Can Mixing Different Battery Brands Damage Your Devices?

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Discussion Overview

The discussion revolves around various myths related to electrical engineering and battery usage, particularly focusing on the implications of mixing different battery brands and other common misconceptions in the field. Participants share anecdotes and explore the validity of these myths, including safety concerns and technical explanations.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants highlight myths about mixing battery brands, suggesting that using different brands in a flashlight may lead to issues such as reversed polarity and potential damage.
  • There is a discussion about the claim that leaving a car battery on a cement floor can ruin it, with some noting the ambiguity in the wording and its implications.
  • One participant mentions the myth that using a wireless phone during an electrical storm is unsafe, while another challenges the rationale behind banning cell phone usage at gas stations.
  • The concept of cars acting as Faraday cages is mentioned, with some participants agreeing on its validity but debating the reasons behind it.
  • Participants share humorous anecdotes related to grounding devices for cars and question the truth behind such claims, indicating a blend of skepticism and curiosity.

Areas of Agreement / Disagreement

Participants express a mix of agreement and skepticism regarding the myths discussed. While some acknowledge certain myths as silly, others propose that there may be elements of truth in specific claims, particularly regarding battery usage and safety. The discussion remains unresolved with multiple competing views on the validity of these myths.

Contextual Notes

Some claims are based on ambiguous wording or anecdotal evidence, leading to uncertainty about their validity. The discussion does not resolve the technical aspects of the myths or provide definitive conclusions.

manzana
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These are some of my favorite myths I have encountered in my EE career...

1. NEVER mix Duracell and Eveready batteries in the same flashlight
2. Never leave your car battery on a cement floor, it will ground out and drain itself ( A metal shelf on concrete is OK)
3. Never use a wireless phone during an electrical storm
4. You are safe from lightning in a car because it isn't grounded
5. Cell phones use satellites to communicate (what are those big towers for?)
6. I need 100 ohm coax so I will just use 2 50 ohm pieces in series

MY FAVORITE:
7. For $20 you can by a rubber strip at the truck stop to ground your car and make it invisible to police radar. (Watch out for lightning though..)
 
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manzana said:
2. Never leave your car battery on a cement floor, it will ground out and drain itself ( A metal shelf on concrete is OK)
Someone posted a thread about this recently. The problematic claim was worded, "Never leave a car battery on a cement floor. It will ruin it." The last sentence is ambiguous, but is meant to warn that fumes from the battery will ruin the cement floor. But, because of the ambiguous wording, it's easy to suppose it means the cement floor will ruin the battery.
 
manzana said:
These are some of my favorite myths I have encountered in my EE career...

1. NEVER mix Duracell and Eveready batteries in the same flashlight
2. Never leave your car battery on a cement floor, it will ground out and drain itself ( A metal shelf on concrete is OK)
3. Never use a wireless phone during an electrical storm
4. You are safe from lightning in a car because it isn't grounded
5. Cell phones use satellites to communicate (what are those big towers for?)
6. I need 100 ohm coax so I will just use 2 50 ohm pieces in series

MY FAVORITE:
7. For $20 you can by a rubber strip at the truck stop to ground your car and make it invisible to police radar. (Watch out for lightning though..)

Those are pretty good. I've heard many of them, and yes they are pretty silly. What's worse is barring cell phone usage at gas stations (petrol stations) citing safety reasons. That's just a load of hooey.

There might be a touch of truth to #1 though. When you change batteries, preferably you should change them together and use batteries of the same brand. The issue is that since the battery cells are in series, as is typically the case with a flashlight ("torch" for all you European yahoos people), as the battery depletes there is a real chance that the cell with the least amount of charge will find its polarity reversed. When this happens it will very likely corrode and may damage the flashlight (torch).
 
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manzana said:
4. You are safe from lightning in a car because it isn't grounded

there's a lot of truth in this one as well. BUT NOT because it isn't grounded, but because it is a reasonable Faraday cageDave
 
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davenn said:
but because it is a reasonable Faraday cage
Poor Faraday, why are there some many people that want to catch him and lock him in?
 
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hahaha
 
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manzana said:
7. For $20 you can by a rubber strip at the truck stop to ground your car and make it invisible to police radar

this one reminds me of something else from days gone by
Cars were sold with or could be added later, a leather strap from the car chassis that the other end would bounce along the road
It was said to ground static build up in the car that was reported to be one cause of people getting car sick ( motion sickness)
I have never done any research into it, so don't know if there is any truth or if it is just another "old wives tale" ? :)

Dave