Varta NiCad to CR2032

Рет қаралды 470

Күн бұрын

Replace leaky Varta 3.6v motherboard backup battery with CR2032, 1n5711 and LM66100
PCBWay Supports High Precision Advanced PCBs: www.pcbway.com/
PCBs at PCBWay www.pcbway.com/project/sharep...
Design files github.com/GadgetReboot/Varta...
Battery Measurements with New Battery Apr 10 2024
Apr 10 Battery: 3.23v Output after diodes: 3.08v
Apr 22 Battery: 3.00v Output after diodes: 2.85v
May 11 Battery: 2.99v Output after diodes: 2.84v
Jun 09 Battery: 2.985v Output after diodes: 2.83v
LM66100 Ideal Diode www.ti.com/lit/ds/symlink/lm6...
1N5711 low rev leakage diode www.mouser.com/datasheet/2/38...
Coin cell reverse charging protection info
www.renesas.com/us/en/documen...
industrial.panasonic.com/cdbs...
If you'd like to support the channel, you can:
Join a membership on this channel: / @gadgetreboot
Support me on Patreon: / gadgetreboot
Become a channel member (click the Join button): / gadgetreboot
Shop through my affiliate links (I may earn a small commission, costs you nothing)!
Banggood www.banggood.com/custlink/3vK...
Aliexpress s.click.aliexpress.com/e/_AFeHwB
Amazon.com www.amazon.com/?&_encoding=UT...
Amazon.ca www.amazon.ca/?&_encoding=UTF...
Videos are mirrored at LBRY/Odysee: odysee.com/@GadgetReboot:4
#ElectronicsCreators

Пікірлер: 7

@benbaselet2026 2 ай бұрын

I have replaced a few batteries with super capacitors, a few Farads will keep the RTC running for weeks and recharge when the system is in use. And they don't leak either.

@DaveMcAnulty 2 ай бұрын

Most RTC's that I have worked with will speedup when hot and slow down when cold. Check the temps on that chip, it's probably unhappy that it isn't getting any air movement over it.

@cocusar 2 ай бұрын

I guess you can tweak the clock frequency with the trimmer cap near the crystal, but it's really annoying that it goes faster when powered up. I guess the circuitry oscillate differently with different supplies.

@borayurt66 2 ай бұрын

Nice thinking with ideal diode. Did you keep the Schottky just as a failsafe?

@GadgetReboot 2 ай бұрын

yes since the UL recommendation was to have either one diode and a resistor or two diodes, and the other reason I put the diode after the ideal diode so that it’s directly facing the motherboard is because the diode can handle up to 70 V but the ideal diode has absolute max 5.5 V so just in case the motherboard creeps above that even momentarily while switching on or off, that should be blocked as well.

@borayurt66 2 ай бұрын

@@GadgetReboot Ahh, I must have missed that absolute max 5.5V thing. But still, I might prefer to clamp the output of the ideal diode to ground with a 5V zener rather than clipping the 3V battery output to 2.85V with a Schottky. The whole point of using that ideal diode IC in this circuit was to prevent any drop on its already marginal (compared to the old rechargeable battery) voltage, wasn't it?

@GadgetReboot 2 ай бұрын

yeah the clamp might work. The other redundancy aspect I liked about the two diodes in series is to help make sure the reverse charging current isn’t going to be a risk so if we only have the ideal diode in the series battery path and something goes wrong, a bunch of current may cause a problem