Pre-Installation Review: Hybrid LiFePO4 + Main AGM Backup for Viofo A329S 3-CH
- Thread starter IgorTa
- Start date
GPak
Well-Known Member
Welcome to DCT, @IgorTa
When two power sources are connected in parallel to a single device, the source with the higher output voltage typically acts as the primary power supply.
However:
- The output voltage of the Energywell P6C is likely unregulated, ranging from 10V to 14.5V, depending on the current battery charge level.
and
- The voltage from a vehicle's alternator+battery can also vary, ranging from 12V to 14.5V.
Thus, these voltage ranges overlap; as a result, the primary power source can be either the vehicle's alternator+battery or the Energywell P6C.
Therefore, you will need not just one, but two diodes—one on each positive lead from each of the power sources.
Note that there will be a voltage drop across the diodes (perhaps around 0.2V).
Therefore, the cutoff voltage on the HK6 must be adjusted accordingly: for instance, if you set the value to 12V, the actual cutoff voltage for the battery will be approximately 12.2V.
This cutoff voltage threshold is necessary to protect the vehicle's battery; however, it is not needed for the Energywell P6C and would merely limit its usable capacity, as that source is capable of discharging down to 10V.
To be honest, I am not a proponent of using diodes and switching between two power sources based solely on voltage differences, as the overlap of the voltage ranges can lead to inconsistent switching.
A more preferable solution would be to use a "Dual Power Transfer Switch"—or, more simply, a UPS (Uninterruptible Power Supply)—devices that we have already discussed here:
To answer your questions:
- Viofo A329S (3ch) may draw up to 10W; consequently, at a voltage of 12V, the current draw does not exceed 0.83 A—thus, a 3A diode should be sufficient.
- Whether or not reboot or errors occur depends entirely on how quickly the power sources switch over.
Viofo dashcams are quite sensitive to momentary interruptions in the power supply. You will have to test to findout.
Finally, I am afraid that with your setup, there is a risk of repeated switching between the two power sources - since, following a cutoff, the battery voltage tends to recover.
IgorTa
New Member
Welcome to DCT, @IgorTa
thank you!! i will order the UPS device and follow your bypass video guide.When two power sources are connected in parallel to a single device, the source with the higher output voltage typically acts as the primary power supply.
However:
- The output voltage of the Energywell P6C is likely unregulated, ranging from 10V to 14.5V, depending on the current battery charge level.
and
- The voltage from a vehicle's alternator+battery can also vary, ranging from 12V to 14.5V.
Thus, these voltage ranges overlap; as a result, the primary power source can be either the vehicle's alternator+battery or the Energywell P6C.
Therefore, you will need not just one, but two diodes—one on each positive lead from each of the power sources.
Note that there will be a voltage drop across the diodes (perhaps around 0.2V).
Therefore, the cutoff voltage on the HK6 must be adjusted accordingly: for instance, if you set the value to 12V, the actual cutoff voltage for the battery will be approximately 12.2V.
This cutoff voltage threshold is necessary to protect the vehicle's battery; however, it is not needed for the Energywell P6C and would merely limit its usable capacity, as that source is capable of discharging down to 10V.
To be honest, I am not a proponent of using diodes and switching between two power sources based solely on voltage differences, as the overlap of the voltage ranges can lead to inconsistent switching.
A more preferable solution would be to use a "Dual Power Transfer Switch"—or, more simply, a UPS (Uninterruptible Power Supply)—devices that we have already discussed here:
To answer your questions:
- Viofo A329S (3ch) may draw up to 10W; consequently, at a voltage of 12V, the current draw does not exceed 0.83 A—thus, a 3A diode should be sufficient.
- Whether or not reboot or errors occur depends entirely on how quickly the power sources switch over.
Viofo dashcams are quite sensitive to momentary interruptions in the power supply. You will have to test to findout.
Finally, I am afraid that with your setup, there is a risk of repeated switching between the two power sources - since, following a cutoff, the battery voltage tends to recover.
GPak
Well-Known Member
@IgorTa
The UPS will not function with your specific setup. I mentioned it to show how the clean switching can be achieved as a reference for a different setup.
Perhaps I should have expressed myself more clearly. (I will edit my previous post accordingly)
In your setup, the UPS's primary input is not controlled by the ACC/ignition signal; consequently, it will remain continuously powered and will never switch over to the vehicle's battery.
Furthermore, once the cutoff voltage threshold is reached, the HK6 unit will shut down the camera regardless.
With the diodes, your configuration may technically work—though not in the manner you envisioned.
In a parking mode, as Energywell P6C voltage will drop to the level of the vehicle's battery, the two sources will begin to "compete/fight".
As I noted in the final sentence of my previous post, this may result in repeated switching back and forth between the two power sources—because, immediately after a switch occurs, the battery voltage tends to recover slightly.
If this scenario plays out, the two power sources will repeatedly toggle between one another, eventually reaching the cutoff voltage threshold basically simultaneously.
It is essential to conduct bench testing to determine whether it is worthwhile to proceed with such a setup.