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

[Wraith_Mac]

Bob & Bob,
Nice, very useful pix, I liked Bob E's method of holding cells in compression for banding/rebanding so much I copied it a while ago for my 'great ideas' folder. LOL
More [LiFe] power to you all, LOL
Mac

[deckofficer]

Yep, lead is dead.

A play on your More [LiFe] power to you...

[ebaugh]

Originally Posted by Wraith_Mac

Bob & Bob, Nice, very useful pix, I liked Bob E's method of holding cells in compression for banding/rebanding so much I copied it a while ago for my 'great ideas' folder. LOL More [LiFe] power to you all, LOL Mac

Mac, When you are in Grenada without access to a proper press, you improvise a solution. Elite Power told me it could not be done, until I sent them the pics. Bob

[Wraith_Mac]

A lot of us 'oldies' here know that "if it can't be done outside of the factory" ask a farmer, sailor or good amateur mechanic. They'll usually have a way.
That seems to apply everywhere doesn't it?
I've used a reversal of that method to pull a recalcitrant rear axle out of a landcruiser 100s of miles from anywhere.
Come a longs, trees, snatch trap, wire rope...won't use the snatch strap again, thing came out like a torpedo..LOL BUT it came out!
I like elegant solutions [with a touch of McGuyver] and your press idea is just that.
Cheers,
Mac

[Wraith_Mac]

Originally Posted by deckofficer

Yep, lead is dead.

A play on your More [LiFe] power to you...

Bob,
We will need a new battery for the Avon this summer, so I'm altering the fittings to take a LiFePo4 battery, LED lights and a small arch with a solar panel.
Even for such a small application [compared to a house bank] I'm sold on the advantages Li provides for night fishing and overnight camping and believe it will be cost effective.
No more than 100ah @ 12v because I'm limited by the Suzuki's charging ability and regulation, hence the solar panel.
The Avon is kept light, no fancy fittings just fuel, engine and steering wheel, so I think adding a panel to provide shade as well as power will be easily pushed along by the DT65.
Li's lot less to worry about when a breaker fills the boat, it's self draining but keeping the enclosed LA away from salt water is a concern.
So yes mate, though I certainly agree with you that while "lead is dead", it's still economical for some uses but that is changing quickly isn't it.
Cheers mate,
Mac

[senormechanico]

Originally Posted by deckofficer

Is that 3.12 volts for all in parallel?

The meter is well calibrated and it's 3.72 volts after about 16 hours.
I ran them up to 4.00 according to the first charge instructions.
Normally, I'll not go above 3.4 v per cell.

[Wraith_Mac]

Originally Posted by senormechanico

The meter is well calibrated and it's 3.72 volts after about 16 hours.
I ran them up to 4.00 according to the first charge instructions.
Normally, I'll not go above 3.4 v per cell.

Mac

[senormechanico]

I don't know how old they are.
Serial numbers are not sequential, but they are LiFeYPo4.

The Astron RS 35 took care of running the paralleled cells up to 4.00 volts.
The voltage rose about 0.01 volt per minute while I surfed the internet.

[deckofficer]

Originally Posted by senormechanico

The meter is well calibrated and it's 3.72 volts after about 16 hours.
I ran them up to 4.00 according to the first charge instructions.
Normally, I'll not go above 3.4 v per cell.

How many amps were you pumping in with all the cells in parallel?

Setting my variable power supply at 4.0 volts I think I only averaged about 3.5 amps, so my bottom to top parallel balance charge took about 9 days for 800 a-hr 3.2 volt parallel bank.

[senormechanico]

The power supply is rated at 25 amps with 35 max, and it took a few hours. I didn't keep exact track, but it was probably about three hours.
The supply was pretty hot by the time I got done, so it got a workout.

I rescued that supply from the metal crush pile at Island Recycling.
It didn't cost me a dime and it ran perfectly.

[deckofficer]

I have an Astron 75 amp PS that I use to power a solid state HF amplifier but it is a 13.8 volt output. What is the output voltage of yours or is it variable? I received my cells at something above a 50% DOD, cycled them in series a few times and saw the cells were out of balance, so ran them down in series, connected all cells in parallel and then the slow bottom to top balance. They have been tight ever since.

[senormechanico]

My Astron RS 35 is a fixed output voltage of 13.8, but it is current limited.
I just hooked it straight up to the paralleled cells and let 'er rip.
It started at 3.8 volts and just put out max current.
When the voltage reached 4.00 I disconnected it.

It will be a few days before I can put them into service.

[deckofficer]

I should have used my Astron 75 amp PS, it would have been so much faster if it could pull it off without overheating. When I use that supply for 600 watt output SSB duty cycle it gets warm but not hot. I use the same PS for a VHF 450 watt amp, and on FM duty cycle (100%) it gets quite hot.

[steelwrk1]

Hello Steve,

I too was impressed with the ''Get it done with what you have'' in Bob's (Ebaugh) photo using the ratchet strap tie down.

I used 4 only 3/8'' threaded rod and 5/16 '' aluminum plates at each end of 14 individual 3.2 volt cell assemblies. I drilled the aluminum plates close to the cells so the rods actually touch the sides of the batteries and then tightened to form a solid block.

Each cell weights +/- 5 lbs each X 14 for a weight of some 74# .

If you do not need to move them around then threaded rod and anything as an end plate to keep them assembled so as not to have any movement at the electrical connection joints should be fine. The tight assembliy is to aid in preventing deformation should the cells become hot. Heating does not occure in my set up.


I have not figured out how to post pictures properly so picture is in members gallery under steelwrk1 titled ''84 Only 60 Amp Lifepo4 Batteries''

Hope this helps with ideas,
Best Regards,
Pete

[Maine Sail]

I used 1/4" Al end plates and 1/2" square Al tube. The square tube fits the grooves on the Winston cells perfectly. The draw rods are 5/16". I fabricated the plates then sent the parts out for annodizing.