eBay li-ion car,golf cart batteries in solar application

[mahendra]

I have noticed some lithium on eBay by a supplier called 1eyedcrusier ,who supposedly boasts batteries from lg,Bosch,chevy etc that are new from supplier .Any thoughts on these when compared to Calb lifepo4 .
Price seems to be very affordable when considering equivalent sizes of batteries compared to other lithium on the market.

[ClassicCrazy]

I have noticed some lithium on eBay by a supplier called 1eyedcrusier ,who supposedly boasts batteries from lg,Bosch,chevy etc that are new from supplier .Any thoughts on these when compared to Calb lifepo4 .
Price seems to be very affordable when considering equivalent sizes of batteries compared to other lithium on the market.

Do you have a link ?

Larry

[mahendra]

Yes definitely.
http://stores.ebay.com/lithiumbatterycenter/

[ClassicCrazy]

Yes definitely.
http://stores.ebay.com/lithiumbatterycenter/

This one  says it does not come with BMS .
http://www.ebay.com/itm/Li-ion-Lithium-48v-50ah-2-4kwh-NEW-2015-VOLT-Battery-EV-Car-Solar-Boat-Golf-/182050626252
Lithium Ion batteries can catch on fire a lot easier than LiFePo4 do from what I know about them.
So guess you need to add in all the costs of BMS and cables  and find the exact specs of the particular Lithium Ion batteries to be able to compare them with new Calb cells.

Larry

[Ocean]

Hi.  I just happened on this forum while browsing Midnight Solar.  I am Off-Grid and I have Lithium Ion Batteries so I thought I would share my experience.

I have three of these (which serve as my House Batteries):  TESLA's 7s for Mercedes B-Class
https://www.ebay.com/itm/Lithium-Li-Ion-EV-18650-Golf-SOLAR-Battery-Pack-24V-26V-120Ah-7S-made-by-TESLA-/263133603034?hash=item3d43fc24da

and MANY of these (some of which are installed in my home-brew Electric Vehicle, and some of which I might one day use as house batteries) :  Chevy VOLT's 6S / 12S
https://www.ebay.com/itm/Lith-ion-Chevy-Volt-48v-50ah-brand-NEW-battery-RV-Golf-Cart-Solar-EV-/182967687242?hash=item2a99b9584a

The Tesla's are awesome.  I'm running a 24 volt system based on an old Trace PS2524.  The Tesla's are 7S which means MAX voltage is about (7x4.2v/cell) = 29.4v and the MIN is (7x3v/cell)=21v.  They are a perfect drop in for a 24v system (the Inverter has LVD at 21v)... I have three wired in parallel (for about 360 Amp Hours)... I just wish I had one more (would make it easy to go to 48v).  But that's ok.  And yes, as someone noted, they have very little sag even under heavy load (my biggest load is a 1.5hp compressor or 1.5hp table saw) and when running these the Tesla's sag less than 0.5v under that load... albiet I'm usually charging at the same with about 800 - 1.4kw depending on the time of day / temp.

My charger is an old Outback MX-60.  It's working great.  I have it set to Bulk up to 29.2 and float at 28.8.  What happens when they reach float???  They sit there... and the charger only brings in what it takes to keep them at 28.8 which is essentially equal to whatever I'm using in the house or shop.

They are awesome.  I do not have a BMS for them.  It's something I am looking into.  But they've been performing well for over 2 years now.  For more info on BMS's look into the DIY Electric Vehicle Forum's.  Lots of info there.

The VOLT's (at least the 1st Gen) are either 6S (max 25.2v min 18v) or 12S (max 50.4v min 36v) which makes them sub-optimal for any standard system unless you can program your inverter to have a LVD Shutdown at about 18v (24v nominal system) or 36v (48v nominal)... because otherwise you won't have access to about half the available energy.  I know the old Trace SW's can do this.  I think some of the Magnum's can too.  Not sure about Midnight I haven't looked.

I do have an old Trace SW5548 (my alternate / backup house system) which I might use with some of these VOLT Batt's when my L-16's give up.  Until then....

I have a set of the VOLT's installed in my EV - 24S x 6P (24kWh) giving me a max 100v and min 72v which is what brought me to Midnight in the first place.  I've been looking all over for a MPPT controller that will let me charge my batts up to exactly 100v.  It looks like the Classic 200 will do that.  Please correct me if I'm wrong!

Midnight:  IMO There's a upcoming market for homebrew EV's needing Solar controllers for Batteries with Nominal voltages anywhere from 100v to 600v.  I wish you had a 30 or 40 amp MPPT controller (with 200v input capacity) that I could set to bulk to exactly 100v and maybe float at 99.6  but I will settle for the Classic 200 if it will do that.

Thanks!
-Ocean

[Ron Swanson]

Please see this thread if you have the time:

http://midniteftp.com/forum/index.php?topic=3924.0

We are still stuck on lead-acid for the time being but always on the watch for something better.

What would you say to the person needing 50 kWh or so?  Would paralleling a bunch of these be a good idea?  We would never parallel that many lead-acids, of course.

I see some circuitry on them of some kind.  Does it balance voltage between cells?  How is that accompished?

What about temperature compensation?

And what happens if they accidentally overcharged or undercharged?  Safety hazard?

What is their expected life span?  And is it something we could sell to a paying customer with a reasonable expectation they will last a really long time?

Always on the lookout for something better.

[Ocean]

I did look through that thread.  I get what you're looking for - to serve your customers with a high capacity, long lasting, maintenance free battery.

Well, the lithiums I have are basically car batteries taken from wrecked vehicles (Tesla's, Hybrid's like the Volt or Mercedes B-Class, etc) so you are dealing with a used battery to begin with.

I'm not sure you want that liability.  BMS systems are still being figured out for the Tesla OEM batteries. I have seen Chevy Volt batteries on Ebay already set up with a BMS.

For me they have performed really well.  If I were you I would try it out for yourself and see what you think before offering it to your customer. 

The whole "Lithium's on fire" thing.  It seems pretty unlikely in a home system.  Rarely would you ever pull as much current from a properly sized home system as these batteries have sees on the road moving a car.

But again, it's the balancing thing.  My Tesla's have not been balanced and I just need to keep an eye on them in case one of the cell block's starts to drift.  So you probably want to get a cell balancing system figured out before you go that route for your customers.

But dang, they perform well!  Oh yes and as far as life expectancy... well just think of what they do in a car!  100,000 miles?  I got mine with about 30k miles on them.  And my system is sized so they rarely discharge below 60% overnight (that is, in the morning they are easily 60%DoD or better).  And the rate of discharge is so low compared to what they are designed for.  And they can go down to 10% and be fine.  So with minimal cycling, I expect them to last a loooong time.  Hoping for 10 years at least.

Good Luck!
-Ocean

[Ocean]

I have three of the Tesla 7S modules in parallel, and I would not be afraid to put three more (although I would want to have my cell balancing figured out before then).  That would be 18kWh (each one is 3kWh).  Then go to 48v (14S or basically two modules in series, then all those in parallel) so double that.  You could have 36kWh and almost all of that useable.  But again, you are experimenting here, so be careful.

[CDN-VT]

LIKE !!
Lack of button !
Keep it coming
VT

[Ron Swanson]

Some more questions....

What is the specific chemistry of the batteries referenced?

What would be the expected lifespan and the expected life cycle cost?

Weight, physical size?  Pictures?

[Ocean]

Chemistry, lifespan / lifecycle cost? These things you will need to figure out for yourself doing some research.  There's plenty of info out there.  Just start searching... Search for "Tesla Battery Chemistry"  or "Volt Battery Chemistry"... You are guaranteed to find some info.  If you want to see pics, look on Ebay.  Search for "Tesla battery" or "Chevy Volt Battery"... you will find some... with pics and specs and all that.

[Ron Swanson]

The trouble I have is Tesla has done such a good job in marketing that all I find when searching are drooling news articles.  Nothing down and dirty.  Nor anything that can be trusted, because if you have ever had any experience with news, anything that cycles through them is downright wrong.

As far as pictures, I was thinking more of installed pictures.  Like how you have them set up.  I see the pictures above but they don't give much context.  I can't even tell how big they are or what all those electronic doodads are for.

[Ocean]

Tesla Batteries are basically built from a Series / Parallel array of Panasonic NCR18650 Cells.  Look for those as far as chemistry goes.  Volt batteries are basically LG Chemical Pouch Cells.  Very similar chemistry.

The dimensions of the Tesla Packs and the Volt packs are in the description on Ebay.

I just have three sitting next to each other, anchored down and connected in parallel with a couple copper bus bars I made to fit.  Maybe I can send a pic later but it's pretty straight forward.

[Ocean]

The electronic PCB that comes on a Tesla battery is an interface / BMS of some kind which is fairly useless unless you can hack it.  Just unplug it.  Maybe find another 7S balancing board to replace it (that's what I'm looking at.. just saw some cheap ones on Ebay)...

Otherwise what you find is a complex but very smart design of housing the individual cells and connecting them together.  Each one is individually fused.  But there is a heavy duty connection on top for the main + / _ Connection.  Special terminal posts threaded with I think M6 or something like that.  Mine came with a bolt to make the connection.  It's just a big fancy battery at the end of the day with one + / _ connection.  29.2v Max 21v Min (my recommendations).  Double it for a 48v system.

[grgdgreek]

Check out "Batrium bms" looks interesting.
Or diy Powerwall.

George