Pecan Media: food forestry and forest garden ebooks
Now available: The Native Persimmon (centennial edition)
Some places need to be wild
Pecan Media: food forestry and forest garden ebooks
Now available: The Native Persimmon (centennial edition)
Nails are sold by the pound, that makes sense.
Soluna Garden Farm -- Flower CSA -- plants, and cut flowers at our farm.
Some places need to be wild
Some places need to be wild
Eric Hanson wrote:Hey, Dan, I forgot to mention something in my earlier post.
I am a huge fan of repacking batteries...
Pecan Media: food forestry and forest garden ebooks
Now available: The Native Persimmon (centennial edition)
Douglas Alpenstock wrote:That said, it's been an amusing flashback to use these work lights with their original incandescent bulbs. Instead of sticking out the way LEDs do, the colour temperature nicely matches fire, candles, and kerosene lanterns. Aesthetically pleasing but less practical.
Pecan Media: food forestry and forest garden ebooks
Now available: The Native Persimmon (centennial edition)
Some places need to be wild
Some places need to be wild
Nails are sold by the pound, that makes sense.
Soluna Garden Farm -- Flower CSA -- plants, and cut flowers at our farm.
Some places need to be wild
Eric Hanson wrote:Kenneth,
Awesome that you are considering repacking a lithium battery to get rid of just one dead cell and not the whole thing.
Also cool that you see the potential of repacking NiCads with Nickel Metal Hydride. I still have a couple old 18 v NiCads that I intend to repack as a NiMH battery. These type of batteries are perfectly good for more stationary applications
Nails are sold by the pound, that makes sense.
Soluna Garden Farm -- Flower CSA -- plants, and cut flowers at our farm.
Some places need to be wild
Douglas Alpenstock wrote:Bump -- great thread!
I'm surveying my collection of "superseded" lithium battery packs from laptops and power tools and thinking it's time for a great big purge.
Except: I know that the individual cells (or paired/ganged cells, even better) match up with my ancient old 15W solar panels. I can direct-charge them to run LED lights, monitoring their charging with a multimeter (4vdc cutoff or they'll pop).
But I have to be practical about how many I will *actually* use.
Life on a farm is a school of patience; you can't hurry the crops or make an ox in two days.
Henri Alain
Nails are sold by the pound, that makes sense.
Soluna Garden Farm -- Flower CSA -- plants, and cut flowers at our farm.
Kenneth Elwell wrote:However, I did learn something about Li-Ion packs in the meantime. I got a "free" M12 6.0 Ah pack out of the recycling shed at my town's transfer station, it had no charge, and when placed on a charger it gave the "damaged" flash code. Oh well, it would be another rebuild to add to the pile. Or, so I thought.
When I mentioned this rebuilding project to a friend, inquiring if he had a spot-welder for batteries, he told me that often if a battery had been too deeply discharged, the charger wouldn't see the voltage it was expecting and refuse to charge the "damaged" battery pack. The solution to try was to make "jumper cables" for the battery packs!
Trees are our friends
Daniel Schmidt wrote:I've recovered a few hundred cells for my ebikes with good success. A lot of times the BMS shuts off for various reasons. It depends on what happened. If one of the safety features turn it off like a short circuit, or the whole pack starts to fall just below the voltage threshold, then it can usually be jump started like mentioned. It can be the same when you install a new BMS, if it doesn't work, a quick tap of the correct voltage range to the input will turn it on.
Another thing that happens if a pack is left for many months or more, the battery management circuit very slowly draws power from only one of the parallel cell(s), because it would be too inefficient/costly/heavier to draw from the whole pack and use a larger buck converter to power itself. So you end up with one of the parallel cell(s) much more drained to the point the BMS shuts off. These are the packs that would be dangerous to just throw at the charger. If one cell is too low, the difference will be added to the other cells which over volts them! That's the dangerous part.
Some tool BMS's don't balance the cells with the BMS. Some only do it on the charger like RC cars. Some only balance near the end of charging called 'top balancing', and often this ends up with it trying to burn off a few mA per cell on the higher ones so the low one can catch up. If a battery sat really long or has a dead cell then it may never correct itself and needs those cells charged separately or replaced.
I noticed some of the USB-PD and other car chargers take 12V and 24V input, often having higher output at the higher voltage. I hooked one up to a couple different batteries advertised as 18V-20V and it was able to charge my Chromebook in use for hours which takes 15V.
Nails are sold by the pound, that makes sense.
Soluna Garden Farm -- Flower CSA -- plants, and cut flowers at our farm.
Trees are our friends
Some places need to be wild
Some places need to be wild
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