First impressions of BlackboxMyCar Powercell 8

[NotThatGuyThatOtherGuy]

I just had my installer install a BlackboxMyCar Powercell 8 to power my new Vantrue N5S with LTE module that he also installed.

The installer complained that the battery does not have any holes for installing it and only came with two strips of double-sided tape. This limited where he could install it to my 2023 Suburban, and he put it under the carpet below the passenger seat vent. After some driving with it during a summer heatwave, the temperature reported by the app is 58°C. This is well below the stated discharge maximum temperature of 70°C, but well above the stated maximum charging temperature of 45°C, so I'm going to have to find a different install location and have it moved, which seems less than ideal.

The app doesn't allow me to set the temperature units to Freedom.

Overall, the installer didn't have any other issues relating to installing the unit or connecting to the Vantrue system. He did recommending using the lower charge rate due to the fact that I'm running the vehicle all day long, so recharge time will easily recover the battery charge.

 

[kamkar]

I will have to agree on if possible, a slower charge should be used, i have never speed charged my electronic pocket turd, it get a little slow charge when i drive in my car, which like my use of the phone is not often.

The freedom units of speed / weight / length, well to me it seem like more of slave units these days as so few countries / people use them, and most inherited them from their once British masters that they either overthrow or at some point just packed up and left.
In my shooting hobby i sadly cater to the people on the ancient system, i really should not do that, but i do use fps and fpe and grains when i should use M/s - Joules and grams.

If i was Ukrainian for instance i would be all for ditching the Cyrillic alphabet as it is shared with absolute crackpots to the north, that once ruled Ukraine brutally.
Even if this is at least as big a jump as changing measurement system.

I had my 70mai power pack in my glove box in the old car, i am tempted to put it in the same place in the new car as there seem to be terrible access to below the dash / firewall.
Under a seat could also be a option of course, i maybe have people on the back seat 1 day of the year, and it is not anyone with feet like Goofy.

 

[Hack_man]

If I had to purchase another external battery it would hands down be the Viofo BP100 vs the Powercell 8.
I own both.
The PC8 self discharges 8% per day with no load. Perhaps I got a dud. The BP100 loss is less than 1% per day.
The BP100 processes warranty claims via a US address vs Canadian for the PC8.
The BP100 has a much better bluetooth range and also can receive OTA firmware updates.
Last I checked, the BP100 was less expensive.

 

[kamkar]

I just dug out my 70mai power pack, that been out of a car for a while, it was fully charged when i took it out a good month ago, but there is nothing on it now,
I think to be safe i will charge it here at home before i move it to the new car.

Just to be safe, as a old RC freak i have seen NIca batteries and lipo go kaboom and Poof in the case of lipo.
Mind you never see a LiFe battery go off.

But i recon it will be a while before the plug i ordered will arrive, holiday time here in Denmark ATM

 

[Hack_man]

I just dug out my 70mai power pack, that been out of a car for a while, it was fully charged when i took it out a good month ago, but there is nothing on it now,
I think to be safe i will charge it here at home before i move it to the new car.

Just to be safe, as a old RC freak i have seen NIca batteries and lipo go kaboom and Poof in the case of lipo.
Mind you never see a LiFe battery go off.

But i recon it will be a while before the plug i ordered will arrive, holiday time here in Denmark ATM

Well that is interesting. Evidently my PC8 is not the only LiFeP04 battery that self discharges over time.

 

[NotThatGuyThatOtherGuy]

The PC8 self discharges 8% per day with no load

My first several days with a standby mode not enabled on the camera the battery was at either 99 or 100. The app reported a load at 63 mA, which I'm assuming is the LTE module.

All battery chemistries will self-discharge, but the amount varies by chemistry and materials used (e.g., lead-antimony plates in lead acid battery will fully self-discharge in 3 months vs. lead calcium plates at 6 months, silica gel electrolyte at 12 months, and pure lead plates at, IIRC, 24 months).

 

[Hack_man]

My first several days with a standby mode not enabled on the camera the battery was at either 99 or 100. The app reported a load at 63 mA, which I'm assuming is the LTE module.

What exactly was the powered state of your camera when your PC8 app reported 63 mA? You said the app reported 63 mA but said standby mode was "not enabled" which I took to mean the camera was completely powered off since you said the battery stayed at 99 or 100 after several days.

 

[NotThatGuyThatOtherGuy]

What exactly was the powered state of your camera when your PC8 app reported 63 mA? You said the app reported 63 mA but said standby mode was "not enabled" which I took to mean the camera was completely powered off since you said the battery stayed at 99 or 100 after several days.

Without standby mode enabled, the camera powers off when the vehicle is turned off. The LTE module is separate from the camera in the Vantrue system.

 

[Hack_man]

My first several days with a standby mode not enabled on the camera the battery was at either 99 or 100. The app reported a load at 63 mA, which I'm assuming is the LTE module.

I'm surprised the PC8 held at 99 or 100% after several days when the LTE module consumed 63 mA which is 0.325 W in a 5V system.
In three days (72 hours) that would be 23 Wh. The battery is rated at 96 Wh, so I would have expected it to decline to 76%.

 

[NotThatGuyThatOtherGuy]

I'm surprised the PC8 held at 99 or 100% after several days when the LTE module consumed 63 mA which is 0.325 W in a 5V system.
In three days (72 hours) that would be 23 Wh. The battery is rated at 96 Wh, so I would have expected it to decline to 76%.

I drive the car every day and every morning it is 99 to 100.

 

[BlackboxMyCar]

Figured we'd jump in here since there's some good real-world feedback on the PowerCell 8.

On the temperature, the 58°C reading is something we'd address. The PowerCell 8 is rated to operate at higher temperatures, but its published charging range tops out at 45°C. So if it's reaching 58°C while charging, we'd recommend moving it to a cooler location with better airflow. Under a seat isn't necessarily a problem by itself, but being tucked under carpet in a Las Vegas summer can make heat management more difficult.

The mounting feedback is fair as well. The PowerCell 8 was designed to be secured using the supplied Velcro rather than screwed into place, and the battery enclosure should never be drilled into. We can see how dedicated mounting tabs would give installers more flexibility though, so that's useful feedback for us.

Using the LOW charging setting also makes sense for someone who drives throughout the day and has plenty of time to replenish the battery.

As for the 63 mA reading, we'd be careful about drawing too many conclusions from that number alone. The app reports the battery's voltage and current information, so we'd want to know exactly what was connected and what the app was showing at the time before trying to calculate the actual overnight power draw.

Hack_man, the 8% per day you're seeing with nothing connected is something we'd be interested in looking at. We wouldn't want to call that normal self-discharge without checking the unit and setup first. If you're still seeing it, feel free to reach out to us and we'll take a closer look.

And yes, the app currently reports temperature in Celsius. A Fahrenheit option for US users is reasonable feedback and something we'll pass along.

Appreciate everyone sharing the actual numbers and install experience. This kind of feedback is genuinely useful to us.

 

[Hack_man]

@BlackboxMyCar I'll send you a DM with additional history.

Most of my testing with the PowerCell 8 was performed with an A229 Pro/HK4 Hardwire Kit (A229 Pro turned OFF) since this is a real world condition but I could perform additional unloaded testing. My terminology "Self Discharge" is therefore not completely accurate. I am still seeing the 8% discharge rate, but only during chillier (below 60 F?) temperatures.

The discharge rate appears to have a strong dependence on temperature. I noticed the Discharge Rate changed during Winter vs Summer, so I started tracking temperature. Testing at (7°C,45°F) shows a discharge rate of ~8% per 24 hours, Testing at (26°C, 79°F) shows a discharge rate of ~ 2% per 24 hours.

The @23°C, 73°F 2025 test results oddly shows the discharge rate (slope of the curve) increases with time.
Below is are plots of Percent Charge vs time. It's difficult to collect this data over a long time interval since the car is usually driven at least once a day.

 

[BlackboxMyCar]

@BlackboxMyCar I'll send you a DM with additional history.

Most of my testing with the PowerCell 8 was performed with an A229 Pro/HK4 Hardwire Kit (A229 Pro turned OFF) since this is a real world condition but I could perform additional unloaded testing. My terminology "Self Discharge" is therefore not completely accurate. I am still seeing the 8% discharge rate, but only during chillier (below 60 F?) temperatures.

The discharge rate appears to have a strong dependence on temperature. I noticed the Discharge Rate changed during Winter vs Summer, so I started tracking temperature. Testing at (7°C,45°F) shows a discharge rate of ~8% per 24 hours, Testing at (26°C, 79°F) shows a discharge rate of ~ 2% per 24 hours.

The @23°C, 73°F 2025 test results oddly shows the discharge rate (slope of the curve) increases with time.
Below is are plots of Percent Charge vs time. It's difficult to collect this data over a long time interval since the car is usually driven at least once a day.


View attachment 93145

It is normal for any battery to discharge faster in the cold. You may have read before that EVs have shorter range in the winter compared to the summer, and this is exactly why.

However, we'd still like to look into this further to determine whether the change in discharge rate you're seeing is entirely due to the temperature, or if there's anything else at play.

Do you recall when you did your (Unknown Temp) 2025 test, and/or when Panzer did his?

 

[Hack_man]

It is normal for any battery to discharge faster in the cold. You may have read before that EVs have shorter range in the winter compared to the summer, and this is exactly why.

However, we'd still like to look into this further to determine whether the change in discharge rate you're seeing is entirely due to the temperature, or if there's anything else at play.

Do you recall when you did your (Unknown Temp) 2025 test, and/or when Panzer did his?

I am comparing the Winter time discharge rate of the PC8 with a Viofo BP100.

The PC8 is configured with an HK4 --> A229 Pro (powered OFF).
The BP100 is configured with the Viofo Hardwire Output Cable (Type-C) (4M) --> A229 Plus (powered OFF).

I do not have side by side Winter temperature data to present of both Batteries but I know from frequently checking each of the battery apps during last Winter that the BP100 was barely dropping in charge overnight (or in 24 hours) in the same cold (45 degree F) garage as the PC8 with the above setups.

I was able to determine using my Mac Computer's Time Machine incremental backups that my "Unknown Temp 2025" test was performed very late January to early February of 2025.
Panzer (@Chuck McCoy) data was taken Late January 2025 and was posted here
Chuck's location shows as California so it was very likely warmer than in my Northern MA location.
Actually, with Chuck's superior data collection and documentation skills, I see that his test temperature was 17 C or 63 F

 

[BlackboxMyCar]

I am comparing the Winter time discharge rate of the PC8 with a Viofo BP100.

The PC8 is configured with an HK4 --> A229 Pro (powered OFF).
The BP100 is configured with the Viofo Hardwire Output Cable (Type-C) (4M) --> A229 Plus (powered OFF).

I do not have side by side Winter temperature data to present of both Batteries but I know from frequently checking each of the battery apps during last Winter that the BP100 was barely dropping in charge overnight (or in 24 hours) in the same cold (45 degree F) garage as the PC8.

I was able to determine using my Mac Computer's Time Machine incremental backups that my "Unknown Temp 2025" test was performed very late January to early February of 2025.
Panzer (@Chuck McCoy) data was taken Late January 2025 and was Posted Here.
Chuck's location shows as California so it was very likely warmer than in my Northern MA location.

Sounds good. Please let us know what your summer test results are for the PC8 so we can further compare and analyze the situation.

 

[Hack_man]

I updated my post #14 to show Chuck's test temperature (17 C or 63 F) and corrected the link to his test data.