Batteries and their technologies, Which is best ?

[Tony Brooks]

4 minutes ago, peterboat said:

Charging is by solar or generator controlled charging is key to long life of LifePo4s.

 

I think that is the whole key to getting the best from LiFePo4 lithiums, along with understanding what states of charge gives optimum life. Personally, I find it difficult to reconcile long lengths of wire with "control" and relying on the BMS to regularly disconnect the charge. having looked at a few UTube videos of such batteries, I have seen nothing in the BMS that looks as if it could reliably and regularly disconnect high charging currents.

 

If I were buying a new boat, it would definitely use such batteries.  I don't think there should any longer be any argument about their superiority over LAs, but can see a number of arguments against low cost retrofitting.

[IanD]

For boats, AGM/gel batteries seem to fall into the gap between LA and lithium -- they're a lot more expensive than LA, and unless you spend a lot on a sophisticated charging system are likely to be poorer value because they won't last any longer. But if you go to this bother then you might as well go all the way to lithium which have many advantages, including costs over lifetime, zero maintenance, better charging, and no need to run engine for hours to charge fully and prevent sulphating.

 

It's not clear that just using drop-in lithiums (low-cost retrofitting as Tony mentions) does this unless they have a (CANbus?) BMS which can integrate with solar/engine/generator charging, most don't have this and just protect themselves against disaster.

 

So either cheap LA and treat them as disposable (though do what you can not to mistreat them) or lithium with properly controlled charging (but more money upfront) seem to be the two best choices.

Edited April 25, 2023 by IanD

[Tacet]

15 hours ago, nicknorman said:

 

We used to have Trojan T105 LA batteries. I thought they were quite good. Now we have LiFePO4 cells and they are in a completely different league, fantastic. Took a punt on 12 x 200Ah prismatic cells from China a couple of years ago.

HOWEVER what a lot of people do is drop a Li battery into a system that was designed for LA batteries, and that creates a lot of problems for charging since how Li likes to be charged is completely different from LA.

LA likes to be kept full, Li doesn't. LA charges slowly, Li charges very fast virtually right to the end.

So in my opinion, dropping in Li to a system designed for LA is always going to be problematic, even if it has a good BMS.

For example, Li will take full alternator output for hours, resulting in the alternator getting very hot and having a very short life. A big alternator under full load can adversely affect even a fairly big engine when it is idling or at slow revs - high belt forces = slippage and big side load on the pulleys, engine struggling.

Alternator charging until the BMS shuts off can cause a big load dump spike of perhaps 80 volts that will likely damage the boat's equipment and the alternator.

In summer with light usage and long cruising days, the alternator will keep the Li at a high charging voltage which is bad for it - charging method Li should be to charge the battery then disconnect the battery (either actually, or by reducing the charge voltage to a low float value). Li does not like being held up at 3.65v/cell for hours on end.

There are some work arounds for these problems but they are all messy. The correct way to do it is to modify the charge sources so that they are optimised for charging Li, rather than to fudge around with an LA charging system and try to make it work for Li. This is why we have a custom alternator controller and BMS that is integrated into the Mastervolt combi inverter charger and the BMV712 battery meter. Everything works together and the system knows the SoC and there is a simple 3 way switch to select the desired charge state, either 50%, 80% or fully charged (the latter is useful for synchronising the BMV7

I am sure your lithium BMS is spot-on. But when living aboard, I have had more problems with fried alternators than with undercharged or expired lead acid batteries.

Is it, pretty much, that the benefit of lithium is its ability to allow the alternator to put out more current longer?  If so, alternator trouble seems more likely.  Presumably, if you were confident of a long days cruising the BMS could be tweaked to keep the current moderate from the start? Not seen any mention of this.

No doubt the real answer is a better alternator.

[magnetman]

If I was doing batteries I would consider importing a lot of the BYD blade modules. They look lovely for making boat battery banks with and apparently Tesla have ordered a lot of them so they must be good.

 

LFP.

 

I would not really like batteries with individual inbuilt BMS as it seems plausible that the electronic components may not last as long as the cells themselves. You could end up binning a perfectly good battery because of a component or board failure.

 

I personally think that this is what will be happening with the 'drop in' replacement batteries before long.

 

A battery made up of individual cells with an external and changeable BMS seems to me to be the way ahead given the advertised lifespan of some cells.

 

 

 

 

[peterboat]

22 minutes ago, Tony Brooks said:

 

I think that is the whole key to getting the best from LiFePo4 lithiums, along with understanding what states of charge gives optimum life. Personally, I find it difficult to reconcile long lengths of wire with "control" and relying on the BMS to regularly disconnect the charge. having looked at a few UTube videos of such batteries, I have seen nothing in the BMS that looks as if it could reliably and regularly disconnect high charging currents.

 

If I were buying a new boat, it would definitely use such batteries.  I don't think there should any longer be any argument about their superiority over LAs, but can see a number of arguments against low cost retrofitting.

Mine is done with quality solar controllers, the batteries have active individual battery balancing and I have active bank balancing as well which is critical. Currently my batteries are nearly charged they are at 13,9 volts and the amps going in is dropping rapidly although its still 17.4 amps going in. Most of my solar is turned over to heating water via an immersion heater, whilst typing amps going in is down to 13,4 and bank balancing is active

6 minutes ago, Tacet said:

I am sure your lithium BMS is spot-on. But when living aboard, I have had more problems with fried alternators than with undercharged or expired lead acid batteries.

Is it, pretty much, that the benefit of lithium is its ability to allow the alternator to put out more current longer?  If so, alternator trouble seems more likely.  Presumably, if you were confident of a long days cruising the BMS could be tweaked to keep the current moderate from the start? Not seen any mention of this.

No doubt the real answer is a better alternator.

Nick designed a alternator control system to stop his alternator getting fried, others have done similar, I rely on quality MPPT solar controllers and quality chargers, which for 4 years have served me well

3 minutes ago, magnetman said:

If I was doing batteries I would consider importing a lot of the BYD blade modules. They look lovely for making boat battery banks with and apparently Tesla have ordered a lot of them so they must be good.

 

LFP.

 

I would not really like batteries with individual inbuilt BMS as it seems plausible that the electronic components may not last as long as the cells themselves. You could end up binning a perfectly good battery because of a component or board failure.

 

I personally think that this is what will be happening with the 'drop in' replacement batteries before long.

 

A battery made up of individual cells with an external and changeable BMS seems to me to be the way ahead given the advertised lifespan of some cells.

 

 

 

 

Andrew you can always retrofit a BMS if the current one goes wrong, plenty have done it on Valence batteries

[canalboat77]

I own a passenger boat and currently have 4 old 12V 115Ah Led Acid Batteries that need replacing. The engine on the boat is a new (ish) Beta 60 has an 175 amp alternator if that helps. I would like to know what my options are to have the latest and greatest battery technology - and would ideally like just one battery moving forward. I'm also UK based if that helps with recommendations for the replacement.

Should I look for something which totals 460Ah?

[magnetman]

I was thinking about things like the Sterling and TN power batteries. It seems one would need to cut the thing open.

[IanD]

11 minutes ago, magnetman said:

If I was doing batteries I would consider importing a lot of the BYD blade modules. They look lovely for making boat battery banks with and apparently Tesla have ordered a lot of them so they must be good.

 

I would not really like batteries with individual inbuilt BMS as it seems plausible that the electronic components may not last as long as the cells themselves. You could end up binning a perfectly good battery because of a component or board failure.

 

I personally think that this is what will be happening with the 'drop in' replacement batteries before long.

 

A battery made up of individual cells with an external and changeable BMS seems to me to be the way ahead given the advertised lifespan of some cells.

 

 

You'll only be able to get your hands on the BYD blade modules if you're a car manufacturer who wants to buy vast quantities. Like many cheap lithium batteries, any you do see on Chinese websites (if they ever appear...) are almost certain to be grade B/rejects (even if they claim to be grade A), which is why it's always risky importing your own like this -- many people have done this and been disappointed. And of course some have been lucky. Do you feel lucky, punk? Well, do ya? 😉

 

I agree with everything else you say, a single external BMS which controls charging (and solar/generator) is the way to go -- assuming you can get a good matched set of cells in the first place. There are ready-built batteries from the better suppliers which do include proper inbuilt BMS with CANbus control, but these tend to be the big ones aimed at the off-grid market (e.g. BYD, MG...) not the small cheap ones intended as drop-in replacements for LA batteries.

 

There are a lot of cheap and nasty lithium "drop-in" batteries which really shouldn't be used on boats...

 

https://marinehowto.com/drop-in-lifepo4-be-an-educated-consumer/

 

"How to Avoid Sleazy Vendors

LFP drop-in batteries have come a very, very long way in the last few years but this does not mean there are no sleazy manufacturers left out there. How do you avoid 98% of the poor LFP products?

Easy; Don’t Import directly from China on your own

This sort of stuff, has been sold as  “A”grade” but, the customer got “B” grade or reject products. This scammery runs rampant on Aliexpress, Alibababa, eBay, Bangood etc. etc. so be very careful when ordering direct from China because you’re on your own once you do..!"

Edited April 25, 2023 by IanD

[bizzard]

24 minutes ago, canalboat77 said:

I own a passenger boat and currently have 4 old 12V 115Ah Led Acid Batteries that need replacing. The engine on the boat is a new (ish) Beta 60 has an 175 amp alternator if that helps. I would like to know what my options are to have the latest and greatest battery technology - and would ideally like just one battery moving forward. I'm also UK based if that helps with recommendations for the replacement.

Should I look for something which totals 460Ah?

Shield the battery makers here at B.Stortford claim they can make any size single battery, though only L/A I think.  A battery around 480A would be mighty heavy.

[matty40s]

37 minutes ago, canalboat77 said:

I own a passenger boat and currently have 4 old 12V 115Ah Led Acid Batteries that need replacing. The engine on the boat is a new (ish) Beta 60 has an 175 amp alternator if that helps. I would like to know what my options are to have the latest and greatest battery technology - and would ideally like just one battery moving forward. I'm also UK based if that helps with recommendations for the replacement.

Should I look for something which totals 460Ah?

I reckon you should read the other thread....

[bizzard]

10 minutes ago, bizzard said:

Shield the battery makers here at B.Stortford claim they can make any size single battery, though only L/A I think.  A battery around 480A would be mighty heavy.

Years ago the old Ford Cost cutter trucks used one huge 6volt battery ''can't remember the amperage'', situated between the two front seats just behind the gear lever. We used an old mobile engine crane to get em in and out.

[MtB]

40 minutes ago, canalboat77 said:

I would like to know what my options are to have the latest and greatest battery technology -

 

I would suggest your options are:

 

1) Spend quite a few hours learning how LiFePO4 batteries interact with your alternator and how to manage them, and about the many ways they can be inadvertently destroyed. Then buy some.

 

Or 

 

2) If you CBA with 1, buy more lead acid batts the same as you have now. 

 

 

[nicknorman]

58 minutes ago, Tacet said:

I am sure your lithium BMS is spot-on. But when living aboard, I have had more problems with fried alternators than with undercharged or expired lead acid batteries.

Is it, pretty much, that the benefit of lithium is its ability to allow the alternator to put out more current longer?  If so, alternator trouble seems more likely.  Presumably, if you were confident of a long days cruising the BMS could be tweaked to keep the current moderate from the start? Not seen any mention of this.

No doubt the real answer is a better alternator.

I did mention alternator controller. It has a fast/slow charge switch. On slow, field current is limited to about 1/2 such that the 170A alternator produces about 75A at idle and 95A at canal cruising speeds. The alternator temperature is around 60C which is quite cool.

 

If I put the switch to fast, maximum field current is authorised until the alternator temperature gets to 90C, then it’s reduced to hold the temperature around 90C. Long term this gives around 125A. At engine rpms below about 1300, maximum field current is reduced until it’s back to 1/2 at idle. This stops the engine struggling with a big load at low rpm, excessive belt load/pulley side force etc.

 

This same fast/slow switch also puts the Combi into fast charge mode so if the travelpower is on, I get another 60A or so from the Combi.

Edited April 25, 2023 by nicknorman

[IanD]

8 minutes ago, MtB said:

 

I would suggest your options are:

 

1) Spend quite a few hours learning how LiFePO4 batteries interact with your alternator and how to manage them, and about the many ways they can be inadvertently destroyed. Then buy some.

 

Or 

 

2) If you CBA with 1, buy more lead acid batts the same as you have now. 

 

...*and* how they can destroy your alternator... 😉

Edited April 25, 2023 by IanD

[canalboat77]

14 minutes ago, matty40s said:

I reckon you should read the other thread....

I did a quick search before posting….couldn’t find anything else. 

[IanD]

 

 

[MtB]

1 minute ago, canalboat77 said:

I did a quick search before posting….couldn’t find anything else. 

 

You're kidding, surely. Here is the most obvious and prominent:

https://www.canalworld.net/forums/index.php?/topic/118212-batteries-and-their-technologies-which-is-best/

 

 

but there are dozens of threads here to read about it.

 

[BEngo]

I think the point is not the detailed activity of Nick's B&AMS / charging control system, but the facts that:

It exists

It, or something similar,  is should have for a proper LFP install, and a must have for any other Li chemistry set up.

The commercial equivalents from Balmar and Wakespeed are costly

The alternator must be suited to this sort of control  or the installer needs the capability/ability to modify an existing alternator to suit.

The installer needs to understand the various parameters and their acceptable values before you can set the system up.

 

Unsurprisingly many look for the cheaper and apparently easier  solution offered by a hybrid set up.  Unfortunately most ignore the risks and shortcomings that come with it.

 

N

 

[Alan de Enfield]

1 hour ago, bizzard said:

Shield the battery makers here at B.Stortford claim they can make any size single battery, though only L/A I think.  A battery around 480A would be mighty heavy.

 

 

I have 6x 230Ah batteries and they each weigh 58kgs, a 480Ah LA battery would therefore be 120Kgs

[nicknorman]

32 minutes ago, BEngo said:

I think the point is not the detailed activity of Nick's B&AMS / charging control system, but the facts that:

It exists

It, or something similar,  is should have for a proper LFP install, and a must have for any other Li chemistry set up.

The commercial equivalents from Balmar and Wakespeed are costly

The alternator must be suited to this sort of control  or the installer needs the capability/ability to modify an existing alternator to suit.

The installer needs to understand the various parameters and their acceptable values before you can set the system up.

 

Unsurprisingly many look for the cheaper and apparently easier  solution offered by a hybrid set up.  Unfortunately most ignore the risks and shortcomings that come with it.

 

N

 

The reason why I tend to bang on about the detail of my system is because it took me some time to accumulate the knowledge and ideas of what the system needed to do. After a year or two of gathering ideas (mostly other people’s ideas!) I was then able to design the system. As you will know as an engineer, it’s important to decide what the requirements for a device are, before you start designing it.
Well in an idea, world that is! In my case I went through various prototype stages whilst gathering knowledge and ideas, 4 or 5 versions of the PCBs for each of alternator controller and BMS I think.
So having refined the concept of what is needed, and given it extensive testing,  it seems sensible to share that as a benchmark for others contemplating the same sort of thing either by their own design or by cobbling together various off the shelf bits.

 

Evolution still goes on a bit. I use the Tyco BDS bistable relay as the last chance battery disconnect. It should never operate. But recently someone mentioned that theirs had gone open circuit. That could be a disaster if the alternator was near full output, even though the controller has a dedicated over voltage protection that shuts off the field current at voltages over 15v (field current takes a while to subside). I had made a small load dump absorber from 8 700w tranzorbs (bit like fast zener diodes) but doing the sums again, I wasn’t convinced 8 were enough. So now there are 16. I feel happier!

Edited April 25, 2023 by nicknorman

[canalboat77]

2 hours ago, MtB said:

 

You're kidding, surely. Here is the most obvious and prominent:

https://www.canalworld.net/forums/index.php?/topic/118212-batteries-and-their-technologies-which-is-best/

 

 

but there are dozens of threads here to read about it.

 

Searched "battery" should have searched "batteries!" 

[magnetman]

Depending on how the boat operates you might be okay with a smaller battery. 

 

If the engine is always running during times when you need electrical power you'd probably get away with a 150Ah AGM battery connected to the big alternator. If you need to have a lot of power during times when the engine is not running then obviously a bigger battery bank is needed. 

 

 

What exactly is the arrangement in this regard? Also is there roof space to fit a decent sized solar panel (6ftx3ft approx)?

 

I believe battery banks are often too large. 

[canalboat77]

2 minutes ago, magnetman said:

Depending on how the boat operates you might be okay with a smaller battery. 

 

If the engine is always running during times when you need electrical power you'd probably get away with a 150Ah AGM battery connected to the big alternator. If you need to have a lot of power during times when the engine is not running then obviously a bigger battery bank is needed. 

 

 

What exactly is the arrangement in this regard? Also is there roof space to fit a decent sized solar panel (6ftx3ft approx)?

 

I believe battery banks are often too large. 

 

When we have customers the engine is always running. We are looking longer term about fitting a solar panel as well. At the moment the 4 x 115 Led Acid are more than fine. I have the Victron Connect App and we don't use much power. We would like the option of possible having an electric kettle just to make life in the galley a little easier. Currently we have a gas water boiler which isn't so cheap to run nowadays.

 

Thanks

 

 

 

[Alan de Enfield]

Just now, canalboat77 said:

 

When we have customers the engine is always running. We are looking longer term about fitting a solar panel as well. At the moment the 4 x 115 Led Acid are more than fine. I have the Victron Connect App and we don't use much power. We would like the option of possible having an electric kettle just to make life in the galley a little easier. Currently we have a gas water boiler which isn't so cheap to run nowadays.

 

Thanks

 

 

 

 

Just remember that a typical 230v 2Kw electric kettle will be drawing around 200 amps from the batteries.

 

A  1Kw "camping kettle" will only be drawing 100 amps, so kinder on your batteries, BUT, it will take twice as long to boil as the 2Kw kettle and you will use, in total, the same amount of 'leccy.

 

Using your engine to generate electricity to heat water is madness. It cost ~£5 per Kw* you can, plug into the 'mains' and its ~30p, even using your gas heater will be far cheaper than your engine.

 

Some clever 'spark' worked it all out taking into account the fuel used, wear & tear, oil, filters, depreciation etc etc etc and it worked out at ~£5.00/Kw. I bet its even higher now that diesel costs have increased so much.

 

[BEngo]

Just now, canalboat77 said:

 

I believe battery banks are often too large. 

Prima facie  that may well be true for LA, when new.  However, ...   First rule of thumb is not to discharge a LA bank by more than 50% if you want a long life from it.  Second  "rule"  is that as a LA battery ages its capacity will fall through sulphation, shedding of plate material etc.  This can be deferred by good practice, but not entirely prevented.  Third is the voltage vs charge state characteristic of LA batteries.  This makes it harder for a partly discharged battery to service a heavy load.

 

Thus, in  order to have a battery which just does the job at the end of its life you need to start with one which, at the beginning of its life,  is apparently well oversized for the same job.

 

N