Anyone with homemade lithium battery bank?

[getyourbone]

Hello!

Very new here. Wife daughter and I are about to move onto a 45 ft sailboat. I am looking into increasing the battery capacity as I am sure "we" will find a desire to use more electronics and comfort items (Air Conditioning, hair dryer, curing iron etc...) than the previous owners of the boat.

Wondering if anyone out there has chosen to make their own battery bank using recycled (or new) 18650 Lithium cells? I have 4 -5 kWh of Cells that I would like to use to build a 48v bank. If all goes well I would probably increase the capacity to 12 to 15 kWh. Currently costing about $150 -200 per kW of power so obviously need to make sure its working and is safe before investing up to $1000 on more!

• I Intend on fusing at the cell level.
• Also plan on encasing the battery bank in a fireproof box.
• Certainly plan on some form of monitoring of the bank
• Will be able to be charged via solar/wind/generator(engine).
• Would like to build in some redundancy so I am sure there will be multiple smaller charge controllers and inverters so that in case one goes bad, we will still have some ability to generate power even if "we" can't curl our hair.

I would love to here insights into doing this from a marine/boat perspective. Already have an inexpensive inverter and a couple of charge controllers one the way to experiment with. Possibly upgrade to better equipment if it all goes well with the batteries.

Anyone care to comment

Thanks,

Steve

[john61ct]

No. On a boat use the big block "prismatic" cells.

Play with the 18650 hobby on land.

Most people will say a "solution system" with a proprietrary BMS like Victron or Lithionics is the only way to go.

DIY protective LVD/OVD and cell-level monitoring is a lot riskier, of your large investment most of all.

$1000 is a drop in the bucket. If you really need PSOC resistance consider Firefly Oasis, lots cheaper than LFP, but even then a grand only gets you two 100AH G31's.

The cells themselves are just one part, usually all the other infrastructure is lots more.

So if you think $1000 is a lot, start with Duracell GCs at $180 a pair, or Trojan T-150s maybe up to top RE quality.

[newhaul]

Not on a boat like john said look to more conventional batteries he mentioned gc2 batteries lets see what the math is for that $180 220ah x13.5 volts = 2970 wh so almost 3kwh for under $200 bucks and the infrastructure to maintain them is cheap compared to lithium ion batteries and safer (imo)

[leboyd]

Here's what I thought was a good video on selecting batteries.

Take it or leave it:

https://www.youtube.com/watch?v=J-kND4PaZm8

Truly brand name Lit batteries are not the fire hazard that cheap no-named Lit batteries are. The problems you read about with the little hover boards and e-cigs is because they're cheap Lit batteries. The problems you read about with cell phones is because the phone manufacturers are trying to max the power of a small battery in a tight, relatively hot space and almost zero air flow.

They're like LEDs. Buy cheap no-name and expect serious problems. Buy brand name and expect serious solutions.

[john61ct]

Sure if you're a wealthy racing boat owner, paying thousands to save a couple hundred pounds is worth it.

Or looking to live on the same boat for twenty years, may end up being cheapest bank per-year overall **if** you're motivated to watch it closely **and** nothing goes wrong.

But huge up-front investment to risk if you're not a 1%er.

[leboyd]

@john 61CT: OP indicated that they are going to live on the boat and want to run a lot of electronics/electrical devices, including A/C off the batteries. Price is always a consideration, but some (as in the video) can afford it the upfront cost to save money and headache over a long term period. I don't know what the financial situation of the OP is. However, your original post addressed technical issues, which is what I (and the video) addressed. Technically, there's no reason to not use name brand Lit batteries in most situations, including a boat.

[john61ct]

I made it clear the way to go **if** he can afford LFP.

Many indicators s/he can't, so indicated better alternatives.

And anything's better than the 18650 idea.

The Wynns are a lovely couple, and make entertaining videos, but for tech advice I'd dig deeper.

[Bleemus]

The Wynns make about $2500 a week just on Patreon. That doesnt include YouTube ad revenue and Amazon affiliate revenue. They are in a different league than the OP.

[leboyd]

Originally Posted by Bleemus

They are in a different league than the OP.

Even if the Wynns made $10,000/week on YouTube or however one makes money, unless you're a good friend of the OP, how do you know they are in a different league? Not everyone who cruises or lives aboard are dirt poor. If they are buying a new '45 top-of-line boat, they could easily spend $500k. $7-10k for 2 or 3 batteries isn't very much.

They may be dirt poor and buying an old boat for $30k, but I wasn't making any recommendation or suggestion whether they could or could not afford those batteries. I was pointing out the Lit batteries are a solid technically viable battery for sailboats.

Haters gotta hate.

[john61ct]

OP is considering using recycled 18650 from scrap laptop batteries.

OP stated

Originally Posted by getyourbone

costing about $150 -200 per kW of power so obviously need to make sure its working and is safe before investing up to $1000 or more!

Both of which imply to me that spending $4-8,000+ needed for a "proper LFP system" is likely not in the cards.

And this all has nothing to do with any disparaging at all, much less "hate" (???!!) Seems you must look down on the poors yourself if that was your interpretation, I only see people trying to be helpful.

[44'cruisingcat]

The batteries we use on boats tend to be LIFePO4.

[getyourbone]

Let me clear a few things up...

The Wynn's ARE in a different league than we are in. Our entire budget for the boat and the next couple of years of goofing off isn't as much as they make in a year just from Patreon. They do things in a very mainstream way. I will/do not. At first I could not handle watching more than 30 seconds of them...Now I do find that they actually provide a fair bit of info that I can use as a baseline to build/deviate from for my own purposes.

1%ers? ya the 1%er's if your measuring unemployed, "homeless", with a 4 year old child and chose to walk away for the simple cracker box home /pool on a cul de sac in the suburbs with a decent jobs, dog 2 aquariums, newer furniture, garage full of tools, and 2 cars in the driveway.

Can we afford 5,000 - 10,000 to buy a new system? Probably...but why the heck would I do that when I can get the chance to build my own for probably not much more and possibly less?

I asked for comments and recommendations...doesnt mean it is what I will do. In fact I appreciate many of "don't do that" comments as it motivates me on one side while making sure it is what I really want to do on the other side...

I don't take offense from comments that are against what I am doing.

Please don't take offense when I don't do what may be recommended. I asked for comments and insights on what I am about to do...not being hired to do something for others.

I would rather have honest opinions FOR AND AGAINST that allow for a good discussion and ideas explored and researched from all sorts of angles.


Those that are squeamish and think what I am doing is certainly going to end in death destruction and fire had better look way from the on coming train wreck.

Those that are curious...come along for the ride. Our world is about to become overrun with left over batteries and we better find a way make use of them...Just as we are left with the carbon monoxide and other pollutants from internal combustion appliances, we will be left with the pollution from portable/mobile electrically controlled equipment...18650's, 2170's,etc...

Just for the record, I have very little experience in both boats and batteries. However I have been a brick and mortar retail business owner, network administrator, dairy farmer, Home repair "professional", heavy equipment operator, residential siding installer, etc...so why can't I be a battery installer on my boat...just saying'

[Bleemus]

Just find a Nissan Leaf that has been wrecked. No sense reinventing the wheel.

[getyourbone]

If all goes well with the first round/learning curve… I will likely end up using 3 or 4 3 kWh tesla modules… With freight, they are closer to $275 per kilowatt of power but like you said… Why reinvent the wheel. They have cell level fusing, water cooling, and I believe the ability to monitor built into the pack... and possibly the biggest upside – professionally fabricated.

Here's a link to a schematic utilizing them…

http://evwest.com/support/EV%20West%...0Back%20Up.pdf

[getyourbone]

Originally Posted by Bleemus

Just find a Nissan Leaf that has been wrecked. No sense reinventing the wheel.

I thought I already replied to your comment but I don't see it… Not sure if somehow I violated a posting rule?… It included a link to a schematic that shows how to use Electric car battery modules in an off grid kind of situation and maybe that's not allowed?… Links to external website?

If I get a basic system up and running, my plan probably would be to use Tesla 3 kWh modules due to the fact that they are cell level fused, professionally fabricated, have the ability to be water cooled, and I believe easily adaptable to a generic BMS if I choose to go that route.