Topic: external batt for ad-20 and rolls pb-223?

[Simp-Dawg]

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?

[jk labs]

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

[Simp-Dawg]

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"?

[dklein]

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.

[Simp-Dawg]

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

[dnsacks]

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.

[Simp-Dawg]

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.

[Simp-Dawg]

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??

[Todd R]

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.