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

[deckofficer]

Do you have any pictures of how the batteries are stowed on the dinghy?

[offpist]

Originally Posted by deckofficer

Do you have any pictures of how the batteries are stowed on the dinghy?

Could not find a good picture of it, but it is located under the seat in the middle of the boat. They just fit under there, when i click the seat back on they cant move. Not in the way at all.

For the second battery sets i made some custom handbags, and oriented the batteries so they are more compact..




But turns out I like the Harley Davidson bags better.

Torqeedo batteries cost like $5200 (for two).
So compared to that, this came almost for free.

I am also working on building a set made out of 7 Nissan Leaf modules (14 cells) That should give me a 51,8V battery with 64AH. Almost half the capacity, but also more than half the weight.

I already have a system containing two Nissan leaf batteries in my shed, running my house on solar energy, but that's another story

[gael]

Originally Posted by Cottontop

If Tesla is going to put batteries in lots of houses, don't you suppose they will have to also supply a fully engineered system? And why wouldn't that system be readily adaptable to a boat?

Does the Tesla car base on LiPoFe or LiCo chemistry?
Any way it need something as 140V pack for propulsion. Far away from ours careabout I'm afraid.
I dnt expect to much from the car industry.

cheer
gael

[Cottontop]

Originally Posted by gael

Does the Tesla car base on LiPoFe or LiCo chemistry?
Any way it need something as 140V pack for propulsion. Far away from ours careabout I'm afraid.
I dnt expect to much from the car industry.

cheer
gael

The new batteries recently announced by Tesla are intended to provide storage for houses that have installed solar panels. While there is not much information yet, I expect (hope) Tesla's complete system will be a safe and user-friendly as that on their cars.

[mdsilvers]

Originally Posted by roetter

Some people seem to wonder how I have done the "before/after" voltage sensing for the alternator.

Requirements:
a - alternator that allows remote sensing. On the Volvo on my mono I have a Mitsubishi that has remote sensing. On my cat the Yanmars have Hitachi without remote sensing, so another solution was chosen.
b - You need true old fashioned diodes. These produce approximately a 0.7V drop. They cost efficiency, but that is what my mono had and I did not want to change it. I try to keep things as simple and cost effective as possible.

Here a schematics. I hope I made no mistakes. I am jet lagged at an airport in Europe now.

Attachment 95559

The Automotive relay has two positions - Normally open and normally closed.
Attachment 95560

I also have Mitsubishi (A003TR0091ZT, 12v 115amp) regulators on my Volvo engines. I've been evaluating the best method to regulate voltage - Balmar or your diode approach.

There is essentially no documentation I can find on my alternators, and I am not sure if I can even attached a Balmar. Do you have any suggestions based on your experience with your Volvo engine and Mitsubishi regulators?

Thanks!

[Dod42]

I specifically asked Balmar recently as I have the same alternators and the answers "sorry we can't help" so I'm setting up with diodes


https://www.facebook.com/SvTwoflower

[KASHMIR]

Originally Posted by gael

Does the Tesla car base on LiPoFe or LiCo chemistry?
Any way it need something as 140V pack for propulsion. Far away from ours careabout I'm afraid.
I dnt expect to much from the car industry.

cheer
gael

Please correct me if I am wrong but my research tells me that Tesla S is LiCoO2 and the powerwall is also LiCoO2 and the Leaf is LiCoO2. The Tesla is liquid cooled cells and the Leaf is air cooled. I don't know how the powerful is cooled, perhaps fire department??

[Maine Sail]

Originally Posted by KASHMIR

Please correct me if I am wrong but my research tells me that Tesla S is LiCoO2 and the powerwall is also LiCoO2 and the Leaf is LiCoO2. The Tesla is liquid cooled cells and the Leaf is air cooled. I don't know how the powerful is cooled, perhaps fire department??

I thought the first generation LEAF was LiMnO2 but the latest battery is LiNiMnCo..?

[Cottontop]

Originally Posted by KASHMIR

Please correct me if I am wrong but my research tells me that Tesla S is LiCoO2 and the powerwall is also LiCoO2 and the Leaf is LiCoO2. The Tesla is liquid cooled cells and the Leaf is air cooled. I don't know how the powerful is cooled, perhaps fire department??

From the internet (cleantechnica) so it must be right:

"And [Musk] mentioned that there are indeed different chemistries in the two Tesla Energy products. The backup power option, the Powerpack, is quite similar to that in the Tesla Model S and X, using a nickel-cobalt-aluminum cathode. The daily cycling option, the Powerwall, is made of nickel-manganese-cobalt (with “quite a lot of manganese in there”). The first is meant for ~60–70 cycles per year, and the other one for 365 cycles a year. Tesla expects the Powerwall to last for approximately 15 years, ~5,000 cycles (but with the warranty being 10 years). The Powerpack is expected to last for, “depending on how it’s used, anywhere from 1,000 to 1,500 cycles.” And they have comparable calendar lives."

Both packs have internal cooling to optimize performance.

[mdsilvers]

Originally Posted by Dod42

I specifically asked Balmar recently as I have the same alternators and the answers "sorry we can't help" so I'm setting up with diodes


https://www.facebook.com/SvTwoflower

Thanks for the info. I'll be keen on following your progress for these alternators. I'll be updating mine in about six weeks when I return to Fiji and do my install. There are a number of other friends I have with the same alternators that will be keen to track the progress. Photos or any other 'how to' and lessons learned will be much appreciated. Good luck!

[hellosailor]

GM and Nissan have both announced systems that will take Leaf/Volt packs and make them into "standby power" units for home clusters aimed at supplementing blackouts from the grid, aimed at providing a 4-hour grid replacement. Not the same as Tesla's plans, at all.


But either way, the cooling could be very different because the operating conditions will most certainly be different. In a car you may need a very high drain for acceleration under load and the system may be designed to do that. In a "home" fixed installation, where active cooling may not have been part of the design, the solution is easy, you just don't allow the pack to be drained that heavily. You pick a different maximum load, add a heat sink, and you say "This is what you get, no more."
Kinda like not letting the kids drink from a fire hose.


But all three players have released so little information, all we know is that GM and Nissan are looking for a way to avoid scrapping lots of "still 70-80% good" batteries, while Tesla is looking for a way to rationalize full capacity at the megafactory.


That's the only technical fact we have right now: All three players are in this in order to FIND A MARKET for those batteries. Not because they have a use for them, but the exact opposite. They have a truckload of "lemons", and no one has yet invented the lemonaid stand.


Maybe they could turn each excess battery into an advertising kiosk. Stand-alone, solar power, paid for with lots of ads stuck on it. Free phone and tablet charging if you plug into it. Heck, free phone calls too, why not?


What else can you do with a hundred thousand retired batteries?

[offpist]

Mastervolt data displayed on Raymarine from NMEA2000.

(Battery 1, Lifepo4 House battery. Battery 2 Lifepo4 Start battery)

[Lagoon4us]

I have had 4 x 400 winston cells for nearly 3 years now no bms, no issues, no problems. simple to monitor yourself have cruised the med for three years loving them. Just go through my previous threads and ignore the naysayers they complicate life, do nothing, achieve nothing and comment from their armchairs.

[Dod42]

Install almost finished. 8 x 400 Winston Cells in, setup as 12 volt 2P4S. Very nice and setup. Victon Multiplus charge charge profile changed and the Solar controllers changed, both working well. 5 x 110AH AGMs out.

Alternators are good at 115amps but I have changed what I was going to do. They are currently set to 14.3 volts and have an external voltage sense and basic temp regulation. You can get to the brushes so its not too hard to tap into the field to "turn off" the charge, however, when you turn it off (in my case) the Volvo alarm goes off as it thinks the alternator is dead. Yes you can alter this but a bit of a pain.

So the plan at this stage is:

I have split the charge bus from the load bus. (Good idea anyway).

I'm leaving one of the old AGM's as a start battery for the Port engine. Always had one for Starboard.

I'm leaving the 2 alternators standard. Gives me 230 amps with both running.

I'm putting a charge splitter between the Port AGM starter and the LifePO4 bank off the charge bus. There is already a battery combiner between Port and Starboard so when charging everyone's getting a piece.

I'm putting a large contactor between the charge bus and the LifePO4 back that is driven by the High voltage relay circuit of the Victron BMV702 monitor so at a set pack voltage it will disconnect all charge source to the LifePO4 bank only and reconnect when it reaches a lower set threshold. AT this stage it's pack voltage of 13.9 high and 13.2 low but easy to change and still a work in progress.

The disconnect shouldn't damage anything as any surge should be sucked up by the AGM Starter that will still be connected. I will probably also connect this contactor to the HVC alarm relay on the House power BMS just as a safety but need to check the voltages its set to. Lots of alarms set between the BMS and and Victron BMV 702 so nothing bad should happen without the world knowing about it first.

This is this weekends job.

Early stages but very happy with the way it has all gone together and it seems to perform as advertised.

I understand peoples comments about BMS being needed or not (personal choice). I wanted one so I had the added safety and flexibility for alarms and automatically cutting things off if needed. In theory these will never occur but nice to know that if needed they should. Yes I could use a simple Cell 8 or the settings on the BMV 702 but I like being spoiled for choice.

[Jman]

I wonder if the victron will shutoff your relay at 13.9 as the agm charge voltage goes towards 14.3 and there by never really charging the li pack? This one reason I by-past this simple sounding solution, but maybe I am wrong.


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