I am building a p60 drop-in for a friend of mine who will only use cr123 batteries. Can a 7135 based driver handle 6 volts? If not, is there another good 2-3 amp 17mm driver that I could use?
Thanks in advance!
105c don’t handle more than 4.5V
105C handles two 3v CR123s just fine, here in the real world. Guess it's a good thing we don't live in a datasheet, huh?
CR123s will “work” with a 7135 driver, but the runtime is going to suck. It may be worth looking into a proper buck driver if your budget allows for it.
Also, the capacity of a CR123 at 3A isn’t too great from what I’ve seen.
Thanks for the responses! Can anyone recommend a good buck driver for this application (17mm)?
I'll trade you half a unicorn for a 17mm 3A buck driver, if you can find some.
Be careful pushing those CR123s at 3A continuous, they get EXTREMELY hot after only a few minutes. Down around 2A continuous is a little more sane with those cells.
Ha ha ha! I know I’ve got a lot to learn.
Thanks for the warning, I guess I’ll have to make it 2 amps. :_(
Some of these guys might have more experience with the CR123s than I do, but they seem to get very hot at 3 amps. I have been setting up my CR123 build drivers to pull 3 amps for 60 seconds then step down to around 1.5 amps. I think that most of them are rated for around 1.5 amps continuous, but that could vary from cell to cell. Best to check that particular cell's datasheet to be sure.
What driver do you use?
Interesting. Would you say this is pretty much a blanket statement for all 105C drivers? I have always wondered whether there would be issues running them on 4 (series) Eneloops. I've only ever read around 4.2V to 4.5V max quoted. "Hot off the charger" 4 AAs could run to about 5.6-5.7V.
I haven't seen any 17mm drivers with 6v ratings but would love to find something suitable for cobbling together a 2 x P60 based bike like with external NiMH battery pack.
Yes. I've never seen any using the 105C layout that used any substantially different components - at most, the resistors are sometimes from different manufacturers and use a different label ('472' vs. '4701', both 4.7K), but nothing other than that. A lot of other non-105C 7135 drivers are still using the same parts in the same circuit, but just on a slightly different PCB layout.
I've seen drivers where the specs say things like 'Input: 2.5-4.5v' and then a few lines down 'Low voltage protection: 2.8v'. How do you use it at 2.5v, if that's below where it shuts itself off?? You can't take these printed specs too seriously since a lot of these guys have no idea what they're selling.
Running a 4x Eneloop light in series with a DrJones driver, I’d be hesitant to use lithium primaries though! As they are around 1.8v