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.

Driving down the road today I smelled a plastic/electrical burning smell, which caused me to stop the truck and run around it quickly checking for any problems in my new Leaf modules. After verifying that they were not on fire, smoking, bulging, or even warm, I sniffed around the truck and decided the smell was emanating from under the hood, and eventually traced it to near my DC-2-DC converter (which keeps my 12 volt accessory battery charged up from the main 128 volt pack, replacing an alternator on an ICE vehicle). When I checked on the accessory battery voltage, it was 13.8 volts instead of the 14.5 volts that normally shows up when the DC-2-DC converter is working, so I thought that I had blown that out.

As it turns out, the only thing that had melted was the leg of the 30 amp 12 volt fuse I have between my DC-2-DC converter and my 12 volt accessory battery. Note: the fuse did NOT blow. One leg of the fuse melted into the holder, melting one side of the fuse and the plastic holder. The DC-2-DC converter was still working (but no longer connected to the 12 volt accessory system), and all of the 12 volt components were working fine on the redundant battery power.

At the time this happened I had the headlights and fan blower on, so the 12 volt load was about as high as it gets, but I’d been driving around like that for several years without the fuse or holder giving me any problems.   The only explanation I can come up with is that the process of moving wires around for the Leaf Module install loosened up the fuse in the holder and caused a loose connection, and the added resistance heated the connection up until it failed. (Although the fuse looked to be fully inserted into the holder even after it melted…)

I will have to replace the fuse and holder, and I’ll probably zip tie the new fuse into the holder when I replace it.

As part of the Li-Ion battery upgrade procedure, I needed a charger that could be programmed to work with the Li-Ion modules and my BMS loop system.   I decided on the EVCC (Electric Vehicle Charge Controller) from Thunderstruck Motors paired up with dual TSM2500 ( a.k.a CH4100) chargers. The total system cost just under $1200 shipped, so it was quite economical for a 4.2 kW system. The trade off for the low cost is that you have to wire both chargers up to the battery pack and the J1772 inlet in parallel, requiring you to make two sets of Y adapter cables. Theoretically the EVCC can control up to 4 of the inexpensive TSM2500 chargers, but I think wiring up two is about the most I would want to do, and if you want a high power charger it would probably be better to purchase one or two PFC-3000 or PFC-4000 chargers (which also interface to the EVCC).

I really like the EVCC, as it supports the J1772 protocol and can monitor my mini-BMS loop both for charging as well as for a low voltage warning when running. It also supports the ability to disable the EV when the J1772 plug is inserted (drive away protection).

The first one I received had a few software/firmware bugs that required me to send it back for a re-flash (one of the bugs made it so that the bootloader couldn’t re-flash it in the field!), but after I received the upgraded module it has been working well and I haven’t noticed any more bugs.

I have it set up with a single charge profile so far, but it actually supports 4 charge profiles that can be user selectable via a resistor network on a rotary switch. I have installed the hardware to select different charging profiles and will be programming them in the future.

The two chargers, EVCC and a few relays (for switching between the J1772 port and 120 volt RV inlet) are attached to a piece of wood that fits into the former front battery bay of my S-10 conversion. Althought I COULD fit two more chargers in there, space would get tight, the wiring would be (more) messy, and I’d be worried about the airflow and cooling. As it is, I’ve found that 4.2 kW charging is plenty fast for me. I can take a 16 mile trip, which is much longer than my daily commute, and be recharged in 141 minutes.

I found a Chinese website selling the same charger with a different model number, and their technical specifications were slightly better, so I made a PDF out of the website which you can access here: CH4100-series_more_info