Posted on Leave a comment

nb Tanya Louise – Gas Locker Corrosion Part 1 – Removing The Old Locker & Replacing the Deck Plate

Severe Corrosion
Severe Corrosion

This is a part of the boat that hasn’t really had much TLC since we moved aboard, and finally it’s completely succumbed to corrosion, opening a rusty hole into the engine space below. I’ve already used a grinder to remove the rest of the locker – and even this had corroded to the point of failure all around the bottom just above the welds. The bulkhead forming the rear of the locker has also corroded fairly severely, so this will be getting cut out & replaced with a new piece of steel.
This was originally a 1/8″ plate, but now it’s as thin as foil in some places, with just the paint hiding the holes.

Replacement Steel
Replacement Steel

I’ve cut out as much of the corroded deck plate as possible –  it’s supported underneath by many struts made of angle iron, and got the new 3mm replacement tacked in place with the MIG. I’ve not yet cut out the rotten section on the bulkhead, this will come after we’ve got the steel cut to replace it, as electrical distribution is behind this plate – I’d rather not have weather exposure to the electrical systems for long! Unfortunately more corrosion has showed itself around the edges of the old locker:

Thin Steel
Thin Steel

Around the corner the steel has pretty much totally failed from corrosion coming from underneath – applying welding heat here has simply blown large holes in the steel as there’s nothing more than foil thickness to support anything.

Some more extensive deck replacement is going to happen to fix this issue, more to come when the steel comes in!

Posted on Leave a comment

ELuc BLU4 Intelligent Lithium Battery Charger W/Bluetooth

BLU4 Battery Charger
BLU4 Battery Charger

Here’s another battery charger designed for lithium chemistry cells, the BLU4. This charger doesn’t display much on it’s built in LCD, apart from basic cell voltage & charging current limits, as it has a built in Bluetooth module that will link into an Android or iOS app.

Above the charger is operating with 4 brand new cells, at a current of 500mA per cell. If only a pair of cells is being charged, the current can be increased to 1A per cell.

LCD
LCD

Not much in the way of user interface on the charger, a tiny LCD & single button for cycling through the display options.

Dataplate
Dataplate

The usual stuff on the data plate, the charger accepts an input of 12v DC at 1A.

Bottom Cover Removed
Bottom Cover Removed

Removing the 6 screws on the bottom of the casing allows the board to be seen. Not much on the bottom, the 4 cell negative connections can be seen, with their springs for adjusting for cell length.

MOSFETs
MOSFETs

There’s a couple of P-Channel FETs on the bottom side for the charging circuits, along with some diodes.

Main PCB
Main PCB

The main PCB is easily removed after the springs are unhooked from the terminals. Most of the power circuitry is located on the top side near the power input. There are 4 DC-DC converters on board for stepping the input 12v down to the 4.2v required to charge a lithium cell.

Second Controller
Second Controller

Not entirely sure what this IC is in the bottom corner, as it’s completely unmarked. I’m guessing it’s a microcontroller though.

DC Input Side
DC Input Side

The top left of the board is crammed with the DC-DC converters, all the FETs are in SO8 packages.

DC-DC Converters
DC-DC Converters

One pair of DC-DC inductors is larger than the other pair, for reasons I’m unsure of.

Bluetooth Module
Bluetooth Module

Bluetooth connectivity is provided by this module, which is based around a TTC2541 BLE IC.

Microcontroller
Microcontroller

Below the Bluetooth module is yet another completely unmarked IC, the direct link to the BLE interface probably means it’s another microcontroller. The Socket to the left of the IC is the connector for the front panel LCD & button.

LCD PCB
LCD PCB

There’s not much to the LCD itself, so I won’t remove this board. The LCD controller is a COB type device, from the number of connections it most likely communicates with the micro via serial.

Posted on Leave a comment

Chinese CO Meter – The Sensor Cell

As the CO meter I bought on eBay didn’t register anything whatsoever, I decided I’d hack the sensor itself apart to make sure it wasn’t just an empty steel can. It turns out that it’s not just an empty can, but there are some reasons why the thing doesn’t work 😉

Cell Disassembled
Cell Disassembled

The cell was crimped together under the yellow shrinkwrap, but that’s nothing my aviation snips couldn’t take care of. The photo above shows the components from inside.

End Cap
End Cap

The endcap is just a steel pressing, nothing special here.

Filter
Filter

Also pretty standard is the inlet filter over the tiny hole in the next plate, even though it’s a lot more porous that I’ve seen before in other sensors.

Working Electrode Components
Working Electrode Components

Next up is the working electrode assembly, this also forms the seal on the can when it’s crimped, along with insulating it from the counter electrode & external can. The small disc third from left is supposed to be the electrode, which in these cells should be loaded with Platinum. Considering where else they’ve skimped in this unit, I’ll be very surprised if it’s anything except graphite.

Counter Electrode
Counter Electrode

Next up is the counter electrode, which is identical to the first, working electrode. Again I doubt there’s any precious metals in here.

Backplate
Backplate

Another steel backplate finishes off the cell itself, and keeps most of the liquid out, just making sure everything stays moist.

Rear Can & Reservoir
Rear Can & Reservoir

Finally, the rear of the cell holds the reservoir of liquid electrolyte. This is supposed to be Sulphuric Acid, but yet again they’ve skimped on the cost, and it’s just WATER.

It’s now not surprising that it wouldn’t give me any readings, this cell never would have worked correctly, if at all, without the correct electrolyte. These cheap alarms are dangerous, as people will trust it to alert them to high CO levels, when in fact it’s nothing more than a fancy flashing LED with an LCD display.

Ironically enough, when I connected a real electrochemical CO detector cell to the circuit from the alarm, it started working, detecting CO given off from a burning Butane lighter. It wouldn’t be calibrated, but it proves everything electronic is there & operational. It’s not surprising that the corner cut in this instance is on the sensor cell, as they contain precious metals & require careful manufacturing it’s where the cost lies with these alarms.