Interrogating your plans for LiFePO4 installations

Poey50

Poey50

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I'm preparing a talk on LFP for a branch of the Cruising Association and thought I would road-test here my list of questions that people should ask themselves before jumping in.

The first set are general questions.
  1. Do you need higher power capacity?
  2. Do you need the weight saving or volume saving that comes with LFP?
  3. Can you replenish the power without turning your vessel into an ungainly power station?
  4. Do you have the knowhow, or the willingness to learn the knowhow, or the financial means to pay someone with knowhow, to install a seaworthy and safe system?
  5. Can you afford the upfront costs?
  6. Will you be able to get insurance?
  7. Will your system meet emerging technical standards ISO and ABYC in the US – which will probably be the same.
  8. Will you be able to fix it, sufficiently to get out of trouble, especially if installed by someone else?
If 'the answer is 'no' to any of these then - time to think again? Otherwise the next set of questions is on system design.
  1. How will you know if your LFP pack is about to disconnect?
  2. What will be the effect of a sudden disconnect and load dump?
  3. How are the alternator and sensitive marine electronics protected from the voltage spike caused by sudden disconnect?
  4. Is your BMS (or BMSs) set up as the final line of defence (catastrophic protection) or used for routine battery management?
  5. You are crossing a busy shipping lane at night under engine and you have a high voltage disconnect. What do you do to stay safe?
  6. If you have a dead short, will your fusing cope?
  7. Will you be able to use your system if the temperature drops below zero?
  8. Where relevant, how will your system cope with high ambient temperature?
  9. How will your system cope with high inrush currents from windlass, inverter, bow-thruster, electric winch?
  10. Will your system operate automatically, or mostly automatically, or will it require regular monitoring and manual switching?
  11. You have a complete black-out. Nothing electric works (a lightning strike?). What do you do?
If you can't give yourself a satisfactory answer or don't understand the relevance of the questions then time to do some more research?
 
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Poey,
I think you'll just freak out most of the participants 😁
I hope that's going to be given at the end of the talk, after spending an hour trying to explain the basics...

cheers

V.
 
vas said:
Poey,
I think you'll just freak out most of the participants 😁
I hope that's going to be given at the end of the talk, after spending an hour trying to explain the basics...

cheers

V.
Click to expand...

If 2/3 come away thinking that LFP is a lot more complicated than they thought, may not be be what they really need, or worth the effort and 1/3 end up better informed then that will be a fair result as far as I'm concerned!
 
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Make sure you ask then whether they think LFP is a significant fire risk. If they do, they don't really know enough to install LFP yet 🙂
 
Will they also be getting a talk from someone less negative? If I went to a talk about Lithium I’d expect to get advice on fitting Lithium rather than someone mansplaining how I’m too stupid to consider it.
You asked for feedback, mine is that you need to reassess and start again with a focus on helping people.
 
Over at Attainable Adventure Cruising they broke down the need / want into just 3 questions. It was quite a robust analysis. Say No to any of the three and then maybe this time round it is not for the individual.
 
lustyd said:
Will they also be getting a talk from someone less negative? If I went to a talk about Lithium I’d expect to get advice on fitting Lithium rather than someone mansplaining how I’m too stupid to consider it.
You asked for feedback, mine is that you need to reassess and start again with a focus on helping people.
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My motive is to give sufficient information for people to be able to decide if they need LFP and can build a safe and seaworthy system. If you think that is negative then I'm not sure what positive would look like to you.
 
RunAgroundHard said:
Over at Attainable Adventure Cruising they broke down the need / want into just 3 questions. It was quite a robust analysis. Say No to any of the three and then maybe this time round it is not for the individual.
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Thanks, yes, I saw that. My first two questions are the same and all my others are just elaboration of their third.
 
Poey50 said:
My motive is to give sufficient information for people to be able to decide if they need LFP and can build a safe and seaworthy system. If you think that is negative then I'm not sure what positive would look like to you.
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It reads very much as if your motive is to tell them why they shouldn’t get Lithium. Try re-reading what you wrote. If you think that’s encouraging maybe you’re not the man for the job. Of course, if you don’t want feedback don’t ask for it.
 
lustyd said:
It reads very much as if your motive is to tell them why they shouldn’t get Lithium. Try re-reading what you wrote. If you think that’s encouraging maybe you’re not the man for the job. Of course, if you don’t want feedback don’t ask for it.
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How you choose to interpret is your responsibility not mine. Have a nice day.
 
lustyd said:
It reads very much as if your motive is to tell them why they shouldn’t get Lithium. Try re-reading what you wrote. If you think that’s encouraging maybe you’re not the man for the job. Of course, if you don’t want feedback don’t ask for it.
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My perception is that is well written from perspective of somebody that knows what he he talking about. There are so many people that think it's just changing the battery.
 
geem said:
My perception is that is well written from perspective of somebody that knows what he he talking about. There are so many people that think it's just changing the battery.
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Thank you. As VAS astutely observed, the list comes at the end of a session where I go through various LFP systems including a couple using drop-ins (although not my personal favourites). Your point about people being battery-centred when they think about LFP is spot-on. If you have four 3.2 v prismatic cells and a set of linking bus-bars you can make a nominal 12 volt battery in about 3 minutes. The rest of the time, effort, and expense is constructing a safe and seamanlike system around this bucket of energy.
 
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geem said:
My perception is that is well written from perspective of somebody that knows what he he talking about. There are so many people that think it's just changing the battery.
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It reads to me as if he wants to look clever. It’s not that hard and it’s not some crazy ambitious project. As discussed on other threads there is presently no issue with insurance either.
Poey50 said:
How you choose to interpret is your responsibility not mine. Have a nice day.
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Then next time I suggest not asking. Good luck with the talk, I’m sure you’ll talk every one of them out of their plans to modernise.
 
imho (after spending a whole lockdown sorting out a lifepo4 system....) the "it's not that hard" is a massive understatement unless you consider a couple of drop-ins Victron or whatever and a change on the chargers profile is sufficient - it is definitely not.
Even getting a bleeding T-class fuse is an issue, realising how big that thing is and finding a place to fit it, is another issue. And a dozen more issues that crop up throughout the project...
Some of my boating mates with similar sized mobos are well impressed with my 304Ah@24V bank and want to help them do the same, I'll probably help the one and avoid the other who's tinkering and messing with electrics all the time without knowing what he's doing, he'll probably set his P45 alight...
 
vas said:
imho (after spending a whole lockdown sorting out a lifepo4 system....) the "it's not that hard" is a massive understatement unless you consider a couple of drop-ins Victron or whatever and a change on the chargers profile is sufficient - it is definitely not.
Even getting a bleeding T-class fuse is an issue, realising how big that thing is and finding a place to fit it, is another issue. And a dozen more issues that crop up throughout the project...
Some of my boating mates with similar sized mobos are well impressed with my 304Ah@24V bank and want to help them do the same, I'll probably help the one and avoid the other who's tinkering and messing with electrs all the time without knowing what he's doing, he'll probably set his P45 alight...
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Anything can be made to seem hard if you want to. The reality is that everything needed for lithium can be discovered in an easy afternoon and a suitable system designed. It’s not rocket science, it’s a battery bank and the number of people successfully doing this without trouble is huge. People like the OP are the reason this isn’t the norm already with prices and availability improving.
 
lustyd said:
Anything can be made to seem hard if you want to. The reality is that everything needed for lithium can be discovered in an easy afternoon and a suitable system designed. It’s not rocket science, it’s a battery bank and the number of people successfully doing this without trouble is huge. People like the OP are the reason this isn’t the norm already with prices and availability improving.
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so you obviously haven't done it yourself, I'm out of this discussion, sorry.
 
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