DIY lithium banks

[X_Factor]

anyone looking into doing the diy lithium battery banks
or have a diy built bank?

Its fairly cheap for the power that you will be getting, and while i know lithium is fairly volatile once it is set up and used properly as intended there should be no harm,
e.g mixing lithium with agm/lead acid without an isolator
choosing proper lithium chemistry, lto, life, li mn etc for your build
using a proper cell balancer etc

[adnj]

Yes but not for audio. What are you trying to do?

[X_Factor]

its becoming widely used in the car audio environment
many people have banks powering up to 20k rms for spl competitions

its cheaper, smaller, lighter and provides stable voltage once matched properly than equivalent agm battery stacks

[X_Factor]

that bank of li mn 35ah will power 5krms easily and only costs 450usd with a proper bms

[nervewrecker]

In for info.
Glad is not me alone thought of it.

[jahs0ldi3r]

Just scrap old laptop batteries, most of them contain 18650 lithium batteries which you can series and parallel connect to suit your voltage, amperage and power needs

Was onto that but sold ask I had to a guy here on tuner who wanted to build a diy tesla power bank for his house

[X_Factor]

18650's have small little ah rating
you need cells that have on average 5ah and up
most common are
yin longs 18650.
..headway 38120
ford cmax ( those guys in the states get them from wrecked electric vehicles)
li mn cells which look like the pic above

[X_Factor]

https://www.youtube.com/watch?v=zuynxo_ ... QcO4hMfQoQ

thats the size of the batteries

[adnj]

Using scrapped 18650 batteries will work if you match type, internal resistance, capacity, and discharge rate.

3000 mah (3 ah) 18650 batteries are very common. How you design your battery bank determines capacity. Panasonic and Sanyo consistently make some of the highest capacity lithium cells.

Yin Long and some other Chinese manufacturers label their 18650 LiIon batteries at capacities in the 3500 mah to 6000 mah range but with tested capacity of less than 900 mah.

If you want greater capacity you can move up to a 21700 or 26650 with typical capacities of around 5000 mah.

Just scrap old laptop batteries, most of them contain 18650 lithium batteries which you can series and parallel connect to suit your voltage, amperage and power needs

Was onto that but sold ask I had to a guy here on tuner who wanted to build a diy tesla power bank for his house

18650's have small little ah rating
you need cells that have on average 5ah and up
most common are
yin longs 18650.
..headway 38120
ford cmax ( those guys in the states get them from wrecked electric vehicles)
li mn cells which look like the pic above

[X_Factor]

I made an error the yinlongs are 66160 35 or 40 ah capacity

[X_Factor]

another pic for size reference

the messy thing about using 18650 is way more batteries to properly wiring in a bms to balance charge the pack...
i dont think they are made to charge at the high amperage of an alternator
failures could creep in and could mean fire

[X_Factor]

one of the reason why lithium is so volatile and why dealing with lithium is very different

[adnj]

another pic for size reference

the messy thing about using 18650 is way more batteries to properly wiring in a bms to balance charge the pack...
i dont think they are made to charge at the high amperage of an alternator
failures could creep in and could mean fire

FB_IMG_1548761914501.jpeg

This or 8 21700 batteries for similar energy storage.

The are advantages that LTO has but for your stated usage I doubt that you will see many.

Building a 3S8nP pack with balancers may end up being simpler than a 5SnP or 6SnP pack using the cell you show because of the lower nominal voltage.

[pugboy]

you have to shop around for the right 18650
the good mfgs make them in various specs, high capacity low burst current, high current lower capacity etc
the cheap ones of often rebranded avg cells
the laptop ones are likely just good for constant low current delivery
tacking/soldering to them has to be done carefully

thats what all the cordless tools using now

if you want big power get radio control lipo packs, they much more dangerous to use as they get permanently damaged by over discharge
all lithium packs should be balanced charged

[X_Factor]

18650 cells are too small in capacity and using to many can result in problems
66160 are the preferred for this purpose

[adnj]

18650 cells are too small in capacity and using to many can result in problems
66160 are the preferred for this purpose

You may not want to use smaller cells but if designed properly, a bank of smaller cells has higher energy density.

I also stated earlier that LTO batteries have a lower nominal voltage than LiOn and more must be used in series. It is the series connection that magnifies the problems of cell imbalance.

[X_Factor]

there are pretty good balancers that can be wired in to reduce cell imbalance and it is recommended to break the bank and balance individually once a mth or two

[X_Factor]

ok so my hurdle is lithium batts like these need hazmat clearance to ship which is around 200usd

also with the ibs charging system in the car it may not charge the bank properly

[88sins]

ok so my hurdle is lithium batts like these need hazmat clearance to ship which is around 200usd

also with the ibs charging system in the car it may not charge the bank properly

since it's for car audio purposes, did you consider using capacitors instead of Li batteries? There's some 2.7v 3000F super capacitors available nowadays, about 5 of those would get you 13.5v & 15000F.

[adnj]

ok so my hurdle is lithium batts like these need hazmat clearance to ship which is around 200usd

also with the ibs charging system in the car it may not charge the bank properly

since it's for car audio purposes, did you consider using capacitors instead of Li batteries? There's some 2.7v 3000F super capacitors available nowadays, about 5 of those would get you 13.5v & 15000F.

That will provide 11.25 Ah of charge capacity. A small 12 volt UPS battery will provide 12 Ah.

[88sins]

caps will be more like 4.1ah, and the small ups batteries are about 7-8ah. but the advantage of the caps is that they will recharge faster, supply more power more steadily, and have a better lifespan and deeper discharge rate than the Pb acid battery.

edit
going to be lighter to, as well as more efficient and cheaper in the long run.

[L'Audi]

A lot of the guys in the audio scene in NY have moved from LiFePO4 (Maxwell and XS) to those yinglong titanate cells and I haven't heard a bad review yet. I'm considering ordering a set with balancers and building an 80Ah bank.

[88sins]

gonna be a pricey setup

[X_Factor]

a 35-40ah yinlong is around 50usd per battery
you will need 4 per bank to get up to a little over 13v and a single bank will handle a clamped 3k rms with voltage not moving from the 13's
if it wasnt such an issue wrt to the shipping (hazmat) i would have ordered it a few mths ago

its now also banned on aircrafts so i cant even take a chance and bring it back in a suitcase

[L'Audi]

gonna be a pricey setup

Already bought the cells - little over $600 USD
In all, I'll end up spending like 7-800 (balancers/hardware). but even then, it'll be a fraction of what an 80Ah lithium battery would cost.

[X_Factor]

Are those cells being shipped to trinidad?

[88sins]

different skyboxes deal with what could be deemed hazmat in different ways. what one won't ship, another will without a problem.

[adnj]

Actually, current supercapacitors have an energy density of 2% to 10% of LiIon batteries and about 8% to 40% of lead acid. They also have voltage/current supply curves that are similar to LiIon .

caps will be more like 4.1ah, and the small ups batteries are about 7-8ah. but the advantage of the caps is that they will recharge faster, supply more power more steadily, and have a better lifespan and deeper discharge rate than the Pb acid battery.

edit
going to be lighter to, as well as more efficient and cheaper in the long run.

[L'Audi]

Are those cells being shipped to trinidad?

I live in NY.

[88sins]

Actually, current supercapacitors have an energy density of 2% to 10% of LiIon batteries and about 8% to 40% of lead acid. They also have voltage/current supply curves that are similar to LiIon .

caps will be more like 4.1ah, and the small ups batteries are about 7-8ah. but the advantage of the caps is that they will recharge faster, supply more power more steadily, and have a better lifespan and deeper discharge rate than the Pb acid battery.

edit
going to be lighter to, as well as more efficient and cheaper in the long run.

yes, but we must keep in mind exactly what caps are and what they are designed to do.
they are not batteries, they don't function like batteries, and they're not made for charging slowly or holding large amounts of electrical current with minimal discharge over long periods of time. that's what batteries are designed to do. comparing them to batteries is kinda like trying to compare apples to grapes. they're both fruit. but that's where the similarities end. same for comparing capacitors to batteries, they both hold and discharge electrical energy, but in totally different ways.

basically, they are used as a way of supplying the amp with all the power it wants as fast as it wants it while protecting the vehicles battery from being drained too low, too fast and too frequently.