A poll Happy with LiFe (PO4)?

[senormechanico]

I wonder how long this thread will last before getting closed down because it's "not fair to Lead Acid batteries".

[T1 Terry]

The only complaints I have had with all the systems I've either set up or had a hand in/gave advice for setting up was choosing the wrong size cells. The advice I gave to use multiple 100Ah cells in parallel was ignoed and larger single cells wer used to build a 4 cell battery. More drama keeping the cells balanced and now that more storage is required the step up is much bigger, doubling capacity rather than adding 100Ah.
My advice, even though the $$ may look huge, build a bigger battery bank rather than trying to get by on an undersized bank to save a few $$. The pain of the high cost soon fades but the continual kicking yourself for not building the system you needed first off just keeps getting worse each time you run short on capacity.

I agree with all Mainsail said, I think I've said the same thing a few times. It's the know everything can't be told mob that will create the problems, not the product itself.
If you treated lead acid batteries the same way they would die in 1/4 of the time, but that will never be admitted, keep 3.45v as the max voltage and 2.8v as the min voltage per cell and they will last a long long time. Mine are up around the 850 cycles now, some of them have been very deep, one to below 1.35v per cell, that was a few mths ago, they are still functioning like it never happened, there is no way you would get away with that using lead acid batteries, it would be the equivelant of pulling a 12v battery down to 5.4v and expecting it to fully recover.
The capacity test in the new yr will tell me how much damage I've done. Up till now every test has produced more than the advertised capacity, even at the 700 cycle test, there is no way in the world a lead acid battery would do that.

T1 Terry

[deckofficer]

Terry,

You have more cycles than any of us. Since the nagging question among early adopters is "will they give their advertised cycle life of 2000 cycles before dropping to 80% capacity" is still floating around the threads, I have decided to find out.

Since I have two banks that are small (100 a-hr), it will be much easier for me to cycle a lot than the folks with the big banks. As of yesterday I have cycled one of the banks 7 times running a 1500 watt space heater for an hour, then charging at 50 amps for 2 hours. I am determined to prove that just like the manufacturer's conservative a-hr rating, their cycle life rating is also conservative.

[T1 Terry]

Hi Bob,
As you only have 100Ah battery banks the load should not be more than 50 amps for the cycle tests. All the makers specs use 0.5C charging and discharging to calculate cycle life. don't take the cells over 3.5v if constant voltage charging or 3.8v if constant current charging @ 0.5C The most important part of the cycle testing is not to hold the cell voltage at anything higher than 3.5v, for long term like a day or so, 3.4v, it's the over voltage that boils the electrolyte and shortens the cell cycle life.
My poor cells have coped a beating over their cycle life, rather severe ones just lately but I’ll detail those else where to save this thread getting bogged down with techo stuff. They are still working though, so they can also take a lot more abuse than some seem to believe, but it must shorten their full capacity cycle life.

T1 Terry

[deckofficer]

Thanks for the tip Terry. The space heater I'm using is 1500 watts on high and I don't know what it is on the lower setting because I don't have my Kill-o-watt meter but the time to discharge will give me a good idea. On the high setting the cables, Anderson connector and cell connectors get hot so I arranged the inverter so that the 3 fans on it that cycle about 50% of the time is blowing across the battery top, cable and connectors. From your recommendation I will now do the cycles on the lower setting and during charging turn off the charger before it tapers to 0 amps because that brings the cell voltage to around 3.7 volts. My cells are 4 years old, 3 years old before I got them from Balqon. When I first got them I top and bottom balanced them and then cycled them about 5 times and then they sat unused for another year. The first cycle at 1500 watts they ran 57 minutes before the low voltage alarm went off at 2.9 volts. As I cycled more they gained more capacity, yesterday ended with them going 59 minutes and today they have climbed to 62 minutes. Looks like they like to be cycled rather than just sitting.

[T1 Terry]

Another tip I picked up from reading their book that came with the cells regarding capacity testing, they let the cells sit till they have cooled between charging and discharging when charging at a higher rate than 0.5C but they also let the batteries sit for 20 mins I think it was between each charge and discharge cycle to allow the charge and temp to dissipate evenly through the cell I'm guessing.

They certainly don't like to sit fully charged for more than a few mths, they should be stored at 50% SOC, any where between 70% and 40% would probably do the trick, just not fully charged.
Do you think your cells had lost capacity due to sitting for 12 mths and that is now returning? It certainly is a very interesting observation, the heavy cycling is increasing the capacity, so possibly cells that have lost capacity for what ever reason can actually regain some of that capacity. Alway something new to discover with these batteries when used as house batteries, a very different application to EV use and that appears to be where most of the documented learning in based, heavy load and deep discharging and over voltage recharging. We are all discovering what happens when they are light load and capacity discharged and more gently recharged, and with those using solar, mini cycling and low voltage float charging to fully charged a well.

T1 Terry

[deckofficer]

Well it looks like my cycle test are going to be more demanding. I haven't done a cycle with the space heater on a the lower setting yet because I wanted to see if the upward trend in capacity was continuing. When I get the same time to low alarm, then I will go to the lower setting. To get all these cycles in, the battery isn't getting any time off between charge and discharge. The cells are a bit warm to the touch. I still think under my harsher testing conditions I'll have no problem reaching 2000 cycles before the 20% drop of capacity.

[senormechanico]

Although I've had some great experience with our 200 aH bank in the boat, I have yet to put my new 24 volt 700 aH bank to the test.
After top balancing them, I installed a Clean Power Auto BMS just for insurance purposes. I made sure all cells were within 0.05 using an automotive headlight and letting them rest a bit before hooking up the BMS. Overkill? Probably,but what the heck.

I have an E-Meter in the circuit ( left over from our boat which got replaced by a BlueSky Mppt controller and IPN Pro Remote).

Now, all I need to do is just kick off the main breaker to our house as well as the solar input to the Midnite 150 MPPT and JUST DO IT !
We'll have 14 people over for Thanksgiving tomorrow afternoon. Do you think this would be a good time after the turkey is cooked?

(Evil Grin)

[deckofficer]

Impress your guests, cook the bird with stored electrons, you got over 18 kw-hr.

[senormechanico]

Originally Posted by deckofficer

Impress your guests, cook the bird with stored electrons, you got over 18 kw-hr.

LOL ! I would, but the inverter is only 2500 watts/120 VAC.
It will run most of the house (not the 240 VAC hot water tank or clothes dryer)
Stove is gas cooktop and 240 VAC oven element.

[deckofficer]

As stout as these cells are, no reason you couldn't up the ante on the inverter to 6 kw.

[deckofficer]

Bump. Only 29 folks on the forum using LiFePO4 cells? At least they are all happy campers with their cells.

[ardoin]

Smug as a bug in the rug!!! Yes.
My boat floats higher on the water line and I have more than double the power.
I'm very pleased. I'm keeping records on the volts/amps/time to see how she performs over time. I only get one or two cycle a week at this time. Bring them up to 13.6volts on charge and down to 12.7 on discharge. So well within the humps on the curve. This gives me over 650Amp/hrs of power with each cycle!
Happy Camper

[deckofficer]

Cy,

Nothing with lead, nickel, or cadmium even comes close to the performance of these cells, glad you like them.

[FlyingCloud1937]

Originally Posted by deckofficer

Cy,

Nothing with lead, nickel, or cadmium even comes close to the performance of these cells, glad you like them.

Bob,

I can see it now.

Directors cut:

cut to cheerleader:

bob; your line : I LOVE lithium.

Lloyd

Have you ever looked at; The Advanced Lead Acid Battery Consortium?

How about Lead Acid Carbon?