Hi Guys
This is my first ever post on BLF so hope all goes well.
I recently took delivery of the new Fireflies ROT66 Gen II, version: Nichia 219B sw45k R9080 (it seems just in time since it now appears to be out of stock). I like it a lot and my only reservation is that I wish the 219b’s were sw40k or even 35…
I took a few goes to figure out that 30Q’s weren’t going to work and settled on using VTC6’s.
At some point I noticed a that the light was not running at full brightness and on investigation found that one of the (double) springs on the bottom plate (if that’s what it’s called?) had melted, tip stuck to the cell on removal, had lost its elasticity and was sitting squashed to the floor of the plate.
Photo
I repaired it by lifting it up some (elasticity had completely gone) and the light has returned to full brightness.
I have 5 questions that I hoped you guys might help with:
1. What could have caused this? (Most prob human error 
)
2. Could I just get three new high quality thicker copper beryllium springs and replace the lot.
3. If I replaced all with a thicker guage spring is there still an advantage to go with a double spring design.
4. It would be interesting to cut a new bottom plate of solid copper (like the Emisar D18) and solder new springs to this – would it work/ cause problems?
5. If replacing with a solid copper plate, would it need insulating covering like the original?
It is quite similar to some of Haikelite products. You can replace the springs better and the problem is solved. You can contact FF customer service and hope to have the active support.
(used the “embed” option)
Thanks Vietnamreview, will also definitely check in with Fireflies customer service.
The thick Emisar BeCu springs can be bought separately on intl-outdoor.com. Maybe they would fit?
My Youtube channel: Alllightson Reviews
My OL contest builds: 7th 8th 9th
My reviews: Sofirn SP31 V2, Nightwatch NI40, Sofirn C8F 21700, Brinyte WT01, Sofirn SD05,Ti AAA keychain, Sofirn SP33 V3, Skilhunt M150
My video-reviews: Brinyte WT01, Sofirn SD05, Ti AAA keychain, Sofirn SP33 V3
Is it possible batteries at different voltages were ever loaded at the same time? That could cause to much current.
Lamlucky13, I have to admit in the search to load batteries where the positive terminal stood out to get a connection, I loaded three unprotected button tops where one was a different make (and probably voltage)
Well, it provides an opportunity to upgrade the light and do some simple modding….
Skylight, thanks for the info on Emisar springs – I will investigate.
Do you have an idea whether putting a solid copper plate in there will cause a problem by potentially decreasing resistance?
Link to Emisar springs
You should measure if they fit.
Decreasing resistance shouldn’t be a problem. I think the Fireflies ROT66 Gen II is build already with a low resistance. Most likely you will not notice the increase in brightness with a tail copper plate, maybe you can measure it but you won’t see it.
My Youtube channel: Alllightson Reviews
My OL contest builds: 7th 8th 9th
My reviews: Sofirn SP31 V2, Nightwatch NI40, Sofirn C8F 21700, Brinyte WT01, Sofirn SD05,Ti AAA keychain, Sofirn SP33 V3, Skilhunt M150
My video-reviews: Brinyte WT01, Sofirn SD05, Ti AAA keychain, Sofirn SP33 V3
Good insight iamlucky13! Amazing how that can create so much current to melt a spring. For my multi-battery flashlights, I always buy new matching batteries and charge them at the same time.
I’d rather use my flashlight around the house than turn on the lights.
Ah, so it seems the most fully charged battery of the 3 did not only have to charge the other 2 but also drive the light by itself…
As NeutralFan above said, but i’ll say it with more emphasis:
NEVER put different cells in parallel NOR in series in ANYTHING !!
And by different i don’t only mean different brands or types or otherwise different specifications, this also means you should NEVER use a half full one together with a full one.
Thanks Jerommel, I was overdue this piece of advice
I do usually follow the rules outlined above, but had a momentary lapse of reason.
Can anyone recommend which is the best type of solder to use when I replace the springs? Thanks in advance..