# Battery powered charger to plug in a DC brick? **URL:** \ **Category:** Factual Questions\ **Created:** [June 7, 2013, 7:09pm UTC](https://boards.straightdope.com/t/battery-powered-charger-to-plug-in-a-dc-brick/660412 "2013-06-07T19:09:50Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [June 8, 2013, 3:41am UTC](https://boards.straightdope.com/t/battery-powered-charger-to-plug-in-a-dc-brick/660412/21 "2013-06-08T03:41:51Z")
I’d just get a AA to USB charger, and get a whole shitload of primary alkaline AA cells. That’s probably the easiest, cheapest and most flexible way to roll. Plus, if you run out, there may be people with spare AA batteries or somewhere that sells them. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [June 8, 2013, 4:01am UTC](https://boards.straightdope.com/t/battery-powered-charger-to-plug-in-a-dc-brick/660412/22 "2013-06-08T04:01:14Z")
Let me rephrase the OP to see if I understand correctly: The OP wants to charge a device while away from home or car. The device comes with a proprietary charging base, and an AC adapter with a cable that plugs into the charging base. OP asked the manufacturer about buying a car adapter for it, and they responded that it doesn’t exist yet, but it would be a device that outputs 9V 1.3 A. Assuming that’s correct, there are two possible solutions: 1. Buy a battery pack + 120V inverter (separately or as a single integrated unit). 2. Put together a battery pack that outputs 9V 1.3A. Option 1 is easy (I posted a link earlier) but such a unit is large and heavy. Option 2 _might_ be as simple as 6 D-cell batteries connected in series, but the voltage won’t be exactly 9V, and there is risk of damaging the unit if the voltage isn’t correct. The _right_ way to do it is to use a higher voltage battery (perhaps 12V) and add a voltage regulator to regulate the output voltage to 9V. (The product **beowulf** linked to may suffice for this purpose.) Also, you’d probably have to cannibalize the original AC adapter and use its cable & connector to connect the battery pack to the charging base. ---
**Author:** ![Cheshire\_Human](https://avatars.discourse-cdn.com/v4/letter/c/5f8ce5/32.png) [@Cheshire\_Human](https://boards.straightdope.com/u/Cheshire_Human)\ **Post date:** [June 8, 2013, 6:04am UTC](https://boards.straightdope.com/t/battery-powered-charger-to-plug-in-a-dc-brick/660412/23 "2013-06-08T06:04:53Z")
One of [these](http://www.autozone.com/autozone/accessories/Electrical/Battery-Booster-Jump-Starter-Pack/_/N-2629) gives you portable car voltage (and starts your car if your battery goes dead), and if you don’t have a suitable car charger, one of [these](http://www.walmart.com/search/search-ng.do?search_query=Ac+Inverter+Car&adid=22222222220202573725&wmlspartner=wmtlabs&wl0=e&wl1=g&wl2=&wl3=21972518687&wl4=&veh=sem) gives you 120 to power your dc brick, and lets you power your computer or whatever in your car, too. I have both. Nice toys. ---
**Author:** ![ducati](https://avatars.discourse-cdn.com/v4/letter/d/cc9497/32.png) [@ducati](https://boards.straightdope.com/u/ducati)\ **Post date:** [June 9, 2013, 1:33am UTC](https://boards.straightdope.com/t/battery-powered-charger-to-plug-in-a-dc-brick/660412/24 "2013-06-09T01:33:47Z")
Am I the only one thinking that the OP already used the “device” and this is where the confusion originates? The website states it comes with one lid… ---
**Author:** ![Rhythmdvl](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rhythmdvl](https://boards.straightdope.com/u/Rhythmdvl)\ **Post date:** [June 9, 2013, 11:42am UTC](https://boards.straightdope.com/t/battery-powered-charger-to-plug-in-a-dc-brick/660412/25 "2013-06-09T11:42:24Z")
> [@ducati](#): > > Am I the only one thinking that the OP already used the “device” and this is where the confusion originates? The website states it comes with one lid… Well, it is the weekend, but travelling to see the in-laws. No, wait, that’s not very convincing, is it? > [@scr4](#): > > Let me rephrase the OP to see if I understand correctly: > > The OP wants to charge a device while away from home or car. The device comes with a proprietary charging base, and an AC adapter with a cable that plugs into the charging base. OP asked the manufacturer about buying a car adapter for it, and they responded that it doesn’t exist yet, but it would be a device that outputs 9V 1.3 A. My confusion really stems from a lack of education and understanding about electronics (tell me again why basic (seeming) stuff like this wasn’t taught in high school?). My basic thought process was basically: if this was marketed ten years ago, it would operate basically the same, but it would be _X_ times bigger to accommodate its (alkaline) battery pack—some number of C or D cells. Then I figured that hey, I have a gadget that transfers the magic smoke from regular batteries to a portable device, but its only output is a USB cable. So I need to check Amazon to find a similar gadget but with the right output. That’s strange. Why can’t I find it? My search terms must be weak! I’ll call the company (I didn’t know at the time the gadget would be hard to find). No, they said, they don’t make such a device. They’re working on a car charger at the moment (which will put out the requisite 9V 1.3a came from), but that won’t help right now—and wouldn’t help in the circumstances anyway. So where do I turn for solutions to any question? The Dope! But I’m now seeing that such a thing doesn’t exist in quite the right form. There are large, cumbersome units that are general purpose and overkill. There are ways I could put something together myself, but that would be a risky venture and could lead to an explosion. Is the problem really in the connector? I remember from growing up in the 70s / 80s they used to sell universial adaptors, ones that came with a set of round female ends that plugged into our Coleco Footbal and whatnot. The charging base does have a familiar-looking round end, so if I call the company is there any set of questions I could ask that would move me closer to safely making my own battery pack? ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [June 9, 2013, 12:17pm UTC](https://boards.straightdope.com/t/battery-powered-charger-to-plug-in-a-dc-brick/660412/26 "2013-06-09T12:17:58Z")
> [@Rhythmdvl](#): > > The unit in question’s charging base only has a DC brick to plug in. > > Since we’re driving, weight isn’t an issue and can bring any additional batteries needed (e.g. D cells or lantern batteries; the unit’s battery isn’t user-accessible). > Anyone? One need way which only needs some wiring is - small (or large) car battery - regulator to match (like a kit you buy at the electronics shop… so good luck matching it exactly. You can use a large (cooling considersations) diode after the regulator to “diode drop” (the forward bias voltage is this drop !) the output (Diode’s forward bias voltage is around 0.3 volts ?) so you can get the output power really close…) - leads and socket This at least makes it portable. Also add a car battery charger , to charge the car battery (if you think it might go flat ? ) OR, You could fabricate your own battery pack and use D cells. Like, take an old torch and use it as the external battery pack. The main issue is the voltage of the wall wart. Is it close enough ? D cells are 1.5 volts nominal.. There are two plans 1. Just make the closest voltage you can. Going over the voltage may destroy your device though ☹ OR 2. Use a regulator (the same as with the car battery soluton), Drawbacks a. the regulator is electronically set to a particular voltage, so good luck matching it exactly. You can use a large (cooling considersations) diode after the regulator to “diode drop” (the forward bias voltage is this drop !) the output (Diode’s forward bias voltage is around 0.3 volts ?) so you can get the output power really close… b. You need to use extra D cells to keep the regulator’s input voltage above the minimum (around two voltages higher than the output.) You know about buying a suitable plug to go into the devices socket, and getting the polarity right, and making one end a springy contact so that the OR ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [June 9, 2013, 3:09pm UTC](https://boards.straightdope.com/t/battery-powered-charger-to-plug-in-a-dc-brick/660412/27 "2013-06-09T15:09:14Z")
> [@Rhythmdvl](#): > > Is the problem really in the connector? It’s the connector, voltage and current. Except for USB, there is no widely used standard for a DC power supply connector. It’s also the power. 9V 1.3A is 11.7 Watt. This may sound small, but it’s almost 5 times more power than a USB port can supply. Even Apple’s non-standard high-power USB (designed to charge iPads at a faster rate) can only supply 5.5 Watt. [Previous page](https://boards.straightdope.com/t/battery-powered-charger-to-plug-in-a-dc-brick/660412.md?page=1)