Smart Battery Protect 65A - 0,315A Fuse blown

DIY
1

We hve encountered an issue with the 65A Smart Battery Protect units. Out of six identical vehicles, two experienced a blown 0.315A fuse.

However, because these are mobile TV broadcasting units, such unexpeccted failures could disrupt live transmissions.

Have you seen similar cases before, or do you have any sugestions on what might cause this fuse to blow?

4

Do you have detailed information about the installations?

Is there any backfeeding caused by other switching operations due to induced voltage (large coils)?

5

Can you provide a schematic or diagram or photos of the setup?

If it is a high RF environment, do you have RF protection (shielding, RF bypass capacitors, Ferrites) to prevent RF from getting into the DC wiring?

6

Hello,

The entire installation is mounted on a 3 mm thick aluminum panel. The DC circuits are not shielded. The most significant source of RF interference in the vehicle could be the two-way radio.

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7

Hello,

Yes, there is a 3 kW / 24 V hydraulic pump, but it is connected upstream of the Smart BatteryProtect, so it is not supplied through the BatteryProtect unit.

8

You should check the transmitters and their grounding (RF ground) to make sure there aren’t any common-mode currents flowing along the cables.

Are the existing filter assemblies working (mains filters, common-mode chokes)?

If you get the transmitter technicians to take a look, they should be able to work it out quickly.

9

The antenna feed coaxial cable may need clamp-on ferrites to ensure the RF is choked appropriately. e.g. make sure the feed line is not transmitting inside the vehicle, proper chokes will ensure it goes out the antenna.

10

I forgot to mention there should be RF chokes on the power leads to the two-way radio, and same for the high-power broadcast uplink/downlink.

11

The hydraulic pump could be one possible cause if it drains weak batteries or sends switching spikes through the system wiring.

Keep investigating this. If it happens again, carefully record exactly what was done, by whom, where and when, so you can identify possible causes afterwards. Network analysers (a type of oscilloscope) might also help.

12

Hello,

We will try to check the shielding and grounding to see whether they could be contributing to the issue. Thank You.