Questions about 18650 DIY battery build - Endless Sphere

So making a battery, eh?

Well I got to start somewhere, so I might as well try to get a little help with things that are on me mind. I must say I am more then a little intimidated by the task at hand.

1: Starting with the basic, when making cells do I start by making blocks in series or parallel? For me it will be a 22s12p battery. Or maybe less cells if my currency keeps dropping.

2: I don't know if I should skip BMS or not. If I do skip BMS it will make creation of the battery pack a little less daunting, and I will save time on soldering. Do I ever need to balance charge the pack, or can I just charge it all up to say 4,1v?

3: I see different ways of making batteries. Some just use nickel strips and calls it a day. Others feel that nickel alone can cause voltage drop because of heat so the solder on copper wire or silver wire on top of the nickel. Is that overkill, or something worth doing? I am thinking most power possible from the battery, and if that trick will help me get more power out without heating battery it just might be worth it?

4: Choosing a brand and a model seems like a lot of work just to know what separates the brands and models apart. I've been reading up for some days now, but I must say I am a little cooked in the head now. So at the moment I am considering one of these; Sanyo NCRGA or Samsung INR--35E. Then there are 20R , 25R and 30Q. Panasonic NCRB same as in Tesla, right? Kind of tempted to go with Sanyo or 35E from tumich.
Is there other cells that might give me higher C rate and more fun for repeatedly accelerations etc? Or are any of those from tumich a good choice?

5: Was planning to fit an on-board charger, like an Eaton APR48-3G. Do they have any way to regulate the charging, like a high voltage cutoff or must I personally keep my eye on the charging if I use this without BMS? I got really bad short term memory so putting me in charge of watching the voltage will end in pain and wasted money. How can I control high voltage cutoff without a BMS?

6: I see a lot of people are making pre-charge, I know it is beside the battery thread but for me it got to do with electricity so for me it is in the same alley. What does a pre-charge do? And should I use it?

7: Do people usually by a bit more cells then what they are building, to count for bad cells, bad welds, bad welder etc? I will use some recycled cells for trial and error on the spot welding. I mean for 264 cell pack how many could be bad - like 1-2% extra should be sufficient?


Forgot to mention that I got a QS 205, and I plan to pump 12-14 kw peak into that hub. The reason I decided to go 22s12p was to give each cell an easier life and get better C rate.



Some phrases might be worded wrongly, if in doubt you should assume I have no clue as to this topic. If I am mixing up words, thinking of this the wrong way or in any way don't make sense to you, let me know and I will try to explain. But I am in way over my head here

macribs said: I must say I am more then a little intimidated by the task at hand.

That's a good start. It's not particularly trivial, and screwing up will, at minimum, get your attention, and at maximum, burn down whatever structure you're building or charging the pack in.

1: Starting with the basic, when making cells do I start by making blocks in series or parallel? For me it will be a 22s12p battery. Or maybe less cells if my currency keeps dropping.

With most modern battery types, you build parallel groups and then string those groups in series. The reason for this is that it makes balancing possible. Your BMS will have a balance wire to each parallel group, and if you don't have a BMS you'll still need to measure each parallel group. There exist some older cell chemistries (spinel LiMn) that supposedly self balance slightly, but the energy density on those is low so they're not commonly used anymore.

Why are you building a battery that huge? With modern cells (mAh), that's a 80v nominal, 36Ah pack, for nearly 3kWh of capacity. That's huge, heavy, 100 miles of heavy throttle use, and it's going to be very, very difficult to build as your first pack.

2: I don't know if I should skip BMS or not. If I do skip BMS it will make creation of the battery pack a little less daunting, and I will save time on soldering. Do I ever need to balance charge the pack, or can I just charge it all up to say 4,1v?

Please use a BMS. They offer you several things, all important:
- Balance charging. The BMS should balance the pack when charged, which is important for longevity and maximal useful energy.
- High voltage cutoff. If a parallel group of cells is overcharged, the BMS should stop charging the pack and throw an error.
- Low voltage cutoff. If, during discharge, a parallel group hits the low voltage cutoff, the BMS should disconnect the battery to prevent dragging cell voltages below safe levels. On most large packs, the swing from fully charged to fully empty is greater than the voltage of a single cell group, so you can end up with a bank of cells at or below 0v without triggering the bulk pack cutoff. This is bad.

If you have a BMS, it should balance charge each time you charge.

3: I see different ways of making batteries. Some just use nickel strips and calls it a day. Others feel that nickel alone can cause voltage drop because of heat so the solder on copper wire or silver wire on top of the nickel. Is that overkill, or something worth doing? I am thinking most power possible from the battery, and if that trick will help me get more power out without heating battery it just might be worth it?

It depends on how many amps you're going to draw. For a low power pack (250-500W), it doesn't matter much. For a high power pack (1kW+), there are some gains to be had from adding conductor capacity. It's probably overkill for most uses. The battery heating will mostly be from the cell internal resistance.

Is there other cells that might give me higher C rate and more fun for repeatedly accelerations etc? Or are any of those from tumich a good choice?

Your pack at a 1C discharge will be sourcing nearly 3kW. What on earth are you planning to do with this pack?

5: Was planning to fit an on-board charger, like an Eaton APR48-3G. Do they have any way to regulate the charging, like a high voltage cutoff or must I personally keep my eye on the charging if I use this without BMS? I got really bad short term memory so putting me in charge of watching the voltage will end in pain and wasted money. How can I control high voltage cutoff without a BMS?

... again, 3kWh + an onboard charger? What are you doing with this thing?

Generally, the charger is set to output the maximum voltage of the pack, so for your pack you'd set the charger to 90.2v (4.1v/cell) or 92.4v (4.2v/cell). When the charger is done, it just sits at that voltage (many BMSs take a bit once the pack is charged to even everything out). Even without a BMS, it won't overcharge the bulk pack, but without a BMS it could severely overcharge a parallel group if a cell is bad. So use a BMS. Seriously.

6: I see a lot of people are making pre-charge, I know it is beside the battery thread but for me it got to do with electricity so for me it is in the same alley. What does a pre-charge do? And should I use it?

I think you may be referring to a pre-charge resistor or similar, which just prevents arcing when connecting a battery to a controller (inrush current). The precharge resistor allows the capacitors in the controller to charge slowly and equalize the voltage before you make the main contact.

7: Do people usually by a bit more cells then what they are building, to count for bad cells, bad welds, bad welder etc? I will use some recycled cells for trial and error on the spot welding. I mean for 264 cell pack how many could be bad - like 1-2% extra should be sufficient?

I generally pick up a few extra. But I don't think you understand just how large, unwieldy, and complex building a 264 cell pack is going to be. Try some smaller stuff first. I've rebuilt a good number of packs and I don't think I'd be inclined to build a pack like you're proposing (though I'd also have no use for it).

Some phrases might be worded wrongly, if in doubt you should assume I have no clue as to this topic. If I am mixing up words, thinking of this the wrong way or in any way don't make sense to you, let me know and I will try to explain. But I am in way over my head here

Yes, you sort of are... seriously, build some small packs first. And what on earth do you need such an insanely huge and heavy pack for anyway?

That confirms Virisenox’s recommendation in the other post :+1: thank you! I try to find the best price…

Xiaolu supply professional and honest service.

edit

I forget to ask 1 question about driver; I have just buy a M2X-UT olight with a extension tube to have 2x battery power.

How to make the light become super hot rod ?? is there a good driver recommended for this light so I can get more power to xpl-hi led?? Reflector is very nice and can throw very good, but people say can boost it…

sorry for asking stupid question but I don’t know very well electronic.

You can do one mod to boost it without replacing the driver, and that is bypassing a spring.

Steel is not a good conductor of electricity compared to copper.

In fact, on average, it has 5% the conductivity of copper.

Take 20AWG copper wire, solder it to the top of the spring, then around the spring, solder it to the bottom, and you are good.

Replacing the driver is going to be harder, so ask people to help. I can’t right now since I need to sleep. Ciao!

There is no need to get too technical. Battery capacities vary based on load, temperature, etc… He just wants to buy some “good” ones. No Panny B, no old ones, Ultrafires, etc…

I consider the best batteries the high drain ones because I usually don’t run them down below 3.5v anyway. That extra capacity is lost on me, but I sure like the reduced voltage sag. :+1:

G is not a mAh cell unless you over-discharge it to a silly level.
See this test:
https://lygte-info.dk/review/batteries/Evva%%mAh%20(Black)%20UK.html
It is extremely close to GA. In this test it shows higher IR (which may be due to protection) and exactly the same capacity. So really more like mAh. Actually we’ve seen some rewrappers (Klarus comes to mind) replacing G with GA in their lineup while retaining mAh marking.
https://lygte-info.dk/review/batteries/Commoncomparator.php
Compare discharge curves of G and GA at low amps, all the bumps line up.

Can’t speak about the others though.

Battery's capacity is defined in the IEC- standard as the capacity at 0.2C discharge to the cut-off voltage (see datasheet) after being charged at the standard charge current (see datasheet) and left for 1-4hrs befor discharging. All this must be done at 25±5°C.

Of course we can charge and discharge at any current and measure the capacity as we want, but the nominal capacity according to the standard and mentioned by the manufacturers is the one i described above.

Further reading:
Galvanized Steel: Types, Uses, Benefits - National Material Company
A Guide To CrossFit Hand Protection - Ripped Hands - Victory Grips
RECOMMENDATION OF PATENTED BOPP TAPE SLITTING ...

If you want to learn more, please visit our website High power INR batteries.

I haven't tested any of Gs so i have nothing to say about their actual capacity. Maybe Panasonic stopped its production due to such poor performance.

You get my point though, right? In real use you don’t get that exact 0.2C discharge, etc…

So in a flashlight the capacities vary.

MrGrun just wants to avoid any duds. All those cells mentioned above are about equal in real world use. Your not going to notice an extra 100mah.

I will order several batteries end of July for me and my friend also. I just want to get the best value product. From the vote, majority say Sanyo is the best (made in Japan) I don’t know HKJ BS procedure testing, but I rather trust BLF users experience. I am just afraid to get fake Sanyo

Any recommendation for some trusted online Sanyo battery seller? (my friend stay in USA)

thank you

Depends what you want.

NCRGA has a slightly higher max amperage than the 35E.

35E, however, has a slightly longer run time at lower outputs (<0.5A and below). They are about the same at 1A.

The MJ1’s are pretty similar but seems to be slightly worse.

LOL

If you had a chance to have sex with Angelina Jolie would you do that or you'd prefer to ask Brad Pitt how she does in the bed?

Having all 4 cells in my hands and a good equipment i preferred to do my own tests at the same time in the same conditions, following the IEC- standard rather than just sitting in the sofa and posting others' tests.

HKJ has inspired me a lot and i think not only me but also hundreds or even thousands of others. King regards to him from Russia!

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