Inverters ,converters and auto batteries
Posted by SoldierExcelsior@reddit | preppers | View on Reddit | 19 comments
Something that seems to be highly understood is the use of inverters converters and auto batteries.. I got a hold of a few 24 volt truck batteries kept them in storage untill a storm came and power was out I was able to use these batteries to charge my small electronic devices for days.
Since then I have used regular 12 volt auto batteries to keep my phones tablets fans and lights charge and running even a battery to dead to start a car can usually charge a phone.
Converters are good to have on hand in case you ever need to power some sort of 12 volt device like an air pump or devices meant to be used in a car.
And inverters work the opposite way you can power regularvhousehold devices off of a 12 volt Automobile power system
Prestigious_Yak8551@reddit
Yep I have a couple of old car batteries, and two old AGMs which I previously used in my camping setup. Now upgraded to lithium. The old batteries arent 100% anymore but each one could keep my fridge running for a few hours, charge phones, run a small water pump, etc; if the power goes out. I keep them hooked up to a small solar panel and regulator to keep them topped up. I dont want to spend the money on one of those fancy jackery/bluetti type setups, so this suits me just fine and didnt really cost me anything really.
smsff2@reddit
I keep my lead-acid batteries fully charged as well. They’re about 2.5 times cheaper than lithium iron phosphate batteries per unit of maximum (i.e., emergency) energy storage.
Ryan_e3p@reddit
Unfortunately, the "cheaper per maximum energy storage" is completely backwards. LiFePO4 batteries absolutely beat lead acid when it comes to energy density.
Lead acid batteries often have only a few hundred cycles. Plus, you can only use about half of their capacity without causing issues with total capacity loss (or even complete loss if fully discharged), with a quick dropoff of voltage as its used.
Lithium iron batteries have thousands of cycles, some tested as high as 10,000. They can be discharged safely down to 15-20%. They can be charged faster than lead acid, have higher density (are physically lighter for the same total battery capacity), and output voltage remains steady throughout most of the discharge.
LiFePO4 is more costly up-front for purchasing, but they have more cycles (often by a factor of 10), can use more of the stored energy, and are more efficient when it comes to charging.
SoldierExcelsior@reddit (OP)
Problem is taping into the lithium batteries
Ryan_e3p@reddit
What in the world are you talking about?
silasmoeckel@reddit
If you can get ahold of them cheap and have someplace to charge them without exporive gas build up worries sure.
AH per AH lifepo4 is cheaper without the downsides of lead.
SoldierExcelsior@reddit (OP)
Lead is re fillable
Ryan_e3p@reddit
I would be vary, vary cautious about using any run of the mill inverter to run household devices off of a 12V system. Most inverters you pick up at places like Walmart or Amazon are bad news.
Most of the cheap ones (costing under $100 or so) are not pure sine wave. Meaning, the voltage is unclean, and a lot of modern electronics (computers, laptops, CPAP machines, etc) are going to have issues with it. You want power that is pure sine wave, not modified sine, not square wave. Pure sine. That is the stuff that you get from the power lines.
Most of the crap ones you find at stores that advertise "300 Watts" are not just outright lying to you, they are ----dangerously--- lying to you. Especially the ones that are powered by you plugging into the 12V "cigarette lighter". Here's why: Most of those circuits in cars are rated for 10 amps, and have a 10A breaker. If you plug in that 300W inverter, and you want to power something that uses those 300 watts, you're going to pop that breaker. Why? Because that circuit is only capable of putting out 120W. 10 amps times 12 volts = 120 watts. "OK", some people think, "I'll just put in a larger fuse, that'll help". So, they put in a 20A fuse that fits. Congrats, you are now at risk of starting an electrical fire, since the wiring going to that fuse from the mains, and from the fuse to the 12V outlet you plugged into, are likely only rated for the fuse that was in there. Wires will overheat, risk melting, and starting a fire.
If you're going to run an inverter higher than 120V, you need to make sure your car's system is designed for it. Or, get an inverter that you can hook up to the battery, but now, you need to also make sure that your alternator is capable of the output as well. Slapping a 3000W load onto a car's battery and expecting some little stock alternator to not only power everything in the car as well as something like a full size fridge is often not going to end well. Research needs to be done to see what the vehicle can 'afford' for alternator output after running everything else in the car.
Jaicobb@reddit
If I understand your scenario correctly a larger fuse turns your wire effectively into the fuse. That's what will heat up and pop, right?
Ryan_e3p@reddit
Not quite pop, more like heat up, melt the wire, and then decide to extend the 4th of July firework celebrations.
SoldierExcelsior@reddit (OP)
In all my years of doing this I've never had it happened I run 30 Amp fuses in my 12 v outlets
Ryan_e3p@reddit
You swapped a 10A fuse with a 30A fuse to run higher wattage devices?
SoldierExcelsior@reddit (OP)
I don't run it off the car I just run it from the batteries the only thing I will do with the car is recharge the batteries...but like I said this really only ideal for small electronics you can keep a phone charged for weeks.
Paranormal_Lemon@reddit
A lot also aren't 120v with a hot and neutral but are +60/-60 split on both lines, so both the both hot and neutral will be 60v from ground. It can cause a shock hazard in some devices and if neutral is bonded to ground will short the inverter.
shikkonin@reddit
If neutral is bonded to ground, you need to throw that device away.
Paranormal_Lemon@reddit
I mean if the user does it for example for a gas furnace to start properly.
Usagi_Shinobi@reddit
If you can scavenge enough of them, any sort of battery that can be charged and discharged repeatedly will work. Marine/RV/Deep Cycle batteries tend to be most suited for this application, in terms of longevity, among traditional lead-acid types.
Paranormal_Lemon@reddit
FYI car batteries have fragile lead plates and can be damaged by draining even a fraction of their capacity. I tested a spare battery I had, it was in good condition, 2-3 years old, after draining about 20% of the capacity the voltage suddenly dropped and it never charged again. I've seen multiple sources say not to go past 20-25%.
JRHLowdown3@reddit
As someone who actually has an alternate energy system that has been in play for 26 years... We are sticking with Trojan L16 flooded lead acid batteries.
We recently changed inverters to a Growatt 10K inverter and had to re-wire to 48volts. Not something I was happy about, but necessary for the new inverter. New inverter has been a PITA compared to others we have had over the years- Trace 4024, Magnum, even the POS Schneider inverter that didn't last a year was easier to set up, didn't have all the "app" BS and used conventional push wire in and tighten screw connections versus the little ferules that are a PITA.
On the batteries- everyone who has never actually lived with an energy system will parrot the common thought that you "cannot mix old and new batteries", pushing the "you HAVE to replace the whole bank all at one time" mantra. I did that once in 2003, and ever since have just replaced the batteries individually that were a problem and re-wired the bank. When we were running 24volt, we usually had 28 batteries in the bank. Strings of 4 each of the six volt batteries. One in a string goes down, it will pull that whole string down. Conventional theory says pony up for 28 new batteries, but that's BS. And we have replaced just a few here and there over the last couple decades. This was one of the reasons I was hesitant to go to 48v- eight in a string versus 4.
We are averaging 8-10 years off of Trojan L16's, so the "lead acid batteries last 3.5 seconds" thing is utter BS.
Yes, you have to do a modicum of PMs to them. And be smart and program your inverter for a higher LVD setting, so the battery bank isn't drawn down as much- the inverter will cut power at the low voltage disconnect value you set versus allowing the bank to go lower. Factory settings on most inverters are really low, I remember seeing 21v on our old Trace 4024 and changing it to 23.1 I believe this also lead to longer longevity with our batteries as well.