Water Cooled Batt Pack

[TCMB371]

Being able to start every moto with the pack at basically early morning ambient temps (60-70F) is a game changer for me. I usually don't hit the thermal limit on the first moto out in the morning (cold pack and cooler air temperatures). Its after rapid charging + higher ambient temps on my second moto and each moto thereafter where ill hit thermal limit, especially on really hot days. Not to mention charging is initially slower after coming back from a moto since the pack is warm and the charging logic limits max amps until the temps come down.

Id be curious to see if there's any benefit in regards to temperature distribution/gradient throughout the entire pack with the second plate added. Id imagine the heatsink effect from the metal shell + the water cooling setup would help equalize the temperatures across all of the cells (middle cells vs perimeter cells), which should theoretically help with cell life as well.

You touched on it a little, but id be curious if the radiator setup is even worth it. Perhaps precooling the pack is enough to prevent limiting and one could just drain the system before the moto and let the passive heatsink cooling do its thing. Would essentially eliminate the weight penalty when riding, where it matters.

What are the power requirements of a water chiller like that?

 

[Mark911]

That particular chiller is 110v about 6 amps, but I'm sure you can get them in other formats. I can run both my charger at 220 and chiller on 110 off my B&S generator. This chiller can generate major pressure so I had to bypass a significant amount of flow to keep pack pressure around 2-3 PSI. It can easily service two, maybe three packs simultaneously volume wise and I'm pretty sure based on the amount it cycles the refrigerant compressor it'll do two packs temperature wise as well (ie; keep the cold plates at or around 10-15C).

I think for hot summer chilling without the radiator will be sufficient for typical moto (15-20 mins). Colder days the radiator might be sufficient without chilling and is obviously better for longer rides. It's all about the difference between pack and ambient temperatures.

Another interesting observation, to add onto what Bryan mentioned, was that I did see a significant difference in module voltages while charging during the above test. The 2 cooler/being chilled modules charged faster, to the point where it was toggling on/off a module to module voltage difference fault. Luckily, everything balanced out by the end of the charge cycle.

 

[testus191]

Mark, what size of plate and what size of fittings did you use to build the cold plates? Also, what is the thermal interface from the cells to the cold plate? Are the cells touching the plate and conducting the heat out or does it transmit the heat via radiation? Maybe its conductive through some sort of insulating layers? Very cool build, curious if you've done anymore work on this.

 

[Mark911]

Mark, what size of plate and what size of fittings did you use to build the cold plates? Also, what is the thermal interface from the cells to the cold plate? Are the cells touching the plate and conducting the heat out or does it transmit the heat via radiation? Maybe its conductive through some sort of insulating layers? Very cool build, curious if you've done anymore work on this.

Those are design details I just can't share right now. Hope you understand.

 

[Vextrek]

Awesome project. Thanks for sharing information.