LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[T1 Terry]

I thought about that, but I don't know what the weight was before I cooked them, the specs are 3.0kg give or take 100grams, the 200 gram variant would justabout equal all the electrolyte that would be in a cell I'm guessing. still, I will track down a finely calibrated scale and weight them. I'vce been charging them to stop them dropping below 1v, I want to pull them to pieces and see if all the pouches dies and if here is a resistance build up at the junction to the terminal block, is that what causes the resistance to accept charge?
May as well get some value from the disaster, still kicking myself for it though.

The case swelling in hard to see on the ends, but you can see that the cells won't stand up straight, that's because the base is blown out round, the top is the same, the lower sections must have been able to make some extra room as they have ballooned out about 3/4 of the way down, made it quite a trial to actually get them out of the pack.

T1 Terry

[daddle]

I asked a while back what the design criteria was for banding or end plates and the only responses were "shadetree". There is a picture somewhere of the press used by some supplier to squeeze cells back into shape. It was a heavy device: implying considerable pressure.

Does anyone know the actual pressure?

[T1 Terry]

For the banding or crush during use or to return them to normal shape after they have bulged. The pressure during use is what ever it takes to get all the cells butted up against each other, that point is quite easy to feel with just a sash clamp pressing the two end plates together, may be adding all the cell thicknesses together in that pack and squash it till you get that measurement, we aren't talking much pressure at all, as long as none of the cells have bulged.
To flatten them back out after they have bulged, sitting in the hot sun, about the same amount of pressure, with the cells at room temp, quite a bit more, you are trying to bend that ribbed plastic case, if there are a lot of cells that have bulged in that pack, two hands on the round handle of the sash clamp, does that give an idea. we aren't talking 10 ton hydraulic press type pressure, hand tight with a G clamp type pressure, 6mm threaded rod with a battery drill and the release clutch on the weakest setting and 3 lengths of rod up each side is plenty to compress a pack for service.

T1 Terry

[dansken]

I have now recieved my 8 sinopoly, 200ah. Did initial top balanse and am ready to install. Question: can they be mounted laying on their side? (They will then fit in the old battery box).

[T1 Terry]

Quite a few people have mounted them on their sides, what does Sinolpoly say about it, they are doing the warranty on them so what they say should be considered.

T1 Terry

[senormechanico]

I put my 200 aH Hi Power cells on their sides with a CleanPower BMS attached about a year ago, and they are perfectly happy.

The fridge has run 24/7 since a year ago February without the boat ever having been plugged in, and between Aerogel, solar, mppt and LiFePo4's, life's good.

Steve

[Zil]

Wow, what a thread. Took the weeks required to read through. Thanks to all for posting the ups and downs , good and bad experiences. We all learn together.
By the way, the Hindenburg fire started by electricity and hydrogen gas.
Flooded cell lead acid. hydrogen gas and electricity.

[Lagoon4us]

Originally Posted by senormechanico

I put my 200 aH Hi Power cells on their sides with a CleanPower BMS attached about a year ago, and they are perfectly happy.

The fridge has run 24/7 since a year ago February without the boat ever having been plugged in, and between Aerogel, solar, mppt and LiFePo4's, life's good.

Steve

Ice for nuthing and the drinks are freezed......

[ebaugh]

Originally Posted by Zil

Wow, what a thread. Took the weeks required to read through. Thanks to all for posting the ups and downs , good and bad experiences. We all learn together.
By the way, the Hindenburg fire started by electricity and hydrogen gas.
Flooded cell lead acid. hydrogen gas and electricity.

Now that's a quote I'm sure to remember!

[ebaugh]

We have previously discussed the difference between "float" and "trickle charge", I saw a related post from Doug out of the EV community. He has done some real testing on the capacity impact of floating LFP for 6 months and measuring capacity before and after.

In this test, no change in capacity was observed. Below is my question and his answer.

---------------

On Sat, Mar 16, 2013 at 8:28 PM, Ebaugh @ DIY Electric Car Forums <Bob> wrote:
Doug,

I read your post over on EVTV. I also use GBS 100Ah cells, but mine are 12P then 4S in a marine house bank. You mentioned floating for long periods at under 3.4Vpc. Have you actually compared before and after capacity by capacity testing?

------- Answer

Yes, but not on the GBS cells. I used the 26650 A123 cells which are about 2AH. I was not able to measure any difference after 6 months of floating at 3.45 volts. I didn't see any reason to test on the GBS cells after the non event with the little ones. I had the little cell in a pyrex oven dish just in case. It would be more difficult to safety the large cells.

------- Not directly related, but interesting:

I don't see this as an issue at all. I did another 6 month test (this one with the GBS 100AH cells) where I fully charged a cell (resting voltage of 3.38v), I half charged a cell (resting voltage of 3.30v) and I discharged a cell to 2.5V (it bounced back to 2.7v resting). I left them sit this way for 6 months and then charged them and retested capacity. I could see no loss in capacity in the fully charged and half charged cells. The one left pretty much fully discharged lost about half a percent of its capacity. A lead acid bank treated this way would have been completely sulfated and ruined. I was quite happy with that small loss. What you are doing is in essence between the mid balanced and fully charged cell test I made.

*** quoted with permission from the author.

[hellosailor]

At the mention of Aerogel and not meaning to get too far OT...There was a lot of enthusiasm when Aerogel came out but for some reason it doesn't seem to have taken over the world. How's that been working out for anyone? Price, durability?

Zil-
"By the way, the Hindenburg fire started by electricity and hydrogen gas."
Common unproven myth perpetuated by Nazi propaganda. The Supermen couldn't very well admit that they made a mistake and coated their zeppelin with thermite. The actual cause of the fire, whether it was static electricity or something else, last I heard was not an absolute. The hydrogen gas was not the problem in any case, the main problem was from the thermite fire that swept around the entire skin enveloping the entire airship.
By comparison, a true hydrogen fire would have ventilated up giving them time to evacuate, it would not have swept down and around the skin the way the thermite fire did.

But it was good propaganda for the Nazis to blame this on hydrogen, and to blame that on the US because we kept the safe helium for our own use and would not let them use it. The Germans and Japanese alike complained that the Allied economic sanctions were bullying them so they had to make war against us. In the case of Japan, it was partly over iron and coal. Germany, a wider range of complaints. What do they say about facts being the first victim?

Kind of the same way that every lithium technology today is THE best and THE only one worth considering.

[deckofficer]

Originally Posted by Lagoon4us

Ice for nuthing and the drinks are freezed......

Sung to the tune "Money for Nothing" by Dire Straits.

[goboatingnow]

Originally Posted by hellosailor

At the mention of Aerogel and not meaning to get too far OT...There was a lot of enthusiasm when Aerogel came out but for some reason it doesn't seem to have taken over the world. How's that been working out for anyone? Price, durability?

Zil-
"By the way, the Hindenburg fire started by electricity and hydrogen gas."
Common unproven myth perpetuated by Nazi propaganda. The Supermen couldn't very well admit that they made a mistake and coated their zeppelin with thermite. The actual cause of the fire, whether it was static electricity or something else, last I heard was not an absolute. The hydrogen gas was not the problem in any case, the main problem was from the thermite fire that swept around the entire skin enveloping the entire airship.
By comparison, a true hydrogen fire would have ventilated up giving them time to evacuate, it would not have swept down and around the skin the way the thermite fire did.

But it was good propaganda for the Nazis to blame this on hydrogen, and to blame that on the US because we kept the safe helium for our own use and would not let them use it. The Germans and Japanese alike complained that the Allied economic sanctions were bullying them so they had to make war against us. In the case of Japan, it was partly over iron and coal. Germany, a wider range of complaints. What do they say about facts being the first victim?

Kind of the same way that every lithium technology today is THE best and THE only one worth considering.

Lets not perpetrate more myths. The thermite fire/reaction myth has been well dispelled. Hindenburg has less then 1/10 of the proportions neccessary for a widespread thermite reaction

Hidenburg was a basic hydrogen fire , like many other airships before her.

Sometimes truth is also propaganda.

The Germans had no major issue with the US in 1937 and it certainly didnt need to use the Hindenburg disaster as justification for war declaration an event separated by virtually 4 1/2 years.

The hydrogen industry has always tried to obfuscate the Hindenburg disaster.

Dave

[Zil]

yes the skin burned and possibly amplified the disaster. But the fire started by hydrogen as the result of static discharge. No more Hindenburg. let us stay with the thread. Thanks all.

[dansken]

Regarding mounting batteries on their side rather than standing (terminals pointing up) the seller (EV-Power | Your Complete Power Solutions) responded:
"Yes, it is possible to run these cells in proposed layout.
However we recommend to use them is standard position"