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28BYJ-48 Motor Buying Guide

There are a lot of different motors that go by the same “28BYJ-48” name.

The two areas of variation are:

gear ratio

common values are 16.032:1, 64:1, and 63.68395:1

coil resistance

I’ve seen variants ranging from 26 ohms to 185 ohms

(For more background reading, see Graham Wideman’s detailed post, though it does not even cover all the variants I have seen)

Both of those factors - gear ratio and coil resistance - have a pretty big impact on output torque, max speed, and control sequence (steps per revolution), but unfortunately most sellers don’t provide that info, or worse, they’ll often provide incorrect info.

Making things worse, it’s not uncommon for sellers on AliExpress to change the item they sell without changing the store listing, so even if you’ve purchased from a listing in the past, there’s no guarantee they will continue to offer the same items.

🔑 The motors that I’ve found work best for splitflap displays have a 64:1 gear ratio and a half-coil-resistance (measured from the red wire to the blue wire) of ~100 ohms.

In my experience, I’ve found these tips improve your chances of getting good motors:

🔑 Only buy motors labeled 12V

It seems like there are more variants marketed as “5V” so you’re less likely to get a consistent item when buying 5V motors

🔑 Only buy motors that have laser-engraved labels; avoid motors with sticker labels

Laser-engraving is more expensive than stickers, so it generally suggests a higher quality product. I’ve received sticker motors with identical “serial” numbers printed on the sticker, whereas the numbers on laser-engraved motors have always been unique in my experience

🔑 Message the seller beforehand to confirm the motors are as you expect

Ask whether the motors have a sticker or laser-engraved numbers on the side

You can try asking what the resistance is, e.g. between the red wire and blue wire, but I’ve had little luck with this in the past (maybe just lost in translation)

Asking about steps/rev or gear ratio is generally not useful; they will give you an answer but it may not be correct because they can’t easily test it

Below are some notes on different AliExpress links I’ve ordered from in the past.

As always with AliExpress, there’s no guarantee that you will get the same quality items that I did; these are not recommended sellers, and I cannot vouch for the quality of motors you’ll receive if you buy from them.

If you have good or bad experiences with any of these sellers, please let me know by either leaving a comment or sending me an email (scottbez1 @ gmail.com), so I can include that info here to share with others.

Order date	Quantity	Store	Photos	Coil half-resistance (Red to Blue)	Gear ratio	Notes
2021-05-12	60	SeasBoat Store		108	TBD	Seller was slow to ship and unhelpful over chat - it took 17 days after order was placed before DHL received the item. DHL delivery was fast - delivered 2 days after they reported receipt of the item. 19 days from order to delivery (should have been much faster considering it was DHL express). With that said, this seller seems to be an ok option. Motors look ok - individually packaged in bags. No additional padding around them in the box, but no obvious damage either.
2021-03-26	110	alinsin Store		112	TBD	Ordered 110, sent in 3 packages. Shipped via Cainaio even though I requested Aliexpress Standard. 1 package with 50 motors is still missing as of 2021-06-13; dispute filed with AliExpress for partial refund, pending resolution.