10180/10440 Charger Interest Form

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Sunnysunsun
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10180/10440 Charger Interest Form

July 14th Update

I’ve finally ironed out a case for my prototype. The version I’m mass producing should be quite similar.

July 10th Update

Here is a link to my form if you’re interested and want to be notified when this is ready

A photo of my prototype 10440+10180 option

_________________________ _________________________ _________________________

I have a GT Nano and have found that screwing and unscrewing the little charger onto the tube is a pain to do every time, particularly when I want to charge a both of my 10180s.

*Link to interest form, it’s the same as the one listed below * old form

I looked at looked and haven’t found anything convenient on the market so I’ve made my own.

The charger will have these convenient battery contacts for easy removal and insertion.

Some preliminary renderings (placement of components not optimized yet)

Chinese PCB manufacturing and production is pretty inexpensive these days and I can 3D print the outer case so I’ve decided to offer this to anyone else who wants one.

I expect this to be ready to ship in mid July. (Prototyping from oshpark to arrive in mid June and if that’s good, I’ll send it to be fabricated)

I’m targeting a price of $10-12 with a shipping cost of $4 to the US and $5 globally in a padded envelope.

I’m using the MC73831/2 charging IC which costs a lot more than Chinese charging ICs but I’m not so trusting of a <5 cent Chinese charging IC’s reliability.

I’ve opted to go for a safe charging rate of 66mA 40mA with an option for fast charging at 120mA for those times when I want to fill my batteries up quickly.

The normal charging rate should take about 2.5 hrs for a full charge and fast charging will take about an hour I reckon. Fast charging will degrade the batteries quicker, imagine charging a 50E at 7.5A! 10180s are pretty cheap though so I’m not too worried and it’s useful to have.

I also added a switch to dim the blue indicator LED so it’s not annoying when I’m using it in my room at night.

Wireless charging is a possibility but I haven’t found an inexpensive source for wireless charging receivers.

Edited by: Sunnysunsun on 07/15/2021 - 10:59
Agro
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66mA is not that good for 10180. I’d recommend no more than 0.5C – that’s 40 mA. And less would be good for battery durability.

Have you seen cottonpickers chargers? They are not available nowadays, but are a similar project. Simple, low volume electronics for a reasonable price. Might give you some ideas.
I have one and I love it.

Sunnysunsun
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1C does seem pretty standard for some battery sizes though 40mA is a pretty acceptable rate too, I might just pick 40mA instead but ultimately I don’t think the difference is too significant.

I have seen the cottonpickers magnetic chargers but I wanted something a little more convenient for my 10180s instead of fiddle magnets. I do see their benefit with being able to charge other sizes but my normal charger handles other sizes already.

Agro
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Not going to discourage you from your current design, I think that a cradle is OK but I’d like to note that in practice magnets are not fiddly, I find them very convenient.

1C is frequently a standard with modern cells and many cells are rated at more than that. But 10180 are very neglected and they were very outdated when I started with the hobby in 2017, yet haven’t seen literally any progress since then. So these tend to be old, high IR designs. I wouldn’t be surprised if there existed 10180 rated for 1C charging….maybe maybe even ones with 1C being recommended…but normally you can’t get any specs other than capacity…which is frequently fake anyway. And I don’t think you can safely assume that any 10180 from a random source is designed for 1C charging. That’s why I think 0.5C is a better default.

Sunnysunsun
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Fair enough, you’ve convinced me to use a lower charge rate. I am very happy with how the batteries fit into the battery contacts so I wont be changing that aspect.

Edit: with demand for it, I think I’ll be adding optional slots for leads with magnets so you can charge other battery sizes

Sunnysunsun
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I added some preliminary renderings. I’ve still got to optimize the passives placement but these are pretty close to how the final boards will look.

How are the cottonpickers chargers attaching the wires to the magnets? It looks like solder but I was under the impression that neodymium magnets get demagnetized when heated up.

Agro
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They are soldered. Yes, your impression was right. Cottonpickers just had good skills and soldered fast enough not to destroy the magnets.
I tried to repeat it and couldn’t do it with SnPb solder….but then I got no problems with SnBi.

Sunnysunsun
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Thanks for the valuable info. I’ll have a go with my 62/36/2 but might just bite the bullet and get a roll of SnBi.

I don’t want to copy cottonpickers’ design after the work and testing he probably put into it, but I see it as kind of unavoidable since his design looked like the maturation of a relatively simple concept.

Sunnysunsun
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An update:

I’m going to keep this limited to 10180s and 10440s. Most other cells will work in our normal chargers and the magnet soldering is not something I really want to pursue.

My prototype board from Oshpark came in and is working well after I assembled it.

Here is a link to my form if you’re interested and want to be notified when this is ready

Sunnysunsun
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I’ve finished my prototype’s 3D printed case. See the video At the top of the thread. I’m rather proud of how well it turned out after the hours and hours of incremental changes towards perfection. Big Smile

I’ll be working on a case made of ABS for the production version but it’s a little trickier of a material to work with so I went with PLA for the prototype.

You can also access the video here: https://youtu.be/lUvTSk6hEs8

djozz
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Really neat! Wel, done. I’m not in for one, but I can see that this will interest people.

skinny_tie
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I’ve registered my interest via the form.

I don’t have an immediate need, but lack of a suitable charger as put me off buying 10180 or 10440 lights. I also just love using things that are DIY products from BLF members. Smile

I’m hoping postage to Australia isn’t a killer. I wonder whether leaving the springs unsoldered would make a difference to shipping costs?

Sunnysunsun
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Yes, I do think leaving the spring tabs unsoldered might help. This is on the edge of fitting in an “oversized envelope” (max 2cm height) rather than the more expensive package shipping option and I’m not sure which side of that edge the packet will fall on. The padded envelope adds some height to the 10mm of the battery tabs, the 1.6mm of the pcb, and the 1.8 mm of the back plate. Added together, the charger should be 13.4mm tall and the rest of that space would be for the thickness of the envelope itself.

I guess it might depend on how lenient postal carriers are.

TimMc
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Interested in 10180/10440. Happy to solder spring tabs. Also Aussie Silly

It might be less likely to crush with the charger placed in a rectangular cut-out of cardboard so that the envelope becomes a bit more rigid (noticed Bob does this with 219B).

Pilo7448
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I would definitely like one of these, I’ve been looking for a better way to charge my 10180’s.