How to become happy with this charger anyway
The [Contact Us] link in https://www.powerstream.com/map.htm doesn’t work. So, rather than following the driving directions or filling the RMA form, I turn to a Review page:
Trying to charge my LIR2025 and LIR2032 cells in their “MLTC-0420-0040 Battery Charger” (bought on 2018-12-03), I started wondering why the cells never became full despite the indicator turning green after a while. To understand what is going on, I deeply dove into the details.
Let me begin with what https://www.powerstream.com/licoin-charg... etc. promise online:
• “(2) Charge rate is 40 mA.” Rate? It starts charging the empty cell with ≈39 mA current and charges at roughly constant voltage around 4.1 V. When the current descends to ≈18 mA, the indicator turns green. See more below.
• “(2) … charge time is listed below” is not true. The charge time is not listed below.
• “(3) … Pressing a button …” - there is no button.
• “Note: These chargers are only for known rechargeable 4.2 volt or 3.6 volt lithium ion coin cells.” is misleading. In fact, the 4.2-V slide-switch setting is there to charge the 3.6-V Li-Ion cells.
https://www.powerstream.com/li.htm about charging: “… The termination condition is the drop in charge current to 10%. …”. The user doesn’t learn when this happens: The indicator turns green already at a still considerably higher current: ≈18 mA, which is ≈45% of 40 mA, so the charge is not completed yet. Since the current is low and decreasing then, it needs more hours to complete the charge - the user doesn’t learn how many [see (2) charge time]. To fix that issue, I had to parallel 68 Ω to R23 and R38 each, thus approaching the 10% rule.
BTW: Disconnecting the power source without removing the charged cells is not a good idea: The powerless charger sucks ≈3 mA from each remaining charged cell.
Addendum: Since the contacting springs tend to behave as loose contacts, I had to solder the ends of the spring wires to their bases.
