Gathering info to build battery pack for Roland SP-505

[Om_Audio]

Adapter is 14V/800Ma
not sure center pin polarity yet
(replacement adapter cheap- http://www.amazon.com/HQRP-Adapter-BRC-120T-A41408DC-Processor/dp/B00D42CEHI)

14v battery packs are avail from $35-$75

https://www.google.com/shopping/product/8566111088062462927?q=14v+battery+pack&safe=off&client=firefox-a&hs=bq6&rls=org.mozilla:en-US:official&channel=fflb&bav=on.2,or.r_cp.r_qf.&bvm=bv.73231344,d.cGU,pv.xjs.s.en_US.jy1SGYsq9dM.O&biw=1920&bih=904&tch=1&ech=1&psi=nIXuU9D7A8njoAS1j4CoBw.1408140696382.3&ei=3YXuU7nVCon7oAT25oDYCQ&ved=0COIBEKYrMAU

http://www.batteryjunction.com/tenergy-14-8v-4400.html?gclid=CjwKEAjw37afBRDO5M3h0qvj9zQSJACvwnOJppwrLfG8SAXLJHXjzzXmKBQpQ9KUlLJ0AI3ckAlPNxoCsBzw_wcB

What is needed is enclosure and know how to connect battery correctly to ports needed for charging the battery and powering the 505. Also not sure how to equate the draw of the 505 with the capacity of the batteries in terms of run time and if it is even worth doing with battery packs in this price range.

Any assistance appreciated-

C

[RobA]

I haven't worked with the Li ion batteries, but their chemistry is much the same as the LiPo's and I've been doing some playing with them lately. I also took a look just now at one of the data sheets for a Li Ion battery on Sparkfun that is similar to one of the batteries in the pack you put up. The first thing is that the 14.8V it lists in the nominal voltage. It's where the battery pack will sit during most of the discharge cycle, but the actual voltage will range from about 4 * 3.2V to 4 * 4.2V, so 12.8V to 16.8V. You'll have to know that the SP-505 can handle that range, or put in a regulator circuit at the level it can handle. So, if it needs to be at 14V, then you'll need an LDO regulator that you can set at 14V. I say an LDO because you'll want to make sure that it works when the voltage drops to around 14.2V or so to get the most life out of the batteries.

The other thing you'll need to make sure of is how the batteries handle charging and what kind of charger you need to use. It couldn't tell from the links at the places, does the pack have a charge controller builtin? The multi-battery packs usually have to be charged using a charger that does balanced charging of the whole set of batteries.

The newegg page for the pack says it'll do a discharge rate of 2.5C = 5A, so that should be good. The battery pack is at 2200mAh which means at 800mA that the Roland PS delivers will give you 2.75 hours of run time. It'll be a bit less than that really because it'll cut out to stop the battery from going undercurrent and destroying it before it uses all of the charge. Does the SP-505 really use that much current. If it's less than that, you can get the runtime by dividing 2200mAh by the current draw of the SP-505.

One place to look for good info on this would be the RC vehicle folks. They use LiPo and Li-ion packs around 14V to run their vehicles.

 

[Om_Audio]

Thanks for the reply. The batteries do seem to have some built in chips:
"Use Smart Universal Li-ion Battery Charger for proper charging. - Made of Four 2200m - Ah cylindrical 18650 cells with PCB and poly switch for full protection Light weight and higher energy density than any rechargeable battery Longer storage life than Ni - MH battery. No memory effect and rechargeable Built-in IC chip will prevent battery pack from over charge and over discharge and prolongs battery"

Will have to some more research- thanks-
C