Category Archives: special offers

Solderless Power Supply Module for Breadboard

Posted on by

We recently came across this handy little power supply module designed and built for use with prototyping breadboard (MB102 size) by YwRobot in China.

breadboard power supply moduleThis is a very useful device for anyone getting started with electronics thanks to its low cost (approximately £1 delivered) and ease of set up and use.

The module simply plugs into a breadboard and gives two pairs of rails which can be configured to give you 2x5V rails, one each of 5V and 3.3V, and you can also set one or both pairs of rails to 0V.

mb102 breadboard power supply modulePictured above we have used the small yellow jumpers to set one pair of rails to 3.3V/0V, and the second pair of rails to 5V/0V. The board is then ready to supply a few hundred mA at 3.3V and 5V to any project you may want to prototype/build on the breadboard.

The module is powered via USB. Virtually everone now has a micro-USB charger at home for mobile phone and table charging etc, so it is surprising that they chose to use a full size USB-A connector. It would have been much better to go for a micro-USB connector.

The module has two low drop linear voltage regulators to supply the 3.3V and 5V outputs. When we tested this with a USB power supply outputting 5.46V, we measured 5.123V on the 5V rail, and 3.286V on the 3.3V rail.

If your USB power supply provides less than 5V (or more likely, you have less than 5V after losses in a long/cheap cable) the 5V rail will always be a few tenths of a Volt lower than the incoming voltage – therefore you cannot guarantee a reliable 5.0V output from this module when powered via USB. Similarly, it is best not to use this connected to a USB port on a PC as the voltage of PC USB ports can jump around a lot depending on what the PC is doing at any particular instant.

There is however a standard DC barrel jack for DC input power. Using a standard 6V DC power supply should give you a full stable 5V output from the module.

There is an on/off switch on the module, with a green LED to show the current status. This is useful not just because it saves you from having to unplug or switch off your USB power supply at the power point, but also because the capacitors in a power supply retain charge after you unplug the power supply and this charge will feed through the module into your electronics project until those capacitors have discharged. That could have unforeseen consequences as the voltage input to your circuit drops.

The quality of the components used and the build quality are as you would expect from a product offered at such a low price, but these modules are still an excellent first purchase for anyone interested in circuit prototyping.

These modules are available on their own, or together with a suitable breadboard and jumper links as a complete starter package. Click here for more information or to make a puchase of one of these power supply modules.

Offer of the Day – 88Ah Deep Cycle Battery £56.95

Posted on by

88Ah deep cycle solar leisure batteryOur recommended offer of the day is this 12V 88Ah deep cycle battery offered in the UK at just £56.95 including delivery (to mainland UK locations south of Glasgow/Edinburgh). As the image above shows, order this battery before 4pm to have it delivered next day, and it comes with a 4 year warranty.

This battery has dimensions of 257 x 172 x 220mm and is suitable for solar charging as well as for general leisure and marine usage.

Click here for more information or to buy this 88Ah 12V battery now at this low price.

Special Offer of the Day – 20W PV Solar Panel £25.99

Posted on by

While the price per Watt of PV solar panels has been tumbling, the cost of smaller solar panels (<30 Watt) have remained relatively high in most cases because of the fixed costs of postage, and manufacturing without the benefit of scale.

Smaller panels are particularly useful for battery powered outdoor projects such as shed lighting, electric fencing, irrigation systems, and much more.

20 watt PV solar panel special offerPictured above is our special offer recommendation of the day – a high quality 20 Watt monocrystalline PV solar panel for just £25.99 plus £2.99 postage (and no extra postage if you purchase 2 or more of these panels).

This panel is 363mm x 529mm x 25mm in size and 2.5Kg in weight, and is fitted with 1.5 metres of cable and a bypass diode to prevent reverse discharge at night.

Click here for more information or to snap up one of these panels now: 20 Watt PV Solar Panel Offer.

Offer of the Day – 80W Monocrystalline Solar Panel £71.98

Posted on by

With the EU about to impose high tariffs on imported PV Solar Panels, and prices of solar panels likely to increase soon for other reasons, now is definitely the time to get your hands on some competitively priced panels.

80w monocrystalline solar PV panel - 12VDC

Our recommended offer of the day is this 80W 12V monocrystalline PV solar panel best priced at just £71.98 while stocks last. It weighs in at around 8kg and has 1205mm x 545mm x 35mm dimensions.

The panel is fitted with a sturdy aluminium frame, a waterproof wiring box, and is supplied with solar cable, plugs, and bypass diodes fitted.

Click here to purchase one or more of these panels or for more information: 80W PV Solar Panel. The panels are despatched from Germany quickly and well packaged in our experience.

Special Offer – Complete Evacuated Tube Solar Water Heating System

Posted on by

Complete evacuated tube solar water heating system

Pictured above is a complete DIY 30 tube evacuated tube solar water heating system for sale here in the UK at £1,662 plus £45 for delivery.

While that obviously sounds like a lot of money (as it is) you get a lot for your money all from one place thereby making savings in postage and the time otherwise taken to spec and source everything.

Evacuated tube solar water heating systems (click link for more information from REUK site) are the most efficient on the market today. A 30 tube system such as this fitted with a 200 litre tank will meet the majority of a typical family household’s hot water needs for 3 seasons of the year, and make a good dent in water heating bills the rest of the time – even when it is freezing outside.

The kit comprises the 30 evacuated tubes, 200 litre insulated twin coil cylinder, roof fittings, solar contoller and pumping station, expansion vessel, pipework, and all the other fittings necessary to put together a complete solar water heating system together with detailed instructions.

Click here for more information or to buy now: 30 tube solar water heating kit. There are many other options – e.g. smaller or larger systems available from the same seller. Click here to view the range: DIY evacuated tube solar water heating.

80 Watt 12V Monocrystalline PV Solar Panel – £69.98 inc Delivery!

Posted on by

Special offer of the week has to be these 80 Watt power monocrystalline PV Solar Panels offered as a pre-order item (to be despatched after 17th April 2013).

80 Watt Solar Panel - Special Offer

The panel, pictured above, has an anodised aluminium frame, 3.2mm tempered glass, and is 824 x 669 x 35mm and just 8kg. Best of all is the price – £64.99 plus £4.99. It comes fitted with standard MC4 terminated cables. It is fully weatherproof for outdoor use.

Click here for more information or to snap up one or more of these panels now: 80 Watt 12V PV Solar Panel.

Testing LM2596 Variable Voltage Regulator

Posted on by

Our LM2596 Variable Voltage Regulator (discussed previously here: regulator with display) has finally arrived after its long journey from China.

LM2596 variable voltage regulator with display

The first image above shows the input voltage as being 13.8V (which was accurate to <0.1V). The second image below shows the output voltage which we set by adjusting the small brass screw in the blue potentiometer to be 5.0V (which was also accurate to <0.1V).

lm2596 with LCD voltage display

The build quality and quality of the components used is excellent throughout, the LCD is bright, and the addition of a red LED and a green LED to indicate whether the input or output voltage is being displayed is very useful. Selecting whether to display input or output voltage is achieved using a small button on the regulator board. In addition to screw-in terminals for connection of the input and output wires, there are also holes with solder pads in both fine and medium sizes so that different sizes of wire can be more securely attached if required.

The only bad point would be that there is no option to turn off the LCD when it is not needed – i.e. it needs three options (display input voltage, display output voltage, or display nothing) instead of the two it has. The LCD draws approximately 25mA all the time, so will take 0.6Ah of charge out of a battery every 24hrs which is a lot. Another 10mA seems to be the quiescent current lost in the regulator when nothing is connected to the output but it is still regulating voltage.

We can think of many uses for these voltage regulators which are made easier thanks to the on board display – first and foremost for small battery charging from a 12V battery, and/or powering USB charged devices (using a 5.0V output). For battery charging of say four series connected NiMH rechargeables, you would just set the output voltage to say 5.8 or 5.9V and connect it to the battery pack with the correct polarity.

Apart from having slightly high self-power consumption, these regulators are excellent quality and fantastic value.

If you are interested in purchasing one of these regulators, click here: LM2596 Voltage Regulators. Prices are around £3.50 each or £17 for five including air mail delivery from China.

LM2596 Variable Voltage Regulator with Built in Voltmeter

Posted on by

We have just purchased one of the voltage regulators pictured below for REUK product testing. This is a variable voltage regulator which will accept inputs of from 4-40V and output a user set voltage from 1.3-37V at up to 2 Amps. (Input voltage must be at least 1.5V higher than user set output voltage)

lm2596 voltage regulator with voltmeter display
This device is just 3.5 x 6.0cm in size and includes a display to 0.1V resolution of the measured input and output voltages AND it costs a hard to believe £3.51 delivered to anywhere in the world from China.

We will add lots of information about this device together with some photos just as soon as we are done testing. For now, here is a link to get your hands on one or more of these LM2596 regulators to test for yourselves.