My buddy and I recently went cave exploring to the Ape Caves in Washington the other week and I really want to build a overkill headlight/flashlight combo and was toying around the idea of using 16850 batteries which are the same ones in laptop battery packs… It turns out I have 32 of them I arranged in a 6x5 arrangement giving me 12volts at some unknown MAH rating… it has powered a little over 10 watt led for 8 hours with less then 1/2 volt voltage drop over that time… “with a constant current regulator”
Although 32 of those batteries is heavy… and stupid.
I was going to buy 2 of these batteries and attach them together for 10400Mah @ 11.1 volts. “Overkill I know”
I have 3 of these things sureelectronics.net/goods.php?id=1288 which is the photo attached. “tempted to do 3 voltage regulators and 3 leds for 30 watts total”
The general layout is
Batteries --> Ubec --> switch --> Linear Voltage Regulator “Attached photo” --> LED
or
Batteries --> Ubec --> switch --> 3 x Linear Voltage Regulator “Attached photo” --> 3 x LED
I need to know what type of UBEC to order for my lipo’s so they dont go chernobyl while I’m trying to see in the dark… and what usually happens when a ubec senses that the voltage is too low, will it just cut power or will it beep at me?
Yeah I had also come to that conclusion looking at all the stuff… It was more so how to work with Lipo’s in general while keeping their life expectancy high.
so I have a bench PSU a extech 382260 power supply, when I power this 10-20 watt led and start increasing power the brightness is at its max at about 12-13 volts and I can dim it until it gets to 8.53 volts then its completely off with about .005 amps of current draw from the circuit, with that said if I powered this with a 11.1 volt lipo would I just run it until the power dropped to 8.53 volts then charge it?
As I had read you dont want to go below 3 volts a cell , which would be 9 volts, taking it to 8.53 would be less and potentially ruin the batteries…
Reasons why I ask as I have never worked with these types of batteries…
I’m tempted to invest in some Lifep04 batteries and avoid all this battery hoopla.
It depends on the quality of the batteries. Most manufactures recommend to not discharge <3v per cell UNDER LOAD. But some has a lower limit at 2,8v (3S = 8,4v). The real limit is around 2,5 volt but for safety most manufactures say 3 volt. I’ve also read that you shouldn’t discharge 100% of capacity but 75-80% to get the best performance from your LiPo’s.
There is also a very big difference in what current draw you have on the battery when reaching the lower limit. At higher current draw they use a higher cut-off limit (3,3 - 3,4v).
What I’m trying to say is that your 8,53v limit might work on a 3 cell if the manufacture say 2,8v. But don’t blame me if you ruin the battery…
These leds I have at 12volts draw 1.517 amps and would potentially have 3 of these with 3 current regulators so that’s about 4.5 - 4.8 amps… It also is possible I could simply run a single led and single regulator / These lipo’s are weird.
