Stop equipment powering off when starting motor - off-the-shelf solution

2 X 18650 batteries work very well for a RPi back up battery.

Sometimes power fails are not good if the SD card gets corrupted.

One way to avoid SD card corruption due to power fail, Is to make all of the files on the SD card Read Only. Only using Ram writes is better.

 

He's talking about modern vehicles that start and stop the engine automatically to conserve fuel. My F-150 has a button to disable it, but some vehicles may not.

 

For me, the permanent solution is a power programmer for my truck. Not only can I retune the trucks's PCM for economy or performance, I can disable the darned start/stop garbage.

 

How about a LiFePO4 instead of an SLA?
https://www.amazon.com/LiFePO4-Batt...ion+battery&qid=1608778349&sr=8-3&tag=mh0b-20

 

No - not talking about hybrids or the like that start / stop the motor automatically. Just usual vehicle key-on key-off when working.

I work in conservation and a lot of my work is weed spraying around the high-country conservation parks of Central Otago. Being retired high-country pastoral runs, these have a reasonable network of 4WD tracks giving good access right into the ranges. But unfortunately these tracks have been corridors for ingress of exotic (non-native) weeds into the high country. A patch of weeds can take anything from seconds to a hour to deal to. So the motor if often off whilst I work then back on when I'm moving again.

I take the Yaesu with me for company - 2m in the day when I'm in the truck, and HF at night from camp. There are repeaters on 2 of the highest peaks in our area, so reasonable 2m coverage - on the tops at least.

The Raspberry Pi is an interfacing project of mine - not directly related to ham radio - but connected to some sensors and a GPS with some software I've written logging the data against position. So being a bit cheeky by asking non radio-related questions on a ham thread - but the issue of equipment powering off seemed to be something that many hams must also have dealt with - so this seemed a good pool of knowledge to tap.

==

Regarding LiPO - the trouble with LiPO is that it needs a LiPO charger with current/voltage regulation. So you can't simply stick it across the 12v (nominal) supply in the vehicle with a diode to stop back-drain as you can with a lead-acid. So then we're on to installing a 12.8v LiPO charger too and quickly making that MFJ unit look like a cheap solution.

 

I suggest using an LTC4364 with two MOSFETs and put a supercapacitor (as mentioned on a previous post) on the output. The LTC4364 will prevent the capacitor from backing up into the car system while it will also limit the inrush from connecting the capacitor online (which could blow a fuse). It also protects your rig from voltage surges (load dumps). If you don't want to assemble this circuit (this IC only comes surface mount), you could get an eval board and just change the sense resistor to limit the current above what your radio takes when transmitting. https://www.analog.com/en/products/ltc4364.html Also make sure the FETs are adequate for the current you are drawing. These LTC "Surgestoppers" are used in many automotive and aircraft systems all over the world. I have personally used them in my professional work successfully.

 

I had a smaller battery mounted in my truck hooked to the cigarette lighter with a $10 trailer battery diode wire and nothing ever turned off when starting.

 

HELLO
W4ezr here. You do not want your radio or other electronic devices connected to your automobile battery and turned on while it is cranking. There is a sharp decrease in power then a spike in power as the cranking stops and the voltage regulator gets the alternator and voltage stabilized. Your radio glitches and shuts off momentarily due to high voltage spike. I damaged my IC 706 by leaving it on while cranking my truck. Also my truck has two batteries and plenty of amps. Good luck. It does seem like a small separate battery operating in parallel to the automobile power would fix our concern.

Olen Persons
W4ezr

 

My Rig I used when travelling in the wife's car was a 5Ah SLA batt.,
4 15amp schottkys strapped with a cig. plug. Radio was a ic-v8000
and mag mount antenna. All except the antenna stowed in a small cooler.
Batt lasted about 6years.
YMMV