Tag: capacity

Voltlog #285 – Is a Cheap Cordless Power Drill Any Good?

Is a cheap cordless power drill any good? That is a question I’ve been asking myself for a while now because I was in the market for a cordless power drill. I can get a well known brand like Makita which sells a kit with two 18V 3Ah batteries, the drill and a charger for about $200. The thing is I’m using a tool like this maybe once every 3-4 months for a couple of drills, generally soft materials or maybe to assemble some new piece of furniture and I don’t feel like spending $200 for a tool that’s not going to be used and worked for that money.

So I started looking at alternatives, there are the clones of Makitas and Dewalts available for probably less than half the price of the genuine stuff but why go that route? I don’t care about what’s written on the label and the color of the drill.  One thing I care about is the shipping of the item, preferably I would like something that can be ordered and shipped from the EU for fast delivery and no additional taxes being paid for customs.

So I started looking at Chinese brands, this particular model got my attention on banggood.com, they call this a 36V cordless drill, it comes with two batteries and it’s available from a warehouse in the EU.

Voltlog #172 – InTheMail

Welcome to a new InTheMail the series that will touch both your passion for electronics and your bank account at the same time.

Here are links to all the products shown in this video:

 

Voltlog #132 – 4 Digit LED Panel Meter Review

Do I recommend getting this module? Yes, the accuracy is good, the resolution is nice 10mV 1mA and you also have the option for adjusting it manually for both voltage and current.

The design is pretty simple, I believe the microcontroller is an STM8S so hacking it and rewriting the firmware should be pretty easy but it already does what it’s supposed to do so I don’t see a point to hacking this module. I think you would be better off designing a panel meter from scratch.

Buy this panel meter from here.

Someone asked on youtube how should a panel like this be wired up, so here is a wiring diagram that you can use. In this wiring diagram our goal is to monitor the voltage and current for charging a battery.

Example 1 shows the panel meter connected before the battery charging module, which means it will measure everything, even the power losses in the battery charging module.

Example 2 shows the panel meter connected after the battery charging module, which means it will only measure current flowing into the battery or whatever load you have on the output.

In both cases voltage sensing is done right at the output but that wire can be moved according to your needs. Also in both cases the panel meter gets power directly from the power supply because at that point the voltage is constant.

The main thing to remember here is that these panel meters are designed for low side current sensing, that means the ground of the logic board of the meter is connected with the input of the shunt resistor.

Voltlog #127 – 0-60V 0-10A 1mV 1mA Panel Meter Review

So I discovered this module a few months ago and it’s been sitting in a box since then, I almost forgot about it, until a few days ago when I decided it will be a good idea to do a video on the subject.

Let me give you a few details on the specs of this module and as usual it’s pretty difficult to find the information as it’s the case with every new module coming out of China. First of all we have an input range of 0-60V and 0-10A and a 5V rail is needed to power the module itself. It has a voltage measuring accuracy of ±0.2% + 0.2% full scale which sounds strange because these figures are usually given in a percentage plus or minus a number of least significant digits. The current measuring accuracy is ±0.4% + 0.3% full scale.

The meter is basically capable of measuring with a resolution of 1mv and 1mA (however the accuracy is quite bad, as shown in the video) which is quite nice and useful (not really useful with bad accuracy) for projects like DIY power supplies or DIY electronic loads. It can also display the power in watts with a resolution of 1mW as well as showing the load impedance.

Here are some links to this product: