[990] Rechargeable Battery Power Pack

Date: June 13th, 2011 | Comments : [9] | Categories: DIY.

rechargeable battery pedal power pack

I have had this battery pack project on the back burner for a long time, and after the good results I got with the Sanyo Pedal Juice, I decided to dust it off and build one to go along with my Sanyo box.

The bottom line is that my homemade unit performs just as well in most aspects but does fall short of the commercial box in a couple of areas. First, it does not provide as much power on each of the outputs as the Sanyo, and second, it cannot be recharged without removing the batteries.

However, because it uses any common AA NiMH rechargeables, the batteries can be quickly pulled out and replaced. It would be simple to have a second set of AA cells as a backup in case the power ran down.

I don’t know anything about what is inside the Pedal Juice since I have never had any reason to open it up and look inside.

pedal power with rechargeable battery pack

The three AA rechargeable NiMH batteries drive a step-up converter that provides a steady, regulated 9v output. I measured the output at 8.96v unloaded and also when pulling 20ma from one of the output jacks. Looking at the output with an o-scope shows a clean DC voltage with a very slight sawtooth ripple riding on the top, which is typical of this type of power supply.

The white stuff inside the box on the left side is a couple of pieces of electrical tape that I placed on the back of the switch to insulated it from the batteries. This proved to be unnecessary since it turned out there was plenty of clearance but I probably will just leave it in place as extra insurance.

My total expense to build this project was $12.68 which includes the box, switch and all parts except the AA batteries, the blue LED and my homemade pcb.


9 Responses to “Rechargeable Battery Power Pack”

[2218] Kerry Maxwell Says: 9:17 pm, June 13th, 2011

Not familiar with Sanyo’s Pedal Juice, but did spring for their eneloop AA & AAA charger system (mainly to keep my various TV remotes in batteries). Are there significant advantages to using a system like this as opposed to other power supply options (one-spot, etc)? Aside from my PNP vintage style effects, I’ve almost completely forgotten my years of battery dependence for my pedalboard, and only very rarely had any noise consequences from modern power supplies.

[2221] Gary Says: 1:08 am, June 15th, 2011

I would be very interested in doing this project that you have done. Please respond if you could help.

[2223] admin Says: 7:26 am, June 15th, 2011

This project is still in the testing stage. I do not know if it will ever become a full project.

The Sanyo Pedal Juice is a much more sophisticated battery power source, which allows charging without having to open up the box and removing the batteries. It can also supply more power from each of the DC output jacks.

My project can supply 100ma max from each jack, which is enough to supply more than 20 TS-9 pedals but only one or two digital devices, which are often power hogs.

The circuit uses some specific parts that I would probably have to supply to make the project reliable, but I’m still refining the design at this time.

[2224] dlp Says: 8:33 am, June 17th, 2011

Nice work. I’d love to see this fleshed out into a full-scale DIY alternative to the pedal juice. I especially like the idea of the replaceable AA batteries.

I’d imagine that the pedal juice is no more than a scaled down laptop power supply section. If I had one I’d have to break it open to see how their design was implemented.

[2403] AMZ-FX Guitar Effects Blog » Blog Archive » The Multi-Fuzz (mini-muff version) Says: 4:51 am, November 7th, 2011

[…] have also powered it with my rechargeable battery pack through the V-Doubler, and that works just as well.   No comments yet Posting your […]

[2617] DrBob1 Says: 2:47 pm, January 29th, 2012

Since each battery puts out 1.5v, why not go with a slightly bigger box and use 6 batteries? Do you still need a voltage regulator in that case, or could you just wire up the batteries and go?

[2619] admin Says: 4:03 pm, January 30th, 2012

A rechargeable NiMh is only 1.2v average, which means that 6 cells would give you 7.2v and 7 cells would be 8.4v, so you would need 8 NiMhs to get to the 9v range.

You could use 6 x AA non-rechargeables for 9v but the point of the box is that you can recharge the batteries. You would not need a regulator for 6 x 1.5v alkaline AA batteries.

regards, Jack

[3653] Mitch Says: 5:29 pm, December 7th, 2012

I would love to try this. Can you share the schematic ?

[3911] Al Says: 5:47 am, June 24th, 2013

Can you send the schematic?


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