These are what I use on some of my spotlight builds. They are smaller at 23mm X 15mm X 10mm, but might fit in a Maglite. They are cheap and work great.
Thats whats so nice about them. Tiny, easy & uses very little current (0.5 uA typ). Also don’t need to be able to program chips. Just connect the voltage monitor chip, indicator led & resistor (aim for <50mA led current).
Haven’t ordered one yet since the attiny can do low voltage detection.
Whoa that is small - size of a sim card. I looked around - cheapest is $5 shipped for these (vs $1.40 for the bigger guy), quite a jump in price for tinyness.
Interesting why the red is always cheaper than green/blue version - easier to build due to Vf probably?
I like the readout style over the lights. It's larger, but if I can fit it in, I will use the readout style. I don't really need a low voltage warning, I just think a readout of voltage would be kind of different.
I don’t think they get cheaper than these. I’m probably going to grab some afterwards. I already have the bigger version in many colours, and I must say the blue LED is the most beautiful - kind of classy, expensive looking.
The numerical LED blocks are standard size. Three digits is too wide (>20mm). Maybe replace it with two digit block if one decimal place resolution is acceptable?
The ones from gigibaobao are better quality than FastTech, with trim pot and work to lower voltage, but still too big.
Another idea, maybe use two or three of the kind Helios posted set to different voltages?
I ordered a few of them from Fasttech and they won’t read voltage until it rises above about 3.3 volts. They do work great for RC lipo monitoring & portable solar cell and checking batteries in the field with out lugging a huge Fluke meter.