21 July, 2015

The Li-ion 18650 for sale on the Internet: There are more false than legitimate

When I started acquiring Li-ion batteries 18650 back in 2012 to restore some packs, there were still no stores in Spain that had them and I started to import them through Chinese pages like DX.com, aliexpress, Ebay, etc.
Note: The reference "18650" refers to the shape and dimensions; 18 is the diameter in mm, 65 is length and 0 indicates the shape; in this case cylindrical.
At first I was confident and I trusted the ads in some extent, I knew the false capacities of some NI-MH before, where manufacturers also indicated many times more capacity than real, so I was prepared. I compared, and bought cheap, but not the cheapest, high capacity (announced) batteries, , and hoped that there would not be much difference.
This problem is very well explained in Energizes or Bateriasdelitio.net , which echo the deceptions of Chinese "smart" guys.
I was wrong. I came to ordering (ouch!) For 3 €/unit. 18 batteries "Fandy-FIRE", the "manufacturer" marked them as 3600 mAh capacity, when in fact they only had 800 or less! When they arrived the first thing that struck me was how little weighed; the larger capacity usually weigh 47 grams / unit, when these did not reach the 30 g / pc., although some manufacturers are "approaching" the weight of the good ones filling them with materials as diverse as flour!

20 July, 2015

Current state of the art LED options in H4 / H1 car bulbs

Model H4 LED high performance
Tired of changing the H4 halogen lamps of my Xsara Picasso car, I was looking for alternatives in LED, checking the state-of-the-art in H4 Led lamps, If I could find one well worth installing, so getting savings in fuel and maintenance .
Is it legal? : To carry LED lamps  outdoor legally in Spain, for now we only have the option of installing a complete approved headlamp, and that must be installed by a certified workshop to carry the certificate to the periodic Technical inspection, because the headlamps are designed for a type of lamps with which it lights the same way (lumens and openness); this could cost easily €150. These lamps in theory can not be used on public roads (although for racing/testing purposes). There is no problem changing the ambiental interior lights to Led ones.
In the following video I commented highlight of these LED lamps H4 "SunnyLight"  and installation:

18 July, 2015

DIY: Turn your bike into e-bike for yourself - Step 5/5: Final details: Active Braking, charge control and legality

This wounded wire is my brake;)
After a few months of using battery-powered bike, I am going to comment how it feels. On the one hand it does very well with the uphills, but the downhills are another thing. In my neighborhood we have slopes with between 8 and 10% drop, and the bike does not stop fast enough with his brakes (disk brake only in the back). I have found that its weight (about 30 kg) is a major handicap, and although putting many banks in each cell increases the li-ion battery life and autonomy, it makes very difficult to go upstairs with it (impossible to carry on daily to an apartment), or braking, the brakes suffer a lot (especially at low speeds when the engine brake don't work).
Although we could use engine braking to stop and derive the energy to the battery, but you can not raise too much the regeneration (engine braking); above 15 amperes (1,5C) batteries suffer much from excessive current (even without reaching 4.2V per cell), and they degrade faster, besides the Golden Motor control is proportional to speed (recovers more amperes the higher the speed), so we could be sending a damaging 40A to the batteries if the slope is steep and we go fast.
Another option is to put LiFePo4 batteries, much more tolerant, but they have less energy capacity per kg, in addition to its high prices. The A123 for example accept for each 26650 cell type up to 10A continuous recharge. For this moment I can' afford them (although they come equally profitable having more recharging cycles).
After investigating, found a interesting solution  about using a resistance as a powerful engine braking (what  a great well of wisdom is Endless Sphere about electric behicles), ¡and they have proved that it works wonderfully!:

Example of resistance brake on a bike from a friend of Endless

15 July, 2015

Changing the hard drive of a Lacie Network Space 2

A couple of years ago I bought this super NAS (Network Storage) Lacie with Linux operating system, good performance and very low power consumption (you can set it to shut off at 20 min. without use, very convenient for longer life of your hard drive).

The disc It had got too small, so using Clonezilla, I opened the box (to do only handle in the area led out all the cover up), and I cloned the 1TB disk to another larger than 2 TB. To exploit its full capacity, we have to resize the XFS partition data to use all the free space remaining with the Gparted (free Linux program).

The Gparted allows us to do all sorts of operations on partitions (image of their web)

13 July, 2015

Avoid the discharge of the car battery when not used using a simple relay and interruptor

Relay connection scheme
An old Fiat Bravo was draining battery when not used for a couple of days, and the battery had to be recharged every time: The electronics had an excess of consumption, far surpassed the admissible 0.3 Amps.
After reviewing the possible cause (alternator regulator in poor condition, or something that was connected) by removing fuses and checking consumption every time, I did not found the source of the problem, so we decided to place a switch controlling a relay to disconnect the battery when the car was not in use.
Thus the battery, although the car is not used for 1 full year, only 30-40% is discharged (typical self-discharge at 1 year for batteries Pb / Calcium). Furthermore we lengthen the life of the Central Computer by completely disconnecting it. 
I also take the opportunity to see how these relays are for my next project, which would be programmatically control the battery charging to save fuel by turning off the alternator.
NOTE : Keep in mind that if the battery gets disconnected, you lose the date and time of the control panel (if any).

Using a relay just have to carry three thin wires into the cabin to turn the switch and voltage indicator, because power is handled as close to the battery as possible.