AC/DC Adapters - Can you help? - Page 1
Forum section: electronics / beginners

author: TymerTopCat
author_rank: Newbie
timestamp: February 15, 2012, 09:21:08 am
content: Hi,I have two small printers that are powered using an AC/DC Adapter. Currently each is connected to a (20 Volt DC 2.5 amp) AC/DC adapter. The printers are barcode printers from Zebra (2824).I would like to power both of the printers using *one* AC/DC adapter.If I puchase a 20Volt 5 amp AC/DC adapter would this be okay?Thanks,-Russ

author: Rerouter
author_rank: Super Contributor
timestamp: February 15, 2012, 09:35:29 am
content: it would be, just you would have to split the wires (not that dangerous with 20V DC, but mainly you would have to triple check your polarity,

author: amspire
author_rank: Super Contributor
timestamp: February 15, 2012, 11:50:57 am
content: Quote from: Rerouter on February 15, 2012, 09:35:29 amThere are some issues you could have with sharing adapters. For example, if the printers happen to draw a high surge current when you plug it into the power, or turn it on, it can affect the other printer by briefly pulling down the power supply. It is probably better using the original two supplies unless you have to use one.May not matter if you are just printing out single labels at a time, but if you print out a large run of labels, it would be very annoying if a few labels in the middle were not printed properly or if the printing run died half way, just because you had to change the paper roll on the other printer.Richard.

author: TymerTopCat
author_rank: Newbie
timestamp: February 15, 2012, 07:40:48 pm
content: Each of the printers uses a 20 volt 2.5 Amp AC/DC Adapter.I figured that if I replaced with one larger adapter 20 Volt 5.0 Amp, this would take care of problem?Why wouldn't this work?-Russ

author: mariush
author_rank: Super Contributor
timestamp: February 15, 2012, 07:56:45 pm
content: The printers most likely have internal dc-dc converters for the processing side and the rest is used by some heating element (if it's thermal label printer or something like that). So, there's probably some room there to work with regarding voltage.Therefore, I'd suggest trying first to see what happens if you run one with a regular laptop charger that delivers19v@ 4-8A of power. Most AC adapters do 19v but some Sony AC adapters do 19.5v which is even closer to your needs. It would probably be cheaper to buy a mass produced laptop power brick than buying something custom, and you also have the benefit of finding them pretty much everywhere, including Newegg, Amazon etc.Example:http://www.amazon.com/Anker-Adapter-Charger-Inspiron-Latitude/dp/B003LHIVUU/ref=sr_1_3?s=pc&ie=UTF8&qid=1329335723&sr=1-319.5v @ 4.62A which should be good, as you won't have both printers running at maximum rating of the individual adapters.

author: Short Circuit
author_rank: Frequent Contributor
timestamp: February 15, 2012, 08:41:34 pm
content: No problem to run them with a slightly different adapter. I have a bunch of Zebra's here, and one is powered by a 16V/3.5A IBM adapter, and it works fine.

author: IanB
author_rank: Super Contributor
timestamp: February 16, 2012, 03:45:22 am
content: Quote from: TymerTopCat on February 15, 2012, 07:40:48 pmIt's mainly to do with isolation. With the two separate adapters, each printer is on its own "power island", separated from other devices. So even if the printer does nasty things like drawing sudden power surges when a motor starts up and causes "brown outs" on the supply, nothing else will be affected.But if you make two printers share a supply, it is possible (perhaps) that a brown out caused by one printer could upset the operation of the other. It's 95% likely that nothing bad would happen, but with the two separate power adapters it is 100% certain that nothing bad will happen.

author: SeanB
author_rank: Super Contributor
timestamp: December 17, 2012, 11:01:01 am
content: No problem as long as both printers are using the same computer to drive them. e.g. both on USB or both on LPT ports. You can use a laptop power supply, it works well as a replacement, I did that when the original went smoke out from dried out capacitors. They do draw high power only when printing, and it is lower if you run at a lower feed speed.

author: ptricks
author_rank: Frequent Contributor
timestamp: December 17, 2012, 12:30:35 pm
content: Open one of the printers to see what they did for the power circuit. I always do this whenever I plan to do something like you are thinking of doing, takes all the guess work away.