Playing With Batteries

rdw777 Fri Dec 30, 2022 8:45 pm

Been chasing a few rabbits lately but got one project out of the way I’ve been wanting to do for a while now….I have two lipo chargers but neither one has a discharge function to bring the cells to a safe voltage for storage so I made a discharger….. Four automotive lamps (resistors)…. Two connected series and two parallel….. Three switches can give a few combinations of drain…. Connectors for single or multiple cell….

A single 200 mAH cell on the two series connected lamps on the right…. Meter on the right monitors voltage, On the left amperage…

A few simple calculations can tell cell capacity, How much capacity left after an outing, And bring the voltage to a safe storage level…. I could have bought a new charger with these functions built in but just used what I had in the shop instead…. Plus the tinker factor Very Happy

andrew Fri Dec 30, 2022 11:43 pm

rdw777 wrote:…. I could have bought a new charger with these functions built in but just used what I had in the shop instead…. Plus the tinker factor

DIY electronics for the modeler has always been of interest to me and, on some occasions, what I needed was not always available or prohibitively expensive. You've done well -- like your buss bar!

I needed a temperature controller for cutting foam cores, but most of the designs used either an AC dimmer, AC chopper circuit or triac. These occasionally tended to leave the surface of the core wavy -- I'm inclined to think it was due to the wire vibrating at certain frequencies generating sympathetic harmonics -- you could feel it in the bow and hear it humming. In any case, I wanted a DC output with a fine adjustment. Here are some pics of one that I put together.

Foam cutter controller: DC PWM output

Case with temperature control knob

PC power supply converted to provide +5v and +12v output

Levent Suberk Sat Dec 31, 2022 12:08 am

Very good works Very Happy

I use Cellmeter 8 for discharging and balancing LiPo cells. It also has a servo tester feature.

https://www.ebay.com/itm/403633883787

sosam117 Sat Dec 31, 2022 9:03 am

I just love my battery dischargers:

This is my Ori / Maylibet battery discharger

I originally purchased from Banggood.
It discharges up to a 6 cell lipo pack.
And it is small and compact at 4" long (10.5cm) x 2.5" high (6.5cm) x 2.75" wide (7.0cm)

When discharging, it will discharge but also keep the cells balance during the discharge cycle.
So, no one cell gets too far out of balance.

It has worked great for me for over 5 years now.
Sad thing is, I tried to purchase a 2nd one 1 year after I purchased the 1st one and they are no longer available.

So, I looked at the same company as my lipo charger -- SkyRC Battery discharger & analyzer -- Model #BD250
And purchased their "Super Discharge!" 250w/35A

Purchased it off of Ebay for $85.00
Nice thing about this discharger is that you can go to SkyRC website and get software updates for the discharger, just like I can with their Lipo charger that I have.

This one from SkyRc has been working now for over 4 years and three software updates.
One update was for the high voltage lipos coming out (HV-Lipo)
Updated my charger on that as well.

rdw777 Sat Dec 31, 2022 5:03 pm

Thank you for your input Gentlemen,

Like that power controller Andrew!… Looks like a stout MOSFET, Maybe a programmable timer, and some peripherals to damp the sympathetic harmonics (capacitor?)….
I built a few of the Ace kits always enjoyed them, Very satisfying when they worked…. And get to learn from them as well and gave confidence to try other things…

That is some fine equipment sosam, Surley worth it for managing large multi cell packs, And nice they can keep of with cell technology with software updates…. Levent’s discharger is nice too, Thanks…

My gadget is certainly primitive and much more manual operation….My cells are mostly small capacity and initially were for small electric planes but can double as power supply for small gas by using two cells and a 5V regulator…. I like keeping notes so will start testing and recording every few weeks…. Can spot trends….I find it interesting…

sosam117 Sat Dec 31, 2022 5:35 pm

rdw777 wrote:Thank you for your input Gentlemen,

Like that power controller Andrew!… Looks like a stout MOSFET, Maybe a programmable timer, and some peripherals to damp the sympathetic harmonics (capacitor?)….
I built a few of the Ace kits always enjoyed them, Very satisfying when they worked…. And get to learn from them as well and gave confidence to try other things…

That is some fine equipment sosam, Surley worth it for managing large multi cell packs, And nice they can keep of with cell technology with software updates…. Levent’s discharger is nice too, Thanks…

My gadget is certainly primitive and much more manual operation….My cells are mostly small capacity and initially were for small electric planes but can double as power supply for small gas by using two cells and a 5V regulator…. I like keeping notes so will start testing and recording every few weeks…. Can spot trends….I find it interesting…

I'm with you with those Ace kits.
Still have them and use them to charge some of my Tx and Rx packs still.

NEW222 Thu Jan 05, 2023 8:55 pm

Looks good, and should serve you well for it's intended purpose.

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