RL-3331 Emergency Light

RL-3331 is a cheap emergency light from a company with a strange web address http://www.yxdz88.com/

It has 30 LEDs although versions with 60 and 90 LEDs with slightly different model numbers exist.

The package lists specifications as:

Name of Product: Emergency Light
Item No.: RL-3331
Recharging Voltage Rate: AC220V-240V
Battery Voltage Rate: DC 4V
Battery Capacity: 1100mAh
Lighting Source: 30 LED
Duration time: >= 5 hours
Standard No: Q/STLM 0016-2011

As usual for cheap items from AliExpress. Not all these specifications are correct.

Some sellers also sell this item as "with lithium battery" and it is not true. Some list this device as 6W and it is also not true. The item has lead acid battery and LED power is much less....

General Construction

The general construction quality is quite high. The case is very tight and difficult to open even after removing the screws. The board inside has good solder joints, although it looks like it was made by hand. Therefore the quality can vary between units. There are not many component and it is a simple 4.82V transformer with a transistor to switch LEDs ON/OFF.

Charging voltage is 4.82V when the switch is at OFF position, it goes down from 4.82V to 4.76V if the control switch is set to Low or High modes.

Battery

Some sellers advertise this product as with lithium rechargeable batteries. However this is not true. It simply has a 2 cell lead-acid battery. Battery dimensions are 35mm 22mm 96mm

The small black cap can be removed to expose the rubber caps (valves) for this type of battery. It use a mat between the plates so no liquid can leak. After years of use, if the battery becomes weak, you may try to add some distilled water. Usually battery loses some liquid slowly in this type of simple construction.

Based on the 1100mAh specification. I first ran a 1A discharge test from full 4.8V voltage to empty 3V voltage

The battery did go from full to empty in about 42 minutes which totaled to 706mAh capacity. It could have given different results with different discharge currents. However it took over 24 hours to charge back 706mAh back into the battery!

After this test, I have tested the high power mode on the lamp. It took about 1h50m until it dipped under 3V

It is quite visible from the drop on the curve to see when battery was totally empty. However I continued this test much longer just to see what will happen. This also shows that clearly the lamp is much less than 6W as the 1A discharge test resulted in average 3.62V which makes a 3.62W usage. But it was much much more lighter load when you compare the graphs.

The voltage becomes more stable after the first drop but this is the deep-discharge territory and probably harm the battery in the long run.  It is not good to use the lamp over 2 hours on high power mode as this will damage the battery.

The charging back to 4.82V took over 55 hours! Yes, the recovery was really really slow.

The discharge of the light with low power mode results in a much more sensible discharge graph and it achieves about 4h30m before dipping under 3V. So the >=5 hour rating is also imaginary.

I ran the test for an extended period of 7 hours. I do need to get it to recharge for 2+ days for the lead acid battery to recover.

Conclusion

RL-3331 is a cheap product with cheap components. It will probably last about 2-3 years before the liquids inside the lead-acid battery vaporize. The seals are not always 100% airtight. Overall, it is a good product when the price is considered.

Once the battery is empty, you can change it with an actual lithium battery using a lithium BMS. With about 4.8V maximum voltage, you should be able to charge a 4.2V lithium battery fully. Perhaps an 18650 battery with 3000mAh can be installed to improve the performace dramatically. However it is sad that the charging back can take several days with such slow speeds.

VW Golf MK4 Rear Wiper Washer Jet Nozzle Pipe Repair

The rear wiper nozzle was rotating with the wiper arm. I had to open and see what was going on. Apparently the o-ring was broken and stuck between the washer jet pipe and the wiper pipe.

Luckily I checked the issue fairly quickly before it developed a worse problem. In many cases people realize this when the washer jet pipe is broken due to friction as it is not centered anymore without the o-ring. This causes washer fluid to leak inside the rear hatch and break latch microswitch and other things.

There is a repair kit for this purpose with part number 8L0 998 711. But it is as expensive as new motor and also fits only Valeo model as the washer jet pipe is slightly different in Bosch.

 
So, it is best to repair it before it develops a worse problem. Below is a picture of the repair kit but I did NOT use it. But it comes with 1 small o-ring and 2 large o-rings (one is not visible in the picture as it is on the wiper arm shaft already.). I don't know if the large o-rings are same size as the front wiper arm shaft o-rings. But it looks like they are probably same size.

Dissassembly And Re-assembly

Luckily there are only 2 screws and 1 panel to remove to reach the wiper motor. In this Golf MK4 Estate / Variant model. The screws are inside the handles for closing the rear hatch. (philips head screws)

Once the screws are opened, the panel can be removed by pulling out. Use some plastic opening tools and start from the middle and be patient. It is easy to break the plastic pieces on this panel, if panel is removed unevenly (eg. one side pops out with force), as the clips are really tight.

Once the panel is removed, you can access the motor. The only thing to do is to remove the electrical connector by opening the latches using a small flathead screwdriver and the washer fluid pipe by pulling out.

Normally, once the small torx screws are removed. The rear panel should come off quite easily. In my case it was very difficult to pull it out as the o-ring was stuck between pipes and it was very difficult to pull it out. I had to use some flathead screwdrivers to pry it slowly out while turning around.

Above is a picture where the pipe is partially out. Once it goes off a little bit, it is possible to remove the rear plate.

Once it is removed, and it is in good condition. You only need to clean inside the wiper arm pipe before re-installation.

I found pieces of the small o-ring inside the wiper arm pipe. The washer fluid pipe outer diameter is 3.4mm and the wiper arm pipe inner diameter is 4.7mm. I found some 3mm inner diameter (I.D.) and 1mm thickness (C.S.) o-rings from AliExpress and it seemed to be exactly same as the original. So this makes 5mm outer diameter so it fits quite snugly.

I only had half of the original o-ring but I measured it was slightly thinner than the new o-ring. Perhaps years of usage may have thinned it a bit. But when I put them on top of each other, the curve matched perfectly.

As I pulled the inner pipe quite a bit when removing. It seems like it moved a bit out from it's plastic holder. I had to warm it up using hair drier and hammer it back in gently.

As you can see, it fit slightly too long before hammering it. It should normally be flush with the outer pipe.

Here is a picture I took when inserting the o-ring in place. I simply put it on top and push it down using the washer jet nozzle. Yes, it is swimming in bearing grease.

The installation is reverse of removal. It appears there fits 2 o-rings (3 o-rings is about 0.5mm too much!). So I pushed in two o-rings so it is now double sealed. Perhaps better than new?

There is another o-ring which is on the wiper arm shaft but I did not remove it. Perhaps it would be wise to check it also once in a while.

Epson Expression Premium Waste Ink Pad Replacement / Cleaning

Many expression premium printers have similar waste ink pads. Epson has 2 part numbers. First one is 1612118 and the second one is 1611102. You can always use the 1611102 in your replacements. They are often the same price and 1611102 has larger capacity.

Why Epson has two different parts? That is a matter of pricing. The smaller waste ink pad will be filled quicker and you will need to replace your printer more often. Epson has the smaller type in cheaper models, such as XP-540. At least mine had the smaller type.

Removing Waste Ink Pad Container

First you have to start by removing the two black screws holding a plastic trimpiece.

After that, you can simply lift it up and remove. You will gain access to two silver screws under it. Unfortunately I forgot to take picture of them :) The one on the right is deep inside the device so you may want to use a magnetic screwdriver head or a magnetic pickup tool.

After removing the plastic piece, you will gain access to one more screw. One was already visible. You may need to remove the paper tray completely to see it.

In this printer all the visible screws are black and others are silver colored. Once you remove these screws, you can also remove the lower cover piece.

You will gain access to one more silver screw. This screw and one under the device holds the waste ink pad container in place. The screw under the printer is shorter.

You may tilt the printer when doing this. However, ink may leak if container is too full. It should not be too full. But you never know.

The safer way is to put the printer on top a straight table and leave the container outside the table. As you can see, printer's legs are inside anyway.

You need a screwdriver to lift the plastic slightly to be able to pull the ink container down. Once the container is removed, you can clearly see the ink outlet.

Cleaning or Changing The Sponge

Normally all you need is to dry the sponges. Once they are dry, they should be able to absorb nearly as much liquid as they did originally. But you can also wash them.

One important thing to remember is to not give in to temptation of squeezing them. They will be flattened and won't work as well anymore.

The best way to clean them is simply putting them under running water until no ink comes out.

You can then dry the sponges on a heater or let them dry out outside etc. Make sure to not leave them on a surface which may absorb the ink. Because there comes out small amounts of ink even after through rinsing.

The installation is reverse of removal :) Here is the end result.

How Much Liquid Was Inside?

When I removed the ink container, first thing I did was to measure it's weight.

It weighted 148.2g then I weighted the container with washed, rinsed and dried pads again.

The weight is 61.6g. This tells me that the container was holding ~85g of liqud.

Some Experiments

I wanted to figure out if I could replace the pads with another material. The most logical choice was "magic sponge". It is super absorbent and easy to cut into shape.

 It was easy to install them to place.

The original sponge was 3.5cm high. But I used even smaller 3cm high magic sponge setting in my experiment.

First the dry weight. It was 57.2g

I have first filled the container with water, then turned it upside down until it stopped dripping. This way I could estimate how much liquid the sponge could absorb.

Wet weight 153.9g. So it managed to absorb ~95g easily. That is a pretty decent result considering I used a smaller piece of sponge.

By the way, you can literally buy 100 pieces of 10 x 6 x 2 cm sized magic sponge for less than 5euro! The container has six ~1cm thick pieces so you can use 3 sponges for 1 refill!

Below is outline of the pads (not to scale!) the last piece in the drawing is the middle part which has 3 of same pieces. Total number of pieces is 6.

The height of the smaller waste ink pad is 33mm and the container holds up to 58mm safely.

VW MK4 Door Microswitch Replacement

The switch which check if a door is open or not resides inside the door lock module and sometimes it gets broken. Mine stopped working and I was forced to investigate the issue. When this happens, the vehicle does not recognize the door is opened. Eg. there won't be dash warning and the interior lights will not come on when the door is opened.

There are many tutorials on removing the door cart and the panel to reach the door lock. So I will skip those steps.

The Switch And The Problem

Switch is near the bottom of the unit and can easily be traced as blue/red wires go to it.

There are several ways the switch is broken. Sometimes the plunger goes off or the rubber seal breaks down and corrodes inside the switch.

In my case it looked like switch was somehow swollen a little bit and maybe the metal pieces of the lock was slightly deformed. As such, the plunger was not under the lock piece which should press it down. When the switch is half way out, the lock piece is not able to push it down. As can be seen below.

The white part is the seal and black round piece on top is the plunger. It is suppose to be pressed down by the black lock piece but switch is half way out of position.

Whatever the reason, the best solution is to change the switch. There are few types of the switch and few different ways it is installed. Older locks have melted tabs which keep the switch in position where newer locks have latches which allow switch to be removed.

Also there are repair kits. For me the right door switch kit code was 3BD 998 786. I obtained a replacement switch from AliExpress. This switch was the latest model which has a metal piece to support the plunger and increase contact area!

3BD 998 786 comes with crimp butt connectors which allow you to cut the wires and reconnect. However I did not use them.

Seperating Electrical And Mechanical Parts

Lock unit has 2 parts. One part houses all the mechanical parts and other part has microswitches, motor etc. First we must separate these to be able to access the solder points of the red/blue microswitch wires.

First remove the microswitch from the mechanical part. It could be in place by plastic tabs, metal retainer or plastic latches.

Then, you need to remove 2 screws and pull the outside door handle latch completely open. Below are these marked with red arrows.

After removing the screws, you need to pull the door handle latch completely and keep it open.

Now you can wiggle the pieces and separate them.

Removing Circuit Board

The circuit board is inside the plastic box. You need to remove the torx screws around it. There are 9 screws to remove. After this, you can pry open the box. It may feel like it is glued due to the seal inside. However,  you can slowly open it.

Make sure to separate the pieces slowly so parts will not fall out.

Desoldering And Resoldering Wires

The circuit board is covered with some sort of resin for moisture protection. That is why the board and solder joints looks dark/red in the photos.

First settle the board carefully using helping hands.

Now you can melt the solder and pull the wires out.

Once the wires are removed, clean the surrounding area first. Then, you can put the replacement part's wires in place and also use flux for a good connection.

Once the connection is made, you should re-coat the circuit. You can use any kind of non-conductive lacquer for water proofing. But best is to use some sort of conformal coating. I used plastic spray for electronics boards.

Simply, I first masked the area and then sprayed over it. It should be good enough for a while.

Reassembling The Lock

Reassembling the lock is simply reverse of the disassembly. You need to re-attach the microswitch to mechanical piece using the same method as original switch was assembled. Mine used melted tabs, so I had to use plastic weld glue to create tab pieces on top.

Final Result

The switch with the metal helper sits so much better in place and I expect it to work for many years to come. You can see the difference below at door locked and opened positions.

Door locked:

Door opened:

Clearly the new type switch works so much better compared to the older type.

LiitoKala INR18650-25R M 18650 Cells

I have recently bought 6x LiitoKala INR18650-25R M cells and tested them using EBD-M05 tester. These cells are great for replacing old cells fron appliances.Below are the results of all 6 cells. They seem to be reasonably homogenius.

It is interesting to note that I had a LiitoKala LG HG2 cell and even though it is rated for higher current, it had larger voltage sag. Below is the data of HG2 overlayed with green line. It seems like the LiitoKala INR18650-25R. performs slightly better than LiitoKala LG HG2 variant.

Unfortunately I do not have precise equipment to measure the internal resistances. But for most purposes the voltage curve should be sufficient. The batteries got slightly warm at 5A discharge test and no battery got too hot to touch.