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

[Hkalan]

Today I picked up the 16 cells. Now I want to buy a new Lagoon Seventy 7 to install them... pity I can't find one of them for $9,000 USD as well !!! LOL

Time to start charging all the cells !!

[offpist]

Originally Posted by alctel

Well, I just sent off 3000 CAD and will get a 8x200AH Sinopoly cells back in a few months.

Excited! Now to figure out what BMS to use. Thanks to all for all the useful stuff in here.

I thought long and hard as I was tempted just to go with 200AH as my daily usage is really pretty low and my 200 watts of solar more than keeps up when I'm at anchor.

Have you checked this out?
REC d.o.o.
We have been using this BMS for 2 years, and are happy with its performance and also the price is reasonable.

[andreas.mehlin]

What setup would you recommend for a 16-20kw electrical engine bank 48v?

[PacificGreen]

Originally Posted by Hkalan

Today I picked up the 16 cells. Now I want to buy a new Lagoon Seventy 7 to install them... pity I can't find one of them for $9,000 USD as well !!! LOL

Time to start charging all the cells !!

Nice blessing. How does the Bertram handle in displacement mode at 10 knots?

Are you planning a repower? I only ever had a 8v71 in a coach and that was enough for me. You could easily power her around all day at <10 knots not planning with electric motors.

Drop some thin film solar panels (4000watts) right from the factory in China. Pull the two 8v92's and replace with QuietTorqueâ„¢ 20.0 Plug-n-Play Electric Propulsion - ElectricYacht or two of the 10kw models.

Remove the two generators out of her and find a couple nice small disposable direct DC generators gas or electric load bearing or just run with standard honda ac generator and run a charger from there. Just a thought as 11.80hkd doesn't look that enjoyable at $100/hr at 1200 rpm.

You got three times the energy storage I got for the same price. Plus you already have your house loads covered with your 400ah bank. Time to start shopping for an ideal catamaran I'm sure. Congrats.

[pacific_voyager]

Originally Posted by offpist

Have you checked this out?

REC d.o.o.

We have been using this BMS for 2 years, and are happy with its performance and also the price is reasonable.

But this BMS is only for a 1P4S bank, right?

[offpist]

Correct. But they also have one for up to 16 cells.
We have an of these also on our 30KWH 48V system at home.

[bcn]

REC d.o.o.

Page for their actual line-up of BMS

[john61ct]

How would one of these be adapted to 4 in parallel, then four of those blocks in series? Could it still monitor on a per-cell basis? Would I need multiple BMSs ?

[Maine Sail]

Originally Posted by john61ct

How would one of these be adapted to 4 in parallel, then four of those blocks in series? Could it still monitor on a per-cell basis? Would I need multiple BMSs ?

A parallel block of individual 3.2V cells is one 3.2V cell as far as a BMS is concerned...

[darylat8750]

Originally Posted by PacificGreen

Nice blessing. How does the Bertram handle in displacement mode at 10 knots?

Are you planning a repower? I only ever had a 8v71 in a coach and that was enough for me. You could easily power her around all day at <10 knots not planning with electric motors.

Drop some thin film solar panels (4000watts) right from the factory in China. Pull the two 8v92's and replace with QuietTorqueâ„¢ 20.0 Plug-n-Play Electric Propulsion - ElectricYacht or two of the 10kw models.

Remove the two generators out of her and find a couple nice small disposable direct DC generators gas or electric load bearing or just run with standard honda ac generator and run a charger from there. Just a thought as 11.80hkd doesn't look that enjoyable at $100/hr at 1200 rpm.

You got three times the energy storage I got for the same price. Plus you already have your house loads covered with your 400ah bank. Time to start shopping for an ideal catamaran I'm sure. Congrats.

A 46ft Bertram at 10 kts would be pulling up a very large wake. I would guess it would take something above 10 gallons an hour to maintain that speed. That would be a LOT of electricity. 7 kts may be around 3 gallons an hour. With a genset running that may be doable with electricity.

[roetter]

Originally Posted by PacificGreen

Much of this is repeated without substantiation or proof other than what one person says or believes. Much of it is based on the experience of a grounding of a racing boat which is highly questionable. Much of the fud may also be related to some manufacturers pushing only certain cells. Large format prismatic cells are used quite successfully in many installations and most manufacturers and distributors have no opinion ether way.

If in fact one person called Ralph has some trouble with his cells is neither here nor there but can certainly be worth considering in your decision. I'm not familiar with the Ralph case myself. You might find earlier in this post #112 one person did a very nice job with large cells. You won't replicate that with small cells ever. Also find http://www.deny.org as a good source of information regarding large cells. Also they do install 10000 ah cells on submarines so you have to really wonder where this 200ah cell limit comes from.

I would buy the cells after verifying there voltage levels and date of manufacture.

I am Rolf and my 1400ah made from 700ah Winstons died. They were "slightly" used when I bought them from Balqon. Early on one set started discharging while not in use. I had to manually balance once a month or so. They died because I had been away for 6 months and the person supposed to balance manually did no do it. When arrived three sets were being cooked at over 4.2V while the bad one was reading below 2v. Charging with the solar was set to 13.2V.

I converted another boat with the same (new cells) and those are still going strong all the way down under in Australia now.

[PacificGreen]

Originally Posted by darylat8750

A 46ft Bertram at 10 kts would be pulling up a very large wake. I would guess it would take something above 10 gallons an hour to maintain that speed. That would be a LOT of electricity. 7 kts may be around 3 gallons an hour. With a genset running that may be doable with electricity.

With 800amp hours usable the math is easy. If it takes him 400amps to push his boat to 10knots he could do that for 2 hours. This is very inefficient use of power though. On the other hand if he can do 50% of his hull speed at 5 knots for 80 amps he could go 10 hours. This would be relative to a return on solar power. He certainly has the energy storage.

This project looks similar and these folks are doing it with lead acid but still works:
https://www.youtube.com/user/WhoIsHayley/videos

Notice how small their motors are

[PacificGreen]

Originally Posted by roetter

I am Rolf and my 1400ah made from 700ah Winstons died. They were "slightly" used when I bought them from Balqon. Early on one set started discharging while not in use. I had to manually balance once a month or so. They died because I had been away for 6 months and the person supposed to balance manually did no do it. When arrived three sets were being cooked at over 4.2V while the bad one was reading below 2v. Charging with the solar was set to 13.2V.

Nightmares for me right now. Still snowing and miserable a week or two before I set out. Will be the first time in a year seeing her. I'm sure they will be fine. Now I piece your story together so the cell failure was not caused by bashing about buy rather a great buy on batteries and then lack of training for those responsible. Did you have a BMS on them from Balqon?

Originally Posted by roetter

I converted another boat with the same (new cells) and those are still going strong all the way down under in Australia now.

How many years now on those ones?

[darylat8750]

That Tollycraft is very cool.

I was just trying to point out that expectations of 10kts even for a very short time are very optimistic. 10 gallons an hour fuel burn equates to somewhere around 170 - 200 horsepower. 5 knots would be a completely different ballgame.

[PacificGreen]

Originally Posted by darylat8750

That Tollycraft is very cool.

I was just trying to point out that expectations of 10kts even for a very short time are very optimistic. 10 gallons an hour fuel burn equates to somewhere around 170 - 200 horsepower. 5 knots would be a completely different ballgame.

Yeah, and when I looked into it turns out it only displaces 9000lbs but might have had the same hull shape as a Bertram not sure. Principle is the same though planing hull doing displacement speed and is the ride tolerable.

I like the tollycraft project. Seems like they let water in the battery compartment somehow and it flooded but they didn't loose any batteries by the videos they show. They did a lot of work to restore that boat and it is ongoing. The fact they did it with lead acid batteries well it just goes to show you that it is doable.

Their motors are the best of their type you can get more or less being the second or third generation of Etek motors made by Lynch Motors | Electric Boat Motors