Protected C and D Li-ion for 1185/ROP Hi

[kaidomain]

Hi all,

I just placed an order for more new 18650, C and D Li-ion cells, and need some inputs on the protected PCB board setting. Since most CPF'ers will be using them for 1185/ROP Hi, so it would be great if these protected babies can power them up with single click, and possibly reduce the likelihood of instaflashing.

Does the 1185/ROP single click requirement has to do with maximum current detection setting on the PCB? It allows us to set from 3 to 6A.

The C is great for 8A (2C / capable of 3C) discharge and 10A (2C / capable of 3C) for the D.

Inputs are welcome.

Kai

 

[eprom]

Hi Kai,

You are my Hero...

I am in for these babies. For the current setting of PCB, I can say push them hardly as you can . I read lots of threads about these Li-Ion Batteries and all CPFers says using over 2C is RISC. So I think you can set them for 2C.

and I am Waiting for M@glites, WA/ROP Bulbs, Quality G4 adaptors, SMO/Hybrid/MOP Reflectors, Hotwire Regulators.

 

[depusm12]

Are these going to be the same size as regular C/D cells.

 

[Rommul]

Hi all,

I just placed an order for more new 18650, C and D Li-ion cells, and need some inputs on the protected PCB board setting. Since most CPF'ers will be using them for 1185/ROP Hi, so it would be great if these protected babies can power them up with single click, and possibly reduce the likelihood of instaflashing.

Does the 1185/ROP single click requirement has to do with maximum current detection setting on the PCB? It allows us to set from 3 to 6A.

The C is great for 8A (2C / capable of 3C) discharge and 10A (2C / capable of 3C) for the D.

Inputs are welcome.

Kai

We are going to need details about capacity and the ability of the cells to hold voltage at higher amperages (discharge testing) before any of this can be decided.

 

[DM51]

Are you saying in post #1 that for the C-cell 8A = 2C, therefore this is a 4,000 mAh cell?

 

[LuxLuthor]

Kai, I think you are asking about the problem that some have had with AW's PTC disconnecting the circuit when initial SPIKE current exceeds the 5A (+/- 0.5A).

If your cells could safely output higher currents, then it would make sense to set the PTC higher, accordingly.

I think people's biggest concerns, assuming these are the Lithium Cobalt Ions (vs. Saphion types)...are quality manufacturing, QA testing, PTC component quality, and just pushing the cell.

That is one reason that many are excited by Plasmaman's potential D Li-Ion cells which have very high QA reputation.

 

[mdocod]

IMO: set the PCBs as high as possible, I'll explain why.

1. When it comes to li-ion, the biggest danger is during charging after a series of abused discharges. Current protection can not prevent a catastrophe during a charge anyways.
2. When it comes to lighting up high power incandescent bulbs, it can take a PCB current limit setting substantially higher than the steady state current of the lamp to reliably light up on 1 "click." but this can vary depending on the reaction time of the circuit, some circuits may need to be set even higher to allow 1-click operation.
3. The best thing the current limit is there for IMO, is to protect the cell in the case of a short or abnormally low resistance connection through something. Selecting an appropriate bulb for safety can be left up to the end user, include appropriate disclosures, instructions, and warnings on the website.
4. The most important features of a PCB for most applications are the overcharge and over-discharge protection, That way we aren't killing our cells inadvertently.

I'd like to see PCBs with higher setting for the over-discharge protection... Most are set around 2.5-3V or so... Something more like 3-3.5V under a load would really help extend cycle life, even if it did come at the expense of some measurable AH capacity. I'd also like to see the overcharge protection kick in at around 4.200-4.210V region, so the cell would basically terminate the charge at an appropriate time if the charger failed to.. A good robust PCB with these abilities would take a lot of the guess-work out of using li-ion.

 

[kaidomain]

Are these going to be the same size as regular C/D cells.

No they are not. If we exclude the 2mm think PCB, the C is about a whopping 9mm longer than the NIMH C, and D is about 4mm longer than the NIMH D.

I used to offer regular size D Li-ion, but the manufacturer is just too slow for delivery, plus a regulat D with PCB is over 2mm anyway.

C is 4000mAh and D is 5000mAh. The C is slightly longer than the AW ones but contain more capacity. I can include a stainless steel made extension tube for 3 cell application.

 

[kaidomain]

We are going to need details about capacity and the ability of the cells to hold voltage at higher amperages (discharge testing) before any of this can be decided.

I have the graph and will show them when I finished my sample testing.

C is 4000mAh and D is 5000mAh. Both are capable of 3C dischage. At 3C discharge, the C is able to hold its voltage above 3.2V for 14 minutes, providing a total capacity of 3500mAh. For the D, at 3C discharge, it is able to hold voltage at 3.3V for about 18 minutes, giving a total of 4600mAh.

 

[gratewhitehuntr]

I want some.

I doubt these will only be used in ROP and 1185 stuff.
I've been looking real hard at emoli cells X 4 in my 6D to overdrive 12v stuff.

What sort of time line are we looking at till they hit stateside?

Someone needs to give the man a list of possible applications
(OMG, like everything they can fit in)
and current spikes at startup so he has numbers to work with.


and do it quickly PLEASE cause I want some !!

 

[kaidomain]

The cells are ready, I am just waiting for the right PCB board to snap on.

Both the C and D Li-ion are capable of handling 3C discharge just fine with usable voltage and just a slightly decrease in overall runtime. At 3C discharge we are dealing with 12A and 15A discharge here, so it should be enought for the initial current spike.

Now back to the cell extender and PCB progress.

Kai

 

[Aircraft800]

Kai,

Will the UnProtected cells be avaliable also? I planned on using a maxFlex boost driver which includes an Over Discharge LED (if installed).

I may also be in for some protected also.

 

[LuxLuthor]

Kai,

I am even more confused reading this post again, after seeing your other thread you just started about 10C Lithium Cobalt C-Cells (not to mention that these should be in the battery section of the forum). That thread is reporting 20A in the title, and 30A in the first post, but this thread says 8 to 10A for C cells. There is also your confusion over the voltages in the 10C C-Cell thread.

I don't understand why you are not providing information about the specifics, reputation, safety, QA, life of cells, manufacturer, etc.

Maybe I got on the wrong bus, but this statement in your post #9 is not making sense to me:

"C is 4000mAh and D is 5000mAh. Both are capable of 3C dischage. At 3C discharge, the C is able to hold its voltage above 3.2V for 14 minutes, providing a total capacity of 3500mAh."
​

 

[plasmaman]

I recently purchased unprotected 4 Li C cells - advertised as 5Ah energy capacity. I was interested because they are significantly cheaper than other Li C cells.
I ran a 2.5amp test on each of the 4 cells on my CBA-II. The cells were fully charged and rested for an hour or so. The test was set to cut off at 2.8v.
The results were disappointing. The tested capacities were 2.46ah,2.17ah,2.44ah and 2.37ah.
The runtimes were 59m, 52m, 58m and 56m respectively.
The voltage held up quite well on start up, declined in a farly straight line, but in the last 10 minutes the voltage falls away very sharply.
Moral of the story - you get what you pay for. These cells are perfectly usuable, but mine did not have 5ah capacity.

 

[DM51]

I recently purchased unprotected 4 Li C cells - advertised as 5Ah energy capacity [snip] These cells are perfectly usable, but mine did not have 5ah capacity.

This bears out my suspicion that a cell that is only

slightly longer than the AW ones

could not realistically be a 4Ah cell.

Like LuxLuthor, I am also sceptical about some of the claims made, including the claim of safe 3C discharge. Li-Ions can take 3C for short bursts without problems, but this should not be CONTINUOUS, which is what is implied here.

I would like to see independent testing of these cells so that these claims can be verified/disproved.

 

[brunt_sp]

Does a D cell fit in a SF M6 so far as the diameter is concerned ? I'm not very knowledgable on the technicalities of protection circuits, I would just like 2 X C or D cells to be able to fire up an MN21 with a single click. I've heard about soft-start facilities and perhaps that is what I should be looking into.

 

[rizky_p]

Any ETA on the product you mention Kai? hope you can give a true specs on your li-ion for the sake of safety. Those are like hand grenade..

 

[NextLight]

Kai,

If they are Li-Ion, I would hope you would split the difference and allow a max continuous room temp current of 2.5C. This balances safety and cycle lifetime with hotwire drive capability.

The ideal protection circuit for each cell would:Allow 5C repeated startup spikes for <= 0.1 seconds without damaging itself when cold, limit startup spikes to the max 2C continuous current when hot; open if continuous discharge current is above 2C at 50 degrees C; Limit charge current to 1C cold; and limit charge current to zero at 50 degrees C or when cell voltage is =>4.25V cold ,and ideally reduce the voltage cutoff value over temperature. And, the voltage drop and resistance in this circuit must be VERY low to avoid self heating.

This advanced protection circuit does probably not exist, but that is the safety level preferred to light a "stick of dynamite" in MY hand, or bring it into MY house where there may be loved ones. (For the less experienced Flashaholics: Warnings about the risks of Li-Ion s are in other threads. Search)

And if I may, we not only need lots of manufacturer and actual measurement data from you, but test results validated by several others from CPF's most experienced and respected battery testers who are properly equipped.

Looking forward to many more great contributions, from you to the community.

David