carnage
Enlightened
What size resistors do I need to do a load test with AAA,AA,D size batteries?
Battery load test question
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TinderBox (UK)
Flashlight Enthusiast
I use an "All-Sun BT21 LCD Display Digital Battery Tester about 20-120mA Digital Battery Instrument" it has 3 load settings, you can buy them for around $12, slightly to small to test an 18650 but i have heard it can be modded.
https://www.banggood.com/All-Sun-BT...0mA-Digital-Battery-Instrument-p-1013031.html
John.
carnage
Enlightened
Do you know how accurate they are? Have you tried it against a DMM reading?
TinderBox (UK)
Flashlight Enthusiast
A DMM does not load a battery while testing, Also you cannot disable the load on this battery tester, So i cannot compare like for like.
My DMM shows an Eneloop AA at 1.3305v
The battery tester with low load = 1.33v
med load = 1.33v
high load = 1.31v
John.
carnage
Enlightened
I was watching a Youtube video where a guy was using a resistor to put a load on the battery to measure the draw. People was replying that he was using a resistor that was to low to measure current drain.
TinderBox (UK)
Flashlight Enthusiast
carnage
Enlightened
Thanks for the replies!
terjee
Enlightened
Quick note: it's probably be really fiddly, but you could use both the battery tester and DMM at the same time. The load from the battery tester would drag the voltage down for the DMM as well, allowing for comparison.
It would however be a bit surprising if the battery tested is way off however. Even $2 DMMs off of eBay usually get the voltage reading in this range somewhat right, with decent margins.
What you're paying for with a more expensive DMM are things like safety, features, getting the hard readings (small and large values) right, a more accuracy than you really need.
Using a resistor is also entirely possible, just a bit of work to get everything just right.
It would however be a bit surprising if the battery tested is way off however. Even $2 DMMs off of eBay usually get the voltage reading in this range somewhat right, with decent margins.
What you're paying for with a more expensive DMM are things like safety, features, getting the hard readings (small and large values) right, a more accuracy than you really need.
Using a resistor is also entirely possible, just a bit of work to get everything just right.
Wrongway
Newly Enlightened
It depends what sort of test your doing and the capacities of the cells. But an electronic variable constant current load might be better than a fixed resistor something like this
https://www.amazon.co.uk/gp/product/B01N95NSSP/ there is a video of it in use here https://www.youtube.com/watch?v=snROh2acybs&t=457s . Its quite cheap, probably even cheaper from Banggood and would test capacity as well as a few other things.
https://www.amazon.co.uk/gp/product/B01N95NSSP/ there is a video of it in use here https://www.youtube.com/watch?v=snROh2acybs&t=457s . Its quite cheap, probably even cheaper from Banggood and would test capacity as well as a few other things.
carnage
Enlightened
Thanks for the replies!
