Re: [EVDL] Question about charging small LiIon batteries

Justin Kenny via EV wrote: Not sure if you understood the previous 2 messages, the Zener diode will drain your battery, and a diode will not stop it from overcharging. I really suggest to use the right tool for the job, $3.25 for a constant-current constant-voltage converter isn't much cost to sa

Re: [EVDL] Question about charging small LiIon batteries

jkenny23 via EV wrote: Another very important note; diodes don't drop voltage the same at all current levels. Meaning; they will NOT stop your 4.5V panel from overcharging your battery to 4.5V if you don't have a dedicated charging IC. If you want to charge your battery to an unusual voltage, I

Re: [EVDL] Question about charging small LiIon batteries

I've had pretty bad luck with MP2307 boards, a lot of them that I use are defective. The LM2596 boards I've used have all worked however, they use the much better 10-turn potentiometers. You could try and replace the variable resistor with your own potentiometer or fixed one, it is a bit of a chall

Re: [EVDL] Question about charging small LiIon batteries

Justin Kenny's suggestion earlier reminded me of something, so I went looking through my spare parts and found some regulators boards that have variable MP2307 regulators. I originally got them to use with 3.3V microcontrollers, but never used them because they have flaky outputs. I'm pretty sur

Re: [EVDL] Question about charging small LiIon batteries

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Re: [EVDL] Question about charging small LiIon batteries

Vehicle Discussion List Cc: Lee Hart Subject: Re: [EVDL] Question about charging small LiIon batteries Peter VanDerWal via EV wrote: > Wouldn't it be better to have a 3.9V zener across the battery? > Unless thay have leakage current when off? > > If I'm going to put it acr

Re: [EVDL] Question about charging small LiIon batteries

Suit yourself, I hope you are using protected 18650 cells. If not please use one of these to protect the batteries from overcharging/undervoltage: https://www.amazon.com/dp/B07KSPYMJ2 - Justin On Tue, Jun 2, 2020 at 3:58 PM wrote: > Yes, Lee has already pointed this out, so I am looking into pu

Re: [EVDL] Question about charging small LiIon batteries

Yes, Lee has already pointed this out, so I am looking into putting the zener in parallel to the PV panel and then a schottky, etc. in series to the battery. The problem I have with the cheap CV/CC circuits from china is that in my experience they have a high failure rate and, just like buttered

Re: [EVDL] Question about charging small LiIon batteries

Not sure if you understood the previous 2 messages, the Zener diode will drain your battery, and a diode will not stop it from overcharging. I really suggest to use the right tool for the job, $3.25 for a constant-current constant-voltage converter isn't much cost to save your battery pack from bei

Re: [EVDL] Question about charging small LiIon batteries

I'm thinking of using two panels, one tilted 45 degs to the east, and the other tilted 45 deg to the west. That should provide a fairly flat power output through the day with something like .375 ma max. If I put a 4.3V zener across the panel, then that should bypass some of the current, so I sho

Re: [EVDL] Question about charging small LiIon batteries

Thanks Lee, I'd just about figured that out by looking at data sheets. :-) > True zener diodes only exist below about 6 volts. True zeners have a large > change in their zener > voltage versus current. For example, a 1N5335 3.9v 5-watt zener will measure > about: > > 5.1v at 1200ma > 4.5v at

Re: [EVDL] Question about charging small LiIon batteries

Another very important note; diodes don't drop voltage the same at all current levels. Meaning; they will NOT stop your 4.5V panel from overcharging your battery to 4.5V if you don't have a dedicated charging IC. If you want to charge your battery to an unusual voltage, I highly recommend using a

Re: [EVDL] Question about charging small LiIon batteries

Peter VanDerWal via EV wrote: Wouldn't it be better to have a 3.9V zener across the battery? Unless thay have leakage current when off? If I'm going to put it across the panel then I'd probably want a 4.3V zener, and then drop ~0.4V between the panel and the battery? The result doesn't have to

Re: [EVDL] Question about charging small LiIon batteries

Wouldn't it be better to have a 3.9V zener across the battery? Unless thay have leakage current when off? If I'm going to put it across the panel then I'd probably want a 4.3V zener, and then drop ~0.4V between the panel and the battery? The result doesn't have to be precisely 3.9V on the batt

Re: [EVDL] Question about charging small LiIon batteries

Peter VanDerWal via EV wrote: Correction, My panels have 2x12 cells. ~5.5V at VMP, ~7V VOC Now that I think about it, I don't think just using diodes will work. The VMP and VOC are two far about to make it practical. How about a zener diode across the panel to limit its peak voltage? Then

Re: [EVDL] Question about charging small LiIon batteries

Windows 10 >> >> From: Peter VanDerWal via EV >> Sent: Wednesday, 3 June 2020 12:55 AM >> To: Electric Vehicle Discussion List >> Cc: e...@vanderwal.us >> Subject: [EVDL] Question about charging small LiIon batteries >> >> Somewhat off topic, but I'm ho

Re: [EVDL] Question about charging small LiIon batteries

Vehicle Discussion List Cc: e...@vanderwal.us Subject: Re: [EVDL] Question about charging small LiIon batteries Now why didn't I think of that? The chargers I've been looking at have MPTT(or at least they claim to), however I could just use two panels. I have a couple dozen panels left ov

Re: [EVDL] Question about charging small LiIon batteries

June 2020 12:55 AM > To: Electric Vehicle Discussion List > Cc: e...@vanderwal.us > Subject: [EVDL] Question about charging small LiIon batteries > > Somewhat off topic, but I'm hoping someone can help. > > I'm building a solar powered weather station and plan to use

Re: [EVDL] Question about charging small LiIon batteries

are you thinking? Sent from Mail for Windows 10 From: Peter VanDerWal via EV Sent: Wednesday, 3 June 2020 12:55 AM To: Electric Vehicle Discussion List Cc: e...@vanderwal.us Subject: [EVDL] Question about charging small LiIon batteries Somewhat off topic, but I'm hoping someone can help.

[EVDL] Question about charging small LiIon batteries

Somewhat off topic, but I'm hoping someone can help. I'm building a solar powered weather station and plan to use 1 or 2 18650 cells. There are tons of small solar chargers available for these, however they all charge the cells to ~4.2V. To maximize life from the LiIon batteries I'd like to keep