The making of a perfect SecondLifeStorage/BLF Charger: the start of a new venture

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BlueSwordM

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Jul 5, 2017
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430
Hello again guys and gals. BlueSwordM here.

So, I've noticed something interesting here.

Over on BLF, a flashlight forum, I've decided to start on the journey of making a product in a domain from which I have a lot of experience in.

In this case, it's flashlights,batteries, and chargers. So, why not build something that would be close to complete?

Over the years on this forum, I've learned so many things, and I finally want to give back to this forum which gave so much to me.

So, why not make a SecondLifeStorage/BLF charger, the ultimate charger from companies that we know, trust, and have confidence in their skills and experience?

It would be the best charger on the market, with amazing features such as these:


COMPLETE FEATURE LIST

Chosen manufacturer: DLYFull (OEM of ISDT products, Liitokala, and OPUS)

1. Adjustable charging current: (0,05A-0,10A-0,20A-0,30A-0,50A-0,80A-1,00A-1,20A-1,50A-1,80A-2,00A-2,25A-2,50A-2,75A-3,0A).

2. Support for multiple chemistries (Lithium-ion 3,6V-4,2V/3,8V-4,35V, LiFePO4, NiMH, NiZn)

3. Temperature monitoring (45C below 2A, 60C below 3A).

4. 4 cell channels, with support for 10180 cells all the way up to 78mm 21700s.

5. Active cooling if temperature exceeds 45C, or/and if all channels are active above 2,5A.

6. Full current cut-off according to charging current (10%).

7. (5-10V)-30V input voltage compatibility. Stops charging if voltage goes below 10V, but keeps charging settings. DOES NOT RESET ON CHARGING INTERRUPTION.

8. Nickel plated brass rails for more accurate internal resistance measurements. Or nickel plated A3 steel just in case. I have a backup plan for that last one.

9. Internal resistance measurements.*

10. Manual low voltage recovery for lithium-ion cells. Numbers based on 18650 capacities
- Below 2,5V: maximum charge rate of 100mA
- Below 2,0V: maximum charge rate of 50mA
- Below 1,75V: has to be manually activated and confirmed if the feature is enabled
- Below 1,0V: maximum charge rate of 25mA
Disabled from the factory

11. Adjustable max charging voltage for lithium-ion: 3,50V-(n1+0,1V)(n6+0,1V)-4,2V-4,25V-4,30V-4,35V

12. Storage charge/discharge mode: 3,6V

13. Individual channel selection

14. 8 button UI (4 for voltage control, 4 for current control and other functions)

15. 100-200-350-500-700-1000mA constant current discharging functionality

16. Automatic charging current adjustment available


OTHER BASIC FEATURES AND EXTRAS

1. Factory voltage calibration.

2. Reverse polarity protection.

3. Charging/discharging data to USB drive.


Wouldn't that be great to have? Our own perfect little charger.

It's going to be an black anodized aluminium charger for good heat dissipation. To be honest though, the actual reason for this is cost, since a plastic mold would cost way too much for such a "low-volume" product.

Cost has been confirmed to be 49$US including a suitable power supply for max power charging. A lower cost 39$US charger without a power supply has been discussed, but not confirmed.

Anyway, that's it for me!

If you want to discuss about more stuff, just do it, and if you are interested, just leave a comment below.

Features can only now be modified, not added.

The more people that show their interest in buying the charger, the better.

Thank you all, and have a good day.

Note: If this is in the wrong forum, then please move it.

Link to the original thread and interest list:
http://budgetlightforum.com/node/67945

Link to the manufacturer: http://www.dlyfull.com/

If you have any questions, just ask.
 

LithiumSolar

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Oct 8, 2016
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2,389
A few ideas that would be great...
1) A way to disable #10 (physical switch, setting, etc).
2) Most of us buy many chargers because 4 slots aren't enough. A single charger that has many slots, such as 8 or 10, would be pretty epic and guarantee you most people would start buying those over the traditional 4-cell devices.
 

BlueSwordM

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1) Why would the feature need to be disabled however? Is it because of risks or something? At these current levels, nothing bad should happen.


2) Yeah, but then, the costs would jump up.
 

daromer

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Oct 8, 2016
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5,666
But the cost should be per cell so an 8 slot should cost 2x compare to 4slot. The system I have here is 3-100+ slot and it scales based on cell basis rather linear. The first unit is actually the most expensive :p
 

LithiumSolar

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BlueSwordM said:
1) Why would the feature need to be disabled however? Is it because of risks or something? At these current levels, nothing bad should happen.


2) Yeah, but then, the costs would jump up.

1) Because I don't want it and would not buy this charger if that's what it did. If I set it for 1000mA, I would want it to charge a 2.0V cell at 1000mA, not 50mA. Having a setting to disable the feature satisfies everyone's preference.
2) Fair statement. Would 2x 4-cell be cheaper than 1x 8 cell then I assume?

Just providing my feedback since you're looking for comments :)
 

brettwatty

Member
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Jan 14, 2017
Messages
81
Hey mate,

That sounds cool. Some things I would like is if it had open source firmware that can be modifies and also some form of serial communication to the micro controller so I can connect to my Battery Database Portal.https://portal.vortexit.co.nz/

Cheers,
Brett
 

Geek

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Aug 15, 2017
Messages
934
Would be great to have external plugs, so other formats can be attached. Also this would prevent leaks from damaging the unit. This would give the unit huge leverage in the RC market. Depending on design, if cells did not share a common ground I would definitely buy one. You would be able to charge even the most stubborn mismatched 4s pack.
 

jdeadman

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Mar 28, 2017
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941
That sounds like an awesome charger. I love my opus's but I would buy one for sure. (If not more than 1)
 

100kwh-hunter

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Mar 2, 2019
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Really good idea, i agree on multi slots.
Make it expandable? so you can add a extra bay of 10 slots.
So when the first bay is ready, it will switch to the next bay, when that one is done to the third, ect.
You would be able to put everything full, have no time loss, pay attention one time a day.
The most expensive thing would be the first unit with all the controllers and psu.

Is the perfect storage voltige not on 3.3 to 3.4v?
At least i thought it was the perfect long term storage voltige.

Great job, incl a good ir meter
 

watts-on

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May 27, 2017
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Another feature to add could be "Discharge for disposal" where you can safely discharge old/poor quality cells before disposing of them.
 

Geek

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watts-on said:
Another feature to add could be "Discharge for disposal" where you can safely discharge old/poor quality cells before disposing of them.

Not really a feature I require in a charger. I use a 4 slot holder with resistors attached.
 

Kna

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Sep 5, 2019
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brettwatty said:
watts-on said:
Another feature to add could be "Discharge for disposal" where you can safely discharge old/poor quality cells before disposing of them.

That is a good idea. I might implement this on my battery tester.

You can even do regenerative discharge that stores energy in another buffer accumulator instead of wasting it in resistors.
I builded a gizmo like this with chinese modules, ZB2L3 + 2 stages of boost converters instead of resistors, it can discharge my bad 18650 down to 0.5V and store the energy in a 12V VRLA battery. Not super-efficient, but it works ;)


BlueSwordM said:
Hello again guys and gals. BlueSwordM here.
.../...
So, why not make a SecondLifeStorage/BLF charger, the ultimate charger from companies that we know, trust, and have confidence in their skills and experience?

Hello all

Just a few words about internal resistance measurements.
I've not tested all charger-testers in the world of course, but I think that no one of the common cheap models can do this properly and give trusty, accurate and consistent IR measurements. Even an expensive model like SkyRC MC3000 is perfectible on this aspect. Nothing can replace a true IR-meter with 4 wires sensing, like YR1030 for AC IR testing.
So, is it worth bothering with this feature, just because (almost) everyone does it (wrongly)?

Anyway, maybe there is a simple way to improve things without using more expensive parts or alloys: the "wire mod" like it is described for The Opus. The goal is to connect the mobile slider and the related rail with a piece of soldered silicon wire, around 18-24 gauge. No more bad contacts, we can even have the luxury of slightly lubricating the mechanical part of the slides for smooth movements without resistance points :p
 

completelycharged

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Mar 7, 2018
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With the temperatur monitoring, why not just automatically reduce the charge current if the cell starts to get warm above a certain limit. This would allow the removal of a fan from the build.

If you know the cell IR and are monitoring the charge current then you can calculate the effective thermal input to the cell and for a givent ambient temperature you should be able to work out a rough indication as to the expected heat loss.

Having a fan switch on and off while charging overnight may be an issue for some.


"Charging/discharging data to USB drive." + Opensource firmware = massive market
 

completelycharged

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I was thinking back to the late 80's (RC cars) with NiCad cells fast charging with a hurricane blowing on them.
 

BlueSwordM

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Since the charger will be made of aluminium, the constant current linear FETs that will be used will need to be cooled, since they can output around 17W firing on all cylinders.

Edit: The MOSFETs will be used in full saturation mode, to use them in a linear fashion to replace discharge resistors.
 

completelycharged

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"constant current FETs that will be used" ?

Do you mean voltage regulators ?

FET's typically have a very low resistance and for a charger they should dissipate very very little heat ?
 

BlueSwordM

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The MOSFETs will be used in full saturation mode, to use them in a linear fashion to replace discharge resistors.
 
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