DIY Emergency Power Supply

[poorfag No.550022]

which, believe me , is quite frequent in the third world dump that I live in)
I want to use it for charging my phone and laptop and to run 2 8W CFLs.
Pic somewhat related , but I guess I'll need a bigger battery and a heavy duty charger and invertor to get more juice outta it and to run it for a longer time.
Also , I'm thinking about cutting the costs , if I could get my hands on some cheap deep cycle batteries.

Suggestions ?


Can I add some mechanical crank system to charge the battery in case of a prolonged failure ?

Help a guy live off the grid

[Anonymous No.550024]

More batteries in parallel? You want to keep them trickle-charged and not discharge them to the point that the voltage starts to drop off. Lead-acid batteries are cheap and effective, but easy to ruin.

Solar cells can be an effective way to keep them topped off, but if your problem is long outages then that's not going to cover you. Other than a generator (or car) I'm not sure what to suggest that isn't going to be elaborate.

For lighting, NiCd batteries and LEDs would be my choice, and that's something where you've got a better chance of being able to recharge during daylight hours using solar power. Or go oldskool with a kerosine lantern or something like that. Learn to make candles.

[Anonymous No.550027]

If all you want to do it run some 8W Lights and a phone charger I imagine a UPS would be good for a couple of hours tbh. Your only going to be drawing about 20W, so if you multiply max load (in W rather than VA to be conservative) by full load backup time you'll get Watt - minutes of power, then devide this by 20 to get your time.

For example say you had a 500W UPS with a 10 minute full load time, that would give you 5000 watt - minutes, or 250 minutes at 20 watts, you may want to add another conservative fudge factor to account for inefficiencies at low load so say 75% of that, which is still about 3 hours.

One thing I would say is that some cheap CFL's have shitty power factors, which will drain your UPS far faster than they ought to, personally I would get a low wattage electronic ballast for linear fluorescents which typically have a very high power factor, and are far more tolerant of line power voltage / frequency being all over the place. While on the subject you can get electronic ballasts that will run quite happily on 12 / 24 V DC and are dim-able for a little more, and rigging up a DC to DC phone charger (just use a car socket charger) would be piss easy, so in short you could run the whole thing off a single car battery and drop the UPS entirely.

[Anonymous No.550031]

>>550027
Didn't see the laptop requirement, so thats another 30W or so, you'll still be able to run the whole thing for several hours off a cheap unmodified UPS.

[poorfag No.550032]

>>550027
Yeah, but are car batteries ideal for prolonged use ?
Also , if I can get say a deep cycle battery , wouldn't that allow me to get more recharge cycles, while keeping the battery discharge level above a safe threshold ?

[poorfag No.550034]

>>550027
I could order them online , or I could replace them by LEDs.
Even one cfl would suffice. I just need the setup for my laptop and phone juice. I thought of a bigger battery in case of a prolonged outage.

Also , any thoughts on the alternative charging methods ?

[Anonymous No.550036]

>>550032
Depends how cheap they are and how long you want to run them for, a battery that wont start a car might be fine for running 50W for a couple of hours.

Likewise a fresh 12v 40Ah battery will give 96Wh without discharging bellow 80%.

[Anonymous No.550099]

>>550022
Get a bigger UPS, or a UPS that specifically is designed for an optional external bank of batteries. Part of the problem is the ability of the UPS to charge the batteries connected to it; if it's not designed for external batteries, you could overload it's ability to charge the batteries, damaging/destroying it.

So far as using a "hand crank generator": you'd soon discover that it's not practical and you'd wear yourself out in less than an hour, and not have charged the batteries more than a tiny fraction of their capacity. Get a white LED flashlight with a handcrank instead.

[Anonymous No.550109]

>>550022
I live in the USA. The power goes out all the time where I live. I have two 12v 105Ah deep cycle marine batteries, a 2KW inverter, and it all rides on a dolly so I can wheel it around where ever I need power.

I have several ways of charging it up when the power is off, but I rarely need to. I also have a 5KW gasoline generator.

Look into bicycle power generators, wind turbines, and hydropower. See which one would be best for you. A surprisingly small wind turbine can trickle charge a battery array.

FYI, car batteries/deep cycle marine batteries are good for about 5 years max. The best batteries for this sort of thing are the ones normally used in some electric golf carts. They are, "Nickel–iron battery (NiFe)", aka, "Edison battery". They are usually more expensive but will last decades in most cases. They are expensive, big, and heavy.

[Anonymous No.550112]

>>550109
forgot pic

[Anonymous No.550118]

>>550109
>two 12v 105Ah deep cycle marine batteries

Where did you get them and how much did they cost?

[Anonymous No.550141]

>>550118
An autobody shop. The first one was around $50 and the second one was just over $100 since the price of lead and batteries skyrocketed. The first one was still under extended warranty and developed a bad cell just the other day. So, I have a brand new one for free. The warranty was worth it.