Replies to This Discussion

Permalink Reply by John W on March 31, 2013 at 12:59pm

I made a solar powered version of my Stella Amp last year: http://www.crazybutable.com/projects/solar-stella

You can cut the cost of the solar panel and just charge it with USB. I have links to the battery, the thermistor, and the charging circuit you would need on my page. (In fact, if you search on adafruit for the USB charger I think it's slightly cheaper than the solar charger if you don't need solar capability.)

The problem is, that's a fairly low voltage to run a Ruby amp on. I designed the Stella amp to run at very low voltages, so it works well with the 3.7-4.1 lipo battery.

If you really want a Ruby amp, you can use the Ruby amp but you will probably have to find a 7.4ish rechargable lipo system. They're out there. When working with rechargable lithium batteries, you MUST match the battery to the charger. NEVER just guess and assume something will work. Lithium batteries are flammable. They have lots of protection circuitry, built right into the battery, but the protection circuit is designed to work with a specialized charger -- so if you use the wrong battery with the wrong voltage or wrong charging circuit it would be a disaster. This isn't the kind of thing you can just ebay and hope for the best.

Is that kind of what you were looking for? Let me know if you have any questions. I have some follow up on how well the solar power worked with long term use if you are interested in solar power.

Permalink Reply by mike smith on April 1, 2013 at 6:22am

Thanks john, nice work and yes i do want a solar amp now.

The ruby aint important but i want it loud as possible. Thanks for the battery warning, I would prob use an old phone and charger, take the battery out and use it in the amp for a day.

Permalink Reply by Blind Lemon Cello on March 31, 2013 at 3:18pm

I just finished building a 20w buskin' amp using a 12v/9ah sla battery. Maybe too large for you, but easily rechargeable. I think the smallest 12v sla is a 3ah.

Permalink Reply by mike smith on April 1, 2013 at 6:23am

Cheers; SLA looks to be the bulky but easy way.

ah means amp-hour right? just looked it up and i can't quite work out what it means. 

Permalink Reply by Jim Dickison on April 1, 2013 at 7:13am

An Amp-Hour (or Ampere-Hour -- I'm gonna use "ampere" for the measurement of current and "amp" for "amplifier" here to reduce confusion!) is a unit of electrical charge. A 1 ampere-hour battery would have enough charge to deliver 1 ampere of current to a load for 1 hour.

So, figure out how much current your amp uses under normal use, divide the ampere-hour rating of the battery by that number of amperes used by your amp, and you have an estimate of how long your battery powered amp will operate.