Question about building an 18650 Li-ion battery bank - how many mAH is required ?

[johnnyhavana]

Hi everyone,

been into solar for about 6 months now with a small rig up and running.

I've watched quite a few videos on people building better battery systems with rechargeable 18650 Li-ion battery banks, i guess something like Tesla offers.

My question is the capacity of batteries, we would need.
I know there are all kinds from 500 upto 4300mAH, but if i understand this the higher the mAH the quicker output like for an electric scooter, but with solar its more trickle, so we would really only need a lower mAH battery since we trickle charge it.

I guess it also depends on your usage/discharge required?? so am a bit confused, for me, i am basically running lights in and outside of my shed for now, so thats my usage, all LED lighting.
Can anyone shed light on this please.
thank you
Johnny

[max2k]

Hi everyone,

been into solar for about 6 months now with a small rig up and running.

I've watched quite a few videos on people building better battery systems with rechargeable 18650 Li-ion battery banks, i guess something like Tesla offers.

My question is the capacity of batteries, we would need.
I know there are all kinds from 500 upto 4300mAH, but if i understand this the higher the mAH the quicker output like for an electric scooter, but with solar its more trickle, so we would really only need a lower mAH battery since we trickle charge it.

I guess it also depends on your usage/discharge required?? so am a bit confused, for me, i am basically running lights in and outside of my shed for now, so thats my usage, all LED lighting.
Can anyone shed light on this please.
thank you
Johnny

have you also watched videos showing Li- ion catching up fire? They burn fast too. It is the most dangerous battery chemistry and you don't sound very comfortable yet with technology involved. Why don't you start with AGM for example? It would require little maintenance and while expensive it won't last much longer than your learning period at which point you'll switch to something else anyway. Otherwise deep cycle FLA would be the most logical choice if you don't mind dealing with their maintenance.

[Mike90250]

I'm becoming more and more fond of advising beginners to get a automotive jump start pack, and plug into the cig lighter or USB socket and start with some factory designed gear, instead of trying to cobble together a DIY firebomb with no circuit breakers or fuses in the proper locations.

[SunEagle]

I'm becoming more and more fond of advising beginners to get a automotive jump start pack, and plug into the cig lighter or USB socket and start with some factory designed gear, instead of trying to cobble together a DIY firebomb with no circuit breakers or fuses in the proper locations.

I am close to deleting any new post concerning a DIY Li battery system to keep nu-bees from thinking it is a safe way to build their own energy storage system.

There are just way too many stupid people out there that believe the Youtube videos showing how easy it is when it is not easy or safe.

[J.P.M.]

I am close to deleting any new post concerning a DIY Li battery system to keep nu-bees from thinking it is a safe way to build their own energy storage system.

There are just way too many stupid people out there that believe the Youtube videos showing how easy it is when it is not easy or safe.

If you do that, it'll only mean one less way to improve the gene pool.

[Gdwats]

The fact that you are talking about mili amphours is a red flag. Please listen to these folks, you wont find better advice anywhere.

[johnnyhavana]

I am close to deleting any new post concerning a DIY Li battery system to keep nu-bees from thinking it is a safe way to build their own energy storage system.

There are just way too many stupid people out there that believe the Youtube videos showing how easy it is when it is not easy or safe.

OK ok ok, sheesh, i have watched many videos and i know its very dangerous, there was one in particular that really did control and test everything properly, made some mistakes but was able to monitor the volts and keep them in check. Was just asking but i'll stick with my good old golf cart batteries . NO BOOOM

[Gdwats]

Excellent plan!

[Gerard Fivewin]

I'm becoming more and more fond of advising beginners to get a automotive jump start pack, and plug into the cig lighter or USB socket and start with some factory designed gear, instead of trying to cobble together a DIY firebomb with no circuit breakers or fuses in the proper locations.

How about if someone ask about the tesla wall, made of li-ion(s) ??

[SunEagle]

How about if someone ask about the tesla wall, made of li-ion(s) ??

There are a few members that have pursued the installation of a Tesla PowerWall unit. I am sure they can provide answers to your questions.

[Gerard Fivewin]

I mean, you guys are worried about using li-ion batteries whether its factory made or DIY.
Is this also a bomb, wow look how they make powerbanks in a factory. Picture, screenprint from this vid https://www.youtube.com/watch?v=XzhtFwmJVDo

[NEOH]

I mean, you guys are worried about using li-ion batteries whether its factory made or DIY.
Is this also a bomb, wow look how they make powerbanks in a factory. Picture, screenprint from this vid https://www.youtube.com/watch?v=XzhtFwmJVDo

I do not think the device in your photo is a "Power Wall".
It appears to be either a "testing" station and/or "top-charging" station.
The device in your photo is not a Retail product.
No, it is not a bomb.

[J.P.M.]

I mean, you guys are worried about using li-ion batteries whether its factory made or DIY.
Is this also a bomb, wow look how they make powerbanks in a factory. Picture, screenprint from this vid https://www.youtube.com/watch?v=XzhtFwmJVDo

Truly awe inspiring ! Although it seems they've got a ways to go before the get the process automation/robotics nailed down. A real confidence builder ain't it ? More lame brain junk from the idiot's bible.

[SunEagle]

I mean, you guys are worried about using li-ion batteries whether its factory made or DIY.
Is this also a bomb, wow look how they make powerbanks in a factory. Picture, screenprint from this vid https://www.youtube.com/watch?v=XzhtFwmJVDo

That video is from a manufacturer that makes small portable storage units using Lithion chemistry batteries. The picture you posted is nothing more than a test station. It is not a home sized energy storage bank and will never be one.

Gerard, if you want to build your own battery bank using Li technology I can't stop you. What I can do is point out to others that a DIY lithium battery bank that is more than one of those portable units can cause fires if not built properly.

For that matter there are a number of "factory made" lithium battery powered devices that do go up in flames like the E cigarette units and those hover boards that have lit up some people. So get off your high horse and listen when I say DON"T PLAY WITH FIRE or build a DIY Lithium battery system.

[jflorey2]

My question is the capacity of batteries, we would need. I know there are all kinds from 500 upto 4300mAH, but if i understand this the higher the mAH the quicker output like for an electric scooter, but with solar its more trickle, so we would really only need a lower mAH battery since we trickle charge it.

No; you are confusing a lot of things here.

First is ENERGY. Energy is amp-hours times volts. That's how long you can run loads.
Second is POWER. Power is amps times volts. That's how large a load you can power. (In EV's it's how fast you can accelerate and how fast you can go.)

Those are two separate ratings. mAH is how batteries are often rated; you have to look at the datasheet to get max discharge.

so am a bit confused, for me, i am basically running lights in and outside of my shed for now, so thats my usage, all LED lighting.

I'd get a lead-acid battery or a well designed lithium ion battery with a protection circuit.

I mean, you guys are worried about using li-ion batteries whether its factory made or DIY.
Is this also a bomb, wow look how they make powerbanks in a factory.

That's a testing facility. Testers like that have VERY good fire suppression systems, because that's where they catch bad cells.