crisjones
Well-Known Member
Might be because his boat is called Viking Star, so no need for derogatory comments when you don't know the reasons behind things.
Lithium batteries - are they worth it?
- Thread starter Koeketiene
- Start date
ghostlymoron
Well-Known Member
How do you know how much life is left in a secondhand battery? And where do you buy them?
KompetentKrew
Well-Known Member
Can anyone recommend a primer on LiPo, please?
A basic explanation of the batteries' properties and what kind of charger I need. I read the MarineHowTo article that was linked earlier in the thread but that seemed to be mostly a criticism of "drop-in" systems.
A basic explanation of the batteries' properties and what kind of charger I need. I read the MarineHowTo article that was linked earlier in the thread but that seemed to be mostly a criticism of "drop-in" systems.
Poey50
Well-Known Member
Not a primer but you will find all general relevant information here. At the moment there are no easy ways into LFP, you have to put some work in.
Lithium battery systems | Nordkyn Design
The series of videos on Will Prowse's Youtube channel is probably the most enabling introduction to constructing packs but you have to keep in mind that he is mainly talking about static solar power systems rather than the specific needs of boats.
TernVI
Well-Known Member
The Wakespeed stuff is interesting.
Wakespeed Products
It seems to take alternator control on a boat a way forwards from the products we're used to, regulating to battery current.
Bear in mind that I have a 13 year old car which does that!
But for many of us yacht sailors, alternator regulation is not the problem. The problem is having alternator, solar and sometimes shore power and making it all work together optimally.
Wakespeed Products
It seems to take alternator control on a boat a way forwards from the products we're used to, regulating to battery current.
Bear in mind that I have a 13 year old car which does that!
But for many of us yacht sailors, alternator regulation is not the problem. The problem is having alternator, solar and sometimes shore power and making it all work together optimally.
Poey50
Well-Known Member
Alternator regulation IS the main problem with LFP mixed charging systems. Standard internally regulated alternators (designed only to keep a vehicle starter battery charged) are barely suited to charging lead acid house banks (hence the use of various boost systems) but will quickly fail if used direct with LFP since the low resistance in LFP will work them to death. That's why smaller and simpler marine systems use an ordinary alternator to charge a dedicated start battery and a DC to DC charger, configurable to an LFP profile, to charge the LFP house pack, and larger systems - where the alternator charges the the LFP direct - must have a robust alternator with external regulation.
If different charging sources are configurable to reliably end when bulk charging is complete then they will have no problem working together. Each will respond simply and independently to the voltage of the battery; they don't care which of their colleagues also brought the battery to that cutoff point or how much each contributed.
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Refueler
Well-Known Member
People always assume that the 2nd hand battery is as bad as the junk car it comes out of ... quite often not the case. No matter how bad a car is - it needs a good battery. People scrap their cars or they get crashed and scrapped ... along with what is usually a good battery. Car Scrap yards take out the batterys and sell on ...
I buy 2nd hand only when the yard has a decent load tester to show battery is good condition and can take the load.
I have used 2nd hand batterys and only once has the battery not lasted more than a year ... but all others have lasted well. One set I had were good for over 5 years ...
In fact its the winter here and when my Gardener forgets to reconnect mains power to my pontoon that any battery has actually failed .. once low state of charge - freezing weather destroys a Wet Lead Acid battery .. it must be charged to withstand the -20C !!
I cruise / use my boat with no worries about those batterys ... at present I have two batts on there .. 80 A/hr ... each cost me 20 euros ... either starts my Perk 4-107 no problem ...
Refueler
Well-Known Member
The problem with LiFe is the charging regime ... and making sure the cells remain balanced. Second that you never drag cells down too low or charge them to too high voltage. That voltage is NOT same as Lead Acid except where compensators or regulators are built in.
Just throwing charge rate at a bank of LiFe cells, like you do with Lead Acid is not long term viable. As the cells get used - they develop greater Internal Resistance and they charge up differently. That is why modellers with LiFe as well as LiPo and other Lithium based cells either periodically balance charge or use balance charge every time. Balance Chargers monitor each cell and detect when full or minimum charge and basically control charging to compensate and balance all cells.
It does not matter that boats are talking far larger A/Hr banks .......... the principle and chemistry is same.
I read and consider what is in various articles about using LiFe and so far I am not convinced of the benefit over conventional Lead Acid with its simpler use.
Lead Acid may be old hat ... but its evolved and does its job. Alternators .. charge systems and the batterys themselves are available easily.
That's my view anyway ..
Just throwing charge rate at a bank of LiFe cells, like you do with Lead Acid is not long term viable. As the cells get used - they develop greater Internal Resistance and they charge up differently. That is why modellers with LiFe as well as LiPo and other Lithium based cells either periodically balance charge or use balance charge every time. Balance Chargers monitor each cell and detect when full or minimum charge and basically control charging to compensate and balance all cells.
It does not matter that boats are talking far larger A/Hr banks .......... the principle and chemistry is same.
I read and consider what is in various articles about using LiFe and so far I am not convinced of the benefit over conventional Lead Acid with its simpler use.
Lead Acid may be old hat ... but its evolved and does its job. Alternators .. charge systems and the batterys themselves are available easily.
That's my view anyway ..
Poey50
Well-Known Member
I'm well aware of that from the other two times you've provided it. Everyone has to make their choice.
TernVI
Well-Known Member
All this kit is developing and will become less and less of a problem.
But at the moment, the ordinary boat owner is forced to have a mixed system with a lot of legacy equipment intended for Lead-Acid.
KompetentKrew
Well-Known Member
Thank you. His "fundamentals" page looks very good.
Poey50
Well-Known Member
Yes, agreed. Fortunately manufactures like Victron can see which way the market will develop and given the drop in LFP costs there will increasing be available charging products that can manage lead acid as well as the range of customisable settings needed for LFP. This has partially been the case for some time but the clunky dip-switch type chargers with a single LFP setting are generally now seen as too aggressive. I imagine those interested in eventually making the change will be doing some forward planning based on when they anticipate having to change their existing lead acids. So versatile chargers like the Victron mains and solar ones can be purchased with the future in mind, used with existing lead acid and then they are ready for the transfer. Costs need to be considered across a 10 - 15 year timescale. And of course, unless someone has a good reason to change then ... don't.
Top-tip. If you buy bluetooth chargers for mains and solar then firmware may keep the charger up to date. Foolishly, some time ago, when thinking about LFP I bought Votronic dual digital as i wanted an MPPT charger what could also keep my engine battery topped up. Sadly the float setting for LFP is too aggressive at 13.6 and because it is a dip-switch unit there is nowhere else to go. Should have got a Victron bluetooth which I eventually did.
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Mikedefieslife
Well-Known Member
Batteries used in EVs are usually not LiFePO4 chemistry. Nothing wrong with that, so long as one is aware of the risks. The problem I see is that most are only available used, and that 'used' is about 80% capacity. Most manufacturers would regard a 80% capacity Li-ion or similar battery as being at the end of it's life. Sure it's not worked anywhere near as hard on a boat, but it doesn't make sense to me, especially when LiFePO4 is so cheap relatively speaking.
I don't know about Monos, but most boaters with Catamarans and LFP banks now will have enough solar charging to not need to bother with alternator, so the only settings are change are those on a the solar controllers, and plug in charger is one uses such a thing.
Even on my tiny boat, on good days I have had yields over 3kWh. On something like a Lagoon 380 you could near double that.
P.S - My 271ah RJ Energy cells are still working well. Almost a year in and 4,000nm on them now.
I don't know about Monos, but most boaters with Catamarans and LFP banks now will have enough solar charging to not need to bother with alternator, so the only settings are change are those on a the solar controllers, and plug in charger is one uses such a thing.
Even on my tiny boat, on good days I have had yields over 3kWh. On something like a Lagoon 380 you could near double that.
P.S - My 271ah RJ Energy cells are still working well. Almost a year in and 4,000nm on them now.
Poey50
Well-Known Member
Very good to know! Are there any lessons learned over the past year that you can pass on?
Mikedefieslife
Well-Known Member
The lessons are normally learned when things go wrong. I would say, perhaps buy a well respected BMS like Orion, or Rec. I went with a Chinese Daly 200a BMS, which Will Prowse was impressed with at the time. In reality whilst it works for most things, it's junk. Without a display or bluetooth (or similar) for error codes, you're left guessing should anything go wrong.
I monitor my cells with a IDST Battery Go. That is a handle little device to have connected.
The only other thing is that I'm not sure many of the battery monitors are really that accurate with LFP banks. My Mastervolt looses sync very easily/quickly. There are lots of reports of people with the BMV 712 and the newer Balmar SG200 not getting an entirely accurate picture of battery state. Something like the REC with optional add-ons, or even the Electro Dakus which is also a BMS, probably provides a more accurate result.
I monitor my cells with a IDST Battery Go. That is a handle little device to have connected.
The only other thing is that I'm not sure many of the battery monitors are really that accurate with LFP banks. My Mastervolt looses sync very easily/quickly. There are lots of reports of people with the BMV 712 and the newer Balmar SG200 not getting an entirely accurate picture of battery state. Something like the REC with optional add-ons, or even the Electro Dakus which is also a BMS, probably provides a more accurate result.
Poey50
Well-Known Member
I did look closely at the REC Active but for all the features I want it is very costly. Also I found the documentation to be less than clear. So I've gone with 3rd version of 123Smart. This has improved current measurement and I hope they have ironed out some of the previous bugs. But probably the main thing that interested me is that it integrates easily with the pair of bistable relays and the level of documentation and support has been good so far. Time will tell. I've got a BMV712 that should cross reference with the state of charge figures from the BMS. I'm not relying on it for any essential systems but have its relay set up to sound an alarm should any of the charging or temperature parameters get close in order to head off a BMS disconnect. (That shouldn't happen as all the charging sources will be LFP compliant.) The only other 'extra' I have is one of the inexpensive active balancers that have come onto the market. These move power between cells at most states of charge (my 123 only passive balances above 3.4 volts) if more than a 0.1volt difference opens up. That might be handy if I don't get to charge above 3.4v on a regular basis as I'm expecting only to mainly cycle between 20-80% state of charge.
Poey50
Well-Known Member
I've just been re-reading the Nordkyn Design articles I referenced above. One thing that struck me was the clarity of his summaries. This one bears repeating as the 5 essentials of design for a marine installation.
1. Before even considering sourcing any battery cells, the on-board electrical system must be reviewed and all connections pertaining to loads must be physically separated from charging sources. On a standard, tidy installation, it all leads to positive and negative busbars. At a minimum, the positive bus must be split into distinct charge and load buses and the corresponding cabling moved
2. High-current DC disconnectors must be installed in the paths between the battery and the new busbars, so the battery can be isolated from loads and/or charging sources if needed.
3. The cells that will make up the battery need to be charged and carefully balanced before they can be interconnected to form a bank.
4. Electronic protection circuitry must be installed to ensure that none of the cells can ever exceed their operating voltage limits and the battery never starts heating up.
5. All charging sources and regulators that will ever feed the new battery need to be re-assessed for suitability: either they can be reconfigured to operate acceptably, or they will need replaced.
Point 1 is impossible to achieve with 'drop-ins'. Taking the five as a whole demonstrates that a DIY build can achieve these more effectively than all but the most expensive integrated systems.
1. Before even considering sourcing any battery cells, the on-board electrical system must be reviewed and all connections pertaining to loads must be physically separated from charging sources. On a standard, tidy installation, it all leads to positive and negative busbars. At a minimum, the positive bus must be split into distinct charge and load buses and the corresponding cabling moved
2. High-current DC disconnectors must be installed in the paths between the battery and the new busbars, so the battery can be isolated from loads and/or charging sources if needed.
3. The cells that will make up the battery need to be charged and carefully balanced before they can be interconnected to form a bank.
4. Electronic protection circuitry must be installed to ensure that none of the cells can ever exceed their operating voltage limits and the battery never starts heating up.
5. All charging sources and regulators that will ever feed the new battery need to be re-assessed for suitability: either they can be reconfigured to operate acceptably, or they will need replaced.
Point 1 is impossible to achieve with 'drop-ins'. Taking the five as a whole demonstrates that a DIY build can achieve these more effectively than all but the most expensive integrated systems.
Refueler
Well-Known Member
So .. you don't like my posts ... that's life.
Until the day literally a simple Plug and Play solution that matches Lead Acid comes along ... I think the average boater will muddle along with his Lead Acid and usual standard charge setups.