The making of the BLF UC4 charger: the start of a new venture, INTEREST LIST, UPDATE 3(Finalized UI and starting design)

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apt323
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sounds awesome very interested! Thumbs Up

BlueSwordM
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Input voltage range: 10V-22V

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http://budgetlightforum.com/node/67401
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hank wrote:
Quote:
That will work well with a 12V solar cell input.

Not for sure yet.

You need to make sure that if a shadow moves across the solar cell and voltage drops below the minimum spec the charger recovers gracefully and continues to charge —- rather than resetting to starting from scratch again. This has been a problem and caution I’ve seen brought up repeatedly with small chargers when people tried using solar cells with them.


DBSAR’s LT1 lantern built-in charger has this issue figured out already. Wink

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BlueSwordM
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@DavidEF, that’s a bit different

But you just gave me an idea on the software side that would be extremely nice.

Why not make an emergency mode in which it turns off charging if the voltage drops between 4,5-10V, trying to consume as little power as possible just to keep itself on and preventing settings from changing?

It should be relatively easy to implement.

My very own high current Beryllium Copper springs Gen 3:
http://budgetlightforum.com/node/67401
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

DavidEF
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BlueSwordM wrote:
@DavidEF, that’s a bit different

But you just gave me an idea on the software side that would be extremely nice.

Why not make an emergency mode in which it turns off charging if the voltage drops between 4,5-10V, trying to consume as little power as possible just to keep itself on and preventing settings from changing?

It should be relatively easy to implement.


Well, what I meant was that the hardware doesn’t have to crash or “reset” when a shadow looms overhead. It can be made to gracefully recover as if nothing happened. I don’t know if it needs software support for that or not. I assume not. But I’m not an EE. Wink

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Only french will understand : drapal !

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If the discharge rate for a single cell was limited to 4.2v at 3 amps it shouldn’t take much more than a 30mm x 30mm space to have it inside the unit.
https://www.aliexpress.com/item/32528721413.html?storeId=923042&spm=a2g1...
In the model above, you would have to have a few more components added to turn the potentiometer into electronically digital controlled. Like this one.

https://www.aliexpress.com/item/32882318330.html?storeId=923042&spm=a2g1...
.
The icharger 208b is relatively small in size with alot of power handling but the power supply to reach the capabilities of the charger takes almost twice the size of the charger.
Charging 4 li-ions at 3 amps each would need around 70 watts from the power supply. The max charge rate would all depend on how small and efficient you could make the power supply for it’s size.

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I think this was going to do 4 cells at once. 4cells*12.6w=50.4w

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Yeah.

You’re going to need at least 50W to dissipate the heat generated by the fully-saturated MOSFETs at full load.

50W would be absolutely massive, especially for a CONSTANT CURRENT load inside of a charger

My very own high current Beryllium Copper springs Gen 3:
http://budgetlightforum.com/node/67401
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

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Joshk wrote:
I think this was going to do 4 cells at once. 4cells*12.6w=50.4w
If your referring to ‘discharge’… I hope it is going to do four cells at one time.

If the heatsink setup mentioned above is added, can the discharge rate be raised above the 750 mAh that is planned now.

Would it be possible to get it up to 2000 mAh (2A) x 4 cells??

Is “mAh” the correct terminology for discharge rate?? Facepalm

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If your trying to find out the discharge capacity and have it graphed like HKJ does, I don’t see why you need to do more than one cell at a time. To me seeing what one cell can do at 3 amps is more important than what 4 cells can do at .5 amps.
Doing 4 cells at a time would require 4 data logging graphs going at once which I guess is possible but the first link I posted would handle one battery at 3 amps, so for 4, you’ll need 4 of those or one 4 times the size.

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moderator007 wrote:
If your trying to find out the discharge capacity and have it graphed like HKJ does, I don’t see why you need to do more than one cell at a time. To me seeing what one cell can do at 3 amps is more important than what 4 cells can do at .5 amps.

The DIY Powerwall community has hundreds of 18650s to load test. They often buy multiple 4-slot dischargers.

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Joshk wrote:
moderator007 wrote:
If your trying to find out the discharge capacity and have it graphed like HKJ does, I don’t see why you need to do more than one cell at a time. To me seeing what one cell can do at 3 amps is more important than what 4 cells can do at .5 amps.

The DIY Powerwall community has hundreds of 18650s to load test. They often buy multiple 4-slot dischargers.


And how much power are they discharging and how big is the load discharger.
If its going to be all in one unit a middle ground has to be meet somewhere, if not then bulkier additional devices could be added I guess.
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They only need to find matching cells, so I would guess the faster they can discharge a set and move on to the next set, the better.

And yes, this would be a use case for the CPU cooler add-on. Not a core requirement of course.

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 How about small cells like 10180?? Make it universal for evey battery out there. And make take protected and unprotected batteries with power bank functionality.

 

 Opus and skyrc and maybe xtar is my choice for manufacturers 

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So I was went over to https://secondlifestorage.com before dropping a link in this thread, and it turns out BlueSwordM is an active member with a matching display pic. So I guess he’s more qualified to explain this use case. lol

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Oh and it seems many of them check the capacity of Thousands of cells. Shocked

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Personally, I do not care about graphing. I’d just like to do a capacity test on 4 cells at a time. Hopefully at a discharge rate higher than 750 mAh.

Other people may have different wants/needs.

You never know how a horse will pull until you hook him up to a heavy load./"Bear" Bryant 

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Graphing can help track the full behavior of the battery, seek for spikes, patterns, etc and understand the real life of the cell.

 

Or put simply: graphs is what makes "lygte-info.dk" so understandable and relevant, it helps bring objectivism to battery tests. A killer feature to me, and probably #1 reason why a MC3000 is sitting a cable away from my computer.

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I hope HKJ don’t mind me borrowing some of his pics. Credit goes to him for the testing.
This is the reason discharging a cell at a higher rate (3 to 5 amps) can determine how good a cell is in the real world flashlight use. This is a bad example because I have chosen probably one of the worst again’t one of the best but it helps to understand the differences.
If you were to only discharge these two cells at .2 amps this would be what you get and the cells would seem very similar in use.
.

.
now try it at a 3 amp discharge.
.

.
In a flashlight 3 amps of current draw is becoming some what low now days, imagine the difference using those two batteries. If you couldn’t run a 3 amp discharge test on some fake 30Q’s with the Ultrafire cell wrapped inside you wouldn’t know the difference unless you had a authentic 30Q to compare it to.
Most all the 4 bay discharge chargers (unless on a professional level) I have seen are limited to 500 ma discharge that requires 4.2v x .5a x 4 = 8.4 watts of power to dissipate.
One cell at 4.2v x 3 amps = 12.6 watts of power to dissipate, 4 at that current would take 50.4 watts of power to dissipate. The 15 watt discharge tester I linked above used a 30mm x 30mm fan and heatsink. To keep the size down it could have a function to discharge only one bay at 3 amps and 750 ma with all 4 bays running.
.
All the hobby chargers I have owned used the case made out of finned aluminum and a small fan to dissipate the heat.

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Logging is going to be harder than expected if it can do high discharge. The resistance of the wires will likely become significant.
Estimating the correction in software would be no fun, and having a separate set of wires for sensing would be no fun. I don’t have a fix, I just wanted to point out the hazard ahead.

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BlueSwordM wrote:
The only problem is that it would add to the cost a lot.

i dont know how much will it add to the BOM, but there are a lot of interesting PD coding ICs from China

we can get rid of included AC adapter if we adapt to QC/PD usb C, so may save some cost

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I really like the idea!
At the moment i am building 2 charger adapter to connect my opus to 2 external battery holder (26650) because my 26650 shocklis are popping out of the charger bay way to often.
But untill i find a charger that suits me better i will use the opus. This charger could be the one that sends my opus in retierment.

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@mrheosuper, that would be a good idea, as the inclusion of a USB-PD power supply would’ve obviously risen the cost a lot.

A 20V 3A USB-C input would be nice.

My very own high current Beryllium Copper springs Gen 3:
http://budgetlightforum.com/node/67401
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

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It offset all these features that will add cost, I propose saving money by making this project just a module. Basically just the heart of the charger, no case. At least until version 1 units are sold to BLF fans. Iterating a full product would be much more expensive than just a module. And functionality is the same.

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BlueSwordM wrote:
@mrheosuper, that would be a good idea, as the inclusion of a USB-PD power supply would’ve obviously risen the cost a lot.

A 20V 3A USB-C input would be nice.


we can detect the protocol of the AC adapter we are using, if it’s low power( 5V2A or 12V1.5A) we can limit the maximum charging current, it’s easy to implement in software, no need to include 20V3A PD psu( 60w adapter is quite overkill IMO)

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We’re not going to include a 60W adapter.

It’s going to be 60W capable.

It needs to be to support 12A of charging current.

My very own high current Beryllium Copper springs Gen 3:
http://budgetlightforum.com/node/67401
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

CLB
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moderator007 wrote:
discharging a cell at a higher rate (3 to 5 amps) can determine how good a cell is in the real world flashlight use.

As a flashlight (not powerwall) user, I think this is important. 2C seems to be a pretty typical discharge rate for this purpose, and for today’s higher capacity batteries, even 3A is minimal. The ideal would be four cells at 3A, but the bare minimum should be at least one cell at 3A. As a side note, the MC3000 can discharge four cells at 2A, with a 60W (12-18V) power supply. The power supply is an in-line brick that seems fine to me, in terms of size.

I know there are compromises to be made here between use cases (flashlights, power walls), size, cost, etc., and I will support this project however those turn out.

BlueSwordM
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@CLB, the MC3000 can only discharge 2A*4 NiMH cells.

With lithium ion, it’s limited to 1A*4 lithium-ion cells.

You don’t need a large power supply to discharge cells at all.

You just need enough heat dissipation.

My very own high current Beryllium Copper springs Gen 3:
http://budgetlightforum.com/node/67401
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

CLB
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BlueSwordM wrote:
@CLB, the MC3000 can only discharge 2A*4 NiMH cells. With lithium ion, it’s limited to 1A*4 lithium-ion cells.

I did not know about the 15 watt limit, so thanks for the correction, BlueSwordM. At least it can discharge one LiIon cell at 2A. (3A would be better. But, yes, 3A * 4 would generate a lot of heat.)

BlueSwordM wrote:
You don’t need a large power supply to discharge cells at all.

My comment about the power supply was not meant to relate to the discharge function, but I realize that wasn’t clear, sorry. Earlier today @Moderator007 posted that “charging 4 li-ions at 3 amps each would need around 70 watts from the power supply. The max charge rate would all depend on how small and efficient you could make the power supply for it’s size.” I was just pointing out that I’m aware of 60 to 90 watt power supplies (including USB-PD) that that seem pretty compact (and cheap) to me, and wondering if the power requirement is a particular challenge for this charger. But I admit I’m over my head in the engineering design discussions, and should stick to commenting on operational features that at least I have a dim grasp of. Carry on!

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