# How can I turn bread into toast with batteries? **URL:** \ **Category:** Factual Questions\ **Created:** [January 30, 2005, 11:34pm UTC](https://boards.straightdope.com/t/how-can-i-turn-bread-into-toast-with-batteries/287494 "2005-01-30T23:34:42Z")\ **Posts on this page:** 6\ **Page:** 2
**Author:** ![quelquechose](https://avatars.discourse-cdn.com/v4/letter/q/6f9a4e/32.png) [@quelquechose](https://boards.straightdope.com/u/quelquechose)\ **Post date:** [February 1, 2005, 2:53am UTC](https://boards.straightdope.com/t/how-can-i-turn-bread-into-toast-with-batteries/287494/21 "2005-02-01T02:53:42Z")
> [@KP](#): > > ONE PROBLEM: > Nichrome wire actually has a significantly higher resistance when hot vs. room temperature. These resistances are listed in the tables I linked. You will have to make a modification to the design, in order to draw 10A when hot without drawing much more (and possibly draining, harming, or blowing the battery) in the first few seconds of operation. I don’t see why this is a serious problem. With the setup you described, resistance should be only 8.6% greater at 1000 degrees F (from the linked site), which should decrease amperage to 0.3853 Amps/wire, giving a temperature of approximately 900 F. This of course decreases resistance to 1.075 times its room temperature value, allowing the temperature to actually go higher than 900 F. I tried making toast in my oven at 400 F, and it worked fine (though it did take a while), so 900 F should be more than hot enough. ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [February 1, 2005, 3:01am UTC](https://boards.straightdope.com/t/how-can-i-turn-bread-into-toast-with-batteries/287494/22 "2005-02-01T03:01:41Z")
> [@quelquechose](#): > > Is it possible to make toast without fire or wall electricity? How would I go about doing this?(The reasons I need to do this are difficult to explain, and not particularly interesting) Sure can do. A propane torch, batteries not included, from the harware store will fill the bill nicely. just play the flame back and forth across one side till it is toasty brown, flip it over. just play the flame back and forth across the other side till it is toasty brown. Voila! Hot toast. Now it your turn to explain why you NEED to do this. ( Or is it a bunch of pneure?) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 1, 2005, 5:15am UTC](https://boards.straightdope.com/t/how-can-i-turn-bread-into-toast-with-batteries/287494/23 "2005-02-01T05:15:23Z")
Um, **spingears** , a propane torch won’t do much without fire. I’m presuming that that restriction is due to fire safety restrictions in the area where **quelquechose** expects to be camping/hiking. When it’s particularly dry, the Forest Service generally prohibits all open flames. I’m not sure if Forest Service regulations would apply to a resistive-element heater, though… ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [February 1, 2005, 12:28pm UTC](https://boards.straightdope.com/t/how-can-i-turn-bread-into-toast-with-batteries/287494/24 "2005-02-01T12:28:47Z")
> [@Chronos](#): > > Um, **spingears** , a propane torch won’t do much without fire. I’m presuming that that restriction is due to fire safety restrictions in the area where **quelquechose** expects to be camping/hiking. When it’s particularly dry, the Forest Service generally prohibits all open flames. I’m not sure if Forest Service regulations would apply to a resistive-element heater, though… :smack: Thinking faster than I read? Mix aluminum and ferric oxide powders, spread a thin layer on a slab of insulation board, add a piece of magnesium wire across the layer. Suspend slice of bread above and connect the magnesium to a battery. Whoosh… instant one sided toast. :smack: That might be considered fire too. OTOH isn’t a red hot nichrome a high temperature heat source close kin to fire and wouldn’t that violate the spirit of any Forest Service regulation? quelquechose should forget the whole idea. I, for one, don’t want to be loaded down with a ‘ton’ of batteries except for the ones in a good LED flashlight for a stay on the trail! 🙂 ---
**Author:** ![Shade](https://avatars.discourse-cdn.com/v4/letter/s/2bfe46/32.png) [@Shade](https://boards.straightdope.com/u/Shade)\ **Post date:** [February 1, 2005, 12:37pm UTC](https://boards.straightdope.com/t/how-can-i-turn-bread-into-toast-with-batteries/287494/25 "2005-02-01T12:37:59Z")
> [@galt](#): > > “Help! I’m stuck in the wilderness with a battery and some bread and I **MUST HAVE TOAST!** ”. 😃 …and an internet connection… ---
**Author:** ![quelquechose](https://avatars.discourse-cdn.com/v4/letter/q/6f9a4e/32.png) [@quelquechose](https://boards.straightdope.com/u/quelquechose)\ **Post date:** [February 1, 2005, 10:08pm UTC](https://boards.straightdope.com/t/how-can-i-turn-bread-into-toast-with-batteries/287494/26 "2005-02-01T22:08:16Z")
Actually this has nothing to do with camping. I have been given a pointless and easy assignment for physics. I need to make series of small vehicles activate each other in a chain reaction, and I thought it would be interesting to have the vehicles (and a few other components) make breakfast in the process. The toaster bit is not a part of the assignment and is in no way related to the grade I receive, so I’m not asking for homework help here. The main reason I’m interested in making toast with batteries for power is because I was told that it can’t be done. I also thought it would be an interesting project to try, and I like toast, especially with peanut butter. 🙂 And with respect to the idea of making toast with a propane torch: I have tried it, and the results were not very good. I ended up with a piece of bread that was burnt on the outside and completely untoasted on the inside. I have one additional question regarding the construction of this toaster: How can I determine what amperage I can draw from the battery without frying it? Will the amperage indicated by a multimeter drain the battery quickly? [Previous page](https://boards.straightdope.com/t/how-can-i-turn-bread-into-toast-with-batteries/287494.md?page=1)