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

[senormechanico]

God help "the clients" when all this "can,t mess up" stuff fails.

Here's an unfortunate example of that.

What Passengers Experienced During AF447′s Final Moments | Jeff Wise

I just got an email with the Captain Hal Pilot Group.
All it took was a pitot tube icing up, and an inexperienced copilot.
They ignored all the warnings and flew it at 60 knots in a stall dropping 10,000 feet per minute all the way down into the ocean.
The transcript is way too long to post here.

[goboatingnow]

Originally Posted by senormechanico

God help "the clients" when all this "can,t mess up" stuff fails.

Here's an unfortunate example of that.

What Passengers Experienced During AF447′s Final Moments | Jeff Wise

I just got an email with the Captain Hal Pilot Group.
All it took was a pitot tube icing up, and an inexperienced copilot.
They ignored all the warnings and flew it at 60 knots in a stall dropping 10,000 feet per minute all the way down into the ocean.
The transcript is way too long to post here.

Massive thread drift IMHO

[T1 Terry]

Originally Posted by goboatingnow

This is wrong, an industry has grown up around LifePo4 that's a bit like the one that used to exist for osmosis treatment. It uses fear of unknown technology coupled with application feedback from other uses, especially EV to build a mini-industry that suggests you need all these bells and whistles. Let me say first, fair play to them. The truth is you can use liFepo4 batteries with the same approach as current LAs. ( in typical boat environments) , in fact they are easier to use , likely to survive much longer and provide you with all the benefits of such technology.

Originally Posted by goboatingnow

You don't need low voltage cutoffs, cell monitors or complicated BMS. While you risk more money then conventional LAs you still don't need these devices. At a very minimum an LVC is useful to have and are readily available as battery watch systems already produced by several marine electronics manufacturers. The rest you can do with a multimeter and even if you don't have a multimeter, it's still difficult to f&€k it up.

As to " However, no professional marine systems installer worth their salt would want to send their clients out to see without a fully-protected system that their client can't mess up." what fantastic irony. God help "the clients" when all this "can,t mess up" stuff fails.

Dave

I guess this post is going to step on a few toes but B/S self promotion of the BMS industry is one of those things that really get under my skin.
But first off,

the various brand names mentioned here (Thundersky, CALB, whatever) are simply CELL manufacturers.

These are not or at least were not manufacturers but merely resellers putting their brand name on them. How often do we see that these days

Now for the real issues:
Cell monitoring, over voltage/under voltage per cell is far closer and safer monitoring than relying on a mini computer system in a hash environment to look after things. The human brain controlling operations seems to be a tad more reliable, fortunately system glitches auto reset using one of these devices where the active BMS needs to be manually reset when it suffers a glitch.
Anyone reading this post will have already suffered a computer glitch in a far more complex computer system with billion $$ technology and brains behind it so it would be extremely naive to think a micro processor control system in a very hash environment built by a fledgling backyard/small workshop industry would suffer the same problems. The EV forums are littered with disaster stories when full reliance was placed in an active BMS system, buggered if I would want to be reliant out at sea with one.

There is an up side with people using these things though, cheap cells hit the market as part of complete battery banks where a few cells have been stuffed due to the BMS stuffing up some where, they replace the complete bank so the dud bank came be scored cheap.
Simply sort though the cells, charging each individually till you get a set that hold charge. Put 4 cells together to form a 12v pack, put them under load and watch the cell voltages, any that drop away indicate a none too well cell, recharge the others and replace the sus one, repeat until you have a reasonable matched set.
A mate bought 20 x 40Ah cells for AU$300, went through this process and now has 4 good 40Ah 12v battery packs for his outboard on the fishing dingy. This was the result of an electric cycle BMS crapping itself.

I think this thread is a very good method of warning the average punter about possible problems simply trusting a rather expensive battery pack to a fledgling BMS industry, it's far better to watch your batteries yourself and not very hard to do. these batteries are not the out of control monsters the BMS industry are trying to portray but rather a far better and more stable battery system than lead acid and much easier to monitor and maintain.

T1 Terry

[bill good]

The supply will need to be better before I will put one into service. I needed to replace a 12V starter battery & found the need for a very long lead time which would have rendered the boat U/S for at least a month so for $150 it was replaced with a good AGM for another 7yrs. If a battery fails I would like to think it has not got to be ordered from China next time an order is being placed. I would have liked to do the weight reduction by changing to LIFEPO4.

[OceanPlanet]

Well, not everyone goes sailing to become an energy/electrical geek. Some just want their stuff to work without having to poke around with multimeters. Or without having to wonder if everything is off/on/ok when they leave the boat. Of course you have to be responsible to be at sea, but anyone can make a mistake.

Most of the top yachts in the world that racing or cruising in extreme conditions where "failure is no option" do depend on various electrical gadgets. Many are now using lithium and want systems that look after themselves as much as possible. Preparation is key of course...many things all over the boat need to be protected to assure trouble-free operation.

Hey, I'm not saying the high-end systems are for everyone. If someone really knows what they're doing and is there to look after a minimal-BMS (or no BMS) kit, they should go for it.

I can appreciate many different approaches; to each their own. Speaking for myself (maybe I've gotten a bit lazy, after growing up cruising with sextants, oil lamps and wind vanes), I like putting to use what I've learned to make things easier to operate.

[goboatingnow]

Not to rabbit on here, but to reiterate. In a typical cruising setup Lifepo4 are as simple to use as LAs. While at a minimum LVC disconnects are useful they are not needed nor are BMSes of any type. Monitoring can be done with conventional battery monitors or a multimeter. There no requirement to be a battery wizard.

Arguably the reliance on active BMS has done more damage to lifepo4 then if the things were never used.

Yes it you are pushing the battery envelope you need to know what you are doing, other then that it's not rocket science.

I'm not having a go at the BMS industry, fair play to them. What I am countering is the tendency to market such devices as a way of controlling "unruly " Li batteries. Nothing could be further from the truth as regards lifepo4 . BMS in such situations area" nice to have" bits of technology. But are actually unnecessary.

Dave

[sytaniwha]

Merry Christmas all,

Just to join the discussion around the merits of BMS, I think I'm probably in the middle between OceanPlanet & GoBoatingNow in terms of my thinking.

Firstly, I agree that my use of LiFePO4 up until now supports the view that this chemistry is more resilient and user friendly than lead-acid, and requires less fore-thought in everyday use.

There are many ways to damage lead acid batteries, many of them fatal. Lead acid also can deteriorate quickly depending on your usage profile.

Although there are also ways to damage LiFePO4 batteries, there seem to be less ways to do this than with lead acid, and those that do exist will also damage lead acid. So if you have a bad set-up, or bad battery management practices, you'll damage your battery regardless of the chemistry, and you'll likely damage lead acid more.

I think all yachts with batteries (which basically means almost all yachts) should have some form of battery management, regardless of the chemistry. Today, it's easy and cheap to do this. I think that this should include a smart charger and/or regulator with 3-stage programmable control, and a low voltage cutoff to protect your battery. Both of these devices are easy to implement on a battery bank scale.

It is my opinion that these two management devices are sufficient for managing both lead acid and LiFePO4 battery banks if you have a decent process for battery maintenance. If you don't have a decent process, then you run the risk of damaging your battery regardless of it's chemistry. In that case I think that there is less chance of damaging LiFePO4 than lead acid, and I don't believe that there is any difference in the risk of a violent event happening (if you read earlier in the thread you'll see discussion around safety being one of the reasons why LiFePO4 is different to other lithium based chemistries).

In my opinion (again), if you are a sailor and own a yacht, then you absolutely should have a decent maintenance and knowledge programme for everything on your yacht. If you don't, and you have a failure at sea of any one of many components, then you may be risking life.

However, I think that more people are now buying yachts with less knowledge, and are trusting more that things will "just work". I think it's great that more people are getting out on the water and discovering the joy of sailing, but it is a bit worrying how little some know about their yachts.

If you add this trend to the opinion that society is getting more litigious and taking less personal responsibility (let's not have a long argument about that), I can understand why boating contractors might view a cell-level BMS as necessary.

And I can also understand why EVs use BMS' given their many cells in more complicated series/parallel arrangements. I just don't think they're necessary for house banks.

Anyway, maybe we should have named this thread "LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks, and who have a decent preventative maintenance programme for their yacht's systems, which should really be all of you."

Maybe we should move back to discussing the real world experiences of buying, integrating, and using LiFePO4 cells for those interested in that.

Have a great New Year's Eve.

Paul.

[sytaniwha]

Regarding Bill Good's comment. I agree that buying an AGM for your starter battery is more practical than hunting down LiFePO4s. We use an Optima spiral wound lead-acid battery for starting, and LiFePO4 for house bank. We have no problems charging both from our smart charger and regulator.

For us, finding LiFePO4 cells for the house bank was worth it, but I agree that at this stage most people won't be bothered. I think this will change, and hopefully this thread will help some people become confident enough to make that change.

Cheers,
Paul.

[downunder]

Originally Posted by sytaniwha

Regarding Bill Good's comment. I agree that buying an AGM for your starter battery is more practical than hunting down LiFePO4s. We use an Optima spiral wound lead-acid battery for starting, and LiFePO4 for house bank. We have no problems charging both from our smart charger and regulator.

For us, finding LiFePO4 cells for the house bank was worth it, but I agree that at this stage most people won't be bothered. I think this will change, and hopefully this thread will help some people become confident enough to make that change.

Cheers,
Paul.

Paul,

Interesting to see you have moved to LiFeO4 and are happy.

For those of us who are contemplating would it be possible to describe your system in some detail, how you went about it, your charging system, maintaince program if possible illustrated with pictures.

I am sure there are others who would like to learn more about how you went about implementing your system.

Glad you dodged the Christmas blow which may well end up over our way yet.

Cheers,

John

[sytaniwha]

Hi John,

We're up on the west coast of Thailand, so there wasn't an Xmas blow up here. We're out sailing from tomorrow for the next 10 days, so hopefully we'll get a little more than the normal 8 knots, but nowhere near as much as what is ripping through northern Oz.

On the implementation, charging system, maintenance, etc, if you look back through my posts on this thread you'll find much of the info you mention (I think you can search for a specific poster name). There's one post where I detail the charging setup. I'd also recommend looking at T1 Terry's posts, as he has also posted a lot of specific info.

Unfortunately I don't have time today to go into detail (packing for departure), but if you have a look over those past posts, and then post any further questions on things that you'd like more detail on, I'd be happy to answer when I get back in a few weeks.

I'll also hopefully have some more info on our usage patterns to post then.

I think I've posted some photos earlier, but I'll see if I can post more when I get back.

Hopefully you're not hit too hard by the weather.

Have a great New Year,

Cheers,
Paul.

[downunder]

Originally Posted by sytaniwha

Hi John,

We're up on the west coast of Thailand, so there wasn't an Xmas blow up here. We're out sailing from tomorrow for the next 10 days, so hopefully we'll get a little more than the normal 8 knots, but nowhere near as much as what is ripping through northern Oz.

On the implementation, charging system, maintenance, etc, if you look back through my posts on this thread you'll find much of the info you mention (I think you can search for a specific poster name). There's one post where I detail the charging setup. I'd also recommend looking at T1 Terry's posts, as he has also posted a lot of specific info.

Unfortunately I don't have time today to go into detail (packing for departure), but if you have a look over those past posts, and then post any further questions on things that you'd like more detail on, I'd be happy to answer when I get back in a few weeks.

I'll also hopefully have some more info on our usage patterns to post then.

I think I've posted some photos earlier, but I'll see if I can post more when I get back.

Hopefully you're not hit too hard by the weather.

Have a great New Year,

Cheers,
Paul.

Paul,

I had mistaken your post for a user with a similar name who was in darwin.

Thanks,

John

[roetter]

Just read from a fellow cruiser who installed 12V/600Ah LiFePo from Smart Battery two weeks ago, replacing his 1200 Ah gel cells:

Home Lithium RV / Marine Batteries

Smart Battery boxes the cells up to be a drop-in replacement for LA batteries. They also developed a battery protection unit. Smart Battery protection switch

Good for people who don't want to bother with making their own packs. Does anyone have experience with these?

Rolf

[roetter]

This is a translation from the German Blog of the “Pacific High” Lagoon 500 – commissioned in April 2009.
14.12.2011 Neue Batterien für die Pacific High | Pacific High
He has posted an interesting set of pictures there.
Important: Make sure to set the language to German (Deutsch), otherwise the blog entry will be empty.

Here we go:
12/14/2011 New batteries for the Pacific High

The power budget on board is important for every sailor, especially on Pacific High with all our power-hungry amenities. We therefore have a (relatively) accurate system for monitoring energy consumption, energy generation and the current state of charge our battery bank on board. For about half a year I have noticed that our GEL battery bank has aged considerably and does not have full capacity anymore. Even worse for us is that the charge acceptance is reduced. Therefore, we are wasting a good portion of our energy already during charging. We had hoped that would keep our GEL battery bank longer than this. We have 9x EXIDE GEL Deep Cycle 4D batteries on board, which now have about 800 charge cycles under the belt. Normally, the batteries were discharge max. 30% to 40% (DOD 70-60%) only about a dozen did we discharge them (60%) down to 40% DOD.

We were faced with the decision to install the same "old" GEL batteries or convert to the "new" lithium ion batteries.

Reasons to stay with the GEL are: simple exchange old for new, affordable price, "proven" technology.
Reasons for lithium ion batteries are: much lighter, much better charge and discharge characteristics, significantly higher specific capacity but also about twice the price.
Since all of our chargers have user-programmable 4-stage charging characteristics we did not have to change anything here.

To come to the point: We decided to go for Li-ion batteries from Smart Batteries in Florida, which were delivered and installed today. Smart Batteries is a young, professinell and dynamical, local company on the Li-ion market in the U.S.. Its two owners, Victor and Conrad are competent, trustworthy and nice. The conversion from GEL batteries to Li ion took us about 4 hours: only 1 hour of true conversion, the rest of the time we spent to build a solid wood construction for the much smaller Li ion batteries and to search for a shop that had two 600A power bars. Thanks to Victor's help the entire conversion went quickly and without any problem. And when we fliiped the main battery switch back flips and turned on the inverter / charger the system worked perfectly right away.

Here is some data to compare the "old" GEL battery bank with the new LiFePo4 bank.


Total GEL battery bank capacity: 1260 Ah, max. usable about 750 Ah, usable in practice about 500 Ah. Charge currents: Bulk (= empty batteries) 200 Amps, absorption ab out 150 Ah, from 85% capacity only about 30-40 amperes are accepted by the batteries, ie for the last 200 amps hours we needed 5-6 hours charging time. Discharge currents: we draw up to 600 amps, during which the battery voltage drops significantly, would be better if we had a max of 300 Amp Total weight: about 430kg



Total capacity Li-Ion Battery Bank: 600 Ah, of which max. usable about 500 Ah, usable in practice also 500 Ah. Charge currents: whatever chargers can deliver, in our case, we load the fully discharged battery bank into two hours again. It is fascinating to watch how the full charging current to about 97% of capacity, then within a few minutes it drops to 20 Amp and after a further 10 minutes at 14.6 volts it stops completely. Discharge currents: almost anything we want, our max. 600 amps are no problem. Total weight: about 80 kg. Space: Just under one-third of the GEL battery bank.



Addendum of 04/01/2012: We have had the Li-ion batteries in use now for 20 days and can fully confirm the statements made above. All 24 cells have exactly the same final charge voltage of 3.65 volts. Under load (400 amps discharge) the voltage does not drop under 13.2 volts. We will set up a separate page under the menu item "Blue Water Info" for the lithium batteries and post regular updates there.

[witzgall]

I need some help getting our 120a balmar alternator and 612 regulator to charge oue lifepo4 bank. Currently, it is set to charge at 14.4v, and I set the float voltage to 13.7. I am getting about 60a max when first charging, and it tapers off in a few minutes to 40, then 30, then 25 or so. This is when the link 10 shows 200a down to start.

[OceanPlanet]

Set the float at 14.4V also to start with. No need for reduced voltage float with Lifepo4.