Reset: Tesla Batteries

Well, I appreciate the advice thusfar, but that thread is getting built up quite a bit so to keep it "real" I start this one.

I have found out that all the guy wants is a regular house refrigerator and a toaster oven. Nothing else will run off an invertor. Lighting will all b e low voltage, stove and furnace off propane and A/C off a generator, maybe diesel, maybe something else. Maybe if I can get a really good A/C unit fo rm an older car it would work, just have to run the engine. Those old big c ars had one hell of an A/C system in them. The new ones are junk in compari son. Now you got an elcheapo cap tube and a weighed in charge. In the old d ays it had an accumulator and a thermostatically controlled expansion valve . Also those big long compressors were six cylinder ran by a swash plate. S uch a system would cool the whole thing. The only question is whether you w ant to run the engine. Or maybe do both. We're already going under the hod for an extra alternator, and I think that will be a rebuilt form about a 19

75 police car for the power. New alternators are not able to charge a dead battery, if you change it the instructions say right out to charge the batt ery first, don't just jump start it. The wimpy alternator cannot handle it.

Someone said to get the real numbers. Well we are going to do that tomorrow . We are going to the DIY (Home Depot I think this time, they are all DIY t o me) and we will plug in a new refrigerator with my clamp on ammeter on it . the first order of business is to grab that meter and test it, see how ou t of calibration it is. I'll either calibrate it to a Fluke or have a corre ction factor to apply. Either way we will have real numbers. The way I see it, the cabinet is going to be warm so the power drain should be within a u seably measurable range. The only other thing I could do is to run it a whi le and cover the condenser with something to build up the heat. That would give us a real worst case scenario, like you are in the desert and it is 10

derive tomorrow. Everything in the system is going to be overbuilt.

Someone said don't count on the plate on the fridge ? I think I must agree. The one we saw is a full size but small unit. I mean it is not for a dorm or anything like that. What gets me is it says 160 watts on the back. Well I got this oceanfront property in Kansas... Not sure how I am going to effe ctively guess the starting draw, but I can just use other motors as a sort of "rule of thumb". And that will be handled like my ex boss used to handle parts - add a dollar and double it. Whatever everything says, we will doub le the capacity. That should mean enough reserve for those dark days as wel l as good charging current on the bright days. I also have to have a talk w ith him about the varying output of the PVs. Another thing to figure out is just where does he intend to go. I don't really need the address (there pr obably will not be one) but the latitude is important.

And then the charger. There is no way in hell we are getting a Tesla charge r for this thing. Oh ye of little faith, I can do this and do it with a SEP IC so that it will charge until the PVs are almost down to zero. If I just get the usual charger and it wants 120 volts it probably will just shut dow n if the voltage gets below about 100 volts. That makes it unsuitable. From what I've been reading the 240 volt charger will charge faster. Logically that indicates that the battery is not that picky about low charging curren t, but of course it takes longer to charge. What does he care if he's out d eer hunting or some shit ?

So, the way to proceed is once I got the numbers, size the PV and storage t o suit, and then some. Maybe the guy wants a stereo, he will want a PC, pro bably a laptop. That will bring on a new set of problems. You can get Hughe snet almost anywhere, the cheap plan which is pretty good is like $70 a mon th including equipment rental. The problem is every time he drives the thin g the dish will have to be re-aimed. I know you can get public wifi in may places but where he is going maybe not. Actually ATT has pissed us off and we are about to get Hughesnet - I think. Maybe I can talk to the installer about that. The only problem I have with Hughesnet is that they got this pr omotional rate, right ? Well they can't tell me what the rate is after the promotional period. They might reveal it because I'll say "OK then, so afte r each year I quit you, you come and get your MODEM and dish, and then come back and put it all back up, right ? But then we'll burn that bridge when we come to it.

All the admonishments about building a charger seem to be about overchargin g. That is apparently the absolute worst thing you can do to these batterie s. Well I know how to prevent that. So let's have a little bit of a vote of confidence here. It simply is not that difficult.

So far, as far as I read the other thread, the only advice I am not taking is "DON'T". I have been told that about test equipment and a few other thin gs and each time I figured it out and met success. there is no reason I can 't do it again. This is something outside of my usual purview, and I WANT t o do it.

And no, I am not clueless. I am getting farther and farther away from cluel ess every day now. Everything I know I learned, why not this ?

Anyway, I am not pissed off that the thread went in all kinds of directions , this is Usenet and that is how it is. In fact this meandering into all ki nds of shit in threads can be useful. I have learned a few things from OT p osts here. This thread is here just to get the chaff out, well it's not rea lly chaff but it started to go off on tangents to the moon...

Anyway, more later. Tomorrow I will have some numbers.

Reply to
jurb6006
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Just a reminder, you will need to power the air handler motor for the a/c, not just the compressor, so add in maybe 1-4 running amps at 110 VAC for that, and the same again when using the propane forced air furnace. A car a/c compressor from that far back will be optimized for R-12 while a current house a/c runs on R-410 at much higher pressures so engineering a diy system will be a challenge (starting with choosing either a retrofit R-12 replacement like R134a or the current R1234yf or a R22 replacement or whatever, then finding a mechanically driven compressor to go with it, then ...). The alternators in current GM stuff (and most others, I suspect) are controlled by the same computer that runs the engine so while 140+ amp units are available I don't know how to run one stand-alone. I'd look at heavy truck units like from a dump truck, I've heard that 250+ amp units are available. Just some random thoughts before this thread dives off-topic :-).

--
Regards, 
Carl Ijames
Reply to
Carl

l, I appreciate the advice thusfar, but that thread is getting built up quite a bit so to keep it "real" I s tart this one.

y wants is a regular house refrigerator and a toaster oven. Nothing else will run off an invertor. Lighting will all be low voltage, stove and furnace off propane and A/C off a generator, maybe diesel, maybe somethin g else. Maybe if I can get a really good A/C unit form an older car it would work, just have to run the engi ne. Those old big cars had one hell of an A/C system i n them. The new ones are junk in comparison. Now you g ot an elcheapo cap tube and a weighed in charge. In th e old days it had an accumulator and a thermostaticall y controlled expansion valve. Also those big long comp ressors were six cylinder ran by a swash plate. Such a system would cool the whole thing. The only question is whether you want to run the engine. Or maybe do bot h. We're already going under the hod for an extra alte rnator, and I think that will be a rebuilt form about a 1975 police car for the power. New alternators are n ot able to charge a dead battery, if you change it the instructions say right out to charge the battery firs t, don't just jump start it. The wimpy alternator cann ot handle it.

ers. Well we are going to do that tomorrow. We are goi ng to the DIY (Home Depot I think this time, they are all DIY to me) and we will plug in a new refrigerator with my clamp on ammeter on it. the first order of bus iness is to grab that meter and test it, see how out o f calibration it is. I'll either calibrate it to a Flu ke or have a correction factor to apply. Either way we will have real numbers. The way I see it, the cabinet is going to be warm so the power drain should be with in a useably measurable range. The only other thing I could do is to run it a while and cover the condenser with something to build up the heat. That would give u s a real worst case scenario, like you are in the dese

y just fine with the numbers we derive tomorrow. Every thing in the system is going to be overbuilt.

omeone said don't count on the plate on the fridge ? I think I must agree. The one we saw is a full size but small unit. I mean it is not for a dorm or anything l ike that. What gets me is it says 160 watts on the bac k. Well I got this oceanfront property in Kansas... No t sure how I am going to effectively guess the startin g draw, but I can just use other motors as a sort of " rule of thumb". And that will be handled like my ex bo ss used to handle parts - add a dollar and double it. Whatever everything says, we will double the capacity. That should mean enough reserve for those dark days a s well as good charging current on the bright days. I also have to have a talk with him about the varying ou tput of the PVs. Another thing to figure out is just w here does he intend to go. I don't really need the add ress (there probably will not be one) but the latitude is important.

o way in hell we are getting a Tesla charger for this thing. Oh ye of little faith, I can do this and do it with a SEPIC so that it will charge until the PVs are almost down to zero. If I just get the usual charger a nd it wants 120 volts it probably will just shut down if the voltage gets below about 100 volts. That makes it unsuitable. From what I've been reading the 240 vol t charger will charge faster. Logically that indicates that the battery is not that picky about low charging current, but of course it takes longer to charge. Wha t does he care if he's out deer hunting or some shit ?

rs, size the PV and storage to suit, and then some. Ma ybe the guy wants a stereo, he will want a PC, probabl y a laptop. That will bring on a new set of problems. You can get Hughesnet almost anywhere, the cheap plan which is pretty good is like $70 a month including equ ipment rental. The problem is every time he drives the thing the dish will have to be re-aimed. I know you c an get public wifi in may places but where he is going maybe not. Actually ATT has pissed us off and we are about to get Hughesnet - I think. Maybe I can talk to the installer about that. The only problem I have with Hughesnet is that they got this promotional rate, rig ht ? Well they can't tell me what the rate is after th e promotional period. They might reveal it because I'l l say "OK then, so after each year I quit you, you com e and get your MODEM and dish, and then come back and put it all back up, right ? But then we'll burn that b ridge when we come to it.

about building a charger seem to be about overchargin g. That is apparently the absolute worst thing you can do to these batteries. Well I know how to prevent tha t. So let's have a little bit of a vote of confidence here. It simply is not that difficult.

I know just about enough to be scared. I read that a Tesla batter y is

11 modules each 9-cells tall in series ~400V. No idea which battery it is, but bear with me...

In a 400V pack, the difference between a cell that's a t zero and one that's at full charge is about 1% of the total voltage. You do not want to overcharge a cell. You don't want to undercharge a cell. The term inal voltage of the pack is INADEQUATE to manage the system.

If one of the cells in a parallel combinati on gets slightly higher resistance, the other cells in that combination will overcharge relative to the

other 10 modules and the effect is cumulative.

Unl ess you purchase a NEW pack, the pack will have been d ecommissioned for some unknown reason.

It takes co nsiderable care to keep the pack balanced. How much o f that is in the pack itself and how much is in the c harger is unknown. You probably won't find documentat ion on the protection management. Look up "balance ch arger" to see the lengths the model car guys go to us e lithium batteries.

Even if ALL the protection/bal ance management is inside the pack, you still have a charging problem. A solar panel is basically a curren t source over much of the insolation range where you want to operate it. MPPT tries to maximize power tra nsfer, and that happens at the knee of the curve.

Chargers designed for on-grid use depend on a stable v oltage over a wide range of current. It's not a stre tch to imagine a limit cycle oscillation as you try t o stuff current into a battery management circuit base d on voltage.

You're gonna buy an expensive bomb a nd design your own detonator. It's certainly possible but, given the lack of documentation, I predict an e xpensive failure with possible catastrophic consequenc es. Don't do your first lithium battery charger desig n on a 400V battery with 50KW of stored energy.

I don't think I'll have any effect on your project, so I'll just try to shut up on the subject. Wear safety gear and don't let your kids watch up close. Good l uck.

d, the only advice I am not taking is "DON'T". I have been told that about test equipment and a few other th ings and each time I figured it out and met success. t here is no reason I can't do it again. This is somethi ng outside of my usual purview, and I WANT to do it.

and farther away from clueless every day now. Everythi ng I know I learned, why not this ?

m not pissed off that the thread went in all kinds of directions, this is Usenet and that is how it is. In f act this meandering into all kinds of shit in threads can be useful. I have learned a few things from OT pos ts here. This thread is here just to get the chaff out , well it's not really chaff but it started to go off on tangents to the moon...

Tomorrow I will have some numbers.

>
Reply to
Mike

up quite a bit so to keep it "real" I start this one.

and a toaster oven. Nothing else will run off an invertor. Lighting will a ll be low voltage, stove and furnace off propane and A/C off a generator, m aybe diesel, maybe something else. Maybe if I can get a really good A/C uni t form an older car it would work, just have to run the engine. Those old b ig cars had one hell of an A/C system in them. The new ones are junk in com parison. Now you got an elcheapo cap tube and a weighed in charge. In the o ld days it had an accumulator and a thermostatically controlled expansion v alve. Also those big long compressors were six cylinder ran by a swash plat e. Such a system would cool the whole thing. The only question is whether y ou want to run the engine. Or maybe do both. We're already going under the hod for an extra alternator, and I think that will be a rebuilt form about a 1975 police car for the power. New alternators are not able to charge a d ead battery, if you change it the instructions say right out to charge the battery first, don't just jump start it. The wimpy alternator cannot handle it.

rrow. We are going to the DIY (Home Depot I think this time, they are all D IY to me) and we will plug in a new refrigerator with my clamp on ammeter o n it. the first order of business is to grab that meter and test it, see ho w out of calibration it is. I'll either calibrate it to a Fluke or have a c orrection factor to apply. Either way we will have real numbers. The way I see it, the cabinet is going to be warm so the power drain should be within a useably measurable range. The only other thing I could do is to run it a while and cover the condenser with something to build up the heat. That wo uld give us a real worst case scenario, like you are in the desert and it i

we derive tomorrow. Everything in the system is going to be overbuilt.

ree. The one we saw is a full size but small unit. I mean it is not for a d orm or anything like that. What gets me is it says 160 watts on the back. W ell I got this oceanfront property in Kansas... Not sure how I am going to effectively guess the starting draw, but I can just use other motors as a s ort of "rule of thumb". And that will be handled like my ex boss used to ha ndle parts - add a dollar and double it. Whatever everything says, we will double the capacity. That should mean enough reserve for those dark days as well as good charging current on the bright days. I also have to have a ta lk with him about the varying output of the PVs. Another thing to figure ou t is just where does he intend to go. I don't really need the address (ther e probably will not be one) but the latitude is important.

arger for this thing. Oh ye of little faith, I can do this and do it with a SEPIC so that it will charge until the PVs are almost down to zero. If I j ust get the usual charger and it wants 120 volts it probably will just shut down if the voltage gets below about 100 volts. That makes it unsuitable. From what I've been reading the 240 volt charger will charge faster. Logica lly that indicates that the battery is not that picky about low charging cu rrent, but of course it takes longer to charge. What does he care if he's o ut deer hunting or some shit ?

ge to suit, and then some. Maybe the guy wants a stereo, he will want a PC, probably a laptop. That will bring on a new set of problems. You can get H ughesnet almost anywhere, the cheap plan which is pretty good is like $70 a month including equipment rental. The problem is every time he drives the thing the dish will have to be re-aimed. I know you can get public wifi in may places but where he is going maybe not. Actually ATT has pissed us off and we are about to get Hughesnet - I think. Maybe I can talk to the instal ler about that. The only problem I have with Hughesnet is that they got thi s promotional rate, right ? Well they can't tell me what the rate is after the promotional period. They might reveal it because I'll say "OK then, so after each year I quit you, you come and get your MODEM and dish, and then come back and put it all back up, right ? But then we'll burn that bridge w hen we come to it.

rging. That is apparently the absolute worst thing you can do to these batt eries. Well I know how to prevent that. So let's have a little bit of a vot e of confidence here. It simply is not that difficult.

l
r
s
n

ing is "DON'T". I have been told that about test equipment and a few other things and each time I figured it out and met success. there is no reason I can't do it again. This is something outside of my usual purview, and I WA NT to do it.

lueless every day now. Everything I know I learned, why not this ?

ions, this is Usenet and that is how it is. In fact this meandering into al l kinds of shit in threads can be useful. I have learned a few things from OT posts here. This thread is here just to get the chaff out, well it's not really chaff but it started to go off on tangents to the moon...

All the stuff you mention is not the crazy part of the deal. The crazy par t is thinking that it is in any way cost effective to design your own charg er from first principles rather than buying the charger specifically create d for the battery.

Maybe some people work cheaper than I do, but I'm quite sure my time is wor th much more than the cost of the equipment.

Rick C.

- Get 6 months of free supercharging - Tesla referral code -

formatting link

Reply to
gnuarm.deletethisbit

It might be of interest that there are many do-it-thyself PowerWall projects online. Using batteries salvaged from electric vehicles is often mentioned, but more common are assembling battery packs from commodity 18650 cells. Judging by the articles and videos I've found, most of the interest is in providing night time electric storage for currently grid tied solar systems.

Random obligatory links, references, and light reading:

YouTube videos for DIY PowerWalls

DIY PowerWalls on Facebook

DIY Rapid Build 18650 PowerWall Module project - design & testing

Jehu's DIY Powerwall PCB Project

DIY Powerwall Builders Are Using Recycled Laptop Batteries to Power Their Homes Some interesting pictures of what builders are doing.

Second Life Storage Forum

Bigger is better

22,000 cells and 10kW-hr.

2.4kWh DIY Powerwall From Recycled 18650 Lithium-ion Laptop Batteries

18650 cell testing station

How To Build A Mini DIY Powerwall with Maker Batteries

Impressive photos of DIY PowerWalls and such:

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

Random used cells. Solder directly to the cells. No provision for balancing anything. What could possibly go wrong? Sigh.....

Reply to
Mike

Using mixed cells is somewhat ok if the battery pack and charger have a balanced charge feature. Some of the DIY PowerWalls have this feature. It also helps to only charge to 90% SoC (state of charge). Most EV's have a balanced charge feature.

To the best of my limited knowledge, some PowerWall projects have balanced charge connectors. For example, the 2x8 pin balanced charge connector on this battery block project:

Also, notice the rather colorful battery combinations of cells: I guess we have to wait a while to see if these burn to the ground.

Most 18650 contacts are stainless steel. These can be soldered if I use lots of activated flux. However, you're right. Spot welding is much safer and better.

Litigation, insurance cancellation, fire, all mightier trying to find the one blown cell...

Powerwall packs DESTROYED! KABOOM! (13:06) Skip to 4:30 to see a cell ignite using a heat gun.

Patience. The survivors will do a better job of implementation. I watched it happen over the years as solar panels and systems progressed from primitive butchery, to commercial standardization and reliability.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

Got numbers on the fridge under consideration. With a peak reading digital clamp on meter it pulls 17.8 amps to start. Once running it goes below an a mp.

The LED lights look like they pull 1.25 amps at 12 volts which is their max , but other LED strings may be chosen instead.

He said he talked to one guy who recommended a simple 12 volt system with a 3,500 watt invertor. Well this is what they guy was selling... Several gra nd and didn't include any PVs or storage cells. We can beat that no problem .

The more I see that truck the more I like it. There is more aluminum than a nything in the thing. I mean a crackhead could stay high for at least two w eeks on this thing. I think we might give some thought to security...

Now at least we got SOME numbers. It took a bit of doing to get the store m anager to let us plug it in with my little outlet thing that separates the wires toy clamp the meter. We talked him into it. I also said we would like to know how loud it is, since it will only be a couple of feet from the be d. Turns out it was pretty quiet. Newer ones do seem quieter than the old o nes. And it was quiet in the store, it was about an hour before closing tim e. Actually if there was a big crowd there I think we could have just done it and not be noticed, but that's OK.

Anyway, more later, got business.

Reply to
jurb6006

More of the same. There are a fair number of Nissan Leaf batteries floating around that are being used to built battery piles for solar power system and PowerWall like contrivances.

Nissan Leaf Battery Modules Reused in Solar Energy Storage (12:13) One big catch is that most of them seem to test at about 50% of rated capacity. It's in the video.

Unobtainable discharge tester used in the video: (OUT OF STOCK INDEFINITELY - PRODUCTION DELAY DUE TO WORLDWIDE ALLOCATION OF COMPONENTS). Whatever that means.

More:

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

It's an old thread, but still useful.

That's probably from the back stack, which tends to degrade faster. They a re keeping the front stacks themselves. My 2012 Leaf came from Seattle (co ld weather), so it's in better condition. The back stack is around 60% to

70%. The front stacks are around 70% to 80%.

Rereading old forums confirm that the Leaf battery only balance during char ging. Using 400 ohm resistors to shunt off higher voltage, the maximum cur rent is around 10mA. When discharged to empty, the voltage difference betw een strongest and weakest cells is around 0.5V. I am using 4 sets of 100V auxiliary batteries to balance the main batteries.

I am using 4 sets of 18 awg orange wires in 100V segments, with a 22 awg ce nter taps via a 10 ohms 2 watts resistor. I am wondering if i need 1 or 2 ohm resistors to limit the current on each segment, or the wire resistance itself is enough. My 100V auxiliary batteries are actively balanced with B MS ICs. The BMS has OV(4.2V), UV(2.5V) and OC(4A) protections at the cell l evel. However, tripping the BMS would require manual reset. I can do it on the road, but other drivers would need to bring it back to the shop.

I believe that the better BMS can unlock the 10% to 15% hidden capacity and additional auxiliary batteries can restore it up to 24kwh.

Other people are working on upgrading to 30kwh, 40kwh and 60kwh with CAN br idge. But i think 24kwh is enough for me, while retaining the old battery c ells.

Reply to
Ed Lee

up quite a bit so to keep it "real" I start this one.

and a toaster oven. Nothing else will run off an invertor. Lighting will a ll be low voltage, stove and furnace off propane and A/C off a generator, m aybe diesel, maybe something else. Maybe if I can get a really good A/C uni t form an older car it would work, just have to run the engine. Those old b ig cars had one hell of an A/C system in them. The new ones are junk in com parison. Now you got an elcheapo cap tube and a weighed in charge. In the o ld days it had an accumulator and a thermostatically controlled expansion v alve. Also those big long compressors were six cylinder ran by a swash plat e. Such a system would cool the whole thing. The only question is whether y ou want to run the engine. Or maybe do both. We're already going under the hod for an extra alternator, and I think that will be a rebuilt form about a 1975 police car for the power. New alternators are not able to charge a d ead battery, if you change it the instructions say right out to charge the battery first, don't just jump start it. The wimpy alternator cannot handle it.

rrow. We are going to the DIY (Home Depot I think this time, they are all D IY to me) and we will plug in a new refrigerator with my clamp on ammeter o n it. the first order of business is to grab that meter and test it, see ho w out of calibration it is. I'll either calibrate it to a Fluke or have a c orrection factor to apply. Either way we will have real numbers. The way I see it, the cabinet is going to be warm so the power drain should be within a useably measurable range. The only other thing I could do is to run it a while and cover the condenser with something to build up the heat. That wo uld give us a real worst case scenario, like you are in the desert and it i

we derive tomorrow. Everything in the system is going to be overbuilt.

ree. The one we saw is a full size but small unit. I mean it is not for a d orm or anything like that. What gets me is it says 160 watts on the back. W ell I got this oceanfront property in Kansas... Not sure how I am going to effectively guess the starting draw, but I can just use other motors as a s ort of "rule of thumb". And that will be handled like my ex boss used to ha ndle parts - add a dollar and double it. Whatever everything says, we will double the capacity. That should mean enough reserve for those dark days as well as good charging current on the bright days. I also have to have a ta lk with him about the varying output of the PVs. Another thing to figure ou t is just where does he intend to go. I don't really need the address (ther e probably will not be one) but the latitude is important.

arger for this thing. Oh ye of little faith, I can do this and do it with a SEPIC so that it will charge until the PVs are almost down to zero. If I j ust get the usual charger and it wants 120 volts it probably will just shut down if the voltage gets below about 100 volts. That makes it unsuitable. From what I've been reading the 240 volt charger will charge faster. Logica lly that indicates that the battery is not that picky about low charging cu rrent, but of course it takes longer to charge. What does he care if he's o ut deer hunting or some shit ?

ge to suit, and then some. Maybe the guy wants a stereo, he will want a PC, probably a laptop. That will bring on a new set of problems. You can get H ughesnet almost anywhere, the cheap plan which is pretty good is like $70 a month including equipment rental. The problem is every time he drives the thing the dish will have to be re-aimed. I know you can get public wifi in may places but where he is going maybe not. Actually ATT has pissed us off and we are about to get Hughesnet - I think. Maybe I can talk to the instal ler about that. The only problem I have with Hughesnet is that they got thi s promotional rate, right ? Well they can't tell me what the rate is after the promotional period. They might reveal it because I'll say "OK then, so after each year I quit you, you come and get your MODEM and dish, and then come back and put it all back up, right ? But then we'll burn that bridge w hen we come to it.

rging. That is apparently the absolute worst thing you can do to these batt eries. Well I know how to prevent that. So let's have a little bit of a vot e of confidence here. It simply is not that difficult.

For Leaf:

48x 12"x9"x2"

For Tesla:

7000x 18650 for model S/X, 21700 for model 3, 50800 (estimate) for future? First 2 digits for diameter (in mm), next 2 for height.

For Leaf, it shunt off cells with higher voltage with a 400 ohm resistor d uring charging. The battery controller expects cells to be closely matched . There are problems with strong and weak cells. When there are strong ce lls, it will limit peak charging voltage. When there are weak cells, the c ontroller will disable the battery system prematurely.

Tesla might have a better BMS, since they learned from the Leaf.

ance,

No, the parallel cells will all get the same voltage. It's the serial comb ination causing cells to overcharge/discharge.

r some unknown reason.

For the Leaf, poor BMS is one reason.

in the pack itself and how much is in the charger is unknown.

Balancing has to be done in the pack.

The Leaf battery system has been reverse engineered to death.

DC/DC converters can help. I am using multiple 5V-12V to 48V boosters to c harge my modules. But i am only charging a small balancing pack, i am still using the main ch arger with the vehicle.

Reply to
Ed Lee

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