Lifetime Capacitor, battery combo

It’s not the electrocution hazard that I’m considering, it’s the discharge through a conductive item like a dropped wrench. That’s a hazard that is not a function of voltage or the resistivity of one’s skin.

A 6V short circuit can be as explosive as a 69,000V short circuit depending on the energy reserve in the source.

This a subject I endlessly consider in my career.

 

Very good point. I have a few scarred wrenches myself. I wonder what would happen here with that much current, but only 10 watt hours of energy.

 

I equals V divided by R.

I've been whacked by HV RF amplifier capacitors that were not discharged. Less than 1amp at 4kv and for 2 days my hand felt like it got whacked with a sledge hammer.

 

It's aluminum, seems better than plastic, until it's not.

 

can the alternator put out enough voltage to keep Lifepo4 batteries charged and healthy? I know 3rd gen alternator voltage output isn't enough for AGMs

 

I’ve got an AGM and thought about this. Even if the alternator charged the battery to 14.7V (it can’t) what benefit would it be for the truck?

 

Human skin offers almost no resistance above 200v.

 

Straight from alternator, no. But you should use some sort of charge controller anyway, unless you have one with built in BMS. Not hard to make a voltage converter, or use a DC-DC charger similar to what the RC car folks use.

You can't parallel a LiFePo4 battery with a SLA anyway....

I put a 100w solar panel on the roof, never have to charge the battery....

 

Again, I’m not discussing electrocution, at all. I’m discussing arc-flash / explosive hazards due to short circuiting a system with a metallic object. Nothing to do with the body.

 

No benefit to the truck, but the battery life will be reduced significantly by charging it only with the alternator (constant current).

AGM batteries have finicky charging cycle requirements. They need bulk charging to a certain point, but then need to be floated. If you just connect it to your alternator, this isn't happening.

 

Relax, boss. I didn't intend to compare it to the body. Arc, flash, explosion, fire, electrocution, whatever. My point is it's all ohms law.

 

What if you put it on a 7 stage charger once a month to 14.7V?

 

Alternator will still be too much voltage for floating. That's why AGM batteries aren't used in cars. Nominal alternator voltage is too low for bulk and too high for float.

 

FWIW, this blue/red LiFePo4 does have it's own internal BMS. Its Recommended to be kept under 15v (16v cutoff) for maximum life. My alt seems to put out 14v on cold days, 13.7 when warm. For last few months, the batt reading is always above 13.1v after sitting overnight or for many days. So alternator charges lifepo4 fine. Another FWIW, lithium iron is the safest of the LI batteries. Basically Is no chemical run away fire hazard like a tesla. lol.

 

I'm just gonna set this here...

https://www.youtube.com/watch?v=nl9p79S1e44

https://www.youtube.com/watch?v=4ivvObWij1g

 

I got one too. Totally unnecessary, but what the hell

I loved how the sticker came unstuck on backing so you could get it how you wanted. I also enjoyed the large sheet of Japanese characters

 

It was $10 defintely worth it’s weight in metal