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Lithium batteries


fudd

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3 minutes ago, fudd said:

Hello. 

Further to my charger thread, would I be better off with smaller batteries to build a 1000ah bank or fewer larger cells?  I’m looking at Winston cells. Thank you. 

I assume you're aware of all the issues about assembling your own lithium bank and BMS?

 

If not -- or even if you are -- I suggest you read this, it's long and a bit US/yacht biased but there's a *huge* amount of useful information in it:

 

https://marinehowto.com/lifepo4-batteries-on-boats/

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3 hours ago, IanD said:

I assume you're aware of all the issues about assembling your own lithium bank and BMS?

 

If not -- or even if you are -- I suggest you read this, it's long and a bit US/yacht biased but there's a *huge* amount of useful information in it:

 

https://marinehowto.com/lifepo4-batteries-on-boats/

 

3 hours ago, IanD said:

I assume you're aware of all the issues about assembling your own lithium bank and BMS?

 

If not -- or even if you are -- I suggest you read this, it's long and a bit US/yacht biased but there's a *huge* amount of useful information in it:

 

https://marinehowto.com/lifepo4-batteries-on-boats/

Fascinating read Ian. I’m only halfway through but have learnt quite a lot. Might take a few ‘reads’ before I ingest most of it. Thanks. 

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28 minutes ago, wandering snail said:

Scary read! What do you think, Moominpapa?

Marinehowto and Nordkyn Design were my bibles when I was designing the installation on Melaleuca. I fear that too many people are jumping on this bandwagon with a "How hard can it be?" attitude and will likely get burned. Let's hope, not literally.

 

MP.

 

 

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15 hours ago, MoominPapa said:

Marinehowto and Nordkyn Design were my bibles when I was designing the installation on Melaleuca. I fear that too many people are jumping on this bandwagon with a "How hard can it be?" attitude and will likely get burned. Let's hope, not literally.

 

MP.

 

 

I’ve been researching this subject for six months and I won’t be making any decisions for at least another year. From what I have read so far is that the installation will be far more complicated for me to deal with. I will be seeking professional advice. 

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20 minutes ago, fudd said:

I’ve been researching this subject for six months and I won’t be making any decisions for at least another year. From what I have read so far is that the installation will be far more complicated for me to deal with. I will be seeking professional advice. 

Pick your professional with care. At this stage, I expect most professional boat electricians know less than the most knowledgable boaters who have fitted them. A bit like asking an 18th century universtiy trained medical doctor for advice on an illness. The best you could hope for is that they wouldn't make you any worse!

Edited by Jen-in-Wellies
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22 minutes ago, fudd said:

I’ve been researching this subject for six months and I won’t be making any decisions for at least another year. From what I have read so far is that the installation will be far more complicated for me to deal with. I will be seeking professional advice. 

Tried and tested, safe, easy to instal, cheap, do a good job and did I say cheap?

BATTERY.jpeg

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4 hours ago, mrsmelly said:

Tried and tested, safe, easy to instal, cheap, do a good job and did I say cheap?

BATTERY.jpeg

Ah, but how many would I need to drive my boat?

4 hours ago, Jen-in-Wellies said:

Pick your professional with care. At this stage, I expect most professional boat electricians know less than the most knowledgable boaters who have fitted them. A bit like asking an 18th century universtiy trained medical doctor for advice on an illness. The best you could hope for is that they wouldn't make you any worse!

I agree and I will. Thank you. 

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9 minutes ago, alistair1537 said:

 A thousand Amp hours is a shed load of power? Are you sure you need that much?

 

1000 Amp Hours at 12V nominal is 12kWh - or slightly less than the practical useable power in a gallon of diesel ...

Edited by TheBiscuits
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8 minutes ago, alistair1537 said:

I think fudd is doing 1000A/h at 48V - so 4 gallons of diesel then? How many hours cruising can you do on 4 gallons?

Probably about 4 hours of cruising but what do you then do to put the charge back into the flat batteries? I have a good idea, maybe an internal combustion engined charger? The sun today wouldnt warm a cup of water up.

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1 minute ago, TheBiscuits said:

 

More like 15-20 hours I'd have said.  Litre an hour not gallon an hour for most narowboats.

 

@Alan de Enfield and @Naughty Cal don't get that though!

You are of course correct, itll be fine then if its blazing sunshine day after tomorrow for a month ?

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Just now, mrsmelly said:

Probably but still plenty on the move past me today. 

Ah those will be the internal combustion type then...Things might have to slow down a bit more if they move us to solar power - like cruise for a day - moor up for 3 days to recharge...and no cruising in winter. I could live like that.

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2 minutes ago, alistair1537 said:

Ah those will be the internal combustion type then...Things might have to slow down a bit more if they move us to solar power - like cruise for a day - moor up for 3 days to recharge...and no cruising in winter. I could live like that.

Luckily that nonsense will not come into play for me at my age. I can still boat properly as it won't happen for many years yet 

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And of course a cold battery delivers less power than a warm one, although drawing a high current should warm up the battery. A technician I used to know who had served with the Royal Signals during the war told me that in the depths of winter, before tryng to start the engine of a tank, it was the practice  to briefly put a dead short across the  battery with a very large spanner to warm the battery up.  Admittedly an electric boat does not needs a heavy cranking starting current like a petrol engine, but we have had electric bikes (kept in an unheated garage) for some 15 years and they always have less "guts" on frosty winter days than in summer. 

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On 23/11/2020 at 18:03, fudd said:

Hello. 

Further to my charger thread, would I be better off with smaller batteries to build a 1000ah bank or fewer larger cells?  I’m looking at Winston cells. Thank you. 

I have 36 KWHs at 72 volts of LifePo4s for my drive batteries, that is 30 batteries at 36 volts, it will give 10 hours cruising with no sun. These batteries have built in BMSs and all are connected to each other. A narrowboat will happily work at 48 volts and would require 1.5 KW to cruise at 3-4mph (figures from Finesse).

I have a lot of solar 4.6 kw in fact, you will need over 2kW, 48 volt is a easy voltage to work with as 48 volt inverter/chargers are around. A 48 to 12 volt converter will take care of 12 volts needs

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  • 2 weeks later...
On 23/11/2020 at 18:10, IanD said:

I assume you're aware of all the issues about assembling your own lithium bank and BMS?

 

If not -- or even if you are -- I suggest you read this, it's long and a bit US/yacht biased but there's a *huge* amount of useful information in it:

 

https://marinehowto.com/lifepo4-batteries-on-boats/

Well worth the read - thanks Ian

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On 23/11/2020 at 18:03, fudd said:

Hello. 

Further to my charger thread, would I be better off with smaller batteries to build a 1000ah bank or fewer larger cells?  I’m looking at Winston cells. Thank you. 

If you are asking this question then you have not done enough research!!!!

See MP's comment below - and read these 2 sites. That was my first port of call before then pestering MP for all his knowledge!

On 24/11/2020 at 20:14, MoominPapa said:

Marinehowto and Nordkyn Design were my bibles when I was designing the installation on Melaleuca. I fear that too many people are jumping on this bandwagon with a "How hard can it be?" attitude and will likely get burned. Let's hope, not literally.

 

MP.

 

 

 

 

On 25/11/2020 at 11:43, fudd said:

I will be seeking professional advice.

If you do that then you will not be following the majority on here and installing 2nd hand batteries. The professionals will not sanction 2nd hand. The peeps on here know far more about our lithium systems than the professionals. Professionals will guide you on what and how to install a commercial system which will be fit for use by  person getting it installed. The problem with 2nd hand systems is that they are not plug and play or idiot proof as the commercial systems are (at four times the cost!). The liability issue for a professional giving advice is a significant problem.

It is very possible to instal a very safe system using LiFePO4s if you know what you are doing. Similarly it is very easy to instal a dangerous system if you dont know what you are doing. Spend time doing your research. Read ALL the Li threads  here (posted in the last 2 years) and then come back and ask the question (along with the marinehowto and nordkyn sites).

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