I don’t think you need to turn down the current just yet. I’d measure the voltage going into the driver with the light turned on. Then redo your calculations for efficiency I bet it will be much higher.
Im using the Panasonic NCR18650B batteries. I would rather use a good protected battery that will do the 6-7A I need. Any suggestions which batteries to get? With a button top. I’m having to use neridium magnets to connect my batteries. Im sure that dont help with the added resistance.
Panasonic ncr18650pd cells are supposed to be pretty good but the 7a draw is a killer, most protection circuits wont go that high. enerpower cells are the only ones I’m aware of and they wont be cheap to ship to you
I’ve not pushed mine that far to test, there are though, precious few 10a protection circuits, regardless of what the cells will do, I also dont think hkj was impressed at the performance at 10a.
li nm cells are supposedly safer as in dont get so excited, so dont tend to be protected in the first place, that maybe the way forwards, but li nm does not automatically equate to high draw, check hkj’s comparitor for whats what, the Samsung/sanyo (cant remember which) 20r’s have the lowest internal resistance, but similarly have a low capacity.
As we say in northern England, you dont get owt f’ nowt
Thanks for all the great suggestions. How about the NCR8650A panasonics? I read somewhere they were good for 6.5A draw and they are protected. This driver is really suppose to stayat 6A according to George at Taskled. I am pushing it already. It would be nice to have a protected battery to cut off at 7A to protect my driver too. :bigsmile:
Thats a good question. I dont think the driver has a protection circuit built in it. George specifically preached to me not to go over 6A. If it does have a protection circuit I would feel more secure if I could utilize the PCB on the battery to cutoff at 6.5-7A in addition.
I thought the driver might be able to measure the current.. but you cant really limit it other than lowering the LED current or taking good care of the battery voltage. You could go as low as 18V input voltage, for ~130W that would be 7.2A and that might be too much already.
Problem with protected cells is, they are not exact. Cutoff could be at 5A or at 7A, depending on the parts used (tolerances..).
Ah ok. So the advertised cutoff does have some flex in it. I definitely make sure the batteries are topped off before I use the light. Im very picky about that. I think I might get a set of the NCR18650B that have a PCB. They also are button top so I can rid of the magnets. Here is the ebay link. I bought several batteries from him. All have been good.
Here is a link to a test of a lot of 18650 batteries I been looking at. The protected ncr18650b is where I need to be. I dont know what PCB they used though. Thats the question.
Why are you adamant about the NCR18650B? The protected NCR18650PD actually provides more juice at higher currents. Enerpower sells one, and HKJ tested it.
Use HKJ’s comparator and compare the PD and the B at 5 amps.
I still cant recommend NCR18650B cells. 6.8A is the absolute limit for these cells. But thats maximum discharge (peak), not constant discharge. If you limit runtime on high to less than a minute.. maybe. But you are pretty hard one the cells.
Woah, I just read this thread. Serious light warning. Do not enter without proper eye protection. Best wishes on this beast. There will be no lumen shortage around you with this baby on fully charged cells. No matter the cell, it will have seriously respectable light output.
Haha! Thanks for getting back to the subject! I have to say this is my favorite little lamp yet! I should have the stock one in a couple of weeks to do some side by side tests.