of them are harmful. Are you confusing me with someone else?

The notion you can't determine a CC-CV profile without elaborate equipment may be true... if you don't understand what the profile looks like from a purely pack voltage perspective.

A simple pack-terminal voltage monitor will suffice.

I never said that the pack circuitry does not provide balancing. In fact it does. I said: "It does not apply a CC/CV profile."

Balancing is achieved during charging as that is active, while discharging is passive and it would be difficult and inefficient to try and do this under load due to the currents involved. And yes, during the charge cycle high cells are drained to achieve balance. Each cell (voltage) is independently monitored via a balancing interface which also contains a switchable shunt.

A different power supply (charger) of increased capacity, as compared to OEM, will not reduce charge times. However, one which provides less capacity would increase charge times depending on the specs.

Chargers which have added capacity can charge multiple packs simultaneously but no one pack will charge any faster than the on-board circuitry will allow. This can be claimed to be faster since it can be a parallel function rather than serial.

BUT BUYER BEWARE... as some only charge serially despite the crafty claims.


Edited for typos.

 

[solentlife]

The battery board regulates the charge rate based on the DJI charger pumping 17.5V at it.

Just because the charger is 100W capable does not mean the battery gets 5.7A .... in fact watching a programmable LiPo charger connected - it never gets that high even on a heavily discharged pack. You can set the charger to high amp - but the board will prevent high rate.

Nigel

 

[solentlife]

Balancing is conducted in any of three ways depending on the charger / unit used;

1. Conventional LiPo chargers bulk charge to near full total voltage, monitoring cells as they charge. Before hitting full total voltage, the balancing circuit cuts in and HIGH cells are discharged through resistors. Cycle can be - discharge and then charge again - basically bring high cells down and then low cells up. This repeats till cells balance.
2. Only discharge of high cells and manual charge all up. Not common now except with dischargers such as 3in1 and similar. This is where the unit has no charge capability.
3. Recycled power where high cells can be bled to low cells - but this is rare and requires a highly sophisticated control charger ... some Pro-Lab chargers do this I believe.

Virtually no balancing occurs at low level unless based on 2. Where user would connect pack and manually initiate balancing.

It does not need investigation in fact to see that DJI system does not conduct full balancing. If it did then we would see increasing charge times on our packs as they age. Regardless of 'chip' - the DJI board cuts off on total voltage. This therefore prevents any balancing of normal sequence. The only balancing it can do is while charge is raising the packs to that final voltage.
Discharge can help - but only because taking battery down to cut off level - approx. 3v per cell will have less Internal Resistance effect at the low voltage.

The bottom line is that DJI do not allow us to interact with our packs except via their control board.

Nigel

 

[Bad Andy]

Sorry if my blanket (unquoted) replies made it confusing for people to figure out what comments were meant for whom. I incorrectly assumed it would have been obvious.

I do appreciate Nigel's discussion of LiPo charging/balancing methods.

I did not claim that anyone said a particular charger was harmful. I did ask if anyone was suggesting that would be the case. Exact wording is above: "If on the other hand you're suggesting that the increased [power supply] capacity may in your experience be harmful, then that means we shouldn't be using DJI's P3P chargers either."

I did not write that anyone was making specific claims about third party chargers or power supplies. I also never said or implied that N017RW or anyone else claimed the DJI control board did balancing. Not sure why all that had to be bold, italicized, underlined, etc. And I'm sorry if anyone thinks an ammeter is "elaborate equipment".

I brought up that question about potential harm because I seemingly got scolded (by Nigel) for suggesting that the 4-in-1 charger could use another amp per circuit, with him writing "ramping up amp rate is actually not good as the battery control board cannot take high rates of charge". Another amp per circuit from that 4-in-1, at 4 Amps per branch stock, still leaves it short of the current capacity of the P4P "charger". So if the higher rate is gonna be bad from that 4-in-1 PSU, then it's gonna be just as bad if not worse from the P4P's 100 Watt PSU. It if is indeed bad from the P4P PSU, that needs to be brought to light and explained.

Further, Nigel wrote "just because the charger is 100W capable does not mean the battery gets 5.7A" and N017RW wrote "no one pack will charge any faster than the on-board circuitry will allow.". So even if the "charger" we use is good for 100 Amps it absolutely will not matter to the battery pack. Plus, that tells me that at least to some degree, current regulation is being performed, which would seem to contradict the claim that DJI's charging is CV all the way.

If any of that needs technical explanation, please speak up.

 

[N017RW]

This topic has been discussed for years here.

I appreciate that you may have ‘lurked’ here for years despite your official joining date but you don’t seem to have searched previous threads.

So, I’m not going to rehash this again.

I have used ‘dumb’ LiPos and ‘Smart’ chargers & balancers for a bit more than a decade so I, as do many others here, have some basis for comparisons to DJI’s implementation.
They have made LiPos safe for the casual user.
Compare their record to the reports of ‘HoverBoard’ battery accidents (remember them?).

I stand by my statements. Do your own experiments and then post your results.

 

[Bad Andy]

And I was experimenting with LM -series regulators, designing constant-current circuits, etc. for battery charging in the 80s, in between fixing people's CB radios and fiddling with digital circuits. My bathroom reading was a Radio Shack catalog. While you think an ammeter is "elaborate".

I defer to your experience with LiPo batteries and specialized chargers but seriously, if you didn't use an ammeter then your experiments with DJI packs appear to involve too much interpolation. I'd be much happier to see you graphing the display readings of an ammeter on the battery side of the battery management board instead of just relying on voltage curves.

 

[solentlife]

Cheers mate -- just for the record - I don't scold.

I post adding or correcting what I read. I can be wrong as anyone else.

As to charge rate - as any load - the amp rate is based on its demand unless read short. This does not mean the battery board will have capability to swap CV / CC mode. The DJI charger bangs out 17.5v whatever ....

When watching my lipo charger display - I see the amp rate declining as expected as the battery level increases. I have as a test set the amp higher - but it never reached that figure - it max'd around 5A, quickly declining as charge continued.

I will try and video / photo example.

Nigel