Nailbender SST-50: Battery Problem?

[herulach]

If you have some way of rigging it up (or a helpful friend) you could try running it on parallel batteries.

FWIW I have a set of those batteries that will run an incan bulb at 3A (after a fair amount of 'bumping'), so they should be able to hold the current draw.

 

[Bullzeyebill]

As a fellow CPF member I apologize for the comment, "UK thing" made to you by one of our members. You, or your nation do not deserve such a thoughtless, unkind, disrespectful remark. Please do not continue to take the "bait" from this individual.

Bill

 

[Larbo]

Would there be a benefit to using IMR 18650's for better current output??:thinking:

 

[bigchelis]

Would there be a benefit to using IMR 18650's for better current output??:thinking:

10000% hell yes:twothumbs:twothumbs:twothumbs

Unless; the drop-in is direct drive those IMR 18650's will also enable the current to go sky high and you may ruin your drop-in. The tint will turn blue just watch for it. I use DX cells when I notice the tint shift, but otherwise I use AW 2600mAh 18650s.

bigC

 

[shilent]

RedForest, how exactly are you taking the measurements? With my L2P + NB SST-50 2.5A + AW 2600, mine will range from 1.5 to 2+ amps due to bad contact with my multimeter leads. If you are using a multimeter, try placing the leads as flat as possible instead of just using the point.

 

[mdocod]

Some thoughts:

Protection circuits do not shunt current and prevent it from rising above a certain level of output. They are all or nothing. When a protection circuit is "tripped" the circuit to the cell goes "open" and whatever is being powered shuts down until the load is removed.

Protection circuits do have an inherent resistance that is a constant. The combination of the internal cell resistance and a PCB can reduce drive levels on direct drive LED and incandecent configurations compared to using unprotected cells with low internal resistance.

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I did a quick read through nailbenders sales thread (just the first few dozen posts) but didn't find what I was looking for... My question would be as follows:
Does the 3.6-6V driver have a true boost/buck or is it just a buck only driver?

The reason I ask this is that, if it's just a narrow band buck with low over-head requirements, then it's very possible that with a high Vf emitter and maybe a slightly higher resistance 18650 than ideal, you could see reduced drive levels as much as you are seeing.

I would personally run a tailcap test on a pair of CR123 primary cells to see what kind of readings you get. With ~2.5A going to the emitter I would expect somewhere in the ballpark of a 2 or more amp reading from a pair of CR123s. If you get the proper ~2+A reading on CR123s, then it's possible that the module is working fine but the luck of the draw on the Vf is what's hurting you.

Eric

 

[nailbender]

Hi

It is a buck driver and if your 18650 are weak, are out of a laptop or just old then performance may be in question. It is just like any other buck driver there is a overhead to work. If the batteries are weak and sag quickly then you will drop below this threshold rather quickly. The batts may be 4.2 out of the charger but do they hold the voltage properly or do they sag to 3.6 in a few minutes.

Every shiningbeam driver I check on a bench supply and at 4.2 volts they will give 2.5 to 2.8 on most of the more recent batches.

I have just talked to Mac in the last couple of days and he is getting the exact same results as I am using these drivers.

I have close to 200 of these drivers in use and have had less than 5 problems with these drivers. Everyone was either a spring missing around the outside giving unreliable switching or it has been weak batteries with the weak batteries being top problems. All were solved by newer batts.

The easiest way to see if the driver is working properly is drop a set of CR123 PRIMARIES into the host if you are getting proper amperage then I would question the 18650.
IMR should not make much difference and are in fact much lower mah so run time will be reduced in this specific module. 2600 or even 3000 mah will work better as we are not worried about supplied amps as much as keeping proper voltage to the regulator.

I use protected 18650's all the time and several members have given 45 minute runtimes on good 18650 protected AW2600

dave

 

[mdocod]

Hi

The easiest way to see if the driver is working properly is drop a set of CR123 PRIMARIES into the host if you are getting proper amperage then I would question the 18650.

Funny, the builder is suggesting the exact same test that I suggest.

Howdy nailbender!

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Run that test and see what happens :rock:

Eric

 

[RedForest UK]

Oh, I now seem to be getting slightly different messages.. :thinking: I had thought the protection circuit limiting current was a good shout as it said on the specs that the cell had a maximum discharge of 1.6 (it didn't mention 1.6 what, but I assumed Amps) which was the same current draw I was getting on my DMM.

The cells are new and only cycled once and I have tried 4 different samples all with the same results, but they are only the Red and Black DX Trustfire 'true' 2400 cells and so there could well be a problem there, although I've never had any performance problems or experienced 'voltage sag' with them before.

I have now tested the module with an 'unprotected' 18650 cell and it drew 2.00-2.14A at 4.2v which is a lot closer to the claimed 2.5A, however now the cell is down to 3.97A the current draw has dropped of again to 1.7A. That being said it is still drawing higher than my protected cells.

I'm afraid I dont have any primary cr123a cells to test the module available, and the only way I can get any is by buying them at £12 each in the local DIY store so I don't think that is really an option for me at the moment.

I'm also going away again for the weekend so won't be able to comment or run any more tests until Monday when I come back. Thanks everyone for your ongoing interest, help and advice, thanks to CPF I'm sure I'll get it sorted eventually.

lovecpf

 

[Norm]

I had the same problem using an FM 26650 light with Nailbenders D36 drop in, the 26650 battery is perfectly capable of supplying the current required but I had to get rid of evry bit of extra resistance in the light, I soldered short lengths wire across both the large and small springs on the drop in and now get a reliable 2.5A draw on high, I started out with similar figure to the ones you quote. I have never been able to get current above 2A from Trustfire batteries.
Norm

 

[herulach]

Redforest, I have a couple of cheap 123s that will suit for testing purposes. If you want PM me your address and you can have them for the price of postage.

 

[RedForest UK]

Thanks for the offer, but as I live in the UK I think the postage costs and time taken for delivery would be slightly prohibitive.

I took the light out down the fields where I walk the dog last night and the tint is beautiful, quite possibly the nicest I own, the output is still pretty great to even if my cells aren't up to the job.

I've been looking at getting some AW 18650's, but theyre £14.95 each here so as we are now pretty much 100% that there are no problems with the module itself I think I will sell it on to someone who has access to some higher quality batteries that will be able to get the best out of it.

Then I'll start researching and saving up for another high output light that doesnt require so much technical knowledge to get the highest output you can from it. :thumbsup:

Thanks for your help everyone, I just hope the next owner is able to really get 100% out of it.

 

[herulach]

Thanks for the offer, but as I live in the UK I think the postage costs and time taken for delivery would be slightly prohibitive.

I took the light out down the fields where I walk the dog last night and the tint is beautiful, quite possibly the nicest I own, the output is still pretty great to even if my cells aren't up to the job.

I've been looking at getting some AW 18650's, but theyre £14.95 each here so as we are now pretty much 100% that there are no problems with the module itself I think I will sell it on to someone who has access to some higher quality batteries that will be able to get the best out of it.

Then I'll start researching and saving up for another high output light that doesnt require so much technical knowledge to get the highest output you can from it. :thumbsup:

Thanks for your help everyone, I just hope the next owner is able to really get 100% out of it.

I live in the uk as well. postage is about a quid.

AS far as AW cells go, get them direct from the MP. I've not had a customs problem with about 5 orders.

 

[RedForest UK]

Oh, sorry I guess I just assumed most people on here are from the US Thanks again for the offer, I'd be very happy to take it up and give you a bit extra too, but I've put the module on MP now and have a couple of people interested already, so I think it might be sold by then anyway.

Thanks to cpf I'm now convinced that it is simply my cheap 18650's that are the problem with the current draw though, as I have been able to up it with non-protected cells to 2.0A, so I'm thinking it's just internal resistance of the cells proving the problem. I've mentioned all this on the sales thread so hopefully the buyer will be able to really get the most out of the module with good quality cells. :thumbsup: