LTO battery fire

[sunshine_eggo]

So you pump in 20Ah per 9 months of balancing current from an extra charger, that works out as 74mAh per day? The Batrium wiki says 50-150mAh per day for cells "at the end of life", so I guess this is in the ballpark. The question then would be why the Batrium BMS needs help from an external charger and doesn't take care of this by itself. Their balancers seem to all be good for a lot more than 74mAh per day.

.15Ah is mentioned here:

Set Up The AutoLevel Bypass Configuration On The WatchMon

How to Set Up The AutoLevel Bypass Configuration On The WatchMon

wiki.batrium.com

EVE 280Ah cell datasheet indicates up to 1% self-discharge per month.

That's 2.8Ah/month or 2.8/30 = 93mAh/day

So brand new EVE cells may be at end of life by the 50-150mAh/day number.

What if a 10,000Ah cell lost .15ah per day. Cell would hold its charge for 183 years. End of life?

I love my Batrium, but they can be complete dolts. Their claim without any context is meaningless. Anything they say goes into the "I need to confirm this somewhere else" bucket.

To this day, their directions for interfacing with a Victron system is still not fixed. I notified them two years ago. They fail to tell you a key setting, and they instruct you to do something completely stupid.

 

[OffGridInTheCity]

.15Ah is mentioned here:

Set Up The AutoLevel Bypass Configuration On The WatchMon

How to Set Up The AutoLevel Bypass Configuration On The WatchMon

wiki.batrium.com

EVE 280Ah cell datasheet indicates up to 1% self-discharge per month.

That's 2.8Ah/month or 2.8/30 = 93mAh/day

So brand new EVE cells may be at end of life by the 50-150mAh/day number.

Even so, this has nothing to do with balancing. It's when the cells in series *differ* from each other that balancing is needed unless they discharge below healthy levels from lack of charge.

You're next comment is spot on....

What if a 10,000Ah cell lost .15ah per day. Cell would hold its charge for 183 years. End of life?

I love my Batrium, but they can be complete dolts. Their claim without any context is meaningless. Anything they say goes into the "I need to confirm this somewhere else" bucket.

And they do a lot of echo the dialog documentation - not a lot of depth behind their docs. While I applaud their attempts at the recent youtubes and I've gleaned some interesting data, they again tend to avoid deeper context and I don't get the sense the guy actually knows the details.

 

[ConnerLabs]

EVE 280Ah cell datasheet indicates up to 1% self-discharge per month.

That's 2.8Ah/month or 2.8/30 = 93mAh/day

So brand new EVE cells may be at end of life by the 50-150mAh/day number.

If every cell in your brand new pack has exactly 1% self-discharge per month, it doesn't need any balancing. When Batrium talk about 50-150mAh per day, that's the amount of charge transferred into a more leaky cell from its less leaky neighbours.

150mAh/day would equate roughly to some cells in a pack of EVE 280Ah having 3% self discharge per month and others 1%.

 

[sunshine_eggo]

If every cell in your brand new pack has exactly 1% self-discharge per month

(they won't. That's the limit, not the guarantee)

, it doesn't need any balancing.

(they will)

When Batrium talk about 50-150mAh per day, that's the amount of charge transferred into a more leaky cell from its less leaky neighbours.

Except Batrium doesn't work that way. Batrium is passive balancing. They only burn off excessive charge. They do not transfer charge between cells. Batrium does not offer an active balancing solution.

150mAh/day would equate roughly to some cells in a pack of EVE 280Ah having 3% self discharge per month and others 1%.

But the range is 50-150mAh/day, right? So you could have cells at .25%/month and cells at 1%/month. That produces a 70mAh/day deviation. A battery built with brand new EVE cells could be bad according to Batrium's generalized statement.

I'm guessing you don't own one, and if you do, you've never had to interact with Batrium and realized how full of crap they are. Do yourself a favor and treat Batrium as I do... seek confirmation elsewhere before you repeat it or put it in practice.

 

[ConnerLabs]

Except Batrium doesn't work that way. Batrium is passive balancing. They only burn off excessive charge. They do not transfer charge between cells. Batrium does not offer an active balancing solution.

I should have said, "charge bypassed around a leaky cell's less leaky neighbours"- it amounts to the same thing. Passive balancers do what the side reactions in lead-acid did. Allow an alternative route for charge to get around a cell that's already full, into other cells in the series string that aren't full yet.

A battery built with brand new EVE cells could be bad according to Batrium's generalized statement.

Indeed, I suspect many batteries that us DIYers build with "brand new" EVE cells actually are bad according to some metric. I wonder how many mAh per day of balancing current EVE expect their big Chinese customers to provide.

I'm guessing you don't own one, and if you do, you've never had to interact with Batrium and realized how full of crap they are.

Yup, definitely not buying one after I hear this

 

[copec]

Passive balance is all that there was in the DIY scene for a long time until JK came around and eventually a bunch of others followed. It's perfectly fine, especially for new cells that are worn in together. Active balancers are great for second-life batteries from cells that don't share a history. Most of what are considered the absolute best BMSs in industry still use only passive balance.

That's why JK only made balancers and not a BMS for quite a while. It was sort of assumed you would only use it occasionally to balance used batteries

 

[Ohms_Cousin]

I hear ya. Sounds like we have similar problem.

You think you got it bad - Murphy is my next door neighbor - not only that but I am an unlucky guy! now THAT is a combination.