Teardown & Test: Nelson Cougar 60 Electronic Downlight Transformer

You never quite go to Bunnings without leaving with quite a few items. While walking around the aisles, the Nelson Cougar 60 caught my eye.

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This is an electronic transformer designed for use with halogen downlights up to 60 watts. The big surprise, at least for me, is that a single transformer is being sold for AU$7.86 at retail, with ten packs at AU$61.98. You can even get a version with a plug and lead for use with GPOs for AU$10.33. There are also Osram Redback 40VA units available for a little more, and higher-end Nelson “tradesman” models. I remember when electronic transformers were much more expensive than this, which was why I never really ever played with these units. As a result, I decided to throw some money at it, despite not really needing it, just to see what ~$8 gets you.

The Item

The unit itself is very small, about palm size. I’ve never met a transformer lighter or smaller. That’s what technological progress brings you!

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It has a two tone curved plastic motif, which is pretty trendy for something that’s virtually never seen and should never be heard. The model and specifications are printed on the top, although slightly blurred. It has a high power factor rating of >0.99. It claims a level III efficiency rating (>=84% under load with <=0.75W idle), which isn’t as efficient as it could be. The output is unusual, as it claims to be 12.5v (a little higher than 12v) which is the opposite of most transformers, which put out a little less than 12v to ensure longer filament life. The unit is dimming compatible, with trailing edge dimmers.

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The secondary contacts are left open at the end to the outside, whereas the primary contacts are enclosed by a plastic screw-down cover, which also has side “click” latching. The cover needs to be pried off to install the cable initially.

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The opposite side is marked 15W04 230, which may be a specific model number.

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A flat base is provided for mounting against flat surfaces. No ribbing or elevation is provided, which implies that the transformer doesn’t put out much heat. Two screws are used to hold it down – one fixed end, and the other as a slot to accommodate slight drilling errors. The design is a simple plastic casing with no screws used in the construction.

Teardown

The unit comes apart once you remove the mains cable cover, and then pry around the white to blue plastic seam, where four “clips” are used to hold the cover down. Internally, the PCB is wrapped by a plastic insulating sheet.

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The PCB is a single layer paper type PCB, with green solder resist and limited silk-screening on the underside. The solder joints on the underside look very consistently made. A clear demarcation between primary and secondary is visible. The PCB is marked ET60W-5.

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From the top, we can see there are no heatsinks and no ICs throughout the design. There are two main transistors, and a pair of transformers (one primary/secondary, and a feedback) which are responsible for the operation of the device. To support this, there are a handful of diodes, resistors, capacitors and a single transistor.

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The input appears to be protected by a fuse wrapped in heatshrink, and an inductor provides some RF filtering.

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Components near the edge of the PCB are covered with a woven tube for fire protection.

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The output has a very unusual winding. For double-insulation isolation reasons, the inner winding is separated from the outer secondary by a plastic shell, and exceeding requirements, is the use of insulated wire for the outer winding. This loose coupling may be part of the reason for a slightly lower efficiency than expected.

Output Waveform

When the transformer is powered with no load, it makes an audible buzz. Checking the output shows a spiky output which follows the mains envelope, much like the Osram Redback transformer, but with a limited peak voltage of about 14v and an AC RMS value of 3.48v.

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Unloaded, the individual spikes seem to cycle at a rate of 5.5khz, and shows a characteristic “ringing” style waveform that you might find from a ringing choke converter, which gives you an idea of the simple regulation method used.

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Loaded with a 50W (nominal) halogen downlight globe, the transformer performed superbly, producing an average of 12V RMS AC over the globe – perfect.

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Of course, this means a peak voltage of about 18v, but this is of little significance as the filaments of the globe are more sensitive to the RMS value which is accurate – although less than the claimed 12.5v. With the correct load, the converter “rings” quicker at 51.72khz. The waveform resembles more of a square wave.

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Reducing the load with a 10W Philips LED replacement, the transformer still ran without audible noise, and the LED globe seems to work happily. The output from the transformer seems to contain taller spikes with ~25v peaks. This is why marrying electronic transformers with LED replacements can sometimes result in unexpected failures.

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The waveform oscillates even quicker at 66.86khz, with two components to it. It is nice to see that it works though.

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Conclusion

This electronic transformer seems to behave similarly to the Osram Redback 60VA transformer I tore down before. For the price and weight, electronic transformers are a marvel. There isn’t even a single IC in the design, which reminds me of the ballast designs of CFLs. Their output, however, is more unpredictable from a waveform and frequency standpoint, so it isn’t that useful for repurposing. That being said, for ~$8, it definitely works, and only buzzes when unloaded.

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Review & Test: Philips LEDbulb B22 14w 1400lm LED Globe

Sometimes you need to solve your own problems around the house, and the best place to visit is a hardware store. Just last week, I took a trip to Bunnings, and I couldn’t resist surveying their array of LED light globes. While consumers are still at a cross-roads when it comes to the CFL versus LED debate, LED technology and prices have continued to improve.

The Product

20150524-1217-5259Since I purchased my first set of Philips LED globes from Woolworths, it seems that Philips’ product line-up has improved. The 13W globe offered 1055 lumens, resulting in an efficacy of 81 lumens per watt, the new 14W LEDbulb offers 1400 lumens for an efficacy of 100 lumens per watt.Of course, these numbers continue to improve with each generation, as the efficiency of LEDs continue to improve. This is great news for those looking for a little more light than the original LED globes could offer.

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Of course, Bunnings has other LED globes on offer as well, many of them in smaller power ratings. The other LEDs are mainly from Osram which top out at 10.5W. As someone who is looking for higher powered globes, this wasn’t of much interest.

I purchased two samples of the bayonet cap (B22) mount globes, at AU$18.99 a piece, in order to cover the rest of the house as we have a mixture of fixtures. This is a bit pricey compared to CFLs, but still not out of the reach of individuals.

As seems to be common with LED globes, the choice of colour temperature is limited. Bunnings only stocks Warm White 3000K globes at 14W in both BC and ES, but also stocks a Cool Daylight 6500K 14W globe in ES only.

The claims made on the packaging haven’t changed much, with an 80% claimed energy saving and up to 15 year lifetime. It also claims light “equivalency” to about 90w.

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20150524-1218-5263The packaging has only suffered subtle changes, with the globe having a claimed lifetime of 15,000 hours, which is a little bit on the low side when it comes to LEDs. This may be due to the lack of external-facing heatsink, which is enclosed within a plastic shell, and due to their conservatism. The Warm White 3000K is slightly less warm compared to the 2800K offered by the IKEA globes. There is a change which claims you should use in >4″ diameter downlight, as opposed to 3″ previously. The globe remains non-dimmable, and is Made in China.

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From the outside, the globe appears the same as the 13w version, with an elongated enlarged shape resembling that of an old GLS globe. Due to the larger size, it may not fit in all fittings. When picked up, the globe feels a little on the lighter side compared to the IKEA 13w globes, which may indicate a slightly smaller metal content, implying a smaller heatsink.

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As expected, the branding and specifications are printed around the neck in grey. It is claimed to operate on a 220-240v range at 50/60Hz, drawing 80mA. Due to the shape of the globe, it seems that the globe is best used on light fixtures where the globe is mounted with the base up, so the diffuser points right at the ground.

As our dwelling uses a vast array of oyster alabaster fixtures, I had to forego the alabaster cover altogether because the globe would not physically fit otherwise. As it turns out, because of the sideways mounting, the lighting in one half of the room was much more than the other half. As a result, I handmade a right-angle adapter based around a short piece of flex, a suspension bayonet cap holder and a bayonet cap adapter, like a very short suspension kit.

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This allowed for a much better light utilization, although with a little glare due to the directness of the light despite the integrated diffusing dome. The light output was relatively impressive – I didn’t note any issues with flicker or brightness, and the colour temperature was as expected. However, the colour rendering index was not stated, and I didn’t have the equipment to measure it, but a difference in colour rendering was noted which made the light appear a little stark and colder, so I’d probably guess a CRI of >82.

Electrical Performance

The performance of the previous 13w globe was relatively middle-of-the-road, showing a loose regulation where the power consumption is strongly dependent on input voltage. The power factor was about 0.8, which is higher than a poor quality CFL, but hardly as good as it could be.

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The new globe improves upon this performance somewhat, with a higher power factor of about 0.9 across a broad voltage range. The regulation is still relatively lax, with the power consumption still strongly related to the input voltage. The claimed 14W is a bit of an under-rating with the consumption about 14.1W at 220v, 14.4W at 230v and 14.8W at 240v. As a result, it’s probably more of a 15W globe.

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From the voltage range being “shrunk”, it seems likely this globe consists of more LEDs connected in a series string, rather than less LEDs connected in a series-parallel arrangement. It also seems likely that the current driver design has changed.

As I don’t have the equipment to measure absolute light output, CRI and colour temperature, these parameters cannot be determined.

Conclusion

While LED globes at retail are being sold at high prices that make their prices difficult to justify based on their claimed lifetimes, it’s always nice to see that they are being offered as an alternative. LEDs reach full brightness instantly, and suffer very little from power on-off cycles which can be very desirable, and the lack of mercury is a positive for the environment.

It seems that Philips has improved upon their former design with a higher power factor current driver, and a much improved efficacy (+23%) at a similar price-point. The current driver does a lax job of regulating power consumption over different line voltage conditions, but doesn’t seem to have any flicker issues. The short claimed lifetime may be down to conservative estimates, or the use of an “enclosed” heatsink with low metal mass, which makes purchasing LEDs for their longer lifetime an unclear proposition.

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Teardown: Genuine Asus A32-1015 Li-Ion Netbook Battery Pack

Normally my teardowns involve taking apart dead compatible replacement batteries, but this post is a little different. My latest netbook, an Asus eeePC R011CX seems to have developed a fault whereby the battery detection is intermittent. When charging from the mains, the battery sometimes shows up, and other times doesn’t. When running from the battery, it likes to shut down as soon as it’s moved.

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I reasoned this points to a broken solder joint where the battery connector meets the motherboard or the connector on the battery itself. As the R011CX is a pain to take apart, and the unit’s useful lifetime is very limited, I decided against fixing it. It’s a 24/7 low-powered server at the moment, so the loss of the battery is hardly a show-stopper as it will run happily off the AC adapter alone. The battery did feel just fine though. Given it was produced in 2012, its time is pretty much up.

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This left me with a battery that I had no use for. I couldn’t be bothered to try selling a second hand genuine battery, as it wouldn’t fetch me much money in return anyway. As a result, I decided to tear it apart so that we can see the difference in quality between properly engineered batteries, and the “cost sensitive” replacements.

Taking it Apart

Unlike the low cost replacement batteries, taking apart a genuine battery involves a higher level of difficulty. It took a lot of strategic prying with a flat-head screwdriver to get the case halves apart, which also involved copious amounts of damage to the case and a slight nick on my finger.

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The top cover is now separated from the bottom, but the internals are still firmly stuck in place. On most compatibles, it only takes a slight nudge to convince the pack to “release” from the case, but in this case, it seems the cells are siliconed into the back. A bit more strategic prying finally released the whole assembly from the rear shell, although with a lot of damage to the rear.

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In addition to a tight-fit design and silicone at the ends and at the rear corner causing damage to the green battery heat-shrink, there was also a line of double-sided adhesive running down one of the cells holding it into the rear.

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The assembly itself uses high quality Panasonic CGR18650CG MH12210 2250mAh Made in Japan cells, resulting in a total capacity of 4500mAh which is a little more than the 4400mAh marked on the outside, probably because it takes into account a 50mAh tolerance in capacity of the cells – the markings on the outside are conservative, what a breath of fresh air!

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The unit itself avoids wires, with only the ground of the pack being connected by relatively thick wire. The intermediate cell balance connections are made by solid tab connections, insulated by paper labels, and soldered directly to the PCB. This makes the construction very rigid.

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As expected, there is a pack thermistor for safety and charge termination purposes. With some judicious use of sharp side-cutters, I finally liberated the main PCB from the battery pack.

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The PCB is marked with SXP2361 2226A1C BLA4AE01 123A. The PCB has strategic “dabs” of potting compound placed over circuitry to protect it from environmental influences. This side contains the main pack controller. We can see the 0.005ohm sense resistor very close to the power connector.

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The underside is marked with ETON ET866, date code Week 7 2012 with UR code E213441. More soft potting compound can be seen, with additional chips on the underside and a secondary protection current/thermal fuse which should kick in, should all else fail. This is considered an essential form of protection, omitted in most compatible batteries.

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Scraping away the potting compound reveals the battery controller is a Maximum MAX1786A. This claims that the MAX1786 is a MAX1788 with a Panasonic specific ROM.

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In what seems to be a space-saving and convenience related move, the fuse was mounted over a pair of TPC8117 P-channel MOSFETs. I suppose the fuse could possibly save the pack in case any MOSFETs burned through and an abnormal charge/discharge condition occurred.

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Of course, there are a few more semiconductors scattered about, with vague markings. Anyway, lets look at pack construction, where we are in for a little surprise too.

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Two different types of tabs between cells were used – one which folds vertically, and the other folding horizontally. Spot welds were extremely clean, and tabs were pretty much right for size.

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There was also a spacing insulating “pad” between the cells, even though they are being connected at the same potential – I’m not sure but possibly the thin parts of the tabs could be acting as secondary fuses, or it’s a measure to avoid friction or corrosive cell vent products from eating away at the base of the next cell.

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As expected for a pack that was not in trouble, all cells were very close in voltage.

Conclusion

The teardown of the genuine Asus laptop battery confirms what we all know – the original OEM batteries are built to higher standards than the compatible cells. The outside labelling is accurate when it comes to cell origin, and conservative when it comes to cell capacity. The physical build of the battery is very strong, and hard to disassemble, with everything fitting in snugly. The cells used inside are quality Japanese made Panasonic cells, with good quality pack construction, and a controller PCB that includes a secondary protection fuse which is often omitted in aftermarket compatible designs.

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