On Mon, 23 Oct 2017 13:49:03 -0700 (PDT), wrote:

All of my speedos use 2032 cells. I used to just buy
a card of them and insert new ones. Then I realized
that they are Li-ion. Do these things charge up again?

No. The common CR2032 Lithium (not Lithium-Ion) cell is NOT
rechargeable. However, you can buy an ML2032 cell that is
rechargeable in a suitable charger.
http://www.maxell.com.tw/images/uploads/2015/05/ML2032_DataSheet_table.pdf
Be careful when shopping. Some of the ML2032 cells for sale on eBay
are counterfeits or reworked CR2032. Real ML2032 cells are
considerably more expensive than CR2032. For example:
https://www.newegg.com/Product/Product.aspx?Item=9SIA7324T45066
I bought some of these:
https://www.ebay.com/itm/Brand-New-Maxell-ML2032-Rechargeable-2032-3V-CMOS-Backup-Battery-/110860774466
which turned out to be genuine.

The chargers are quite cheap:
https://www.ebay.com/sch/i.html?_nkw=ml2032+charger
If you're going to make your own charger (such as a solar charger),
note that the ML2032 is rated at 2ma maximum charging current:
http://www.maxell.com.tw/images/uploads/2015/05/ML_Warnings_11e.pdf



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558