can I discharge a battery with a 220V hair dryer?

Thread Starter

learneager

Joined Jan 19, 2024
17
I would like to discharge a 12V battery but I don't have any 12V appliance. Can I use a 220V hair dryer to discharge it? Don't know if they are a completely resistive load
 

Thread Starter

learneager

Joined Jan 19, 2024
17
What is the battery capacity, and how fast do you want to discharge it (and why)?
The battery is 100Ah and I want to discharge it as a final test to know if it's OK. If it takes the corresponding hours to discharge assuming is full, I would be OK.

As Ian0 stated, a hair dryer would take too much time.. my hair dryer is 1200W so it has a resistance of aprox 40 ohms. Correct me if I'm wrong but that means

hours = 100 * 40 / 12 = 333 hours

I'll look for a power resistance then, thanks for the responses ;)
 

Ian0

Joined Aug 7, 2020
10,079
Is it a lead-acid battery? Is it new? If so, avoid the temptation to discharge it and believe the manufacturer. A full discharge really doesn't do a lead-acid battery any good.
 

Thread Starter

learneager

Joined Jan 19, 2024
17
Is it a lead-acid battery? Is it new?
Is a LifePo4 lithium batthery.. for what I know, it that be safely discharged to 100%. It has a very strange behaviour.. I asked about on another thread. It's quite new.. it only has few cycles of use
 

Thread Starter

learneager

Joined Jan 19, 2024
17
Thanks for the link :) didn't know that I had to wait some minutes to measure its open circuit voltage

So, why not stick to 20% as an end point?
The thing is that the batteries (I have two) show more than the 100% voltage according to the manufacturer (13.46V) after charging them with a charger.. so I certainly don't know if I can trust the voltages. I have 13.89V on one, and 13.56V on the other :/
To be sure, I can discharge it to 100% and immediately charge it again to a safer state
 

Alec_t

Joined Sep 17, 2013
14,386
Many hair dryers use a low-voltage motor, and connect it in series with the heating element.
The last time I checked, the motor was in parallel with a tapping off the heating element, with the element acting as a potential divider.
 
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