Automotive battery charger

I bought my DL24 load tester to test repaired 10AH 2P5S Samsung INR21700-50S packs. As a control and to make sure I am doing it right, I started with two brand-new DeWALT 20V Max XR 10AH DCB210 packs fully charged to 20.6 volts. The DL24 said “Complete” after only 6AH… not 10AH. The manual was no help, so what am I doing wrong?
I set a 1A constant current discharge test with a cut-off voltage of 15 volts (3v per cell) and set an excessive time (24 hours) while I went to work. Over 6 hours into it the voltage had momentarily dropped to 15v but recovered and was showing over 17v when I got there. Since it wasn’t 15v I ran it again and it said “Complete” minutes later with the voltage rebounding from 15v to just under 17v.
My Opus BT-C3400 can’t test a whole battery pack but when I do a 1A discharge test to a bank of cells you can watch the discharge rate slow as the battery drains (not nearly 1A in the end). That doesn’t seem to be happening with the DL24 since it uses constant current. It momentarily hits 15v then reports “Complete” as the voltage rebounds to something well over 15v. The pack’s charge level indicator (simple volt meter) even reads 2 bars out of three.
I did try resuming the DL24 at 250mA but it still didn’t get past 6.475AH and voltage is still nearly 17v. Progressively lowering and re-running it is the kind of thing I’d hoped to avoid by getting this. Babysitting my BT-C3400 smart charger one bank at a time over more than a week to fully test one pack was too much.
Less than 6.5AH is a far cry from what should be 10AH so I can’t use it unless someone can tell me how it’s supposed to be done. How are others testing full battery pack capacity with the DL24?
Will any of the other modes approximate the discharge test of my smart charger to measure the full 10AH? If I picked one like Constant Resistance or Constant Voltage, what resistance or voltage should I set? Thanks!

My lawnmower is dead and I have been charging it at 12V automatic for a while now with no luck, will I damage the battery of the mower if I use the 70A start option on the battery charger? Apologies if my terminology is incorrect, I usually use my car battery but I’m stuck on the back long and there’s no way to get my vehicle back here!

Hi everyone can it be real for that price with good condition as it says ,it’s seem too cheep what is the chances it’s real?? Full price around 400$

I bought a truck that was previously owned by the electric company. It came with this streamlight litebox. The charger is wired in to the truck. The battery is no good. It has the xenon bulb. I’d like to upgrade it to LED but am unsure if the upgrade kit will work because I don’t know the model of this light. Can anyone help? Thanks.

I was on here for a similar issue months ago but that was mostly for using usb>usbc cord I had bought and later learned wasnt strong enough for headsets.
I recently bought a Quest Pro and merged it with my Virtual Desktop PCVR setup. It was perfectly fine a few days ago until all of a sudden, my headset dies while its plugged in.
In the (very shitty but hopefully still readable) photos are my settings for my Acer Nitro 5. I originally set myself to 90FPS with Ultra VR Graphics Quality with Snapdragon turned on but I reset it to default that pushed me to Medium and 72FPS. It helped but very slightly, like it doesnt drain the battery as quick but it still doesnt hold/increase charge.
All the Meta app tells me is to make sure theres no debris or moisture in the port and charger and to only plug it in at 50%.
In the VD Streamer app on Desktop, I turned off “Boost Game Priority” and changed the Codec from AV1 10-bit to Automatic and my OpenXR Runtime is still set to VDXR.
What else do I need to change?
TL;DR: My headset cant hold a charge with the charger it came with and Im trying to change settings on Virtual Desktop to try and destress my headset to charge properly.
Any help is appreciated.

I'm currently working on a master's thesis during an internship at an automotive company that manufactures EVs. The thesis focuses on improving a pre-charge circuit for an EV. In EVs, a pre-charge circuit is a circuit used to slowly charge the capacitor within the motor's inverter to the battery's level in order to limit the inrush current. Traditionally, this is done using a relay/resistor combination. The battery is isolated from the rest of the system with two contactors, one on the positive rail and the other on the negative rail of the battery. Initially, the negative contactor closes, followed by the relay. Once closed, the relay provides a resistive path to the inverter's capacitor to limit the current flowing through it, thereby slowing the charging rate of the capacitor according to the time constant au=RC. Once the capacitor reaches to battery's level, the positive main contactor closes, and the relay opens, allowing full current to flow through the inverter.
https://preview.redd.it/ghri8dwdvk5d1.png?width=762&format=png&auto=webp&s=6f7fe4cbb1d1b144e89ea4ff5312431b4223b005
This circuit works as intended, but that doesn't mean it doesn't have its shortcomings. One of the major problem of this circuit is having an electromechanical relay. Because of its mechanical nature, it is prone to wear and tear. To address this, I though of basing my solution on something that doesn't rely on components having moving parts. Since the goal here is to limit the inrush current, I thought to myself, why not using a proper inrush current limiter to do the same job as the pre-charge circuit. Through some research, I stumbled across this article that discusses an active inrush current limiter circuit (AICL for short) based on a MOSFET. After reading the article multiple times, I found the information along with the design relatively simple to grasp ( bear in mind that I'm not an electrical engineer, so I might be lacking on certain areas when it comes to electrical engineering) , plus the solution is based on semi-conductors, so no moving part for me. Since this approach ticks all my boxes, I decided to go with it.
From what I understood, this design exploits the switching characteristics of the MOSFET to control the rate of change of the drain-source voltage, thereby controlling the drain current. Here is the circuit mentioned in the article:
https://preview.redd.it/b27tvpptvk5d1.png?width=487&format=png&auto=webp&s=4f0ca604372997b0746d38946334f30077b31063
Here C_{filter} is the capacitor that we want to pre-charge. So by putting this capacitor between the positive side of the battery and the drain of the MOSFET, we can effectively limit the inrush current running through the capacitor.
The article lists design equations so we can customize the circuit to our needs. The following equation is all I needed to put together my own implementation:
https://preview.redd.it/odaab67twk5d1.png?width=827&format=png&auto=webp&s=6b9f155e6c4ddbeea4f26138695e8c6a944fa60d
Here are the values for my specific application:
https://preview.redd.it/96kl2kiwwk5d1.png?width=820&format=png&auto=webp&s=224368918fecb755b6feddd70ca0438d6eee14de
I plugged these values into the equations, and I got the following results:
https://preview.redd.it/s0kr7zeywk5d1.png?width=805&format=png&auto=webp&s=44db470b218ab82d89cf4896544714a9c7518dec
Bear in mind that these values are supposed to limit the inrush current to 15A.
To test the validity of these equations, I put together a software simulation in LTspice.
https://preview.redd.it/ybjkhzv2wk5d1.png?width=795&format=png&auto=webp&s=f6d6af54ab15f0134811d5c1196a5c680ea796ad
After running the simulation, I was surprised to find that the inrush current was above 450A, far exceeding my expectations. I'm genuinely confused and unsure where the problem originates and how to approach it. I thought that by following the design steps outlined in the article, I would achieve the desired result, but unfortunately, that didn't happen.
https://preview.redd.it/rng70qcewk5d1.png?width=1913&format=png&auto=webp&s=299557a26c5524a1e8b14c03a8daf8956f7b8824
I haven't completely lost hope in this approach because I'm certain there's an important element I'm overlooking. My last resort is to seek help from experts in the field, and there's no better place than this awesome community. If anyone has any ideas about this or is already working in this field, please don't hesitate to help me. I would greatly appreciate it. Thank you so much for taking the time to read all of this.
Here is a table that lists all major components used in the simulation:

MOSFET	R6020PNJ
Diode	1N5408
Zener diode	PDZVTR12B

When I unplug the power charger the thing dies, so I imagine that my problem is related to not being able to charge or hold the charge. Seems to try to boot when plugged into the charger but just cycles through this and the screen never comes on, except for the little flicker. Ideas?

https://preview.redd.it/awr65poxxk5d1.png?width=558&format=png&auto=webp&s=e4ff9e95b5a29aeca20638a7210c0ba27c655c2f
I have a Samsung laptop for 7 years now, and I use it a lot every day. Today, when I ran a battery report check in Command Prompt, I discovered that my battery has almost 2500 cycles now, and the full charge capacity is at 10 mWh now. Is that dangerous? Should I worry about that? Currently, the battery lasts for less than a hour when it is not charging, so I just use it while charging all the time.
Also, since I woke up in the morning and plugged in the charger, the battery is stuck at 4%. I don't know if that's the charger's or the battery's fault. My charger has faulty contact, so if I bump into it, it stops charging. So, staying at 4% can be kinda annoying.