Thinking of "building" a Lithium battery

[laknox]

So, my cousin and her husband are converting a bus into a MH and have chosen to go virtually all-electric, with massive solar and a Nissan Leaf battery to power everything. (See www.beginningfromthismorning.com for details.) I'm wanting to be much less ambitious and only use a few Leaf modules for a more modest battery. Simplest would be to use 2 modules to build a 14.8v battery, then connect several together to give me the amp-hours I want. This means that I'd need a higher-voltage charger than what's stock; say 15v. Are there any RV-style chargers that will charge this high that aren't a 3-stage? Or, would a 3-stage work and be able to sustain a 15v charge for more than a few minutes? Just beginning to research this, so am looking for info, lots and lots of info. :B

Lyle

[MEXICOWANDERER]

It's called "Bypassing Reality Via Virtual Reality Management Fiefdoms"

It is why and how I sneered at joining a corporate engineering entity. Good companies have board members that have a BS detector mentality. You read headlines about those companies that do not have this talent.

"Losing Face" may be the epitome of the idiocy of reality via fiefdom"

[Huntindog]

Has anyone noticed how many large companies with mega million dollar budgets and many engineers have catastrophic battery failures?

[laknox]

MEXICOWANDERER wrote:
I just started fiddling with lithium in 2016 and only can tell you about my experience.

Series cells must be graded to match characteristics. Test, grade and sort. I found it was a total waste of my time to ignore the matching and grading of individual cells.

Trouble is, the lack of enough inventory to make pick and choose feasible.

This is why I'd like to buy an entire battery. Test each module, match the best for what I need, then sell the rest. :B

Lyle

[MEXICOWANDERER]

I just started fiddling with lithium in 2016 and only can tell you about my experience.

Series cells must be graded to match characteristics. Test, grade and sort. I found it was a total waste of my time to ignore the matching and grading of individual cells.

Trouble is, the lack of enough inventory to make pick and choose feasible.

[Itinerant1]

Acampingwewillgo wrote:
Great work on their Bus conversion....I found myself fully engaged in reading each step on the progress on the build. Not that I'll be tackling any such project but its fun to read about it!! 🙂

If you haven't read/ seen this newer bus conversion it's a good read and interesting to see the end result.
http://jdfinley.com/category/rv/

[Acampingwewillg]

Great work on their Bus conversion....I found myself fully engaged in reading each step on the progress on the build. Not that I'll be tackling any such project but its fun to read about it!! 🙂

[laknox]

I'm aware of the BMS, and will address that if/when I do this. In talking to my cousins about this, proper charging can be a =big= issue, if not done right, which is why I'm asking. 8 modules would give me double the amp-hours with half the weight, both big bonuses IMO, but we're not hard-core 'dockers. If we were, I'd be going much bigger, with solar to match. :B

Lyle

[GordonThree]

Bms isn't really magic. It's a microcontroller measuring volts and allowing small current to flow between cells in an attempt to equalize the cell voltages. More complex units will also interrupt current for over-temp, over-discharge, etc.

While they used to be special and custom made, the industry now is spoiled for choice on chips that do it all. Everybody and their brother is selling these units on eBay. Solar and EV supply companies are also providing programmable and networked BMS that can control inverters, charge controllers, etc

[time2roll]

deleted

[MEXICOWANDERER]

Ordinal Of Importance

1) Battery energy management system. How are you going to go about getting one?

2) With hurdle number one out of the way, the design of the bank can commence.

[GordonThree]

I'd like to take a whack at building a pack, but finding a donor pack proves difficult in Michigan. Talking to a few scrap yards, they report companies in California buy totaled electric vehicles almost as fast as they come in, for the batteries and electric motors.

[Itinerant1]

If you're just starting to research look here.
https://www.solarpaneltalk.com/forum/off-grid-solar/batteries-energy-storage/lithium-ion

[2oldman]

Li's don't usually have an Absorb phase. I use a golf cart charger specially modified (free of charge by the manu) to do just bulk and float.

You'll (obviously) need to know the charging characteristics of your modules. And you'll need to do your own BMS. For all-electric I'd consider going to 24, 36 or 48v. Much easier on batteries and cables and inverters.