LTO (Lithium Titanate Oxide) – The Ultimate Battery for Dash-Cam parking mode (DIY)

[EricSan]

Still running strong at the end of a hot (50-54c in the trunk), sunny day! . Even my radar detector thermal protection function turned itself off shortly after I started the car…

 

[GPak]

For what it worth, I tested the Charger at 16A charging rate.
I completely discharged my 230Wh, 5S LTO Battery and then charged it from zero to full at 16A.
The average charge rate was about 195W.
The orange light stayed on from start to about 12.1V (2.42V per cell), then turned off.
The charger was 92% efficient from start to finish, regardless of the orange light state.
The temperature peaked at 105°C, the hottest part being the inductor, the grey box on the charger.
Unless I am missing something, I can confirm that the Fan doesn’t work, I even unplugged the fan and checked two pins with voltmeter to rule out bad Fan.
Conclusion:
The 16A/200W charging rate requires active cooling/fan, and possibly an additional heatsink, and even some baffling to direct hot air away from the battery cells.
I think that the more suitable maximum charging rate for this charger would be around 12A max/150-170W max, for 5S-6S LTO accordingly.

 

[mentadent]

150 watts is still badass.

 

[EricSan]

Thanks for the charging heat data! 105c is pretty hot! Bummer that the fan control doesn't seem to work (a previous suspicion). Given the configuration of this charger, it is supremely easy to attach a heat sink to the already drilled and flat aluminum cooling plate. I didn't think to check mine, but I'm presuming that the aluminum backer plate is electrically isolated from both the +V and the Ground power supply lines. If this is indeed the case (I suspect it is), all that is required is to cut a hole in the box that is the same size as the charger board, mount the charger directly to a larger heat sink with some thermal paste and a few screws, and affix the sink to the outside of the box with a new set of screws. This will allow for passive cooling on the outside of the box using a sink that is much larger than the size of the charger board. This should dramatically lower the thermal rise of the charger board.

For a forced-air cooling approach, I'd look for a small aluminum finned "heat tunnel" (hollow, aluminum, rectangular tube) so the charger could be mounted to the "side" of the tunnel and a fan can be mounted to one of the open ends of the tunnel forcing airflow through the tunnel and out of the box. The fan should be a 12v fan than runs from ACC power in the car, so it only runs while charging. Setting up the fan to "push" air through the tunnel (as opposed to pulling) should help mitigate impacts of overheating the fan while it runs.

 

[EricSan]

I completely discharged my 230Wh, 5S LTO Battery and then charged it from zero to full at 16A.

Did you happen to capture the charge time at 16A? Curious to know how fast you went from flat to full…

 

[EricSan]

JK just released a new app version for their BMS. Didn’t restore the auto smart sleep function