Whats better for 12v Lithium 3s vs 4s

Tools used in this video:
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FAQ:
8) Why not use Supercapacitors?
A. Batteries work better at this time, caps are rare and expensive devices that are very good at doing things not needed for storage systems typically.
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[towmater]

As nearly all 12v stuff is designed for automotive use it is most common that is has an operating tang of 10.5 to about 15.1. A 3s system is over taxed and under power for such a work load in comparison to the 4s. 3s has to be max charged to give any range at 12 and above where as 4s has it in spades. A slight under charge adds life to a4s and stopping discharge at 12.2 would also add Life. Comparing the two with flooded lead acid that only has about 35%discharge and such a short life, lithium in either combination is better. I think for the money we spend to build these packs, that the 4s with its longer life span is money better spent! Thank you for the great videos Jehu!

[alejandroluna]

I USE 4S PACKS FOR MY 300W INVERTER I TRY TO KEEP AT 13 TO 15 VOLTS WHIT A COUPLE OF DIODES AND WORKS SO NICE AND THIS IS CHARGING WHIT 100W SOLAR PANEL , IS VERY USEFUL AND SAVE ME A LOT OF POWER!!!!THANKS FOR SHARING

[AlexandreLollini]

In the end 24 V has a lot of advantages : smaller wires/longer wires wider voltage tolerance of devices, battery easier to manage, and 7S.

[emmanueloffiong]

To add to this, when using 3s battery system, you need to increase the ampere of the battery pack so that it stands the long time duration and by using this method it will mashup with any type of 12volt inverters instead of using 4s battery system which will select some brand of inverters

[pleasecho]

My testing with 24 used cells in 3S comes out to right around 12v which doesn't allow for much use before the inverter freaks. Better off using 4s for those cells because they won't always get to 4.2 anyway. I find 4.15 - 4.17 about as charged as they get

[poman]

I tested 3S 12vdc vs 4s14.4vdc for my portable boombox. The Kenwood amp m3004 will operate at 16.6vdc so by the time the bms shuts off at 11.2Vdc I have outlasted the 3s version by 30% as well as having more power because the higher voltage allows for greater amperage to be delivered.

[totesdev]

Hi Jehu, “Victron” make inverters with programmable upper and lower limits. Their 12v inverters go up to 17v so perfect for 4S. Another point to demonstrate is that each time you add Li ion batteries in series the transient voltage range from flat to charged becomes larger. 1S = 3 to 4.2 so 1.2v range. 2S = 6 to 8.4 so 2.4v range and so on. Easier to demonstrate in a chart. Keep up the great vids and trim out a little waffle :-)

[jestronixhanderson]

I've run 3s as a test to my larger system I'm building, I charge to 4.0 and go down to 10.5 or 3.5 per cell. I've found on 3s you are getting the best meat out of the discharge curve. There's very little up above 4.0 and little below 3.5. Have a look how quick the fall off is after 3.5 when discharging I'm getting around 70% use, which is perfect as far as being kind to the cells and cycle life. I pull 1.2kwh out of my 1.8kwh pack of 240 x2ah 18650 pack. 8 months and haven't needed to balance the packs. Discharging to 3 or lower I think my packs would become unbalanced.

[DrFruikenstein]

I like how you put a condensed version of the stream on YouTube.

My portable computer project already has a buck/boost ATX PSU to run the computer, and a buck/boost DC to DC converter for the twin displays in the lid. Both will run from 6 to 30 VDC, and the AC power supply is a 19 Amp 13.8 Volt unit.

I had already decided that LiFePo4 cells would be best for battery power. While I may pay a bit more, I'm planning to get my cells from a local eBike shop. I'm hoping I can get a good BMS there, too. If not, there are other options.

[tjmazur]

The Xantrx Freedom X inverter has an adjustable LBCO of 10.0 to 12.8 volts and a High Voltage Cutout of 18.0 volts. You could use either 3s or 4s with this inverter.

[rajeevranjan]

In yesterday's live session, I too had brought this question. One of the guy @JulianRandomProjects suggested that a lead acid inverter can be configured to set the cutoff limits by changing the resistance. And then I looked into it and he was right. It can be configuration to exactly our need i.e. 9v- 12.6v. There are 5-6 resistances and preset to configure lower cutoff, and so does for upper cutoff voltage. And this would work in almost all the inverters whose pcb is not multi layered and which don't use a single micro controller instead of multiple individual components. Some people call these inverters a Digital inverter. I don't know whats the correct term.
In general anything you import from China is highly probable that would be multilayered PCB and would not be suitable for it. In my country, 12v inverter system is used in almost every house and all the local brands are configurable. On gathering information about pros and cons of these two types of PCBs from local repair shops, came to know that the Multilayered PCBs are better choice for longer run unless you play with it. The local PCBs have much more components and their some of individual components tend to fail after some time. So they are easily repairable but don't have that great life without going anything wrong and those multilayered works great for a long time without any issues if operated within their range

[phizicks]

4S is probably best and under charging would also make them have a longer life.

[powerbatterychannel]

Discharging to 3.33V has one great advantage: in case you don't discharge the battery completely, the number of cycles considerably increases in comparison with discharging to 2.8V or even 3.0V.

[sntk]

The reason why the alarm didn't sound till you wear at 16.3 volts has to do with the components used in the inverter if the inverter is built with cheap components, it will have an accuracy of +/- 10% if it built with quality components they Will have an accuracy of +/- 5%

[sntk]

IMPORTANT - You should also note that you are using a pure sine wave inverter which is what household electronics are engineered for and the cheaper inverters are square wave And if you want to look up the science behind it, you're more than welcome. But basically your electronics will run hotter with a square wave that can create potential hazards and drastically shorten the life of your electronics.

[SeanBZA]

4S 2with undercharging will give a very much longer cell life though, as you will not have as much cell degradation. Might give you 5000 cycles of full discharge compared to 1000 for the 3S version, plus you would have much more usable capacity of the battery pack anyway.

Better still is to modify your load so as to be able to use the 4S full charge voltage, or use a cheaper inverter with modifies sine wave instead, which is a lot more tolerant of input voltage range, though it likely will need slight modification to have better smoothing capacitors on the input side to handle the higher ripple current.

[mondotv]

10.32 “Who’s good at math here?” just when I was asking myself why Jehu needed a calculator for this video. LOL.

[OHSTN]

Awesome video.
LiFePO4 is definitely the way to go for 12-volt gear, we just need to parallel them to get greater capacity. Li-Ion is not a deal breakernot. try 3s2p-3s4p without the DC/DC buck, or 4s2-4p with the buck or under charge.
I really enjoy these problem solving videos.
Thanks for sharing

[skaltura]

That inverter is meant for automotive use, so flat battery is around 10V, and faulty alternator may give you 15.5V. 13.8-14.4V is typical voltage.

[snoopyjc]

Losing 200 out of 2200 is 200/2200 = 9% loss