Build a 12.8V 150Wh LiFePO4 Battery 4S2P

Рет қаралды 14,363

Жыл бұрын

Quick build of a 12.8V 150Wh LiFePO4 battery. This battery uses eight 32650 cells in a 4S2P configuration. The cells are connected together using printed circuit boards.
www.lithiumbatteryshop.uk/

Пікірлер: 41

@6kill6god68 Жыл бұрын

buying one of those batteries is my half month salary ... its nice to see you putting them together because i cant buy those kind of batteries ..

@JulianIlett Жыл бұрын

Really? The cells cost me £4 each, so eight cells is £32.

@6kill6god68 Жыл бұрын

Yes the batteries are cheap but I live in south America and shipping alone to here is about srd 1500 to srd 2000 ..yes "srd" is my currency.. and I work about srd 4500 a month .. so yeah buying just one battery is already close to half my salary .. 😔 I have to stick to 18650 and lead acid batteries for now .. thanks for the video though 😁

@mr.makeit4037 Жыл бұрын

I guess living in the US and UK, we don't realize the expense involved for electronics in other countries.

@himselfe Жыл бұрын

Surprisingly affordable too for the capacity you get. Might have to get myself some of these!

@followthetrawler Жыл бұрын

This gave me a great idea for building my own battery pack for astrophotography. The commercial power banks/tanks are so expensive, and perversely offer much more than I need in connectivity terms. Just a simple car lighter socket is fine. Looking forward to seeing how you build this out with balancers and chargers,

@KuntalGhosh Жыл бұрын

I bought 16 of them for 30$ because they were 4 year old cells made in 2017 and i bought them in 2021. I am using them on my ups and regularly test them they are holding full watt hour rated capacity. I am tracking the full cycles and run time every day to see how long these cells last and if they are any better than the leadacids i use for ups. These cells were cheaper than new lead acid in watt hour capacity. And they run longer than leadacid due to no pukert effect.

@ai6mk897 Жыл бұрын

I've used similar 6Ah cells in a 4s/1p configuration to power my satellite ground station using a small (100W) solar panel. I did lose 2 of the cells but after using an active balancer, the cells have been behaving perfectly. The balance across all cells is quite remarkable at 1-2mV using a Heltec capacitance based balancer.

@JulianIlett Жыл бұрын

Yes, I've found the active capacitor balancers work very well.

@-Graham Жыл бұрын

1oz copper plane seems very thin for 10A let alone 20A. I know those boards are convenient but they seem vastly under spec for those discharge ratings. I would certainly be wanting something a lot beefier, especially as the bottom voltage seems to be around the 2v level for LiFePO4 cells.

@JulianIlett Жыл бұрын

There's a copper plane on both sides of the PCB, so I guess it's 2oz total. These PCBs are on my 8S4P pack which has been charged and discharged hundreds of times at about 10A.

@-Graham Жыл бұрын

@@JulianIlett I'm sure they work fine, but I have no doubt they do heat up a fair bit. It would be interesting to measure the resistance and see/calculate the voltage drop across one at 10/20A. I hate leaving extra capacity on the table. I am currently building a custom scooter from and old hoverboard and trying to use both 350w motors so I have been doing extensive testing of 37v lithium packs the last few weeks.

@jameshancock Жыл бұрын

@Jehugarcia does some great stuff with PCB bridging of batteries. You might want to take a look. 1000A on headway cells.

@jamhough22 Жыл бұрын

I much prefer LiFePO4 chemistry, soo much safer than Li-on, and you can charge & discharge much harder too. There really isn’t much energy at the top and bottom of the curve, so i suggest cut-off voltages of about 2.9/3v and 3.5-3.55v. That should also extend the lifespan of the cells too.

@JulianIlett Жыл бұрын

On my 8S battery, I'm charging to 28V (3.5V per cell) and discharging to 23V (2.875V per cell). As you say, this is to minimise cell degradation.

@abzaman77 Жыл бұрын

Do you have the PCB files for public usage?

@hi-tech-guy-1823 Жыл бұрын

I would of added a Dubble Screw Terminal block to the PCB For the BMS & Bi Cell Equaliser "Suyep Screw Terminal Block Connector KF301-2P Blue Copper " or 3 ~ 4 Thermals so you can still poke a Multimeter Probes around

@MasterIvo Жыл бұрын

Hi Jullian, I am amazed by how few active (series) capacitor balancers are on the market. Do you know how they are officially called, so I could better find them? Thanks!

@JulianIlett Жыл бұрын

Try these three links: www.aliexpress.com/item/1005005050192601.html www.aliexpress.com/item/1005005244785767.html www.aliexpress.com/item/1005005241453498.html

@JulianIlett Жыл бұрын

I just use the search term "active balancer"

@MasterIvo Жыл бұрын

@@JulianIlett Thanks, but... I think I wasn't clear enough. Im looking to balance series super capacitors. so... not batteries. but to protect my super capacitors (skeleton)

@JulianIlett Жыл бұрын

Ah I see. I've only seen the passive top-balancing circuits (protection circuits really) that are fitted to the supercapacitor PCBs. I've not seen anything with BMS functionality for supercapacitors.

@MasterIvo Жыл бұрын

@@JulianIlett Isn't that weird? Maybe I would have to adjust an active BMS, for the right voltages... or... design one myself, using coils instead of caps to balance them.

@brianhoskins1979 Жыл бұрын

I'm interested in such custom battery packs, but I am worried about safety. I know that you said these particular cells do not tend to catch fire, but I'd still be worried about it. With the setup you've got there, how do you intend to monitor them for problems such as one cell going bad and then that set of series cells getting continously charged from the other set of cells? Or do you not see this as a big concern?

@RandomNoob Жыл бұрын

Lithiun-Iron-Phosphate cells of any size are incerdibly difficult to get to burn, even if you drive a nail through them you will get a lot of smoke and a hot spot but very unlikely a flame. Even if you short them out they will generally just get hot and vent.

@brianhoskins1979 Жыл бұрын

@@RandomNoob I might just have to try that to put my mind at rest. I have a project going on, which needs to use Lithium cells, and will go into the homes of friends and family. I can't have any possibility that they catch fire. So if this particular technology of lithium cells is safe, that is definitely a good thing.

@RandomNoob Жыл бұрын

@@brianhoskins1979 You can get them to burn but it takes some serious damage to the cells to start it unlike lithium-ion that will burn from minor damage or abuse.

@timhull8664 6 ай бұрын

Seem a bit big for only 6ah

@101rotarypower Жыл бұрын

Julian, is here a BMS that would operate in a “automotive like environment” for power sports vehicles, lawn tractors etc? Something that can tolerate variable alternator output to charge the cells back on the charge circuit, allow starter motor currents and both LVC/HVC? Really want to find a board that can do that and is affordable if possible!

@JulianIlett Жыл бұрын

You just need to check the cell data sheets for maximum charge current, maximum discharge current, low temperature limits, high temperature limits. Also, the cells must not be discharged below their minimum discharge voltage or charged beyond the maximum charge voltage.

@magnets1000 Жыл бұрын

what are you going to use to charge it?

@JulianIlett Жыл бұрын

A 60- cell solar panel

@roidroid Жыл бұрын

5:55 Venting is NOT SUS? Things have changed since the 2018 game _"Among Us"._ What a time to be alive. (Don't worry boomers i gotchu, consume thine above referenced material & thusly stay under the radar of later generations and their hunger)

@leungyikwai Жыл бұрын

is it suitable to use it as a car battery?

@JulianIlett Жыл бұрын

Not directly. The starter motor pulls a very large current which may exceed the cells discharge rating. Also, you'd need a BMS to prevent overcharge and overdischarge. Some sort of cell balancing is also needed.

@321tryagain Жыл бұрын

Charge management needs to be done very carefully below 0*C to prevent damage.