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Lithium Battery Charger Board With Confusing Connections

rictrajano — Fri, 01 Nov 2024 20:43:49 GMT

Hello Smart people,

my objective is very simple, to connect 3x 14500 3.7v lithium batteries in parallel and charge them with this module:

https://www.aliexpress.com/item/1005004957459719.html?spm=a2g0o.order_list.order_list_main.38.44211802hKnngk#nav-specification

I have two questions:

1 - Would I need a BMS?

2 - In the product's description they reference two pads that should be shorted if your batteries don't have discharge protection (or is the other way around?) I can't really understand the english. Would someone be able to understand what should be done in which situation?

Here's the description

Instructions for use

Output voltage adjustment potentiometer

VO+VO. IN-IN+

output input

LX-LCBST

VO+ Vo B+ B- T point

battery output battery

The module supports type-c interface input and solder joint input of back annotation input. You can choose one, the recommended voltage is about 5V. The module is marked with two outputs. The two outputs are the same, and the lines are connected in parallel. You can choose one of them. The following focuses on connecting the battery.

If your battery comes with its own protection board, you can choose our package without discharge protection. After the battery is connected to B+ and B-, you must short the T point to charge and discharge.

If your battery does not have a protection board, choose a package with discharge protection. This is very important, because over-discharge of the battery is likely to cause the battery to be scrapped. Most of similar competitive products do not have discharge protection. After -, the T point cannot be shorted, otherwise the discharge protection will be invalid.

After connecting the wires, you can use a screwdriver to adjust the output voltage you want.

The battery chooses 3.7V lithium battery, and the full voltage is 42V. The battery type can be 18650 polymer and other batteries.

Thanks for your help

RE: Lithium Battery Charger Board With Confusing Connections

shabaz — Fri, 08 Nov 2024 21:32:37 GMT

Took a photo since I was charging my flashlight battery..

This 14500 battery has less than a quarter of the energy that the one you're using advertises. And it costs more than 6 times as much and has various built-in protection features. And built-in charger, with status indication LED.

RE: Lithium Battery Charger Board With Confusing Connections

colporteur — Mon, 04 Nov 2024 16:45:28 GMT

Thanks BD! Another 20 minutes gone with my missus asking what are you looking at.

RE: Lithium Battery Charger Board With Confusing Connections

shabaz — Sun, 03 Nov 2024 19:54:53 GMT

The text isn't clear. I think it's better to just use a board with better description/documentation. Adafruit will have some.

And the actual battery you choose might have protection built-in, I hope you're not actually intending on using those AliExpress batteries.

Some 14500 batteries come with an in-built USB port incidentally, and then the problem of charging circuit goes away completely.

RE: Lithium Battery Charger Board With Confusing Connections

rictrajano — Sun, 03 Nov 2024 11:22:54 GMT

Why does it give you the impression that I wouldn't need to use the jumper or BMS?
The charging speed is not too bad actually.

RE: Lithium Battery Charger Board With Confusing Connections

rictrajano — Sun, 03 Nov 2024 11:21:38 GMT

Thanks, I also follow Big Clive and seen the video. This is for one battery only though and doesn't address the charger I'm using.

RE: Lithium Battery Charger Board With Confusing Connections

rictrajano — Sun, 03 Nov 2024 11:17:15 GMT

Thanks for your help. I'm well aware that the charge is not what is advertised, just wanted to show exactly what I was using. My concern is more about if I would need or not the BMS.
The adjusting screw bit is on the step up part of the circuit and not on the charging side.

Thanks

RE: Lithium Battery Charger Board With Confusing Connections

beacon_dave — Sat, 02 Nov 2024 20:37:46 GMT

Big Clive's video on simple charging/protection of Lithium batteries may be of interest

https://www.youtube.com/watch?v=M88e1r8nvYk

RE: Lithium Battery Charger Board With Confusing Connections

shabaz — Sat, 02 Nov 2024 20:00:18 GMT

There isn't even a remote chance that those batteries will support the capacity they claim. You won't get the capacity claimed from a single cell, even if you parallel three of them.

Even a single 18650 sized cell can support more capacity than three of those batteries.

I think you'd be better off buying your batteries from a (reputable) local supplier to you, rather than these from aliexpress.

Also, regarding:

"After connecting the wires, you can use a screwdriver to adjust the output voltage you want."

That doesn't sound like a good charging circuit. For something reliable, see if (say) Adafruit has anything suitable, I think they will.

RE: Lithium Battery Charger Board With Confusing Connections

dougw — Sat, 02 Nov 2024 19:50:25 GMT

It sounds like you don't need the jumper and you don't need a BMS. The charge current is set for a single cell so it may be quite slow to charge multiple cells in parallel.

RE: Lithium Battery Charger Board With Confusing Connections

rictrajano — Sat, 02 Nov 2024 09:50:56 GMT

This is the battery I'm using:

www.aliexpress.com/.../1005007800512403.html

There is no protection circuit.

Any idea on the second question?

Thank you

RE: Lithium Battery Charger Board With Confusing Connections

bidrohini — Sat, 02 Nov 2024 06:03:57 GMT

If each 14500 battery has its own integrated protection (like protection circuits built into the battery itself), the need for an additional BMS may be less critical. But if the batteries are unprotected, then adding a BMS is definitely recommended.

RE: Does any one know what this (automotive thing) is ?

michaelkellett — Thu, 09 May 2024 12:30:03 GMT

Hello,

It's wired across the battery supply between the alternator and the battery.

The symbol is for a 14.5 V bidirectional transient suppressor (what I call a "transorb").

It makes sense.

If the battery is accidentally disconnected from an alternator driven system then , depending on the alternator regulator you can get a big surge in the alternator voltage. (Google "load dump")

When I designed automotive stuff we routinely fitted load dump protection, usually a unidirectional transient suppressor across the nominal 12V supply (like a zener diode but designed for lower slope resistance and the ability to deal with large single pulses).

I've never seen one installed in the vehicle on the wiring harness before - but this is a tractor !

And the symbol was new to me:

One of the symbols shown on Wiki is similar to the one on the mystery part.

https://en.wikipedia.org/wiki/Transient-voltage-suppression_diode

Thanks to all who offered suggestions.

Does any one know what this (automotive thing) is ?

michaelkellett — Tue, 07 May 2024 14:07:09 GMT

A friend (who mends agricultural machinery) has asked me.

MKI

RE: Does any one know what this (automotive thing) is ?

shabaz — Thu, 09 May 2024 12:16:26 GMT

I showed the photo to a vehicle mechanic just now (approx 30 years experience) in case he recognized it, and he's never seen such thing : (

RE: Does any one know what this (automotive thing) is ?

colporteur — Wed, 08 May 2024 17:07:02 GMT

Wow great reference link.

RE: Does any one know what this (automotive thing) is ?

robogary — Wed, 08 May 2024 16:31:30 GMT

back to back schottkey diode used for voltage suppression

https://www.electronicshub.org/types-of-diodes/

12. Transient Voltage Suppression Diode
In semiconductor devices, transients will occur due to the sudden change in the state voltage. They will damage the device’s output response. To overcome this problem, Voltage Suppression Diodes are used. The operation of voltage suppression diode is similar to Zener diode operation.

The operation of these diodes is normal as p-n junction diodes but at the time of transient voltage its operation changes. In normal condition, the impedance of the diode is high. When any transient voltage occurs in the circuit, the diode enters in to the avalanche breakdown region in which a low impedance is provided.

It is very spontaneously because the avalanche breakdown duration ranges in Pico seconds. Transient voltage suppression diode will clamp the voltage to the fixed levels, mostly its clamping voltage is in minimum range.

These are having applications in the telecommunication fields, medical, microprocessors and signal processing. It responds to over voltages faster than Varistors or gas discharge tubes.

The symbol for Transient voltage suppression diode is as shown below.

RE: Does any one know what this (automotive thing) is ?

dougw — Tue, 07 May 2024 16:02:42 GMT

My first guess is its a load dump protection module. (which could be performed by a beefy transorb) But again, this is just a guess.

RE: Does any one know what this (automotive thing) is ?

kmikemoo — Tue, 07 May 2024 15:27:06 GMT

I'm going with a Transient Voltage Surge Suppressor. Probably a Zener back-to-back with a standard diode since it's on a DC circuit. Basically a crowbar circuit.
We use anti-spike diodes all the time with relay coils, right?

Varistors and MOV's are used regularly on field windings of alternators. I think javagoza is on the right path.

https://en.wikipedia.org/wiki/Transient-voltage-suppression_diode#:~:text=A%20transient%2Dvoltage%2Dsuppression%20(,spikes%20induced%20on%20connected%20wires.

RE: Does any one know what this (automotive thing) is ?

michaelkellett — Tue, 07 May 2024 15:01:22 GMT

Thanks - That was my first guess but I'm looking for more confidence. If it was mine I'd open it up.

I found this by searching for "transorb symbols"

So my guess is that its a 14.5V transorb.

Won't be able to tell for sure without opening it unless someone recognises it.

RE: Does any one know what this (automotive thing) is ?

javagoza — Tue, 07 May 2024 14:42:02 GMT

No idea. Playing around, could it be some regulation for an alternator?

PTC Thermistor

Alexis_992 — Thu, 23 Feb 2023 07:27:59 GMT

Hello all,

Recently I have a problem with PTC pill.

So, the problem is that the surface of the PTC pill is “burned”.

This problem occurs on the AC with 115 V.

My questions would be:

1) Why is this happening?

2) Why is this happening only on one side of the PTC pill?

I would be very grateful if you can help me or provide some advice to me.

RE: PTC Thermistor

Gough Lui — Thu, 23 Feb 2023 09:38:00 GMT

Judging from your later photos - my best guess is that the PTC is somehow overstressed or aged and is dissipating more power than expected.

The heat seems to be affecting the plastic, causing it to melt slightly, bowing outwards to the point that the springs no longer supply enough pressure to make good contact with the PTC or changing the metal spring properties to become less springy (hence applying less pressure)

One side always will end up with better/worse contact than the other, and the weaker mechanical contact is probably leading to small arcs, generating even more heat and burning away more metal material in the process, which is why the damage is only on one side. Ordinarily you might expect because of AC currents, damage from AC effects on the PTC would show up evenly throughout the pellet (i.e. from both sides).

That's just my best guess at this stage.

- Gough

EDIT: Compressor vibrations may also affect the contact especially when its weak ... that may make it even more likely for arcing to occur because a weak spring would cause rapid "bouncing" of the metal on the surface similar to a noisy switch.

RE: PTC Thermistor

Alexis_992 — Thu, 23 Feb 2023 09:25:23 GMT

Hello!

Sure I can.

So, it is mounted like it is shown on the picture in attachment. On the first picture, you can see the PTC pill mounted, and other is without so you can see the springs.

So both sides are equally conected (with four pins), but the damage is only on the one side. (previous pictures)

"Is one side connected to a heavy chassis which might sink heat?"

-Answer: I would say no.

"Or is there parts that vibrate or deform with heat?"

-Answer: There is one frequency because the PTC is assemblyed on the compesor in the refrigerator.

"Power/current it is handling or dissipating?"

-Answer: 100-115 V, 50-60 Hz, and the current is AC average was 2,9 and the highest measure was 3.4 A.

"Duty cycle?"

-Answer: Max "switching" per hour is 6-7 and in 24/7.

"Ambient temperature?"

-Answer: 20-30⁰C

Thank you very much for your support!
If you have any further questions I will do my best to provide an answer to you!

Best regards.

RE: PTC Thermistor

Gough Lui — Thu, 23 Feb 2023 07:38:14 GMT

Can you elaborate more about the mounting and pressure applied to the contacts? Is one side connected to a heavy chassis which might sink heat? Or is there parts that vibrate or deform with heat?

What application is it being used for? Part number? Power/current it is handling or dissipating? Duty cycle? Ambient temperature?