Powering pedals with coin cells

[MBFX]

See title. I want to stick an Electra into my beater Mustang, to make it a better jam session guitar. It's a little too small and thin to route a battery compartment, so I am thinking of using coin cells. Any reason a low power use circuit like an Electra wouldn't work with 3 stacked coin cells? I know they don't put out much current.

 

[Feral Feline]

You can make it work.

Having a "senior" moment and can't remember the name, but there was a guy making nano-pedals about the size of 1/3 to 1/2 a 1590A (making the enclosures himself, too I think) and they ran on a watch battery. This is before SMD, so it was quite a feat to produce such a small pedal.


AHHHH FINALLY FOUND IT AGAIN...
TONE BUTCHER's POCKETPUSS!

There's Japanese brand Albit, which also did a few micro-nano type pedals.
Three in upper left corner:

Hard to search for them because of EHX Microsynth, NanoPog etc etc.

Check out MAS Effects' SMD BazzFuss. You could maybe tweak that into an Electra.








Good luck !

 

[MBFX]

Already have the board, actually! 3x10 vero build I found online. I ordered some coin cells on Amazon, and I'm working on some sort of 3 coin cell holder because those apparently do not exist. Need to find a way to make it easy to access, too - either that or have a way to check battery life with a DMM before taking it out.

 

[MBFX]

 

[Feral Feline]

RE COIN HOLDER What about cutting up a plastic coin holder (like they use at the bank), or if you've got a mother who's on every type of medication known to geriatrics then maybe a pill-bottle you can cut-up, glue together, poke holes into... Or an old film canister.

If you build another one of these onboard-electras, I quite like these little GBOF boards from GPCB. A buck-twenty on sale now.




They are TINY! Easily fit in most geetar cavities. Here's one I socketed so I can "breadboard" on it (and other socketed nonsense), chip socket for scale:

The little boards have their limitations and it's honestly sometimes better/easier to just go perf or vero, but ... they're such FUN!

 

[DailyDovetails]

https://www.amazon.com/Zehhe-Copper...eywords=conductive+tape&qid=1703539241&sr=8-3 we did a girlscouts project on circuits a few years ago that used coin batteries. It might not be a good long term but as a minimalist solution you could use conductive tape around them and tape a lead on top. If I recall the sides are positive.

 

[RetiredUnit1]

Just a word of caution, small children think they are candy. They are often fatal to those that eat them.

 

[Erik S]

There’s some projects on thingiverse that look like they might work.

Parametric button cell holder version 2 by WardElder

Modification of Nils Roe's "Parametric button cell holder" Ability to extend opening outwards to protect battery Can change wire size hole diameter Added hole to allow you to push battery out Added ability to stack batteries Auto reorientation to place properly on build plate No...

www.thingiverse.com

 

[derevaun]

Some possibilities here, including some coin cell holders:

Batteries Products Category on Adafruit Industries

Adafruit Industries, Unique & fun DIY electronics and kits : Batteries - Tools Gift Certificates Arduino Cables Sensors LEDs Books Breakout Boards Power EL Wire/Tape/Panel Components & Parts LCDs & Displays Wearables Prototyping Raspberry Pi Wireless Young Engineers 3D printing NeoPixels Kits &...

www.adafruit.com

Also a couple LiPos in series would get close to 8v, and they're easy to charge with the USB chargers on that page. I always just use their JST connectors rather than trying to cut the wires, because, you know, kaboom.

 

[MBFX]

Revisiting some old threads of mine, and I thought I should add to this one. This project was a success, and went into a Mustang. I have since stuffed effects into two cheap guitars, one expensive guitar, a bass, and an amp head. For all except the amp head, three coin cells work great! Stack them up, hold a lead with a good amount of conductor exposed to each side of the stack, wrap in electrical tape, and done. For things that have low current draw such as boosts, distortions, and some compressors, this is a viable option if you don't want to route a proper 9V battery chamber.

 

[lcipher3]

kicking an old thread ....
how do you get much time out of coin cells at all?

Anything over a few mA will KILL a coin cell in minutes: for example a 2V CR2032 lasts maybe 20-30min at 20mA draw -ts 240mAh rating is only for something like 0.2mA.

Most coin cells are designed to be very lightly loaded. the mAh rating is only good for sub 1mA current draws.

 

[MBFX]

kicking an old thread ....
how do you get much time out of coin cells at all?

Anything over a few mA will KILL a coin cell in minutes: for example a 2V CR2032 lasts maybe 20-30min at 20mA draw -ts 240mAh rating is only for something like 0.2mA.

Most coin cells are designed to be very lightly loaded. the mAh rating is only good for sub 1mA current draws.

I haven't had a problem, but I'm using a stack of three coin cells to make 9V and I use them to power an Electra that's inside my Mustang. It's been 2 years and I haven't had to change the battery. Pile still reads 8.97V, started at 9.3V.

The compressor was switched out for a proper 9V due to battery life issues

 

[Ginsly]

I haven't had a problem, but I'm using a stack of three coin cells to make 9V and I use them to power an Electra that's inside my Mustang. It's been 2 years and I haven't had to change the battery. Pile still reads 8.97V, started at 9.3V.

The compressor was switched out for a proper 9V due to battery life issues

I assume it’s set up to “turn off” the battery stack when a cable isn’t inserted in the instrument? Or do you have an Off switch that cuts the connection so it doesn’t discharge?

 

[MBFX]

I assume it’s set up to “turn off” the battery stack when a cable isn’t inserted in the instrument? Or do you have an Off switch that cuts the connection so it doesn’t discharge?

Yes, TRS jack with the effect ground on the ring.

 

[JTEX]

kicking an old thread ....
how do you get much time out of coin cells at all?

Anything over a few mA will KILL a coin cell in minutes: for example a 2V CR2032 lasts maybe 20-30min at 20mA draw -ts 240mAh rating is only for something like 0.2mA.

Most coin cells are designed to be very lightly loaded. the mAh rating is only good for sub 1mA current draws.

Design the circuit for low current draw. There are good dual op amps amps drawing 0.2 to 0.3mA (as in, at least as good as TL072) but they're SMD-only.

 

[MBFX]

Design the circuit for low current draw. There are good dual op amps amps drawing 0.2 to 0.3mA (as in, at least as good as TL072) but they're SMD-only.

My eventually intended project is a tiny, pot mounted, SMD boost

 

[JTEX]

Here are my favorite low power op amps for guitar stuff, from lowest noise to lowest power (and price):
OPAx205
OPAx196
OPAx990

The last one works fine even at 3V or less (single CR2032).