Voltlog #92 - InTheMail

[@MrBrymstond]

When I was in grade school we had show and tell, this takes the cake! Awesome...

[@GeekMustHave]

Thank you for these videos, I look forward to them. I like how you have them time stamped in the description so you can jump around between the items. Thank you also for the AT30 unboxing, just in time for a power supply project where I have burned up a couple of XL6009's. Keep publishing!

[@voltlog]

thank you for watching.

[@pirateman1966]

While binge watching your videos from video #1, I came across this one today, and noticed that we both had the same idea about combining a PSU with an electronic load! I will build one as I said in my other comment today, and will let you know how it goes. I don't know why I didn't find your channel sooner! Its a great channel. Better than that whiny and long winded channel I've been watching for years. (lets not name names, but you know which one I mean).

[@voltlog]

thank you, I'm glad you like the content. Let me know how your project works out.

[@chrismoen5853]

Absolutely love your VoltLog videos! I'm purchasing many of these little circuits you recommend. Question on this 0-30V 2A p.s. I purchased four of these kits to build up for my lab, and I would like to add a push-button to show the preset current limit that reads out on the digital ammeter without actually placing a "brute" load on the circuit. I have the schematic. Could you suggest a way to do this within the circuitry?

[@voltlog]

+Chris Moen I would use a microcontroller to read the value of the analog pots and approximate the current limit based on a lookup table or linear function.

[@chrismoen5853]

Thank you for the idea.

[@nomadic_rider42]

using digital POTs would give you better controlled readings.

[@Peter_S_]

This series is great. Thank you. More please!

[@voltlog]

thanks! more is coming :-)

[@peterfielden-weston7560]

I really couldn't do an "In The Mail" type video. As soon as any parcel or package comes into my house I'm ripping it open and drooling over the new toys inside.

[@voltlog]

I have come up with a system, all the items that arrive first go into a storage bin. Then I try to group them and those that are somewhat similar or related will go into the next inthemail :-) With my current stream of orders coming in, the storage bin usually holds enough stuff for two videos at any given time..

[@TheDefpom]

I would move the diode on the buck converter , to be across the D.C. Input, will blow fuse if reverse wired at least.

[@voltlog]

+TheDefpom that would be a better option indeed. Though I don't like distructive protection features.

[@bertoid]

Hi Voltlog, love your InTheMail videos, especially as you provide links (and they are good for you too). But I'm not sure if your criticism of the TPS40057 is completely accurate. Admittedly, I don't know that much about synchronous or standard buck converters, but maybe the inefficiency caused by the diode in the standard buck converter is worse when it's in the switching section, than that caused by the use of a protection diode? I don't know, just thinking out loud there. But certainly at the higher input voltages, when the input current is lower, the loss caused by the (presumably) schottky diode should tend towards minimal.

[@voltlog]

That's an interesting question you raised but I don't think it's the case. It might even be the other way around. In the converter circuit the diode only conducts momentarily, while in the input section it will pass current continuously.

[@iceberg789]

nice purchases ! but i would just like to tell, if you need a lm317 supply for a project, it's easy if you just solder in a lm317 with 2 resistor at left, with 2x close positioned small caps at i/o lines. just 5-10mins work.

[@voltlog]

yes, it's easy to solder an LM317 but It's my personal preference to have everything nice on a PCB :-)

[@iceberg789]

(^.^)

[@nomadic_rider42]

I looked into TP5100, but they don't seem to have cell balancing capability.

[@voltlog]

no, unfortunately they don't..

[@GorkemYildirim]

is it safe to charge 2s 18650 with TP5100?

[@nomadic_rider42]

I would NOT suggest using it for 2S batteries, but 1S should be OK.

[@pirateman1966]

Well I knew it was too good to be true! Also doesn't seem to have any UV or OC protection. One can not rely on the built-in ones inside the batteries, as some Li-ion knock-offs, don't have any protection.

[@Luke-san]

Very interesting li-ion charge module. Will order that one straight away.

[@voltlog]

+Luc Peeters yup, worth having them.

[@Luke-san]

And already delivered in a weeks time from China. Just crazy sometimes.

[@voltlog]

I'm guessing in the US? awesome postal service

[@Luke-san]

Nope, Belgium. Really weird getting things from China. Yesterday I received a module that was sent 2 months ago. The charging modules I ordered on ebay from Alice (and then a long number) Actually now I need boxes to keep all these small modules in and actually print out what they are and how to connect them. I found a couple modules that I ordered long ago and I had to dig in my mails etc to find out how and what.

[@voltlog]

I broke the record yesterday, I received a product ordered Nov 23 2016

[@MrBrymstond]

That AT-30 module I purchased one and the heatsink fell off in the mail so I just glued that back on and they sent me a fuse and a extra capacitor for some reason.

[@voltlog]

oh yes, I remember, there was a fuse in the envelope but I miss-placed it..

[@MrBrymstond]

I have that same thermal silicone glue. I didn't use just any and I found that strange about the fuse but they must be thinking you're going to blow a capacitor, did you get one?

[@voltlog]

+MrBrymstond I didn't get the cap

[@MrBrymstond]

TP5100 4.2/8.4V Lithium Battery Charging Module. This chip doesn't balance the 2 batteries so why not use any sepic buck/boost converter? A buck or a boost can achieve the same results and also have the ability to charge upwards a 10S battery pack. I have to be missing something, if I am please tell me, thanks

[@voltlog]

a simple buck/boost converter doesn't have the features of this special lithium charging ic: charging with 3 phases: tricle charge pre-charge, constant current, constant voltage and the protection features.

[@battlecoder]

Awesome stuff, as always. I'm also guilty of ordering Wemos modules because of Andreas!

[@voltlog]

+Elias Zacarias thanks

[@zubberification]

You know you have a eBay/Alliexpress/online shopping addiction when you have to buy 2 of those 2S charger modules before the video even finished.

[@voltlog]

+TookErrrJerbs awesome!

[@daijoubu4529]

I would look at using 18V power tools battery pack to power a class-D amp, it may go into clipping at lower voltage, also, the TPA3118 and TPA3116 board seems much better, lots of info on diyaudio. There​ is a 2S BMS with "balancing" but the best would be using multiples TP4056 with isolated grounds.

[@voltlog]

thank you for the hint, I will look into those amplifiers. (I checked and they are too high power for my application, I need a maximum of 2x15w)

[@JeffLMisc]

any thoughts on messing with the highland 0-28v , 0.1-2A power supply kit with an LCD? I have one here, and it works fairly well. also easily hackable :)

[@voltlog]

+Jeff L is that the switching model? I have one of those kits but haven't tried it yet.

[@JeffLMisc]

i think it is switching. it uses a A1941 PNP transistor, with everything running back to a atmel micro :)

[@wi_zeus6798]

(In reference to the Buck Boost Converter): "Higher efficiency" bla bla bla an then you see the ABNORMALLY LARGE heatsink... Ya, sure, definitely very high efficiency... ;) Cool Video!

[@voltlog]

+Manuauto thanks

[@Newsparklabs]

Nice video, as always.

[@voltlog]

+NewSpark Labs thank you!

[@BIBIwood]

The problem with most of the D class boards coming from china is the gain is always fixed on the higher setting, where you have distortion most of the time. The TPA3110 has two pins for gain, so four values, so if you feel courageous you could try to solder a DIP switch.

[@voltlog]

+BIBIwood yes, I have seen that issue. I will hack this module if too much noise is present.

[@cccyberfamilydk]

Nice as usual

[@voltlog]

+Christian Christiansen thank you for watching.

[@TheDefpom]

Looking for a collaboration eh...

[@voltlog]

+TheDefpom it will take some time to get something ready, but I will get in touch later on.

[@nickpelov]

English translation for TP5100 chip datasheet: www.microlab.info/datasheets

[@SKElectronics]

Make the build video of dual channel power supply with dummy load I had also build something like that really helpful think to have.

[@voltlog]

+Electronic projects I will look into that for future videos.

[@AbhishekKr1902]

I have also got this endless habit of spending money ordering a lot of electronics kits, components and stuff from china. aliexpress :p

[@voltlog]

you are in the right place for that :-)

[@akarshagarwal4516]

first

[@ceptimus]

second

[@TheDefpom]

ceptimus 10th

[@voltlog]

Currently last..

[@akarshagarwal4516]

no you are wrong