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

[roetter]

Originally Posted by markv

I am just about to put in my order for a new Lagoon 450, taking delivery mid July. I've researched what I want to have for power etc and listed it here, be grateful for any info I might need to avoid costly mistakes..

I had a 440 for 7 years and for 4 years had 640W from 4 panels mounted in an array extending out from the bimini. After changing lights to LED, those panels started to become a lot more effective, and this time I want to avoid getting a large generator. We had a Fischer Panda and always had problems with it, so I can make do with a 2.4kw portable Yamaha. No intention to get AC this time, hardly used it last time.

I talked to Balqon and am ordering 2 x 9kw (700Ah x 4) units with built in BMS, and 1800W of solar panels (6 x 300W, 2x3 grid) extending off the bimini as before (4.7m wide by 2m back, of which 25cm will overlap the bimini top. I want to add 2 x Flexmax 80 solar controllers, each one connected to 3 of the solar panels. I am getting conflicting reports as to if I can connect both of these Outbacks to the same battery bank.
For battery space, I think there is room as the current battery space under the main bunk is 1.6m wide, and dimensions of the Balqons are 700mm x 650mm. Weight of each pack is about 90kg each.

I also want to change or add alternators on the engines, each to 150A or 200A and I will need to get a voltage regulator on each.

Part of the equipment supplied by Lagoon includes 60 and 40amp chargers i think supplied by mastervolt, don't have a choice on those, but will either add or replace them with Victron inverter charger 12/2500/200.

Still have to figure out the physical aspects of connecting all of this to the batteries, so any advice or even better, pictures, would be great. Will be doing some of it ourselves, and hoping there might still be some contractors around in late July/August in Les Sables d'Olonne, France to help. Or maybe they won't know LiOn tech, so learning as much as we can now before we get there.

What you are doing is almost identical to my installation on our L450. I went for 8x700Ah cells, but 4 is enough. However, I needed them in January for a 12-day rainy period.Everyday I went a little bit down, but then we have a lot of electrical stuff running. We have no generator at all.

I was able to fit the cells in the battery compartment, just had to build a sub-floor under them from 2x4 and plywood so I could fit 8 cells side-by-side into the cavity. The cavity has a lot of slope on the front and aft side,so raising the cells gave me the extra 15mm i needed.

I am running 2 Flexmax 60, one on each set of 3 panels. Maximum I have seen is 106A (53A each). I have one set of panels in parallel the other in series. I am still planning to do partial shading experiments.

[roetter]

Originally Posted by markv

I also want to change or add alternators on the engines, each to 150A or 200A and I will need to get a voltage regulator on each.

Part of the equipment supplied by Lagoon includes 60 and 40amp chargers i think supplied by mastervolt, don't have a choice on those, but will either add or replace them with Victron inverter charger 12/2500/200.

Still have to figure out the physical aspects of connecting all of this to the batteries, so any advice or even better, pictures, would be great. Will be doing some of it ourselves, and hoping there might still be some contractors around in late July/August in Les Sables d'Olonne, France to help. Or maybe they won't know LiOn tech, so learning as much as we can now before we get there.

Alternators: Since July 2013 the L450 comes with 125A alternators, not the old 80A. They are also running on serpentine pulleys now. That would make it easy to switch over to the 150A or 200A you are considering. I never used the alternators to charge the engine, except when I needed the engines to go somewhere. So with all your solar you should be fine.

Chargers: They are Cristec 60A and 40A, not Matservolt. However, the new L450 comes with a Mastervolt battery monitor that you are locked out of, so you can not make changes to the settings. I have had no reply from my Lagoon dealer yet as how to remove the lock. The monitor logs things such as over charge, abuse to very low voltages or very high currents. I guess they had a lot of warranty claims for the batteries.
I assume you will put in inverters. I use Victron, and use them for chargers as well. They are fully programmable, so will work with your LiFePos. make sure to purchase the USB programming device to do the programming from you PC laptop.

You can still use the Cristec for the times that you need to connect to shore power of a different AC voltage than your boat is. Just disconnect them completely from the AC system and run a separate shore cable that only connects to the Cristec charger to charge your batteries. In the manual there is a setting that works somewhat for LiFePo.I would still put a timer in the cable and switch the charger off after a certain time.

[darylat8750]

Originally Posted by goboatingnow

I think steves summary was excellent and I agree with his charging patterns.

In my own case I re-engage charging after a 20 % drop in capacity

Dave

Dave,
What do you use to trigger the re-engagement of charging at the specified capacity?
Thanks again for all the effort of all you guys on this thread.
Daryl

[sparrowhawk1]

Originally Posted by roetter

I was checking the shop page on the site when "Steve" came in with a message on the "Chat Line" to ask "how can I assist you". 10 minutes later and with two or 3 emails going back and forth with "James Li" for the credit card authorization it was all settled.

I have not opened the boxes yet, as they are with a friend in Annapolis. I am going over there next Monday.

When you inspect them can you tell me if the bolts are included and if they come with any connecting bus bars. if I get 8 batteries I'll need 14 bus bars. I don't see on their website where you can buy the bus bars or bolts and they didn't answer my emails. Thanks

[roetter]

Originally Posted by sparrowhawk1

When you inspect them can you tell me if the bolts are included and if they come with any connecting bus bars. if I get 8 batteries I'll need 14 bus bars. I don't see on their website where you can buy the bus bars or bolts and they didn't answer my emails. Thanks

I ordered the bus bars and bolts with the batteries.

For 8 cells you need 22 bus bars and 32 bolts.

I will inspect the cells on Tuesday.

[sparrowhawk1]

Originally Posted by roetter

I ordered the bus bars and bolts with the batteries.

For 8 cells you need 22 bus bars and 32 bolts.

I will inspect the cells on Tuesday.

The cells I'm getting have olny two bolts each. I was thinking of connecting them

Attachment 79624

like this. Can you put the positive and negative sign in each cell of your attachment I can't quite understand it. Thanks

PS. I know that three of the bars are redundant on my setup

And I could do it like this but it's my understanding the extra bus bars help the two separate "banks" equalize each other. Photo next post.

[sparrowhawk1]

Attachment 79625

And I went back to the website to try and find the bolts and bus bars but I can't seem to do it so if you could tell me what to click on I would appreciate it

[sparrowhawk1]

Okay I understand your photo on the bottom its 4 negatives then 4 positives.

[sparrowhawk1]

Oops. It should be negative negative positive positive negative negative positive positive on the bottom terminals. And I think the batteries will fit my box better if I lined them up this way. So thank you very much.

[IceDog]

The busbar hardware is not shown on the web store. You just have to ask them to include it. For my 4@700ah set it was very inexpensive. I believe it was around $26.

[sparrowhawk1]

Originally Posted by IceDog

The busbar hardware is not shown on the web store. You just have to ask them to include it. For my 4@700ah set it was very inexpensive. I believe it was around $26.

Thanks. Spent a long time trying to figure how to order them. Weird that they don't list them on their site.

[roetter]

I guess my diagram is sorted out then. The two red circles on each cell indicate the positve terminals, the black circles are the negative terminals. I parallel two cells each first to get four sets of two cells in parallel, then do the series connection.

Smaller cells only have one terminal for positiv and one for negative.

The cost for the bus bars and bolts was $75.

[roetter]

Originally Posted by KASHMIR

I wonder if anybody has tried connecting the 17.5V from the solar panels direct to the LiFePO4 bank of cells? I would have thought that the BMS would cut the solar cell current when the battery terminal voltage reached the required 14.6 V or would it cook something before that happened?

Peter

On my mono with 360Ah of LiFePo I currently have a 120W solar panel directly (no charge regulator) connected to the cells. I run a programmable voltmeter that triggers a solar cutouff relay (automotive relay) at 14.0V to cut the solar off. At 13.4V the solar is switched back on.

I do not use a BMS for the many reasons that have been explained on this thread.

[sparrowhawk1]

I'm looking at the picture on a cell phone and the lines are very thin but I can't believe I didn't notice that some of the circles are red. Thanks for the info. as soon as I figure out exactly how a BMS works and which one I want or if I even need one I'll try contacting them again

[ele2014]

Wow this is a huge thread related to LiFePO4 for stationary energy storage.
I wish the same level of interest will exist in the OffGrid House community.
Almost all still use the expensive and inefficient Lead Acid.

I live Offgrid since last year is somewhere in the middle of Canada Saskatchewan.
I build an energy efficient house and decided energy storage will be done with LiFePO4. I got the batteries about two years ago 2012.

The house uses between 60 and 90kWh/month mostly closer to 90kWh.
I have 3x 240W solar panels and a small 300W wind turbine storing the energy in a 24V 8s cells of 100Ah from GBS so just 2.5kWh of storage around 2kWh useful.
Since battery is still the most expensive /kWh of used energy during the lifetime I wanted to keep the battery size to a minimum.
I have the advantage of both good sun and good wind resources in my area and that helps a lot with the battery size.

Most of the power I use is during the day where is used directly form the solar PV panels as it is produced and the small difference only from the battery.
Over 60% of what I use is during the day and mostly for food preparation.
The kitchen is the only one with an AC outlet provided by a 2400W power inverter form Tripp-lite around 92% efficient.
The rest of the house is powered directly with 24V DC. Since most electronics like laptops use little energy is not a great idea to use AC (loss on conversion and even standby) and then form AC back to DC another loss.
I use DC-DC converters like Battery 24 - 28V down to 19V for laptops.
Lighting is also 24V DC with LED's. And heat recovery unit will be custom made also with 24V DC fans.
Power generation is 60kWh/month in December worst month and up to over 100kWh in the rest of the months 3x 240W PV
And from the wind turbine (300W) about 40kWh/month in winter and less around 30kWh/month in summer.

I needed to design a Solar BMS charge controller that works with 3 up to 8 series connected Lithium cells (any type of Lithium cells) so 12V and 24V max possible for small systems.
It can do up to 40A charging from solar PV and 80A discharging this is ideal for my offgrid house since I have less than 40A 1000W of panels and under 2000W load that is why I went for this numbers.
Is now on Kickstarter just a few days left is quite close to making the minimum goal but I expected way more interest in LiFePO4 solar charging so I'm a bit disappointed.
If it makes the minimum goal that is set quite low just about 50 units then it will become Open Source and hopefully someone will take this and build more products around my design.
If you are curios about the Solar BMS or my offgrid house just follow the link in my signature and from there you get to Kickstarter where when you push on the photo with my house will send you to my youtube channel where you find more videos with battery tests both GBS and A123.
Most technical stuff is there but if you want to ask anything else about LiFePO4 or Solar BMS you ca do so here.