i'd like to get a rechargeable battery pack for my ad-20 and rolls pb-223, the ad-20 just takes a 9v and the rolls has been modded to take 2 9vs, any ideas on what to get?
Quote from: Simp-Dawg on June 29, 2004, 02:25:02 PM
i'd like to get a rechargeable battery pack for my ad-20 and rolls pb-223, the ad-20 just takes a 9v and the rolls has been modded to take 2 9vs, any ideas on what to get?
The Rolls pb-223 has an internal 12 Volt linear regulator (the schematic is available on the net I found).
It accepts 14 to 18 volts as it is. I take this to mean that the 12V regulator is mounted without
a heatsink and simply gets too hot if you go above 18 volts.
The AD-20 (Vin 7(?) to 24 VDC) has an internal 5 V linear regulator. No heatsink. At a draw of
50mA you get worst case (24 Volts in=> 19 volts across regulator: 0.050 x 19 V drop =
1 Watt). I would guess the small regulator is HOT trying to get rid of all that heat.
What options do you have then?
The minimum common voltage is 12 volts:
Both units could be run on a 12V SLA (11. - 14. volts). This voltage is too low for the regulator in the pb-223 to work and a mod could be necessary. Max phantom voltage available ((not counting losses) is 4x the voltage on regulator output.
Mid range voltage:
Add together rechargeable cells (9.6 + broken pack) to get 13.5-18 Volts and run both units unmodded.
High range voltage (from 2 x 9.6 NiCd/NIMH (or 2 x 12 volts SLA))
Now you face a thermal issue. The regulators get *hot*. That means you have to add heatsinks to the regulators and/or insert a carefully sized power resistor (and a diode or two is a good protective measure
against polarity reversal) in each feed to drop the voltage seen by each unit when in operation.
And a fuse close to the battery is always prudent.
Best
Jon
i've read this a couple times and still don't truly understand, but i give you props for knowing this shit.
can someone tell me, in idiot terms, what i need? the mid range voltage sounds right up my alley, but what do you mean exactly by a "broken pack"?
I think he just means a 9.6v pack and the cells from another pack. I think batteryspace sells some 14.4v packs (12 cells) that would qualify for the mid range voltage. You don't need much current here - just voltage so go for a small cell.
ok, so if i get a 14.4v battery, what do i need to do to power both of these? i'm not at all experienced with powering devices...if you couldn't tell ;)
You'd have a much easier time selling the rolls and buying a ps2 -- the ps2 and ad20 will both run off of a readily available 9.6 volt nimh pack (or a wallmart lion battery) without any more hacking.
true...although i like the size and build of the ps2 as well as the commonality to the ad20, the rolls is not mine to sell and i don't want to put anymore money into this "budget" rig...when i invest again it will be for some higher end gear. but i would like to have rechargeable power instead of burning through 9v's.
thanks for all the help y'all have tried to give me, and especially to jk labs for pm'ing me about this stuff, but i can't seem to find the right size battery for this project...i think i could put it together myself, maybe, but i might need a little help finding the right parts. anyone wanna lend a hand here??
Easiest might be to get two battery packs. One 9v or 9.6v pack for the AD20 and one ~18v pack using 2x 9v batteries, or 2x 9.6v batteries. For the AD20, use a 9.6v RC (toy car type) battery--9.6v NiMH, not NiCD as those will have memory effect problems. Something like the radio shack one would work:
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F009%5F010%5F000%5F000&product%5Fid=23%2D331
Or there are probably alot of other choices, do a search on UA5 power options and you'll probably get more.
For the Rolls, you could get 2 more of these batteries and make a harness to run them both in series to give you 19.2v which would work fine. (I wouldn't try to make something up to run just 2 batteries for everything, ie. 2x the 9.6 for the rolls and use only one of them to run the AD20, without something in a way circuit to control them--this wouldn't be the best.)
Or instead, you could just get NiMH rechargable 9v batteries (that come in the same form factor as a 9v alkaline battery). Check thomasdistributing.com for options. I can't remember the current draw of the Rolls. I would imagine the 200mA 9v rechargeables would last for at least 5-6 hours, but it could be more or less. I'd imagine to be safe, you'd want 4x of the 9v batteries, plus the charger, which would be about $70 or so shipped.
Also, maybe you should just get a rechargable option for the AD20 and not bother with the Rolls. I remember the rolls running forever on the 9v lithium batteries I would get for it. Something like 80 hours of use or something? Perhaps not the best for the env't, but you could probably run the Rolls on 9v lithiums for a year of taping before you broke even on what you'll spend to put together a rechargable battery pack for it.