Low voltage cutoff for 1s... - RC-Monster Forums

lincpimp · **Low voltage cutoff for 1s... -** 09.27.2010, 12:29 AM

Looking for something that can switch off a circuit when the voltage reaches 3-3.2v... No buzzers or lights, need it to switch off.

Would like to find something pre-made. And it needs to be no larger than 36mm in in all directions...

Making a flashlight battery and would prefer to use the lipos I have rather than buying batts that have internal protection.

Thanks!

What's_nitro? · 09.27.2010, 12:36 AM

What about a Zener diode on the base of a transistor? I found 3V and 3.3V diodes on eBay, there doesn't seem to be any values in between those.

lincpimp · 09.27.2010, 02:04 AM

Quote:

Originally Posted by What's_nitro?

What about a Zener diode on the base of a transistor? I found 3V and 3.3V diodes on eBay, there doesn't seem to be any values in between those.

My complete lack of any sort of intelligence on this subject may be showing here...

Max current draw will be less than 3amps... Not sure if that matters when using a diode...

Sounds like you know more about it than I!!!

What's_nitro? · 09.27.2010, 02:12 AM

I forgot I drew this earlier... I'll bet my diode polarity is backwards, too. W/e

The 180 ohm resistor limits the base current to 20mA, which is fine for most small transistors. When the voltage is above that of the Zener diode's rating, the circuit is on. The diode stops passing current when the voltage drops too low, and the circuit shuts off. Just need to find a suitable NPN (could be PNP as well with reversed batt. polarity) transistor to handle the current.

_paralyzed_ · 09.27.2010, 02:15 AM

Quote:

Originally Posted by lincpimp

My complete lack of any sort of intelligence on this subject may be showing here...
!

Yes, yes. That and your penny pinching scrooge like ways. I'm pretty sure a few packs of duracells will be cheaper and easier than building an lvc for a flashlight.

Take them out of the rectal rooter toy you're always trying to impale me with

_paralyzed_ · 09.27.2010, 02:45 AM

stick a digital voltmeter on the outside of the flashlight?

http://cgi.ebay.com/Digital-LCD-Volt...item2c5605d18b

I googled a little and searched hobbyking for all their do-dads and couldn't find anything for 1s. Step up to 2s and there are cheap lcd displays, a 4a ubec with low voltage horn and other stuffs.

JERRY2KONE · **Friends -** 09.27.2010, 02:54 AM

Quote:

Originally Posted by _paralyzed_

Yes, yes. That and your penny pinching scrooge like ways. I'm pretty sure a few packs of duracells will be cheaper and easier than building an lvc for a flashlight.

Take them out of the rectal rooter toy you're always trying to impale me with

Now thats what friends are for. Feel the love James. It sounds like you know his wheelchair intimately to.

_paralyzed_ · 09.27.2010, 02:57 AM

Quote:

Originally Posted by JERRY2KONE

Now thats what friends are for. Feel the love James. It sounds like you know his wheelchair intimately to.

he has felt enough Jerry....

JERRY2KONE · **Imagine?? -** 09.27.2010, 03:02 AM

Could you imagine if there was an event where all of us would show up and be in the same place at the same time. What a party that would be. I have visions of something like the old Hells Angels gang get togethers. I can see James dragging some poor guy behind his truck because he brought a nitro to a BL gathering. What a hoot.

sikeston34m · 09.27.2010, 07:16 AM

Quote:

Originally Posted by lincpimp

Looking for something that can switch off a circuit when the voltage reaches 3-3.2v... No buzzers or lights, need it to switch off.

Would like to find something pre-made. And it needs to be no larger than 36mm in in all directions...

Making a flashlight battery and would prefer to use the lipos I have rather than buying batts that have internal protection.

Thanks!

Getcha one of these James.

http://www.all-battery.com/protectio...it-pcb1sr.aspx

Cheap, premade. Should fill the order quite nicely.

lincpimp · 09.27.2010, 10:18 AM

Quote:

Originally Posted by sikeston34m

Getcha one of these James.

http://www.all-battery.com/protectio...it-pcb1sr.aspx

Cheap, premade. Should fill the order quite nicely.

Looks good Sike.

Now looking at the specs it appears that the battery + and - are soldered to the B+ and B- and the load is soldered to the P+ and P-... An I correct?

Thanks

And I would like to give a huge thanks to Harold and Jerry for adding absolutely nothing useful to this thread!!! I taught them well!. As far as me being familiar with a perv in a wheelchair, well that is not my style. Closest I get to people like that is when I "accidentally" push them out into traffic...

pinkpanda3310 · 09.27.2010, 10:58 AM

Quote:

Originally Posted by lincpimp

As far as me being familiar with a perv in a wheelchair, well that is not my style. Closest I get to people like that is when I "accidentally" push them out into traffic...

Is that like the New Zealand equivalant of 'helping a sheep through the fence'?

sikeston34m · 09.27.2010, 05:26 PM

Quote:

Originally Posted by lincpimp

Looks good Sike.

Now looking at the specs it appears that the battery + and - are soldered to the B+ and B- and the load is soldered to the P+ and P-... An I correct?

Thanks

And I would like to give a huge thanks to Harold and Jerry for adding absolutely nothing useful to this thread!!! I taught them well!. As far as me being familiar with a perv in a wheelchair, well that is not my style. Closest I get to people like that is when I "accidentally" push them out into traffic...

Yes, B's are the Battery and the P's are the load/charger. You charge through this circuit also.