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

[catakate]

Excellent thread!

Originally Posted by Intentional Drifter

Although I believe that I understand the overall advantages of using LiFePo4 batteries for a house bank, I'll be the first to admit that I quickly get lost in the technical details. Has anyone assembled a tutorial or something along the lines of "LiFePo4 for Dummies"?

And excellent question! I got the skills, a few spare fingers to work with and space on my servers to envision a DIY guidance website in 20 languages for the average users... but!
Although I learned that electricity flows from plus to minus before I learned the outcome of 2 * 2 (son of an aviation electrician) I wouldn't embark alone on this boat, should any of you experienced ones be willing to put all this info together in a doable form for the average user, I'm in!

[Lagoon4us]

Hot pink will always lead to trouble, you should know that by experience!!!

[ebaugh]

Originally Posted by deckofficer

My numbers were bogus. My multi color LED light when placed on the "run through all the colors" pulled different wattage depending on the color. I guess I should have known that, but when the 50 amp charger tapered to 38 amps after just 37 minutes I realized my load couldn't have been a constant 30 watts. Put the amp meter on it and saw it swing from 0.89 amps to 3.08 amps depending on the color. So 11.8 watts to 41 watts. Hot pink happens to be the highest draw. When I first got this light, they forgot the remote and it was on hot pink, so I did my first draw down at 41 watts. Because of this, that draw down that I thought was at 30 watts and showed the battery only delivered 980 watt-hr, it really delivered 1340 w-hr.

What is your bank capacity? I'm getting confused on watts hours vs amp hours. My 1200 Ah bank is around 15 kWh or 15000 watt-hr. 1340 w-hr is about 100Ah at 12.8V.

[Lagoon4us]

The following i just received from my supplier regarding 'Brand New' batteries:-


Hello Frank,


thank you for email.

1. BMS123, cheaper variant to RT-BMS including all functions and is even better for car/boat/anything that moves projects. You would need control unit for the pack, 4 cell units and I would recommend current sensor for more detailed monitoring also. You can check all here : EV-Power | BMS123 System

2. Ideal relay might be EV-Power | DC Power Contactor 100A, Coil 12V or EV-Power | DC Power Contactor 200A, Coil 12V

3. Before first use, it is important to charge the cells to 3,95V. Optionally you could use single cell charger EV-Power | Charger 3.6V/6A for LiFePO4 cells (1 cell) or any other charger with manual control to prevent the damage. No further processing is required, just keept he BMS connected for the rest of use and it should be fine.

4. balance at low voltage is not required, the cells are rather cut from the load once any of them reach their minimum to prevent damage

MPPT regulators are perfect for LiFePO4 cells.

For much much more information about the BMS and actual connections schemes, check our blog : lithium & solar power LiFePO4, Search results for: BMS123

Let me know if you have any further questions or if you decide which parts to order.

[Maine Sail]

Originally Posted by deckofficer

My numbers were bogus. My multi color LED light when placed on the "run through all the colors" pulled different wattage depending on the color. I guess I should have known that, but when the 50 amp charger tapered to 38 amps after just 37 minutes I realized my load couldn't have been a constant 30 watts. Put the amp meter on it and saw it swing from 0.89 amps to 3.08 amps depending on the color. So 11.8 watts to 41 watts. Hot pink happens to be the highest draw. When I first got this light, they forgot the remote and it was on hot pink, so I did my first draw down at 41 watts. Because of this, that draw down that I thought was at 30 watts and showed the battery only delivered 980 watt-hr, it really delivered 1340 w-hr.

Bob,

Grab a Victron BMV-600 or another Ah counter or a watt hr meter that keeps track of the watt hours, not just shows them as happening..

[Maine Sail]

Originally Posted by catakate

Excellent thread!



And excellent question! I got the skills, a few spare fingers to work with and space on my servers to envision a DIY guidance website in 20 languages for the average users... but!
Although I learned that electricity flows from plus to minus before I learned the outcome of 2 * 2 (son of an aviation electrician) I wouldn't embark alone on this boat, should any of you experienced ones be willing to put all this info together in a doable form for the average user, I'm in!

I will eventually write one, once I have had ample time to see these batts in use, and see that the "claims" bear fruit. I got burned hard being an early adopter of AGM technology so don't want to be an early cheer leader without ample physical experience with the product.... GEL was fine but AGM not so much..

When I complete it the article will not be open to the general public and will be password protected. Unless of course things change dramatically in the near future for assembling, balancing and protecting packs.

This is not something that is, IMHO, ready for the average DIY prime time so I would want to have readers request a password so I can give them ample warning about safety etc. before giving them a password.....

I don't want to make it so simple that people don't, won't or have not done sufficient homework on their own first, and no single article or "how to" can give anyone the info they'd need, at this point in time........

Just my .02...

[ebaugh]

Originally Posted by Maine Sail

Bob,

Grab a Victron BMV-600 or another Ah counter or a watt hr meter that keeps track of the watt hours, not just shows them as happening..

There is a coulomb counter / amp hour meter in the BMS I installed. I just think in amp hours since my bank and most others are 4 cell 12V ones.

[Maine Sail]

Originally Posted by ebaugh

There is a coulomb counter / amp hour meter in the BMS I installed. I just think in amp hours since my bank and most others are 4 cell 12V ones.

What BMS did you use? Does it come with a shunt?

[ebaugh]

Originally Posted by Maine Sail

What BMS did you use? Does it come with a shunt?

I used the Elite Power BMS for GBS cells. Comes with a shunt. It works OK, was priced right, but I'm hesitant to recommend it at this point. I need a firmware revision to get the display working 100% right, and one of the cell boards ended up drawing much more current than the rest unbalancing the pack. The vendor has been supportive and will replace or upgrade (newer version on the way), but I want to see it 100% right before I endorse it. It would require some customization of the cell boards to work on Winston cells since the terminals are different.

[ebaugh]

Originally Posted by catakate

Excellent thread!

And excellent question! I got the skills, a few spare fingers to work with and space on my servers to envision a DIY guidance website in 20 languages for the average users... but!
Although I learned that electricity flows from plus to minus before I learned the outcome of 2 * 2 (son of an aviation electrician) I wouldn't embark alone on this boat, should any of you experienced ones be willing to put all this info together in a doable form for the average user, I'm in!

I have a document that might help. Just posted it on our blog site here:

http://marazuladventures.wordpress.c...-and-research/

At the bottom of the text in that entry is a link to a several page PDF file intended as a primer for someone interested in LiFePO4 house banks. Thanks also goes to Terry who proofed this for me a few months ago.

[catakate]

Originally Posted by ebaugh

I have a document that might help.

To not affect this thread, I started a new one for building a knowledge base of known methods for putting this technology to work.
http://www.cruisersforum.com/forums/...ase-96365.html
Thanks for your input!

[ebaugh]

Originally Posted by catakate

To not affect this thread, I started a new one for building a knowledge base of known methods for putting this technology to work.
http://www.cruisersforum.com/forums/...ase-96365.html
Thanks for your input!

Interesting...that was the original intent of this thread a long time ago. But it's gotten kind of long and very difficult to read through. Not sure how on CF to make a FAQ like area for something like this. Eventually any thread tends to get pretty cluttered up....

[catakate]

Originally Posted by ebaugh

Interesting...that was the original intent of this thread a long time ago. But it's gotten kind of long and very difficult to read through. Not sure how on CF to make a FAQ like area for something like this. Eventually any thread tends to get pretty cluttered up....

Yeap, this is the raw data, now we need to get organized and sum up the results

[ebaugh]

Originally Posted by catakate

Yeap, this is the raw data, now we need to get organized and sum up the results

Feel free to post my link over there and I will follow both threads. That's sort of what I attempted to do with the PDF article I wrote, but not everyone will share my conclusions.

[NahanniV]

Originally Posted by ebaugh

I used the Elite Power BMS for GBS cells. Comes with a shunt. It works OK, was priced right, but I'm hesitant to recommend it at this point. I need a firmware revision to get the display working 100% right, and one of the cell boards ended up drawing much more current than the rest unbalancing the pack. The vendor has been supportive and will replace or upgrade (newer version on the way), but I want to see it 100% right before I endorse it. It would require some customization of the cell boards to work on Winston cells since the terminals are different.

I spoke with someone at the company that manufactures that BMS.
The cell boards are really a custom fit to the GBS cells with the four screw terminals, they come assembled in strings spaced for the GBS cells and they use the bus bar as a heat sink.

They seem to have a good product at a good price. I also suggested they might try working with someone like Garmin to get into the marine market with the CAN BUS version of the BMS displaying on a Garmin GMI-10