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

[T1 Terry]

Originally Posted by typhoon

Terry mentioned a good conductive anti corrosion grease to use to mate the terminals together , can't remember what it was for the life of me. What is everyone using. Just about to get some. .

Regards

The stuff I use is called Alminox. Use a nylon scrubber pad scrub the terminal till it's bright metal, easiest on a drill with a backing pad, these are an off the shelf item where good tools are sold. Once you have it clean and shiny, a small flat art brush and paint a film of Alminox on thick enough that it's not see through. If you are using the copper multi leaf links that come with the batteries then give the mating surface on the bottom and top leaves and paint them with Alminox as well. Have a clean large rag with you, the stuff is like Never seize and travels every where you touch if you aren't real careful.
The majority of cell out of balance problems are created by not having the terminals clean and protected at the very beginning. Give yourself a better chance of success and start the job out the right way from the very beginning, it will pay you back bucket loads over the yrs with maintenance free operation yr after yr.

T1 Terry

[T1 Terry]

Hi Bob,
The chart to the left below shows the expected loaded discharge capacity and voltage, under load. The chart to the right is the discharge rate shown in to upper right corner 0.5C and these show the cut off voltages under load.
There is another chart some where that I'll try to hunt up later that show a different and better curve by not pulling the loaded voltage below 2.8v

T1 Terry

[deckofficer]

Originally Posted by boatpoker

Look to the right of the AGM. The two stainless steel boxes without markings are the Li units.

I believe those are just boxes someone made to place the cells inside.

[boatpoker]

Originally Posted by deckofficer

I believe those are just boxes someone made to place the cells inside.

I hope not given the quality of the rest of the installation !
The number 1 recommendation on this survey was not to connect the boat to shorepower until this entire installation had been reviewed and revised by a qualified marine electrician. Unfortunately I don't know any in this area who are up to speed on these batteries, their safe installation or BMS.

As I said I know very little about them but from what I have learned, I'm not sure the average dock walking shade tree mechanic should be allowed to buy cells of the shelf and built his own thermal nightmare. If Boeing can't get it right. Billy Bob dosn't stand a chance.

[deckofficer]

Originally Posted by boatpoker

I hope not given the quality of the rest of the installation !
The number 1 recommendation on this survey was not to connect the boat to shorepower until this entire installation had been reviewed and revised by a qualified marine electrician. Unfortunately I don't know any in this area who are up to speed on these batteries, their safe installation or BMS.

As I said I know very little about them but from what I have learned, I'm not sure the average dock walking shade tree mechanic should be allowed to buy cells of the shelf and built his own thermal nightmare. If Boeing can't get it right. Billy Bob dosn't stand a chance.

I'm confused as to what you are asking. At first I thought you were just curious as to a installation you saw, and now it sounds like a boat you are interested in buying when your refer to a survey. This is what a LiFePO4 cell made by Winston looks like, but other the the color of the case CALB and other makes are constructed the same with a rigid and reinforced case.

These are (4) 100 a-hr Winston cells banded together.

[Jd1]

Originally Posted by deckofficer

A side note, this inverter is a Aims bargain basement 2000 watt modified sine wave at a cost of $190. Consumes 12 watts just to be on without load. I was concerned that my HDTV wouldn't like anything other than a clean full sine wave power but other than a very low buzz that can't even be heard unless you turn down the audio, no problems. Does anyone know what items will not tolerate the cheap mod sine wave inverters? Probably a laser printer.

As another side note, I don't think you can trust your power figures all that much if there is a modified sine wave inverter in the mix. It may affect the current readings at the input and it will affect current and power readings on the output. You can't trust that a 1500 watt space heater is still dissapating 1500 watts if the input is not a pure sine wave.
Having said that, I can't speculate on how much off things might be and it might be less than 5%. The point is more in line of 'watch out what you are measuring' because it could be all over the place unless you are sure that the measureing instrument can handle whatever signal it sees.

[deckofficer]

That is why I just purchased an Amprobe to measure DC current leaving the battery. I'll revise all my figures when I know for certain what is coming out of the battery. Even if the numbers are lower, which they could be, still doesn't change my mind about LiFePO4 cells for house and propulsion banks. For the price there is nothing better and they are much cheaper than lead in the long run.

[Maine Sail]

Originally Posted by boatpoker

I hope not given the quality of the rest of the installation !
The number 1 recommendation on this survey was not to connect the boat to shorepower until this entire installation had been reviewed and revised by a qualified marine electrician. Unfortunately I don't know any in this area who are up to speed on these batteries, their safe installation or BMS.

As I said I know very little about them but from what I have learned, I'm not sure the average dock walking shade tree mechanic should be allowed to buy cells of the shelf and built his own thermal nightmare. If Boeing can't get it right. Billy Bob dosn't stand a chance.

If those really are Li batteries that install is pretty scary..

On the Echo Charger, they are installed between batteries and are not switched. They can be but 98% of the time are not. They turn on and off automatically any time the house bank is above 13V. Solar, wind or a surface charge could be keeping the bank above 13V. In cold weather AGM and FLA batts hold surface charge longer.

However, if that device is connected to a LI bank it will NEVER turn off as the resting voltage of a Li bank will be over 13V.... They don't draw much but over time could kill eventually drain the Li bank. Hope it is protected against an LVE....

[deckofficer]

I looked at all of boatpoker's pictures, scary was an understatement. IMHO the system design, execution, and wiring is an insult to whatever LiFePO4 cells that are being used.

boatpoker, what is the deal on this boat? Is it a boat your thinking of buying?

[diugo]

Originally Posted by deckofficer

Does anyone know what items will not tolerate the cheap mod sine wave inverters?

MSW inverters are notorious for ruining laptop batteries, because typical brick chargers expect the peak voltage found only in the PSW wave form. I also personally fried the brushes in a Dremel tool, though I am not 100% MSW was the culprit.

Because large PSW inverters are usually ridiculously overpriced, my RV has two inverters---a 1500W MSW for the microwave and vac, and a 300W PSW for everything else.

BTW, I was perusing Amazon last weekend and saw a 1500W generic PSW for under $200---first time I've seen them that low.

[deckofficer]

Originally Posted by diugo

BTW, I was perusing Amazon last weekend and saw a 1500W generic PSW for under $200---first time I've seen them that low.

Now you tell me. lol

That is such a good price for a pure I might get it also since I have two small banks. During a power outage it would keep me from having to run cords all over the house from a single inverter and battery. Might lose power this weekend because a foot of snow is predicted at low California elevations. When that happens the big oak trees that are at 1000~2500' elevation break under the snow load and take out power lines. 4 years ago when the snow got that low I was out of power for 5 days. Went through a lot of gasoline running the generator 24/7. These batteries should reduce gen set run time from 24 hours per day to 4 hours per day for charging.

[senormechanico]

Originally Posted by boatpoker

I know very little about Li batteries and have never even seen any on a boat until a couple of weeks ago. Then two more last week. I am reading furiously trying to get caught up and am fortunate to have access to a brilliant electrical engineer who is up on these things (no, he does not work for Boeing

This link is to photos of the first installation I saw. These batteries have absolutely no markings on them and no monitor other than a cheap LED voltage indicator.

I'd appreciate it if anyone can identify these batteries as I'd like to learn more about them.

Thanks

EWWW !!! That looks like a fire waiting to happen!
I posted the above before reading any of the following responses.

Also, I purchased one of these:

http://www.ebay.com/itm/Tiger-Claw-1...item1e80168c59

for the boat at least two or three years ago and am very happy with it.

[deckofficer]

Originally Posted by senormechanico

Also, I purchased one of these:

Tiger Claw 1500W Pure Sine Wave Power Inverter DC AC 1500 Watt 3000 Watt Peak | eBay

for the boat at least two or three years ago and am very happy with it.

That is the one I just checked out. Same heatsink/case as my 2000 watt mod sine wave. 80% efficiency for the full sine wave vs. 90% for the mod wave.

I have you put a scope on the output to look at the waveform? Do any of your 120 VAC electronics have a faint buzz?

[senormechanico]

Originally Posted by deckofficer

That is the one I just checked out. Same heatsink/case as my 2000 watt mod sine wave. 80% efficiency for the full sine wave vs. 90% for the mod wave.

I have you put a scope on the output to look at the waveform? Do any of your 120 VAC electronics have a faint buzz?

That's the first thing I did. A beautiful sine wave regardless of load, very slight crossover notch at zero, but no adverse symptoms anywhere.

[deckofficer]

Originally Posted by senormechanico

That's the first thing I did. A beautiful sine wave regardless of load, very slight crossover notch at zero, but no adverse symptoms anywhere.

I read some of the reviews. One knowledgeable user noticed that the RFI/EMI was high and kept touch pad devises like iphone, ipads not to accept touches if too close to the inverter, also same applied to charging these devises to close to the inverter. He is a HAM radio op and noticed the hash on his HF freq because of harmonics of the PWM of the waveform.

I think I'll just stay with this unit and string the extension cords during blackouts as that will allow me to swap out batteries with no loss of inverter output due to the dual Anderson plugs I put on the inverter.