Which 18650 for Tool-Battery-pack?

L4M4 · 2018-11-02T10:22:38.000Z

Hi!

I own a Makita 6317DWDE since nearly 10 years and I used to use a 4S 5Ah LiPo with it, but that thing died and because of the higher voltage, the switch is now only on/off.

I would like to rebuild it, but with a smaller battery and only 3S - also LiIon because of the critical storage voltage of LiPos (I don’t use that drill often, maybe once every two months).

But which battery should I choose? I measured the amperage of the drill with a 3S LiPo and it goes up over 50Amps if it’s stuck.
The classic would be the Samsung 25R green as far as I know - but that battery is pretty old - is there a new one with maybe higher capacity?

Also I would like to use a 4A quickcharger with those - is that possible?

moderator007 · 2018-11-02T13:25:07.000Z

You have not mentioned it but how many batteries are you looking to parallel together in the 3 series pack. If its just a 3S1P pack each battery will see the full 50 amps. If its a 3S2P pack each will see 25 amps. How many you intend to run parallel will determine the battery needed to use at that current.
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How many you run in parallel will also determine your max safe charge current. With a 3S1P pack all three see the full 4 amps of charge current.

L4M4 · 2018-11-02T15:00:27.000Z

only 3S1P, I want to use the original battery casing and there is only place for 3 18650 in it.

As far as I see, the 25R can be loaded with up to 100A for a very short time - that plus a 50A protection/balancing-board and I think I’m set pretty good. Then I even do not need a “real” charger, just a CC/CV PSU with 12.6 Volt.
I will have to check, how fast those cells cahrge with 12V, because 12V PSUs are just so much easier to get than 12.6V - also, those final 0.2v per cell take an awful lot of time…

BlueSwordM · 2018-11-02T15:26:24.000Z

The Samsung 24S would be your best bet for the lowest internal resistance possible with still nice capacity.

L4M4 · 2018-11-04T19:27:25.000Z

The 24S is nowhere available, so I just ordered a bunch of 25Rs - they are common in other drills, so I don’t think that they are a bad choice.

Thank you a lot!

BlueSwordM · 2018-11-04T19:30:28.000Z

Oh yeah, forgot you were in Germany :person_facepalming:

The VTC5A would have been even better in terms of internal resistance than the 25R:

eu.nkon.nl

Sony / Murata US18650VTC5A 2600mAh - 35A - 18650 - Li-ion - Rechargeable...

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HONDARIDER · 2018-11-04T19:32:57.000Z

Samsung 20r is what is found in a lot of the Dewalt battery packs. Seem to be a good compromise in capacity and power. Lots of choices actually.

HydrAxx · 2018-11-04T20:26:31.000Z

L4M4:

The 24S is nowhere available, so I just ordered a bunch of 25Rs - they are common in other drills, so I don’t think that they are a bad choice.

Thank you a lot!

The Samsung INR18650-25S(they are better than 25R or VTC5A) would have been a better choice and were available on akkuteile.de at a fair price, it would have been interesting for you who lives in Germany.

moderator007 · 2018-11-05T05:15:26.000Z

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The 25S Does pretty well at a 30 amp load. At a 50 amp load the 25R may trigger the protection circuit pretty quick.
Borrowed HKJ’s comparator graph.
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Let us know how the 25R’s do, I’m curious how this turns out.

L4M4 · 2018-11-05T06:22:52.000Z

Oh, OK.
I try to cancel the order but it might be too late.

I ran a little test yesterday, a long big screw in wood, no pilot hole, and it used 10-12Amps in the end to drive the head deep into the wood - so I think the 25R wouldn’t be too bad if the cancellation doesn’t get through.

Those 25S are very expensive compared to the 25R - For 6 of those I only paid $13.74 - for 6 25S I would pay over 50$

Barkuti · 2018-11-05T06:49:35.000Z

Check here L4M4: https://eu.nkon.nl/rechargeable/18650-size.html

VTC5A from €4.99/piece.

At least for me shipping from NKON can be quite affordable.

Cheers ^:)

P.S.: when looking for the actual performance of 25Rs at https://lygte-info.dk hope you look at it in some recent rewrap like Enercig or Vapcell. HKJ's tests of the name brand cells are pretty outdated.

HydrAxx · 2018-11-05T07:42:42.000Z

L4M4:

Oh, OK.
I try to cancel the order but it might be too late.

I ran a little test yesterday, a long big screw in wood, no pilot hole, and it used 10-12Amps in the end to drive the head deep into the wood - so I think the 25R wouldn’t be too bad if the cancellation doesn’t get through.

Those 25S are very expensive compared to the 25R - For 6 of those I only paid $13.74 - for 6 25S I would pay over 50$

$ 50 ?? For 6 units of 25S, it is 40.20 € (45.8$ ) because beyond 4 units of 25S, akkuteile sells for 6.70 € the 25S.

HydrAxx · 2018-11-05T07:58:05.000Z

There, the 25S is at 6.49 € / piece: https://www.hendelkens-vape.de/produkt/samsung-inr18650-25s-2500mah-max-35a-36v-37v-li-ion-akku/

Barkuti · 2018-11-05T08:55:19.000Z

Here is a more accurate 25S versus 25R comparison:

L4M4 · 2018-11-05T20:15:09.000Z

Wow, what a difference.

Till now the 25R aren’t shipped but the cancellation hasn’t been approved by the seller, too.
but to be honest - I could use those 25R for other high current lights - I am currently out of spare 30Qs anyway.

@HydrAxx 45.8$ + shipping
I think I will order from www.hendelkens-vape.de - thanks for the tip!
6 25S + 4 30Qs = 54,74€ with free shipping
I can never have too much 30Qs

Another question - what about balancing?
Most balancers just discharge the cell if they hit 4.2V - I plan to only charge up to 4V so that type of balancer is useless for me.
How do I balance those 3 Cells at 4V?

Barkuti · 2018-11-05T20:31:06.000Z

You could charge to 4.2V from time to time and them balance L4M4, or use a switchable by hand LiFePO₄ balance board :-) LoL.

^:)

HydrAxx · 2018-11-05T21:03:37.000Z

L4M4:

@HydrAxx 45.8$ + shipping
I think I will order from www.hendelkens-vape.de - thanks for the tip!
6 25S + 4 30Qs = 54,74€ with free shipping
I can never have too much 30Qs

I’m glad to have helped you, no worries.
You will see the 25S are very good cells, they can maintain 30A a good time, despite the continuous 25A announced by the manufacturer because at 30A, it rarely exceed 78~82°C (it varies from one cell to another) , it is certainly not very good for their lifetimes such temperatures but it will not explode nor degass at these temperatures, on this generation of cells it begins to be a risk when you exceed the range of 95~100°C, after made good as you seem. Personally, I find these cells much better than the Sony VTC5A, both in performance and lifetime, after it should not be forgotten that the 25S is much newer than the VTC5A, which makes all this a little logical in a sense .