I thought a lot about how this would be done (hibernate from suspend). It requires support from at least the BIOS. The problem is that in my S3 state everything (including the disk and processor) is powered off. So you'd essentially have to wake from the suspend, run a few instructions on the CPU, hibernate (run a few more instructions on the CPU, page out your RAM ti disk), then turn off. I've heard laptops do this, I've never seen it. I'm not sure it can be done from S3.Quote:
Originally Posted by arebelspy
Latter numbers: I'm not sure why you think this, it's working perfectly. More reasoning/links to other thoughts or suggestions? :)
So I don't know how the tank circuit is constructed. I'm guessing, that could be the problem. I assume it's a diode and a resistor. Let's label the connections:
- 1 ,the car side. This input into the tank circuit from the car's electrical system (sometimes car's battery, sometimes car's alternator)
- 2, the tank battery side.
- 3, the load. your carPC, inverter, whatever.
Here's my idea of how the tank circuit works.
- Car running. The alternator is at 1. It's supply 13-14V. Both 2 and 3 act as loads (2 is being charged by 1, 3 is being powered by 1). The resistor prevents a ton of current from slamming into 2 all at once.
- Car is starting. Alternator off, big voltage drop on 1 since car is cranking. 2 has higher voltage now and would normally flow into 1 but the diode prevents this, instead 2 powers 3. CarPC runs during crank.
- Car is off. For me 3 is still a load (because of suspend) Car battery supplies 1, is this voltage higher than 2, then 2 will be charged by 1, and 3 will be powered by 1. 2 will never charge 1, but 3 will either discharge 1 or discharge 2. I think it'll sort of "take turns", The point is with your car off 3 will run off 2 until 2 is drained to a lower voltage than 1. At that point 1 will supply both 2 and 3. This will cycle, draining both 1 and 2. I would still be draining my car's battery.
As I said, I'm guessing and I'm new to electronics, but this is how I see it.
azzuro: Be careful with "just a relay". You have to prevent your car's system from charging your 2nd battery two fast. Voltage will try to equalize in the system as fast as it can. So, your car is off. You drain 2nd battery pretty low. You start your car and your charging system is cranking out 14V at whatever amps your alternator can minus what the car needs. Can you recharge that second battery that fast? I've been lead to believe various batteries have current limits for recharging. You have to be careful that they don't overheat. They'll vent gas (inside your car!) when they overheat. sealed lead acid batteries probably aren't completely sealed. They're sealed with a provision for an emergency vent. They vent rather than explode as a last resort.