Startup when cranking = crash

[Ouch77]

My car has a fairly large diesel engine, and a less than perfect condition battery, though still serviceable, so it's not getting replaced yet.
At the moment I'm using the supplied ciggy lighter power supply, and if plug in at the wrong time (permanent supply to the lighter sockets) the camera will be booting up when I hit the starter, which then crashes it (repetitive startup sound, needing a disconnecting of the power and a long hold on the power button to reset).

My long-term aim is to hard-wire the power supply into the cabin light area of the roof and drop the USB cable through the front of the headlining. However I'm thinking I'll need to do something to ensure the supply to the camera isn't affected by cranking, perhaps with some fat capacitors or something..
Has anyone else had this problem? Anyone got any suggested solutions, preferably ones that would cost lest than a 900CCA battery?

 

[Nigel]

Yes, others have had the problem, continuous beeping = too little power, but it is normally because the lighter socket gets disconnected while cranking so all power is lost. The power adaptor should be able to supply the correct 5 volts to the camera even when the battery voltage drops to 7 volts which would probably mean that your battery is so poor the engine wouldn't start, should only drop to 8.? volts when cranking with a decent battery.

Probably you just need to connect into a circuit which doesn't switch off while cranking the engine. You could reconnect your lighter socket to a circuit which doesn't switch off while cranking. I have my power adaptor perminently wired to the ECU circuit which turns on with the ignition and doesn't turn off until 4 minutes after the ignition is turned off so it stays on while at the fuel station and if I turn the engine off while waiting for trains etc.

 

[Nigel]

Read your question again, if the problem really is as you describe then you would need a fairly large capacitor and a decent diode to stop the capacitor feeding it's power back to the starter motor. Fairly easy to do if you are hardwiring it anyway.

 

[jokiin]

The adapters will only work down to 8 volts

 

[Nigel]

The adapters will only work down to 8 volts

In that case there is the possibility of using a different adapter which will go a bit lower, though I guess it's still going to be marginal so not an ideal solution except that it wouldn't require anything more than plugging in.

 

[jokiin]

Not aware of any that work below 8v, even that is low, either needs a time delay circuit or a startup delay option in the firmware for best results

 

[Nigel]

Not aware of any that work below 8v, even that is low, either needs a time delay circuit or a startup delay option in the firmware for best results

Then solder a better regulator chip into the existing adaptor, this one will go down to about 5.5V if your only using half an amp: http://cpc.farnell.com/stmicroelectronics/l4940v5/ic-v-reg-ldo-5-0v-4940-to-220-3/dp/SC10587 - same pinout so a straight swap I think.

 

[jokiin]

Not suitable for this application from a manufacturing perspective but if you want to make your own then that's something else altogether

 

[Ouch77]

Nigel: What you say makes perfect sense, like you I assume power is cut to the ciggy socket on cranking, however I have yet to confirm with a meter. I'll admit the battery isn't in the first flushes of youth, but it still just about starts the car on a frosty morning, so it stays. I can't justify £100 on a new battery right now anyway.

Jokiin: I like the idea of an option in the firmware to delay startup, though it would need to be variable as sometimes I'd need to let the glowplugs warm up before starting.. Could it be linked to temperature as well please?

My intention is to find a non auxiliary switched live in the area and use that as a supply, your suggestion about the ECU supply has merit, I'll have to check the behavior on my car though the ECU is fairly inaccessible under the passengers floor. I have a variable voltage bench PSU so I might try some experiments as to the lowest supply voltage tolerated by the ciggy lighter adaptors (I figure I'll just rip the guts out of one of those). Though I do like the look of the switching supply featured here: https://www.amazon.co.uk/gp/B008VORADW

 

[Nigel]

I used a "fuse tap" in the fuse box, much better than tapping into wires, but if your going to use the interior lighting circuit then that is a lot closer so will save a fair bit of effort! That Amazon adaptor still only goes down to 8V, but it is very efficient! The original adaptor is perfectly decent for hardwiring if you solder a couple of wires into the inside and remove the positive pin and spring - remove the chrome ring and then the two halves of the case separate, works fine on my car and my battery is a little 32Ah one.

 

[David106]

Why not just turn the ignition on, wait 10 seconds and then crank the engine, problem has then gone away.

 

[Ouch77]

David: Not a bad idea, but it's the sort of thing I'd forget to do, and then there's the hassle of disconnecting the power and restarting when I do forget. I'd much rather there wasn't a problem, than having to work around it.

Nigel: Personally I don't like the fuse tap idea, it's okay as a bodge, but I'm a bit OCD, I like my wiring tidy and OEM looking..

 

[Nigel]

Nigel: Personally I don't like the fuse tap idea, it's okay as a bodge, but I'm a bit OCD, I like my wiring tidy and OEM looking..

I understand that, however these do look pretty much OEM when in place except for the wire which needs routing out the top of the fuse box instead of the bottom. Unlike the normal wire tap things there are no dodgy connections.

 

[Ouch77]

Yep, they're definitely preferable to scotch-lock type connections and the other horrors you'd often find behind a poorly installed after-market stereo. If I can't piggyback onto a spade type terminal behind a panel with proper crimped connections then I usually strip, solder and heat-shrink onto a suitable wire. The particular issue in my car is the fuse panel doesn't have the clearance behind the cover for anything taller than a regular fuse:

..and it's right on the end of the dash, the drivers door shuts right onto it (pic above is for LHD).

I'll need to pull out the schematics and start poking around with a meter in the headlining over the weekend. Thankfully I ordered the 'hardwire kit' freebie from JooVuu which consisted of another ciggy lighter charger so I've got a spare to butcher..

 

[mr_milo]

Since you have open slots you have some options.
The easy way is to butcher a fuse and solder onto one of the legs or use a spade lug crimped onto an in-line fuse holder to get your power from an open slot.
The more difficult but much nicer path is to order some crimps from the dealer and add your own circuit.

 

[Ouch77]

No open slots on my model, besides I'm pretty confident I can get power closer to where I want it.

 

[Nigel]

The particular issue in my car is the fuse panel doesn't have the clearance behind the cover for anything taller than a regular fuse...

I see, your manufacturer has gone to a lot of trouble and expense to make DIY difficult! My fuse box looks like the manufacturer had several DIY sessions themselves over the 10 years the model was in production and adding an extra wire would make no difference to the appearance!

However, I did take my power from the engine compartment fuse box rather than the cabin fuse box, that might still be an option for you if your lighting circuit turns off with the starter.

 

[Ouch77]

There is a relay box in the plenum which I can probably get power from, though it's not ideal as I've then got to route cables through the bulkhead, along the dash and up the A pillar. The more I pull apart the greater compulsion to clean everything and thus a 2hr job takes all weekend..

Car electrics can be a nightmare, poor access, harsh conditions, EMI, quirky conventions and the risk that someone has been in there beforehand with scotch-locks and sellotape...