scalability of LifePO4, an insane® battery pack.

[brandnewb]

arggggg. even though having set the SPS to 3.6V I wake up today to find my cell charged to 3.74V it's not screwed now is it?

 

[brandnewb]

in the meatime I have a tester. one of those heaters that Will mentioned in his video for beginners

 

[wattmatters]

arggggg

Patience grasshopper.

 

[upnorthandpersonal]

even though having set the SPS to 3.6V I wake up today to find my cell charged to 3.74V it's not screwed now is it?

Did you verify the supply with a multi-meter before connecting?

 

[brandnewb]

Did you verify the supply with a multi-meter before connecting?

You know me a bit by now ;( of course I did not ;(

Is the cell screwed now?

 

[Steve_S]

It is more often than not, the Most Painful / Expensive lessons are what it takes to Learn before leaping. Most of us burn our hands on the stove only ONCE but a few have to do it 2 or even 3 times before getting it. There have been Many Years of Experience & Lessons learned (all at great expense too) shared on here.

Impatience, the Instant Rice Society Metality IS NOT for THIS ! Patience is a requirement along with Due Diligence.

@3.74 there is No Damage BUT get it down to below 3.650 quickly, it will self discharge anyway but may take time and that's not good.
Always PRESET the voltage at the connectors BEFORE attaching to cells (single or string) for Top Balancing.

 

[brandnewb]

Patience grasshopper.

It is more often than not, the Most Painful / Expensive lessons are what it takes to Learn before leaping. Most of us burn our hands on the stove only ONCE but a few have to do it 2 or even 3 times before getting it. There have been Many Years of Experience & Lessons learned (all at great expense too) shared on here.

Impatience, the Instant Rice Society Metality IS NOT for THIS ! Patience is a requirement along with Due Diligence.

@3.74 there is No Damage BUT get it down to below 3.650 quickly, it will self discharge anyway but may take time and that's not good.
Always PRESET the voltage at the connectors BEFORE attaching to cells (single or string) for Top Balancing.

wise words indeed.

I am afraid it's in my nature to bang into walls ;(

 

[brandnewb]

my brain hurts ;(

I am running a cap test on the aforementioned cell and the beginner friendly tester Will suggested seems not too beginner friendly ;(

I mean whicht reading am I supoosed to trust? My mmeter at 3.31V or that tester at 2.77V?

or of course none of those as I am doing it completely wrong as usual ;(

Anyone please?

 

[upnorthandpersonal]

Depends on where you measure. You probably have a large voltage drop over the cables and because of those alligator clips.

 

[brandnewb]

i think it must be the aligator clips then because I used 10mm2 wires, since your suggestion to up the diam, so I do not expect a noticeable voltage drop there.

 

[brandnewb]

ohh btw, do I let the test run until depleted? I mean going to 0 for once can't hurt too bad can it?

 

[upnorthandpersonal]

I mean going to 0 for once can't hurt too bad can it?

Go to 2.5V max. There is no energy stored beyond that point. You will just end up damaging the cell.

 

[brandnewb]

thank you

 

[brandnewb]

Depends on where you measure. You probably have a large voltage drop over the cables and because of those alligator clips.

Yup it's confirmed now. The tester got accidentally disconnected but went on after reconnecting. So I figured to also change the connectors.

Now the tester is displaying much higher volt readings. Problem solved

 

[brandnewb]

WOW, after having ran the test (non continuously) for +33hrs I have reached 280 Ah on the aforementioned cell with 3.04V left.

If got 15 more cell to either test or just assume they are all the same grade.

Back to this cell. Do we want to know how much Ah is in there when hitting 2.55V?

Now lets get back to the more insane aspect of it all.

If I get 125(-16 as I already got them) of the same cells than that would mean a 400V pack if connected in series with a 280Ah capacity.

Is there a real world use case in where that is needed? Or could one better stay at 48V, and have many packs in parallel, and then invert to 3 phase loads if/when needed?

 

[brandnewb]

Or to keep things more newb friendly just keep it @12VoltInstalls 12volt and then maybe if needed transform upwards later down the line

 

[brandnewb]

Is there a real world use case in where that is needed?

Non mobile of course. I have no plans to power my premises with engine like loads powerful like an EV vehicle.

 

[brandnewb]

loads powerful like an EV vehicle.

I meant, although EV engines are cool!! they are nothing insane yet (yes gang here I go again )
But sure I am in awe of the power of a tesla P100D

 

[wattmatters]

Is there a real world use case in where that is needed?

30 seconds on Google will answer that for you.

 

[brandnewb]

30 seconds on Google will answer that for you.

Please NO
when I do search I get shit..
400v lifepo4 battery was the search term and let list I got was... shite...


How about we act like adults and add to the thread please.