Second battery for my car computer

[96eb96]

My android car computer shuts down when the car starts or goes from accessory to off. This causes it to cycle. I have dashboards and other apps that are a pain to restart. There isn't enough voltage to keep it alive during start.

I'm thinking of one of those small SLA batteries that the cable boxes and fios have to backup the phone service. Then I would need I believe some sort of battery isolator.

I can use the accessory wire that that controls the lights (they shut off in about 10 minutes), but they do go out during start, I could probably add a capacitor on the accessory wire to keep it alive.

Another option could be those 60 dollar jump packs, and it can be used to jump the car if necessary.

Anyone deal with this?

 

[CDW6212R]

It sounds interesting. I'd think about some kind of capacitor that could be included in the power circuit to your car PC, which can support the momentary power loss during starts.

I looked here in case the isolator circuit might be an option for a Lithium(LiFePO4) battery I'd consider for a backup. My problem with them is that they cannot handle common car alternators, the biggest versions can only handle 60amps before they destroy themselves. I wish there was a way to limit alternator output.

 

[96eb96]

I think it would need quite a large capacitor to power it, and they get expensive. Capacitors are used to keep voltage on the accessory line, some radios don't need full 12V to run.

Lithium batteries need specialized charging, but there are small sealed lead batteries for computer UPS, cable boxes, digital phone. Those are 12V. cheap, and may be able to work off the alternator. The alternator may be a bit too much current for that small battery. An isolator would be needed because the starter would drop the voltage.

The other option are the $50 jump packs, they are all over amazon. They charge from the vehicle and could be the power source for the stereo except in run(relay driven). They even have usb ports to power phones, but there is also a 12V terminal.

 

[CDW6212R]

The small lead acid batteries used for PC backup supplies sound like your best bet. I recently bought two new ones for my first UPS, and gave it to my dad to run his TV and VCR(power outage kills the clock and he can't reset it).

Those batteries are easily in the $25 range. I'd try one of those first, they are small and sealed, and last several years.

The new Lithium 12v batteries may be the new thing soon. Right now they require special chargers, and some(Earth X) do come with a built in BMS to save from low/high voltages. To use those in a car I believe would require the special charger and an isolator to keep it separate from the alternator. That doesn't sound feasible or convenient right now.

 

[96eb96]

Yes, I think I can get away under $50 with the SLA solution. A battery isolator and the battery. I don't need the CD anymore so it may be able to fit in the console, turned 90 degrees. Looks smaller than the changer. I also like to run the computer with the car off, so I can do work in a parking lot, I don't have to worry about the battery. It has a keyboard and mouse that I keep in the seat back pouch. I think I can trigger off the accessory delay, it does shut down in start but a capacitor or override should fix that.

 

[CDW6212R]

Sounds good, and please keep this updated with what you do. I don't have any immediate plans like this, but my mail truck now has a switch and diode that lets me run the radio and extra circuits with the key out. I may later install a double DIN radio for a back up camera, and who knows what else might come up.