Making Lithium Batteries?

Toecutter's Ghost

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18650 is a case size, not a chemistry. 

The problems I've seen in series / parallel setups have been related to the weak cells in the parallel strings getting stressed and hot. BMS's I've looked at monitor the parallel strings as if they were single cells. That is simple but not ideal.
True, but 18650's are somewhat notorious for being dubiously specified in the budget price range since they are essentially the "AA" battery of lithium chemistries and there's no mention of chemistries in the OP's link. In fact, the Samsung battery mentioned is regular Li and is brilliant for rebuilding power tool packs. If you're after LFP, first check is to make sure they're 3.2 VDC and not 3.7VDC when charged, I guess.

If you buy batteries already fitted with spot welded nickel tabs they are ridiculously easy to solder together.

 

weightless

Super Anarchist
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 there's no mention of chemistries in the OP's link.
Yep but doesn't your post say that 18650s are unsafe because of their chemistry?

Don't use 18650 cells because ... the chemistry isn't really safe enough for use on a boat
I just wanted to make it clear that LiFePO4 and all the other common lithium-ion chemistries are available in 18650. In any case (as it were) I believe the current wisdom is that LiFePO4 is the best Lithium-ion chemistry for boat batteries.

 
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Toecutter's Ghost

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Yep but doesn't your post say that 18650s are unsafe because of their chemistry?

I just wanted to make it clear that LiFePO4 and all the other common lithium-ion chemistries are available in 18650. In any case (as it were) I believe the current wisdom is that LiFePO4 is the best Lithium-ion chemistry for boat batteries.
Fair enough, but the OP's link isn't discussing LFP batteries. It's discussing "regular" run of the mill batteries. it also mentions (to paraphrase from memory) that batteries "should be between 3 and 4 volts". This might work for a scooter repack that individually monitors each cell, but scaled up to, say, a 1kW battery? I dunno.

 
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weightless

Super Anarchist
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Fair enough, but the OP's link isn't discussing LFP batteries. It's discussing "regular" run of the mill batteries. it also mentions (to paraphrase from memory) that batteries "should be between 3 and 4 volts". This might work for a scooter repack that individually monitors each cell, but scaled up to, say, a 1kW battery? I dunno.
Got it. Yes, the OP's link is to a battery build using LCO cells. I think nominally over 40 volts and just about six amp hours. I hadn't looked at it before. The OP said he wanted a house bank. ¯\_(ツ)_/¯

 
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Murphness

Super Anarchist
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What could go wrong? 

Have a look here... Jim, the proprietor, is a full time liveaboard in Marathon, a good guy

https://lithiummarinebattery.com/
Hey Max - Thanks for posting this. Do you have experience with this battery? I talked to the proprietor yesterday and it gave me a confidence boost. At $650 for a 100AH G31 it becomes an easy decision over AGMs. I'm seriously considering picking this up over a battleborn. Savings is $300.

 

Max Rockatansky

holy fuckfarts!
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Hey Max - Thanks for posting this. Do you have experience with this battery? I talked to the proprietor yesterday and it gave me a confidence boost. At $650 for a 100AH G31 it becomes an easy decision over AGMs. I'm seriously considering picking this up over a battleborn. Savings is $300.
I have no experience with the batteries, but Jim is a decent sort of fella and I think he’s on the level

Regardless, always be informed. Check out Marinehowto.com’s info pages as a start

 

martin 'hoff

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PSA - for anyone following this thread - these things pack a lot of energy - think hand grenade - and go boom at unexpected times. I've worked with this -- manufactured, shipped products, - LiFePO4 and NiMH batteries. Huge efforts go into making sure things don't go boom. Of the lithium-based family of batteries, LiFePO4 at the more stable end of the spectrum, but all of them require a lot of care.

NiMH is stable -- I've seen videos of well-designed NiMH batteries being "cooked" in a microwave oven and they produced a modest flame. A lithium-based battery would have probably resulted in anything from fireworks to real harm.

Playing with this stuff can put you in contention for the Darwin awards. So tell us all about it -- by all means, we're a curious bunch. And have life insurance.

[ If you really know what you're doing, this is not a criticism. I just hope you actually know what you're doing. Keep the old Dunning-Kruger effect in mind. ]

 

solosailor

Super Anarchist
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Oh my what a non-public service announcement.   Yes they have a lot of energy but LiFePO4 in particular don't go boom.   Shooting fire is from LiPo (cobalt, manganese, etc.) When a cell gets damaged and overheats they can literally melt down but a boom isn't happening from LiFePO4.

 

Ocean View

Member
383
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Australia
I'd suggest you're doing it the hard way

Much easier to find a local supplier of CALB or Winston LifeP04 3.2v cells in your area who is supplying the EV Conversion market.

Then buy some BMS modules such as the ones below and ideally a BCU-NEV to protect you from overcharge and low voltage instances - and your pretty much ready to go.

We've been running the EV-power 100hr 12V battery below for 9 years now and it's still going strong and it's done 6 or 7 x Hobarts and 3 times that distance in delivery trips to get there and back.

https://www.ev-power.com.au/product-category/webstore/lithium-bms/

https://www.ev-power.com.au/product/bcu-nev/

https://www.ev-power.com.au/product/evg12v100ah/

EV won't ship the batteries but he will ship the BMS modules overseas as far as i know.

And if you want to read a warts and all (good and bad bits)  review of Lifep04 on a boat have a read of this post. 

https://marinehowto.com/lifepo4-batteries-on-boats/

Trust it helps.

 

Ajax

Super Anarchist
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Edgewater, MD
Technically possible, of course, but the one-time expenses for the tooling (e.g. battery terminal spot welder) will offset any savings. Not to mention the fact that a typical 130Ah 12V battery has over 300 individual 18650 cells that all need to be matched electrically and connected properly. A fool's errand now that we're long past the hobbyist/tinkerer stage of lithium battery commercialization and commercial production by reputable manufacturers has reached scale.
Exactly.

Long before Tesla ever existed, I converted a 1976 VW Beetle to battery-electric drive, using lead acid 8v batteries. I immediately investigated upgrading to Lithium batteries. It made some sense then, but definitely not now.

Some of my friends keep asking me "Why don't you build another EV?"  That's just silly, now. There are so many models to choose from, superior to anything that I could build at home, that are safer and that would overall, cost the same or less.

 

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