Switchable Dashcam powerbank circuit

So I wanted my dashcams to run for 12+ hours whilst parked, and I did not want them running down the main car battery whilst doing so.

There are a few commercial solutions available. Namely the Cell link B, which is basically a UPS for your dashcams. You connect the dash cams to it, and it powers them whilst your ignition is off. When the ignition is on, it charges the pack, and also powers the cameras.


Problem is, that its £180, which is too much.

So, I built a relay solution that does the same things with Ravpower USB power banks.

Here is the diagram:


It looks complicated, but it isnt. All it does, is use 2 relays to switch the USB connection from the vehicle to the powerbank, when the ignition is turned off. Keep in mind you could use a DPDT relay to do the same thing, but with one relay instead of 2.

This is what the end device looks like :


The 2 USB feeds are at the top. The output is on the right, and the two wires on the bottom left go to switched 12v. (there is a 1 amp inline fuse in these).

Keep in mind some devices support “chargethrough”. They say they support charging a device, whilst itself is charged. I find this dangerous unless it bypasses the battery circuit inside, and as we cannot be 100% sure, this is much safer solution.

I get roughly 16 hours on a “20,000mah” ravpower battery pack. I also use quick charge 2.0 chargers to replenish the packs, as short journeys will not put much into them.

Time will tell how long the Memory cards in the cameras last too.


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Mercedes S65 AMG M275 Airbox repair

My S65 AMG has the right hand side airbox tab broken off.

As a result, the airbox isnt secured into the inlet of the turbo, no good!

I designed and 3d printed a replacement.

Here is the bit that is broken.


and here is what its meant to look like:


Now I was not about to pay £500 for a new airbox so I set about 3d printing a replacement.

Some time later, I had a template:


After some measuring and printing, I had something usable.

I trimmed some of the broken pieces from the airbox and then epoxied it into place. Annoyingly, it dried in a slightly odd angle, but it should be fine!

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W123 – Alternator Bracket

A lot of the jobs on this 123 are delayed by having to fix the previous owners bodges and damage.

A simple belt change was a pain in the …. as the previous mechanic had over tightened the alternator tensioner bracket.

This meant that the alternator had one position, which in this case, was over tight!

Alternator mounting bracket

Hmm Rather bent

After a bit of work with a hammer and a vice, I had it pretty straight:

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Cleaned up with a wire brush, and a couple of coats of satin black (as ed china loves):

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On the car and no more squeaking!


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