Lithium Ion batteries on a boat

[seb123]

Hello chaps,
I am Sebastian, working as an electrical engineer (in automotive), without much experience in boats, but willing to learn.
Long story short:
My father bought himself a used boat (not this one, but it is similar in size, design and interior: http://www.yachtworld.co.uk/boats/2006/Bayliner-305-2837345/United-Kingdom#.VWXOpka8-xE)
Which has been using flooded lead acid batteries (12V 200Ah overall) to power the domestic part of the boat. These (5 year old) lead acid batteries seem to be completely dead, the multimeter shows only 9.8V.
They definitely need to be replaced and this is where the thought about lithium batteries (LiFePO) came up, as .
What do you think?
Does anyone have experience with lithium batteries on his boat?

LiFePO is not as dangerous as LiIon as it is a lot less likely to catch fire.
Until now the most interesting battery would probably be the
Mastervolt MLI Ultra 12/2500
(http://www.mastervolt.com/marine/products/li-ion/mli-ultra-12-2500/)

At the moment there is only the basic board electronics (compass, gps, vhf, radio(CD Player), microwave and an old fridge) that are powered from the battery (if it was working).

If we go for the lithium batteries, do they normally have some kind of communication (e.g. CAN Bus in cars)?
And are there any "boating standards" to be met?

Have you any experience about things we should look out for? (e.g. things you are missing on your battery power supply)

Thanks for your replies,
Sebastian

 

[rafiki_]

Good question Sebastian, and a very warm welcome to the Mobo forum. We have 1 or 2 experts who can comment on this, notably Annageek, so I will be very interested in her thoughts.

To my knowledge, the biggest hurdle for the Lithium batteries is the cost of entry at the moment. Lead acid are so relatively cheap, they are the default route. If you know better....................?

 

[jfm]

Hi Sebastian. Yup, poster on here Annageek is a battery expert.

The Mastervolt unit has canbus communication. you can plug together a cat5 cable network and get lots of mastervolt items to talk to each other and display to colour screens. Quite significant £££ though. I've looked at switching to Mastervolt's LiFePo but not done it yet. Imho the downside is:
1. initial cost, and the thought that next year there will be something fasterbettercheaper
2. Physical size means joinery work to accommodate them
3. High cost of peripherals (canbus network etc) plus the personal time burn of running all those cables
4. to take advantage of the high charge acceptance, I'd need to install a paralleled 3rd battery charger; that's another £1000 and another item on the jobs list...

There are no other boating standards to be met if you don't use the boat inland on British waterways., You just install what you want and go

 

[matt_lake]

Welcome Sebastian,

The Mastervolt LiIon batteries are very expensive. I recently supplied a set to a customer for a 48v propulsion system. They come with a built in shunt and are capable of linking into Mastervolts own CANBUS as part of a complete system. Not all chargers will manage LiIon batteries so that may also need to be changed. In short, for cranking and domestic power on a boat that size, you're better off sticking with Lead Acid, AGM or Gel. What I would advise is that you don't mix and match.

 

[Trundlebug]

I would echo what's been said above.

It's early days for Lithium batteries and charging systems in boats (as it is in automotive) so unless you want to go that route for your own hi-tech reasons, it isn't yet economic and there is very limited choice. It's not just the batteries you have to consider, it's the charging system which would require replacement, and as I said there's limited choice and currently high £££

It will come, but probably only after automotive have led the way and so far there isn't much sign of it except in pure electric cars and some hybrids.

 

[seb123]

Hello again,
thanks for your replies, I was worried that the price is quite high, but was hoping, that there was a sensible reason to use lithium batteries in boats (like a possible plus in lifetime/maintenance).

It is sad that the advance of the lithium batteries is relatively slow, as it seems to be a quite nice technology.
I guess we will stick to lead acid batteries then, although I would still be very interested in annageeks opinion about that!

Thanks for your replies,
Sebastian

 

[annageek]

Christ! It seems my reputation precedes me!

Yep! I agree with all of the above, really. In my opinion, in such applications, lithium batteries should only be used when they solve a problem that isn't solved by lead-acids. LiFePO4 (lithium iron phosphate), as you rightly say is considered safer than other li-ion battery chemistries such as LiCoO2. Just to nit-pick though, strictly speaking, LiFePO4 is also a li-ion battery, although it's rarely marketed this way.

Often, people look at the cycle life advantage of LiFePO4 vs Lead-acid. While it is true that, in theory, you can get more cycle life from the lithiums, in reality, this is based on conservative discharges, 'perfect' recharging, at constant temperature on cell level. Scale this up to a large battery system, in the challenging thermal environment of a boat then start haphazardly charging/discharging and all bets are off. I just don't think commercially availale, large LiFePO4 blocks have been around long enough to prove the claims of 2000-7000 cycle lives that you see in product documentation. Lead acid blocks have been around for decades, and have a proven, reliable track record.

Also, something you'll never see written anywhere... any large LiFePO4 block will have a battery management system (BMS) for battery balancing and over discharge/recharge protection. This is almost certain to be the weak link in the chain and be liable to fail before the cells in the battery do! It's just something I would take into account.

LiFePO4 has some real advantages, and if it was a close call price wise, then I would choose them over leas-acid. However, as people have pointed out, they're (at the moment) several times more expensive, and I suspect that in reality, they won't really last all that much longer than lead-acid batteries. In marine applications, one of the oft-overlooked advantages of LiFePO4 is the absence of hydrogen gas generation (as with lead-acid), meaning they're suitably for use in small sealed spaces, which could be of particular interest to small power boats/ribs etc.

My advice: Go for a good quality, maintenance free sealed lead acid battery (e.g. 2x Lifeline GPL31-T batteries (105Ah each) is genuinely what I would use if it were my boat to replace your current setup). Get a decent charger, and low voltage disconnects where necessary to ensure you don't unduly bugger them up, then enjoy the boat! If you really want to take the extra step to get better reliability and longer life of the battery system, increase the capacity a bit (just put some more 31-T's in parallel), as the shallower a lead-acid battery is discharged, the longer it will last.

It's worth saying that many go for an even cheaper option of going for Trojan T-105 (6V) flooded lead-acid batteries. From reports (on here) they're pretty rock solid and reasonably cheap to replace when it comes round to it... afterall, all batteries are 'consumables' and WILL need replacing at some point. These will need maintenance, though (electrolyte top-up).

Hope that helps, and happy to ask any specific questions.

 

[rafiki_]

Thanks Annageek, all very clear.

 

[MapisM]

It's worth saying that many go for an even cheaper option of going for Trojan T-105 (6V) flooded lead-acid batteries.

While I wouldn't actually call Trojan batteries cheap (not for FLA technology, anyway - you can get much cheaper FLA stuff), a set of T-105 is exactly what I just finished to install in my boat.
And together with the upgraded, much more sophisticated recharger (Victron Multiplus), I'm really curious to see how long they'll last.
Will report about the experience in due course - hopefully rather later than sooner!

PS: thanks for a very clear and effective summary on lithium batteries. That's pretty much what I already thought, but it's good to hear that explained/confirmed by a pro!

 

[Hugin]

Lithium batteries could be justified if they either solve a specific problem better than the alternatives or if they add a capability you want and can't have any other way for comparable investment and effort.
If your problem is that the old batteries are dead and you just want the system to work as before then obviously the only answer is new lead-acid batteries.

If you OTOH want to increase capacity, so you can manage without access to land-power for longer periods then Lithium batteries could be the answer. The batteries currently would have a capacity of 2,4 kWh if they worked according to what you write. With Lithium batteries you could probably increase it to around 6 kWh without adding weight to the boat..... and as you probably know, added weight to a planing boat kills speed and increases fuel consumption. With 6 kWh in store it might even make sense to add an inverter and get 220V anytime to run your dead cheap new 220V fridge, your 50" flat screen and all the other necessities Homo Sapiens, version 2015 can't do without

You can probably source EU-approved Lithium batteries directly from China for around £350/kWh compared to around £700/kWh which seems to be the price Mastervolt, Victron and other marine suppliers have somehow all arrived at. All prices excl. VAT of course.

 

[annageek]

If we go for the lithium batteries, do they normally have some kind of communication (e.g. CAN Bus in cars)?
And are there any "boating standards" to be met?

I forgot to answer this. Yes – larger ones generally have some sort of SMBus based communications for the purposes of battery array monitoring/control. That said, it may not even need to be used on a 12V 200Ah system, depending on the manufacturer/model of battery used. There are 12V 100Ah LiFePO4 blocks available that can be used that have fully self-contained battery management system, meaning they can be paralleled up just like lead-acids (although there’s more of a limit on series connection with these).

Usually, any communications system tends to be for the battery’s sake only. That’s not to say you can’t get some form of network bridge for most battery systems that will allow you to ‘look inside’ the batteries’ brains – I believe these do exist, especially for CANBus. A marine equivalent would be NMEA2000 or something – but I’ve never seen a SMBus / Smart Battery System to NMEA2000 bridge. That said, I’ve never looked, either.

With Lithium batteries you could probably increase it to around 6 kWh without adding weight to the boat

I would guess though, that space is going to be as much of an issue as weight. In which case, LiFePO4 isn’t going to help much, as it’s roughly equivalent (volumetrically), once formed into large capacity blocks, as similar capacity lead-acid blocks.

You can probably source EU-approved Lithium batteries directly from China for around £350/kWh compared to around £700/kWh which seems to be the price Mastervolt, Victron and other marine suppliers have somehow all arrived at.

You definitely can! I have evaluated a lot of them. In fact I’ve evaluated Far Eastern, European and North American manufactured LiFePO4 based batteries. It is a simple and unsurprising fact that the more you spend, the better the quality/reliability. Also, after sales support should be considered… even the best battery manufacturers make a duff battery once in a while, and on such an expensive battery, this may very well prove its worth! You pays your money and you takes your chance!

I once dealt with a customer who had been helping a catamaran over in Norway who had some (European) LiFePO4 batteries on board. After about 9 months, the batteries gave up the ghost and leaked lithium hexaflourophosphate everywhere (nasty stuff that decalcifies your bones!). It may have been an application issue that caused the problem, and not the batteries’ fault, though. I just don’t know. That said, they were covered by the European company by their warranty and a full refund was provided with little fuss, but these were LiFePO4’s that sit at the less expensive end of the market.

Also, even when buying in reasonably large quantities, the individual LiFePO4 cell cost comes in at around 350USD/kWh (about 240GBP) and that's before any support electronics, cases or assembly... unless your name is Elon Musk, it would appear!!

If it was me, and I was spending anything more than a couple of hundred pounds on a battery setup, I’d go for a known brand with proven aftersales support. This way, the chances are the quality/reliability should be average at worst.

I should point out, also that this is all my genuine unbiased opinion. I'm not trying to drum up any business for the company I work for (in fact, today is my last day of y five-and-a-bit years working here before I move onto my next job as a more senior professional geek!), and ultimately we supply B2B rather than B2C when it comes to simple 'block-shifting' of batteries, anyway.

 

[MapisM]

I move onto my next job as a more senior professional geek!

A well deserved promotion, if your posts around here are anything to go by. :encouragement:
All the very best!

 

[seb123]

Wow, thanks a lot for your help chaps!
Looks like we will go for the lead acid batteries then, looks like they make a lot more sense for us.

Thanks for clearing everything up!

 

[Delfin]

Christ! It seems my reputation precedes me!

Yep! I agree with all of the above, really. In my opinion, in such applications, lithium batteries should only be used when they solve a problem that isn't solved by lead-acids. LiFePO4 (lithium iron phosphate), as you rightly say is considered safer than other li-ion battery chemistries such as LiCoO2. Just to nit-pick though, strictly speaking, LiFePO4 is also a li-ion battery, although it's rarely marketed this way.

Often, people look at the cycle life advantage of LiFePO4 vs Lead-acid. While it is true that, in theory, you can get more cycle life from the lithiums, in reality, this is based on conservative discharges, 'perfect' recharging, at constant temperature on cell level. Scale this up to a large battery system, in the challenging thermal environment of a boat then start haphazardly charging/discharging and all bets are off. I just don't think commercially availale, large LiFePO4 blocks have been around long enough to prove the claims of 2000-7000 cycle lives that you see in product documentation. Lead acid blocks have been around for decades, and have a proven, reliable track record.

Also, something you'll never see written anywhere... any large LiFePO4 block will have a battery management system (BMS) for battery balancing and over discharge/recharge protection. This is almost certain to be the weak link in the chain and be liable to fail before the cells in the battery do! It's just something I would take into account.

LiFePO4 has some real advantages, and if it was a close call price wise, then I would choose them over leas-acid. However, as people have pointed out, they're (at the moment) several times more expensive, and I suspect that in reality, they won't really last all that much longer than lead-acid batteries. In marine applications, one of the oft-overlooked advantages of LiFePO4 is the absence of hydrogen gas generation (as with lead-acid), meaning they're suitably for use in small sealed spaces, which could be of particular interest to small power boats/ribs etc.

My advice: Go for a good quality, maintenance free sealed lead acid battery (e.g. 2x Lifeline GPL31-T batteries (105Ah each) is genuinely what I would use if it were my boat to replace your current setup). Get a decent charger, and low voltage disconnects where necessary to ensure you don't unduly bugger them up, then enjoy the boat! If you really want to take the extra step to get better reliability and longer life of the battery system, increase the capacity a bit (just put some more 31-T's in parallel), as the shallower a lead-acid battery is discharged, the longer it will last.

It's worth saying that many go for an even cheaper option of going for Trojan T-105 (6V) flooded lead-acid batteries. From reports (on here) they're pretty rock solid and reasonably cheap to replace when it comes round to it... afterall, all batteries are 'consumables' and WILL need replacing at some point. These will need maintenance, though (electrolyte top-up).

Hope that helps, and happy to ask any specific questions.

Very helpful explanation. Have you (or anyone) any experience with carbon foam AGMs? 3000 cycles and they seem to have no memory issues with declining charge acceptance in response to less than full re-charge.

http://www.bruceschwab.com/uploads/2014-firefly-handout2.pdf