LiFePo4 A123 Systems, best rechargeable Battery 18650 for EV, Solar, Wind and more.

[PERIZ99]

Good info-

[9493760]

THANK YOU SIR. GIANFRANCO FRONZI. JAN.21/12

[thegreatnoleander]

According to user responses on EV forums, A1234 is the worst for the money. It's an awesome battery buy it's way too expensive. Thunsder-Sky and CALB took the lead, with Headway not too far behind. A123 cells are only good where you can't fit anything else in the given area and you absolutely need that high discharge rate or you can afford to buy the most expensive thing around.

[electrodacus]

@thegreatnoleander I paid 0.6$/Wh on this battery. How much cheaper are the others? and do they offer the same reliability and cycle life?

The cost of battery for comparison is usually done as $/kWh during the life of the battery.

This A123 have at least 2000cycles to 80% discharge and cost 2$ 3.3V 1000mA = 3.3Wh x 2000cycle = 6.6kWh for the lifetime so about 30cent /kWh stored.

Now the prismatic A123 20A may be better for large system but I do not think is under 20cent /kWh.

[ShadowwwLFS]

What's the ebay seller you got them from? sz_ohmygod?

[electrodacus]

@ShadowwwLFS Yes is the only one on eBay with this batteries.

[ShadowwwLFS]

@electrodacus Hehe, good to know. I have 8 batteries from him (18650, going to use in 4s2p config for bike light with a 8W LED), and I still wasn't sure if they are genuine. Now I do, thanks. :)

[electrodacus]

@ShadowwwLFS I do not know for sure that they are genuine but they work great.

I will also probably by more but I will need 1kWh battery and this are a bit small for this next application. I will still get LiFePO4 since this is a great technology for what I need but probably go with Headway 16Ah parts less soldering :)

[ShadowwwLFS]

@electrodacus A123 Systems also has 20 Ah pouch cells - they're hard to find, but if you're lucky you can find them for $40/cell or so. :P

For 1 kWh you'd need just 15 of them, which'd cost you $600. Pretty expensive, but depending on what you need them for they may be worth the investment. :P

[electrodacus]

@ShadowwwLFS Thanks I need to search and see how they are.

Most LiFePo4 are about 0.6$/W including shipping and that is fine for me.

[justlivemyway]

Thanks for the info. I was not able to understand the fun part. Why does the battery switch off when there is less load drawn @ 400 watt compared to 1600 watt?

By the way R u from China ? Your accent says so.

[electrodacus]

@justlivemyway At 600W (200W bulbs + 400W hair dryer) the inverter shout down the load because the battery voltage drops under 10.5V.

The inverter is designed for Lead acid batteries and they are not allowed to work under 10.5V

At 1600W the over-current protection acts first to shut down the load.

I'm from Romania :).

[staticxmako]

hi great video, im really interested in getting a lighter solution for my four wheeler battery, and ive been in the rc hobby for a wile now. but i never got any a123 batteries or lifepo. is lifepo4 the EXACT same thing as a123? becuase these cells are shaped like NIMH's or nicads and i was looking at a lifepo4 on hobbyking and it looks like lipo cells. would a lifepo4 be safe on my quad were no heat will get to it?

if you could explain the 2 it would help me so much!

[electrodacus]

@staticxmako A123 and LiFePo4 are the same first is the brand and second the technology.

This are 18650 so 18mm diameter x 65mm length.

Lipo are totally different they have about 2x the energy density of LiFePo4 but much less power density.

So a Lipo at the same size will have over 2000mAh but will be able give less current probably less than 2C to be safe compared to over 10C on LiFePo4.

LiFePo4 are extremely safe is impossible to make them burn or explode. 

[staticxmako]

@electrodacus thanks man i REALLY appreciate the help. so my next qeustion is. whats your experience with balancings these? do you really need to. and put in the application of a race quad. where the magneto is constantly charging it, would this be safe without ballancing. becuase hyperion does sell a balancer that may work for this application. but if i can stay away from buying it that would be great.

in simple turms how bad it is to constantly charge, store for long, and then draw

[electrodacus]

@staticxmako Yes unfortunately this need to be balanced and since this are not to exceed 3.6V compared to other Lithium technology 4.2V / cell there is not that easy to find BMS for LiFePo4.

I did not used any balancing just manual cheeking during charging that none will exceed 3.6V but I only made tests and was not important.

Storing this batteries is absolutely no problem they have really low self discharge probably less than 10% on 3 months storage.

[staticxmako]

@electrodacus ok thanks for all the info man this realllllyy helps me out alot

[electrodacus]

@staticxmako You can find some 12V with BMS on eBay, 4.6Ah and the price is about 300$ they are from Taiwan but I guess is a bit to expensive.

The reason this are expensive is that they are not really mass produced as of now.

[staticxmako]

@electrodacus ok i was looking at welllll youtube wont let me show you lol. i was looking at a rc pack from hobbyking for $40 its a 4 cell 4200mah i think it should do fine i dont know how much draw each like 2 to 6 second start my starter motor will draw but 4200mah is alot less than 4.6ah's right?

[electrodacus]

@staticxmako I guess is this Z42004S-30-2P but not sure if they are LiFePo4 since there are 8x 18650 size cell inside judging from the size and the one I have are 1100mAh but they claim 2100mAh / cell and I do not think is possible.

Either there is no LiFePo4 cells inside or or not 2100mAh/ cell.

Anyway something like that will not work on you Quad since there is no electronic to regulate charge and discharge.

4200mAh is 4.2Ah so quite similar to 4.6Ah except that are real and have electronics.

[craftymaggot]

Where are these batteries available from??

[electrodacus]

@craftymaggot I purchased them on ebay search for A123 LiFePo4 this are 1000 - 1100mA there are also larger the 2300mA or if you want even more capacity on one cell then you can get the Headway they are from 8Ah up to 16Ah.

[poweressen]

Wow, what an awesome demonstration, if you need cheap batteries, i searched and found a 200AH agm battery for 300 bucks, the brand is Powerstar But that battery weight 130 Lbs, four battery like that could push 480 watt for 20 hours(on torture mode), for 1200$, :) But personaly i would run them in series with a 30v-60v dc/ac inverter to use smaller wires, and lower the heat in the battery. Realy nice demonstration, and your accent is pretty cool!

[electrodacus]

@poweressen Thanks, I appreciate your comment.

The 200Ah AGM at 300$ is a good deal but it depends on your application.

Here in Canada the best price for a quality AGM was 300$ for 100Ah so double.

There are some problems with this battery in my application I need 2000W and with this battery the capacity will drop at this power to much and also it will reduce the life of the battery.

So this battery is about 12V x 200Ah about 2400Wh capacitate but you can use just half of that on AGM battery

[electrodacus]

@electrodacus So the price for AGM battery is 0.125$/Wh but not including shipping that can double the price.

Then for the same useful capacity you can get about half the Wh of LiFePo4 since they can be discharged down to 80% with no effect on battery life.

Also it can easy provide me with 2000W gain without damaging the battery. I do not know how many recharge cycle you can get out of that AGM but probably much less than from LIFePo4.

[electrodacus]

@electrodacus I will also have some wind turbine that in high winds will put to much energy for AGM and they can vent hydrogen. For up to 500W solar panel 4 of those will probably be fine.

In order to make a good comparison between batteries you need the spec and need to calculate how much energy you get from each then compare with price/wh

Ex AGM 600 recharge down to 50% 2400Wh*0.5=1200Wh*600= 720000Wh=720kWh

LiFePo4 2000 recharge down to 80% 2400Wh*0.8=1920Wh*2000=3840000­Wh=3840kWh

[kaynd]

Nice demonstration but I was expecting a more useful test at the end. You could try for example, just one 40w bulb and see how long that battery pack would last. This could show the useful capacity of the batteries under more realistic conditions. (Taking account of the inverter losses and the capacity drop due to high discharge current)

I don't think that anyone expects from a 3.3Ah 12V battery to power a 600W load.

[electrodacus]

@kaynd Thanks, You can see how long a single battery last at the beginning of the test (about 16minutes with over 3A load ) as for the 12V pack it will last about 4 to 5 minutes at 400W load and it will be close to one hour with 40W light bulb the inverter is quite efficient over 90%.

I just want to demonstrate that they put up to 15A/element continues about 15C. They really have about 1000 to 1100mAh capacity so is easy to calculate how long they will last with different loads.

[kaynd]

@electrodacus Ah ok I guess. :) I was hoping for a more detailed measurement. The 3A load for one cell is realy high. Voltage and, at the end, Amps drop significantly during those 16minutes. So we are definately not talking about a constant power load like the inverter. Different loads cause different rates of discharge. The faster you discharge your battery the less capasity you are able to use out of it. so that mAh capacity doesn't apply to any load.

[electrodacus]

@kaynd Yes for most battery this is true that the faster you discharge the less capacity you get but is not true for this LiFePo4 batteries. I have an LED flash light with one of this batteries that uses 60mA constant current and it will work for about 14 to 15 hours. And 3A for this battery is not much the spec advertise this battery 30C continues and 60C peak so 3C is just a fraction of this.

This battery was designed for electric cars where they need to provide high current.

[kaynd]

@electrodacus aha that's nice. those batteries should have incredibly low internal resistance. I sould take a closer look to their specs. :) They must be commonly used for RC cars planes etc applications.

[electrodacus]

@kaynd Yes they have extremely low internal resistance so they can provide high current and almost no heat generated.

Yes they are used in RC cars and some time planes but the have less energy density than other lithium batteries Li-polymers have close to double the capacity / weight size.

For RC cars are great since they can fully change in 20 minutes with no problem and they are much safer they will not explode or catch fire.

They are also used in portable power tools.

[Vlakpage]

@electrodacus Of course it is true for any battery which has non-zero internal resistance (and the connected wires too). As kaynd said Ah and Wh are two completely different things.

High current yes, but not 30C, you would discharge that in about 1 minute, who would buy such car? :)

[electrodacus]

@Vlakpage Ah and Wh are not to different o this battery since the voltage on this battery is almost constant from 3.2V down to 3V is about 70% of the energy.

30C is the continues discharge for this battery according to spec and 60C peek in this video I had a bit over 15C when I was using the hair dryer the idea is that most batteries don't have this power density.

If is an RC car 1 minute can be enough :)

If you use a 30C battery at 3C you get better efficiency than using a 3C battery.

[Vlakpage]

@electrodacus You probably mean linear not constant, 3.2 to 3.0 is 6% change, but that's only for light loads. Just look at the measured voltage: 12.15V for the bulbs, that's already almost 3V / cell, then 11.3V for the dryer. That is significant drop, similar to what datasheet says.

Ah assumes constant voltage, so you must say at what voltage which of course varies with load. Wh represent the real energy.

Yes, it's better than usual li-ion but still far from ideal or perfect.

[electrodacus]

@Vlakpage I know the difference between Ah and Wh and yes the Wh represent the real energy. My tests in this video where stress tests not likely to need this in real life.

The voltage drop included the cables and contacts that was significant look at the single battery discharge at 5C 3.15V measured directly at the battery.

For electric cars fast recharge of the battery is very important need to be 20minutes or less to bee acceptable no other battery is able to do this.

[electrodacus]

@electrodacus I do not sell this batteries and have no interests to make this look good.

But they are currently the best battery technology available over 2000 recharge cycle very low internal resistance and not dangerous no explosions or hydrogen gas.

My point is that this is the battery I will use for my off-grid house is the best value battery you can currently buy.

Is safe to say that under 3C this battery has an capacity of 3.1V * Ah * 0.8 = Wh for 80% discharge.

[Vlakpage]

@electrodacus That's nice but which car uses them? I haven't find any yet. For example the Nissan Leaf uses Li-ion and on fast charge it can get 80% under 30 minutes.

[electrodacus]

@Vlakpage Yes there are not to many full electric cars on the road. I think Tesla a luxury sport car is using a123 systems battery and there are some electric motorcycles but there will be probably much more in the future.

Li-ion have better power density than LiFePo4 so they can give better range.