6 ms·

> I have a couple old kindle fire tablets lying around. One of them has a battery that lasts about ten minutes. You might want to check if the battery is going

by Netcob 3y ago

> I have a couple old kindle fire tablets lying around. One of them has a battery that lasts about ten minutes. You might want to check if the battery is going "spicy pillow".

seanthemon 3y ago
Lithium hotpocket
wkat4242 3y ago
Yeah for this reason I replace the battery of old tablets that I use as control panels, with a DC-DC converter. Simply removing the battery isn't enough because most tablets refuse to run on usb power alone.
- danielvf 3y ago
  URL to an example of what you use?
  - cheeko1234 3y ago
    https://www.instructables.com/Powering-a-Android-Device-From-Wall-Adapter-And-Ma/ https://www.instructables.com/Powering-a-Android-Device-From... https://old.reddit.com/r/homeassistant/comments/13ovuqn/ive_created_a_guide_on_how_to_replace_your/ https://old.reddit.com/r/homeassistant/comments/13ovuqn/ive_... You can use an LM2596 to step down the voltage.
  - wkat4242 3y ago
    I use cheap ones from Amazon (link below). I power them with 12V adapters which I "shucked". 5V is not enough to provide enough voltage because you lose some in the conversion. https://www.amazon.es/gp/product/B07PBCYTFW https://www.amazon.es/gp/product/B07PBCYTFW These adapters seem similar to what's used in that instructibles link. I didn't pick these for any specific reason other than they were available on Amazon. It uses the same LM2596.
- londons_explore 3y ago
  You can also replace the battery with a much smaller one - eg. a coin cell, and it'll normally run fine.
  - wkat4242 3y ago
    But what will a coin cell do when it's trying to get charged? That sounds a bit worrying. But I didn't realise that. Perhaps I could use a voltage divider then or simply input 5V. 5V is too high for a battery but most devices accept it there anyway.
    - londons_explore 3y ago
      > But what will a coin cell do when it's trying to get charged? You can get rechargeable lithium coin cells. It will just recharge fast. The cell usually has enough internal resistance and surface area that it can't overheat or violate the charge current limits. I still wouldn't recommend this approach, simply because the DC/DC converter approach you specified is slightly more power efficient (onboard chargers tend to have poor energy efficiency - many are simple linear regulators from 5v!).
deleted 3y ago
[deleted]

by Netcob 3y ago

> I have a couple old kindle fire tablets lying around. One of them has a battery that lasts about ten minutes. You might want to check if the battery is going "spicy pillow".

seanthemon 3y ago

Lithium hotpocket

wkat4242 3y ago

Yeah for this reason I replace the battery of old tablets that I use as control panels, with a DC-DC converter. Simply removing the battery isn't enough because most tablets refuse to run on usb power alone.

danielvf 3y ago
URL to an example of what you use?
- cheeko1234 3y ago
  https://www.instructables.com/Powering-a-Android-Device-From-Wall-Adapter-And-Ma/ https://www.instructables.com/Powering-a-Android-Device-From... https://old.reddit.com/r/homeassistant/comments/13ovuqn/ive_created_a_guide_on_how_to_replace_your/ https://old.reddit.com/r/homeassistant/comments/13ovuqn/ive_... You can use an LM2596 to step down the voltage.
- wkat4242 3y ago
  I use cheap ones from Amazon (link below). I power them with 12V adapters which I "shucked". 5V is not enough to provide enough voltage because you lose some in the conversion. https://www.amazon.es/gp/product/B07PBCYTFW https://www.amazon.es/gp/product/B07PBCYTFW These adapters seem similar to what's used in that instructibles link. I didn't pick these for any specific reason other than they were available on Amazon. It uses the same LM2596.
londons_explore 3y ago
You can also replace the battery with a much smaller one - eg. a coin cell, and it'll normally run fine.
- wkat4242 3y ago
  But what will a coin cell do when it's trying to get charged? That sounds a bit worrying. But I didn't realise that. Perhaps I could use a voltage divider then or simply input 5V. 5V is too high for a battery but most devices accept it there anyway.
  - londons_explore 3y ago
    > But what will a coin cell do when it's trying to get charged? You can get rechargeable lithium coin cells. It will just recharge fast. The cell usually has enough internal resistance and surface area that it can't overheat or violate the charge current limits. I still wouldn't recommend this approach, simply because the DC/DC converter approach you specified is slightly more power efficient (onboard chargers tend to have poor energy efficiency - many are simple linear regulators from 5v!).

deleted 3y ago

[deleted]