Category Archives: Projects

Craft, Hardware, or Software projects I’ve done

TSM2500 (CH4100) Chargers Overheating

Posted on by
3

Twin Chargers in Box

Now that it is summer, and outside temperatures are reaching 26-35 C (80-95 F), my dual TSM2500 (Rebranded CH4100) chargers are overheating. After about an hour charging at full power, they reach around 74 C (165 F) and shut down. The ThunderStruck Motors EVCC records this as a “normal” end charging event (because the Amperage output goes to zero), and for some reason it triggers a ground fault on my EVSE (perhaps they have a thermal switch that shorts the charger to ground to shut it down, or maybe my JuiceBox Pro 40 is just overly sensitive?)

I guess the overheating is to be expected, as the chargers are in a five sided box (with only the top open) and mounted to a piece of (thermally insulating) plywood. Although there is a tangle of wires in front of them, the wires really don’t interfere with the airflow as much as it looks like from this top view.

In my defense, the charger’s manual (v. 1.05) specified that I should leave a 50mm (2in) gap in front of the charger for proper ventilation and I left around 8 inches. It also noted that the “Working temperature” for the chargers was -25 to 55 C (-13 to 131 F). It didn’t mention anything about thermally bonding the charger to a heatsync.

As a temporary solution, I have re-configured my 80% charging profile to only run at 1.2 kW (8 amps total, or 4 amps per charger on a 128-131 volt pack). This is about 25% of the 15 amp max power that the chargers are capable of in cold weather. At this relatively low power, each charger is outputting just over 500 watts, and even in 32 C (90 F)   weather the charger temperature hold steady at 50 C (122 F).

Charging at one kW may not sound terribly fast (it’s not), but this workaround is actually fine for 95% of my charging needs, as I rarely need to refill more than 8-10 kWh (20-30 miles) per day of use, and L1 charging overnight works fine for most of my needs.

However, I purchased the dual charger setup so that if I was necessity charging away from home I could charge at a 4 kW rate, so I want to make improvements to my cooling so that I can run the chargers at full power (without them overheating after an hour) if needed.

ThunderStruck Motors suggested that I mount the chargers to an aluminum heatsync, which is a good idea, but difficult and costly to implement.

I have decided my first order of business is to drill two 4″ air intake holes into the bottom of my charging enclosure and duct them to the top of the chargers right over the fan using dryer hose. This will allow the fans to draw cool(er) outside air directly over the vanes on the charger, and keep the heated exhaust air from mixing with the cool(er) incoming air. Since the top of the box is open, the heated output air should have no problems escaping, as convection will assist the fans in exhausting the hot air upwards.   If adding intake air vents doesn’t solve my problem, then I’ll worry about making an alunimum heatsync plate to take the place of the plywood.

Scantek 2000 CNC Lathe – First cut with LinuxCNC

Posted on by
Reply

I converted my Scantek 2000 CNC lathe to work via Parallel port control (for Mach3/LinuxCNC software control) and have been learning how to hand write gcode (because the Linux compatible CAM lathe software options are not terribly good).

IMG_20160415_220855

Unfortunately, the LinuxCNC   software doesn’t support many of the automated cycles (G71 I’m looking at you!) for lathe turning (yet!), so I had to write up a gcode file with many manual G1 passes to cut down the cone shape you see here.

IMG_20160415_220832

Instead of hand coding the whole thing, I wrote a small python script that automated the gcode generation, which takes 0.2 mm passes off the stock, stopping 0.5mm shorter each time from 10mm down to 5mm radius. But I did the first few by hand….

Here is a video of the process in action:

And below is the full gcode file for those who care….

Continue reading →

Monster UPS just got bigger….

Posted on by
Reply

A few years ago I built a Monster UPS using an RV Inverter/Charger and two golf cart batteries.   Seeing as how I have a lot of extra golf cart batteries just hanging around, I upgraded it to use eight GC2 batteries (that’s 720 AH x 12 volts, or 8.6 kWh when new). Because more is better, right? (Except for the 500 lb system weight…which is probably getting close to the capacity of the steel cart I’m using to make it semi-mobile.)

IMG_20160327_143204

Continue reading →

MicroMill Mach3 / LinuxCNC conversion complete

Posted on by
2

I have mounted the parallel port break out board inside the enclosure of my ScanTek 2000 (Denford Micromill). I routed the parallel port cable out to the previous DB25 (RS-232) outlet on the case and sealed up the back.

bob_mounted

With the built in wire management trays, the job looks almost professional…except for the fact that I used a triangular piece of 1/4″ acrylic scrap I had for the mounting plate, so I had to orient the break out board at an angle. But since it’s inside the case, nobody can see it anyways. bob_mounted_closeup

 

parallel_port_cable_inside_panel

Outside the case, the only visible difference is that I took off the black “RS-232” sticker that used to live next to the DB-25 connector. Continue reading →

How far can it go?

Posted on by
4

Summary: I drove my truck 46 miles on one charge (and had some juice left over).
Instant-1457835710687

When you have an electric vehicle, everybody wants to know how far it can go.
I typically tell them “19,800 miles so far.”

But then you have to answer their real question, which is “What’s your range on a single charge?”. If you have a commercial EV like the Leaf or a Tesla, you can just refer to the EPA range figure for a nice apples to apples comparison. But when you have a conversion EV, the number is unique to your particular vehicle, motor, controller, battery pack and testing methodology. (And changes as the pack ages…)

I used to know the answer to that question for my truck with a (new) lead acid battery pack (“25-30 miles without killing the pack”), but I haven’t fully characterized the trucks’ power usage and range with the new (lighter weight, more powerful) pack made up of Nissan Leaf cell modules. My truck is heavier and has more air resistance than a stock Nissan leaf,   the motor/controller is slightly less efficient, and the (big fat!) tires have quite a bit more rolling resistance. I figured “half the range of a Leaf” would be a good ballpark estimate.

Continue reading →

Upgrading a 5 gallon portable compressed air tank

Posted on by
2

IMG_20160312_140530

I was given this 5 gallon portable air tank, but you can purchase them from Harbor Freight or Northern Industrial in the $30-35 price range. It is filled with a car tire (Schrader) valve and has a built in pressure gauge, overpressure release valve and car tire fill hose.

I have a small garage compressor. It is a 1.3 HP compressor that provides 2.4 SCFM at 90 psi, which is reasonable if you need to blow stuff off, drive the occasional air wrench, or do some light spray painting, but not a very high output. It only has a 1.5 gallon tank, so if you start using a lot of air it doesn’t last long.

IMG_20160312_144129

My plasma cutter wants 6 SCFM, which is more than the compressor can provide, but I only need about a 10% duty cycle.   (make a cut, then move the metal, re-clamp it, set up a straightedge or jig for the next cut, etc…)

IMG_20160312_141338

I bought some items in the tools / air-compressor isle at Home Depot to add the ability to attach the 5 gallon tank between my small compressor and the plasma cutter using standard quick connect fittings. The air fill hose that comes with the tank is mounted with a standard 1/4″ NPT connector, so all I need to buy was a T, a ball valve, a quick connection package, and a male to male adapter. I had to screw the pressure gauge 90 degrees to get room for both ends of the T.

IMG_20160312_143730

One end of the T goes to the ball valve and the quick connect fill connector. This side is connected to the air compressor and allows the tank to be filled by my small compressor and to act as an air buffer. The other end of the T goes to the female quick connect adapter, allowing me to plug in any standard QC hose. I included the ball valve so that I could close it and disconnect the tank from the compressor and have it remain full, although primarily I’ll be using the tank “in-line”. The cost of these parts was $15, or about half the cost of the tank if you bought it new.

IMG_20160312_143741

Here is a video:

ScanTek / Denford Micromill 2000 bent spindle motor bracket

Posted on by
Reply

spindle_motor_at_angleWhen I purchased the ScanTek 2000 Scan Mill (A rebranded Denford Micromill) from a surplus supply house, the spindle motor was at an odd angle and the drive belt had frayed (probably due to the angle).

When   I took the motor off, it was clear that the problem was a bent bracket.
bent_original_bracket
Since I needed to purchase a new drive belt ( Sherline PN 40040   – $9) I decided to just buy a new Sherline spindle motor support bracket (PN 40020 – $7 ) at the same time because it was relatively inexpensive.
Continue reading →