iPhone Battery dc-ac circuit

[liamoc74]

Hi all,

Ive an astronomical amount of old iPhone batteries, not good enough for phones and just sitting there. I own a phone repair business so will also have a constant supply of them. They all have power in them too, well most of them.

How would I go about building a circuit with a DC-AC inverter so I could power some household stuff(i'm actually thinking about a mining rig :/) with these?
Could I build little packs out of them and hook them into the circuit as needed?

Any ideas welcome - just a thought... but a project i'm definitely going to give some time too as the batteries are just building up and its not going to stop..

Thanks,
Liam

[eccerr0r]

Re: iPhone Battery dc-ac circuit

They're batteries, not power sources, once they deplete, they won't supply any more power. And likely they won't be holding more than a watt hour per battery (they ARE dead, aren't they?)

Or do you mean you want to make a very poor density battery pack to just store energy? Even this will be tough as the batteries are in such poor condition that you'll need to parallel and series them to get enough voltage, but if you do that you'll also need to somehow balance them.

If you find a way to balance them and you have...hundreds of them...

Because they are "poor" and "unknown" condition I'd build packs of probably at least 10 in parallel. Mix and match these cells in 10-packs so that you have 42 of these packs (420 cells). You'll need to make sure each of these 42 packs have exactly the same capacity. Connect these 42 packs in series and now you have a large ~168V battery.

Then comes the electrical part: With a microcontroller and a bunch of P and N MOSFETs you want to make an modified sinewave H-bridge. Make sure you drop to 0 for a while just like the modified sinewave inverters.


If you don't want to do this, you can always just pack them to a large 12V battery and use an off-the-shelf inverter. You still need to balance them however.

The balancing in either case will be the difficult part as if you screw up, expect your whole pack and anything nearby to be:

[momaka]

Re: iPhone Battery dc-ac circuit

Building a large battery pack with old tired Lithium batteries = sure way to start a fire!

That said, any self-respecting pyro should have attempted that at least once in his/her career by now.

[CapLeaker]

Re: iPhone Battery dc-ac circuit

it's a good idea at first, but yet not. On top of that, you would have to control each cell. Not worth friggin around with old cell phone batteries to make a Frankenstein battery bank in a big scale.

[liamoc74]

Re: iPhone Battery dc-ac circuit

Ahhhh this all sounds so mad scientist like and good.. exactly what i wanted to hear!!
I'm not sure how or what I want to do but its just a shame having all that power just sitting there and not putting it to some use..

i think building the 12v packs and an off the shelf inverter would be the best way to start or else i'll just end up blowing the whole village to pieces which is probably best avoided.

What sparked the idea initially is the crypto mining rig i have, i was wondering how i could power it for free and basically get free crypto - then i thought of the batteries.
theyre not all dead, alot of them would have been replaced because they had so many cycles etc and power off at a certain percent but when replaced they still had power in them.

ive two retail stores so were constantly getting old batteries with power in them, if i could build them in packs, and then just rig them into the system to extract the power and then i could dispose of them dead.

Is it possible, am i raving? could we build it on a small scale to power just a laptop for any amount of time and then build it bigger to power a full mining rig..
if it worked it would be pretty cool in fairness...

[eccerr0r]

Re: iPhone Battery dc-ac circuit

There is likely not enough power in them to be worth the effort. The power you use to solder everything together is likely more than how much remaining power you'll get out of the batteries, unless you were planning to use your pack to steal power from somewhere else.

[liamoc74]

Re: iPhone Battery dc-ac circuit

OK.. Ill grab 10 at random right now and throw the multi meter on them and see whats in them..

[liamoc74]

Re: iPhone Battery dc-ac circuit

- 3.8V
- 3.7V
- 3.7V
- 3.7V
- 3.9V
- 3.9V
- 2.2V
- 0.1V
- 3.9V
- 0.7V

The average on this batch of 10 is 6.45Whr, stamped on each battery..

[liamoc74]

Re: iPhone Battery dc-ac circuit

- 3.8V
- 3.7V
- 3.7V
- 3.7V
- 3.9V
- 3.9V
- 2.2V
- 0.1V
- 3.9V
- 0.7V

So thats 29.6V in total, 2.96V Av per battery..

The average on this batch of 10 is 6.45Whr, stamped on each battery..

[CapLeaker]

Re: iPhone Battery dc-ac circuit

Only because they have 6.45Whr stamped on there, doesn't mean they actually have it. After all they are all used and they must have had suffered capacity loss, because that is the reason they got changed out first place. Whatever you decide to do, you have to be able to charge and discharge the cells individually. If you don't, it's gonna blow sooner than later. So be aware what you are doing with that type of battery chemistry. Also your battery back voltage (lets say those 10) will be all over the place, since all batteries are going to be different.

you will find out soon that this project cost more and the risk of fire is higher than what it is worth, to power something large scale for a period of time. You've got quite a bit of reading to do.

[budm]

Re: iPhone Battery dc-ac circuit

Testing batteries without loads does not really tell the true condition of the batteries.

[momaka]

Re: iPhone Battery dc-ac circuit

There is likely not enough power in them to be worth the effort. The power you use to solder everything together is likely more than how much remaining power you'll get out of the batteries, unless you were planning to use your pack to steal power from somewhere else.

OMG! It's like you took these thoughts away from my head! I was thinking about posting that all day today.

I guess we are square now, as I did take that JEE joke away from you in that Deer thread.
https://www.badcaps.net/forum/showthread.php?t=64563

[eccerr0r]

Re: iPhone Battery dc-ac circuit

Well, the question needed to be asked when the physics doesn't quite make sense