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

[bcn]

It seems to me that the pages 19 and 20 of this thread are resuming the findings up to date quite well and are reflecting the solutions and parameters.

bcn

[gael]

Originally Posted by gscriba

Oops. Yes, of course. 400 amps total (4 x 400 amp, 3.2 cells). Thanks for pointing that out. I would like to hear from anyone who is actually using the LiFePO4 as a house bank. What system would you build with the situation I described previously?

Hi,
I have no update on the cell pricing and even know if 400Ah cells are available now . I have in mind 220Ah cells widely marketed.
I guess your pilot and few other"mission critical" items are powered by your bank.
So two banks of 12V/220Ah, each one having specific users.
But still the facility to switch the power from bank1 or bank2 in case of deep low - or BMS failure- on a bank which also could occur.

Regarding the charging, I have a simple battery splitter from Victron connected on the main alternator & the shore charger.
The solar panel is connected only on banck1-but this just for my local organisation and trials.
hope this help
rgds
gael

[Surf City]

Just got a quote in from Lithium Storage for 3 banks of 200 ah each totaling 600 ah at 12 v for $3600 and change. This included 12 CALB 200ah, MiniBMS's for 12 cells, banding, buss bars for connections, and shipping. I am not sure if I can beat the price anywhere else.

Have I missed anything in the quote?

I wish I could have Sinopoly batteries but they are not available at this time frame. We are looking to splash in June.

Wil

s/v Full Monty | Keep up with us as we sail the world and its many remote places.

[deckofficer]

Well lets see, the current hot price is $1.35 per amp per 3.2 volt cell. So that is 600 X 1.35 X 4 (for 12 volts) = $3240 for just the cells. Banding, buss bars, BMS all for $360, yes I'd say you got a very good deal.

[gael]

Originally Posted by gscriba

Love the idea of a LiFePO4 system. To summerize what would be good setup for a 40 foot live aboard sloop with an daily average use of approx. 120 amps - 12 volts.

• 400 amps (4 x 100 amp 3.2 volt cells)
• Approp. connectors to create a 12 volt pack
• High and Low volt alarms (brand?)
• Battery charger with customizable settings (brand?)
• Alternator with output 120 - 150 amps (for use on a approx. 40 hp diesel) with customizable regulator
• Alternative power supply: Solar - 125 watt panels x 2 if San Fran or further south (more if further north in PNW?). Panels side by side over the bimini wired in...oh boy, here we go...series or parallel?
• Solar regulator MPPT such as a Morning Star TriStar 45 vs 60 amp (room to grow)
• Wind generator? (trying to stay away from one if possible, but if I must...brand?)

Currently have installed house 420 amps 12 volt system (4 x 6 volt lead-acid golf cart batteries that are several years old); BlueSea VSM 422; 60 amp alternator with Balmar MC612 regulator; on the dock with shore power at present; no solar or wind generator.

What would you build, keeping simplicity in mind, but with the desire to upgrade to the LiFePO4 house bank?

Thanks.

Just to complete my previuos answer, regarding the packs charging.
The shore charger: It is a Victron configured as a Voltage source; No fancy equalisation ..flood... ect. It is tune at 28V for my application, so 14V for a 12V system.
THe alternator is a Leec-Neville 24V/75Amp heavy duty. In a real life it delivers 55 to 65Amp. It run very hot but so far after 2years seem OK.
The regulation is very basic _bang bang style and it is tune to shut off at 28V too. Two belts with a 2.5 ratio. So I got my max current after 1000Rpm. This for 2 130Ah banks
I guess I have been too conservative. An higher fan out, let say 0.5C should work well also. IE 200amp in your case, but hump! this will be a massive alternator for a 40HP.
Also I have wired 1 Victron battery monitor per bank, with their own High/Low Volt alarms.

cheers
gael

[sytaniwha]

Just to clarify the point about Li based battery fires: LiFePO4 are also part of the generic "Lithium-Ion" family of batteries, but the FePO4 part of the equation was specifically developed to remove the fire hazard associated with the more flamboyant versions of Li-Ion batteries.

The trade-off (since there always is one in this industry) is that the energy density is slightly lower than other Li-Ion chemistries, and the charge/discharge rates allowable are also lower.

However, compared to SLA, all of those attributes are much better. For house banks, LiFePO4 is a great and safe chemistry.

[sytaniwha]

Gscriba,

There's plenty of very specific comments about cells, battery size, charging, discharging, components, pricing, etc, in previous threads, so you should really take the time to read all 24 pages and take out specifics relevant to you.

A brief summary of my take on your requirements based on my implementation of 400Ahr @ 12V CALB cells is:

> 400Ahr @ 12V would be plenty if you use 120Ahr per day since it would give you over 3 days at max DOD,

> Appropriate connectors should be supplied with the cells - if not, buy from elsewhere,

> High voltage cutoff should be part of your charge devices (i.e. your regulator and shore charger),
> Your existing Balmar regulator should be programmable to LiFePO4 charging parameters (see earlier posts for specifics on parameters),
> Low voltage alarm should also be a cutoff (you should have this for SLA batteries also). Victron does a good one.
> I use a Victron shore charger,
> Use as big an alternator as your engine can comfortably handle - the batteries won't have a problem with it,
> I don't use alternative power, but solar should be enough.

Hope that helps.

Really though, read all the good stuff in previous posts - that's what this thread is for.

Cheers,

Paul.

[sytaniwha]

Re my comments on connectors in the last post - the "buy from elsewhere" meant buy the cells from elsewhere if the connectors aren't available. All the cell makers supply appropriate connectors.

Paul.

[gscriba]

Thanks sytaniwha,

I have read the thread through and through; however, there is a huge variety of applications discussed with lots of conflicting information that, yes, eventially gets clarified. My situation is well defined in my question, and was intended to get specific recommendations. Thanks for yours. I would guess that there are many who are interested in a set up very similar to what I have descibed. I look forward to stepping up to the LiFePO4 and solar! New sails first.

Gordon

[sytaniwha]

Hi Gordon,

No problem - hope my post wasn't too grumpy it wasn't meant to be.

There isn't a lot of major changes to equipment that you should need compared to your SLA batteries (I even charge my LiFePO4 house battery and my AGM lead start battery using the same chargers, and it works fine).

I think the critical points for putting together your own LiFePO4 battery without a BMS are:

• get impedance and capacity matched cells from the same run from the manufacturer,
• Bother to go through the conditioning process detailed earlier in the thread to get all the cells at the same SOC,
• Make sure that your charging mechanisms are all smart (i.e. have a CC/CV charge regime with an appropriate upper voltage limit),
• Be a bit conservative about the upper voltage limit (see a discussion between T1Terry & myself much earlier for details on that),
• Have a low voltage cutoff device which disconnects your loads (the Victron one I mentioned is adjustable, but its 10.5V default is fine) - (I believe that this is essential for lead batteries too),
• Every month or so check on the cell voltages, and bring the errant cell back to the same voltage if you see them more than (say) 0.2V out. There's a discussion about doing that earlier also. After over 1 year of use, my cells haven't shifted in balance, so you shouldn't have to do it very often,

Good luck with things, and please do post any more questions - this is a thread that's supposed to help people get started with LiFePO4 for house banks, after all.

Cheers,
Paul.

[gscriba]

Paul,
Thanks! And much better tone.

Unfortunately, I have a Xantrex TrueCharge 40, which if memory serves correctly, I will not be able to adjust settings adequately, but I will double check.

Gordon

[sytaniwha]

Gordon,

Actually your Truecharge 40 will do fine.

Although we have a Victron fully programmable shore charger, I haven't installed it yet. We have been using one of the older Truecharge 40i shore chargers since we installed our LiFePO4 battery, and it works great.

Our Truecharge is over 12 years old now, and I think that is before Xantrex bought the original company that made them, but in fact the features are very similar to today's Xantrex model.

If you have one of the newer models, you can set the charging profile to either 2- or 3-stage. For LiFePO4, set it to 2-stage. (On ours you can't do that - it's automatically 3-stage, which is fine, but 2-stage is better. LiFePO's don't need a trickle charge).

Then set the "Battery Type" to Gel. This results in the lowest voltage cutoff point.

If you have a remote battery temperature sensor, disconnect it from the charger.

Then set the battery temperature setting on the Truecharge to "Hot". This effectively reduces the charge cutoff voltage again, and puts it in a good range for LiFePO4 cells. On our older charger it sets the charge cutoff at 13.8V (3.45v/cell), and the trickle charge at 13.4V (3.35V/cell): these are just fine.

In the newer model which allows you to set a 2-stage charge regime, I think it sets the cutoff voltage at 13.93V (3.48V/cell) with no float, which is also fine (maybe a little above optimum if you've read previous posts, but way below the normal maximum given by the battery manufacturers, and so absolutely no problem).

And as I said before, I think your Balmar alternator regulator should be able to be programmed to similar levels (they don't have to be identical to the shore charger). If your regulator is one of the newer Balmars, then it should be possible to programme the ideal charge regime on that since every stage of the charge cycle is fully adjustable in 0.1V increments.

No need for expensive new charging gear.

Now just get that low voltage cutoff if you don't have one (e.g. Victron BP-60i for about US$130), and you're all set to go.

Have fun,
Paul.

[gscriba]

Paul,

Wow!!! Thanks! I'll confirm the settings that you have stated for my own learning benefit, but that sounds fantastic! I was worried the transition to LiFePO4 was going to be a LOT more painful. I'm excited!

Thanks again!

Gordon

[JoeFish]

Paul,

I want to echo Gordon's thanks here. This thread has been an enormous help to me in my decision process.

I will admit that I was both intrigued and hesitant to use this technology before reading through this entire thread. Now that I've read through it all I realize that these are really not any more complicated than other battery technologies and they address many of the problems associated with many of the other chemistries.

I'm going to have a chat with the guys at NKE to determine a proper daily amp budget for my instruments and AP with some of the new energy saving solenoid valves from L&S. Once I have that and the installation location sorted I'll get back in touch and let you review my plan.

Many thanks,

J

--
Bonne Amie
S&S Design No. 1068
Nevins Yacht Yard, 1955
http://bonne-amie.blogspot.com

[JoeFish]

I've been looking at a couple different sources for batteries and I am considerng these:

Thunder Sky LiFFePO4 40Ah Cell

I am wondering if to get a proper 12v bank I need to get 3 or 4? There seems to be some variability in the voltage of these. That or I'm missing something, i.e. they can be made with voltages anywhere between those stated numbers.

Input?

This has pretty direct bearing on where I can put these things...

Thanks,