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Recommend me a battery setup


Rory_d

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I rather think that when newbies make their first tentative posts about battery systems and management they hope to get a paint by numbers response - I can understand that, electrics are my nemesis and I'm terrified I'll never understand them. 

 

I really wish the answer could be "this is the minimum amount of batteries you will need and if you buy one more than this you'll be fine" unfortunately int's not. ?

 

 

Edited by Tumshie
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14 minutes ago, Tumshie said:

 

 

I really wish the answer could be "this is the minimum amount of batteries you will need and if you buy one more than this you'll be fine" unfortunately int's not. ?

 

 

But it is nothing to do with the 'number' of batteries it is to do with the type of battery (chemistry) and the total AmpHours. and that is related to doing an audit and putting in place a battery bank 6x the daily usage (using 50% of capacity and having 3 days storage/usage)

 

You could have 20 x 20Ah Lead acid batteries, or you could have 2x 200Ah Lead acid batteries etc etc.

or

You could have Lithiums with their sooper-dooper charge-discharge characteristics.

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16 minutes ago, Tumshie said:

I rather think that when newbies make their first tentative posts about battery systems and management they hope to get a paint by numbers response - I can understand that, electrics are my nemesis and I'm terrified I'll never understand them. 

 

I really wish the answer could be "this is the minimum amount of batteries you will need and if you buy one more than this you'll be fine" unfortunately int's not. ?

 

 

 

You put things in kinder, more measured and tolerant way than me!

 

On reflection, I think the OP had read some previous threads and knew the power audit was necessary, and was seeking to head off such answers with this bit:

 

"I have no idea how much power I will need etc so please can I have recommendations on battery’s and how many would be advised."

 

And you are right, a paint by number answer was sought. I suspect the OP also knows that "four, average sized ones" is what most boats have and has read about all the problems people have with this, as WAS hoping for an easy, paint by numbers' answer. And seeing such a long thread thought there was going to be a lot of serious discussion for him to peruse. And was sadly disappointed hence his shirty second post in the thread.

 

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1 minute ago, Alan de Enfield said:

But it is nothing to do with the 'number' of batteries it is to do with the type of battery (chemistry) and the total AmpHours. and that is related to doing an audit and putting in place a battery bank 6x the daily usage (using 50% of capacity and having 3 days storage/usage)

 

You could have 20 x 20Ah Lead acid batteries, or you could have 2x 200Ah Lead acid batteries etc etc.

or

You could have Lithiums with their sooper-dooper charge-discharge characteristics.

I know that it is much more complicated than just the number of batteries but it doesn't stop me wishing.

 

I also some times think that new members think that it will be that simple and that when seasoned member start to ask about things which are much more complicated than they expected they get annoyed, thinking that people are trying to over complicate things - when actually they really are that complicated. 

 

That all made sense in my head. :blink:

 

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4 minutes ago, Mike the Boilerman said:

You put things in kinder, more measured and tolerant way than me!

But then I also not answering this same question over and over again every time a new boater arrives and hopes for a magic wand. 

 

6 minutes ago, Mike the Boilerman said:

And seeing such a long thread thought there was going to be a lot of serious discussion for him to peruse. And was sadly disappointed hence his shirty second post in the thread.

The answer to that is don't post a serious question at stoopid o'clock and then not be there when the serious posts come in. :glare: Just sayin'

 

?

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I know the advice here it's to always do a power audit, but how many people on here have actually done a power audit? And how many did one before getting a boat (and if so how accurate was it!)?

 

I know we use about 100-120ah per day on average, but that can vary quite a lot depending if we are home or at work, using washing machine etc. Some days are as low as 60ah or less,  and others as high as 160ah or more. I only know that from monitoring actual usage, not from any power audit. 

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39 minutes ago, Tom and Bex said:

I know the advice here it's to always do a power audit, but how many people on here have actually done a power audit? And how many did one before getting a boat (and if so how accurate was it!)?

 

I know we use about 100-120ah per day on average, but that can vary quite a lot depending if we are home or at work, using washing machine etc. Some days are as low as 60ah or less,  and others as high as 160ah or more. I only know that from monitoring actual usage, not from any power audit. 

Out of interest what is the difference between a 'power audit' and 'actual usage'??

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4 minutes ago, Chewbacka said:

Out of interest what is the difference between a 'power audit' and 'actual usage'??

None of course. But I presume that T&B are taking power audit to mean ‘theoretical’. 

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51 minutes ago, Tom and Bex said:

I know the advice here it's to always do a power audit, but how many people on here have actually done a power audit? And how many did one before getting a boat (and if so how accurate was it!)?

 

I know we use about 100-120ah per day on average, but that can vary quite a lot depending if we are home or at work, using washing machine etc. Some days are as low as 60ah or less,  and others as high as 160ah or more. I only know that from monitoring actual usage, not from any power audit. 

When buying batteries or starting out you should know if your a low/medium or high user and if your on shore power or not.   All these have a influence on how many (and what type) batteries are good for you.   A power audit may not and  won’t be accurate but it will give you a ball park figure of how much you need to generate and store.

11 minutes ago, Chewbacka said:

Out of interest what is the difference between a 'power audit' and 'actual usage'??

Flat batteries. :) 

Edited by Robbo
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47 minutes ago, Tom and Bex said:

Some days are as low as 60ah or less,  and others as high as 160ah or more. I only know that from monitoring actual usage, not from any power audit. 

The starting point always has to be a power audit, because until you have built something there is no actual to compare with.

A proper power audit is , or should be, based on an everything day.  Include the dhobying and the dishwashing and the ironing etc etc because you are otherwise in danger of going into damaged battery country. It will not matter if you overegg it a bit ( a lot would be A financial hit) but you will always have a reserve.

Then build it,use it and see how good you were. Adjust as required.

N

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58 minutes ago, Robbo said:

When buying batteries or starting out you should know if your a low/medium or high user and if your on shore power or not.   All these have a influence on how many (and what type) batteries are good for you.   A power audit may not and  won’t be accurate but it will give you a ball park figure of how much you need to generate and store.

Flat batteries. :) 

 

And in my view the charging calculations are the more important because that is when new to boating people find out just what is needed to fully recharge their batteries.

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4 hours ago, Tom and Bex said:

I know the advice here it's to always do a power audit, but how many people on here have actually done a power audit? And how many did one before getting a boat (and if so how accurate was it!)?

 

I know we use about 100-120ah per day on average, but that can vary quite a lot depending if we are home or at work, using washing machine etc. Some days are as low as 60ah or less,  and others as high as 160ah or more. I only know that from monitoring actual usage, not from any power audit. 

Thirtieth year as a liveaboard. Never done a power audit, never had a survey. Life is all a learning curve and I know precisely what works for our lifestyle but it wasnt learnt over night or from any forum. Good there are such things now though as it makes things easier for those noobs that listen to the answers even if they dont like what they hear.

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1 minute ago, mrsmelly said:

Thirtieth year as a liveaboard. Never done a power audit, never had a survey. Life is all a learning curve and I know precisely what works for our lifestyle but it wasnt learnt over night or from any forum. Good there are such things now though as it makes things easier for those noobs that listen to the answers even if they dont like what they hear.

 

Yes but you have decided that buying £300 of new batts every Autumn is the best solution for you!

 

 

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Just now, Mike the Boilerman said:

 

Yes but you have decided that buying £300 of new batts every Autumn is the best solution for you!

 

 

Nope, every other autumn. They last two years the way I use them minimum. Probably longer this time as I am plugged in again this winter. I am not saying its the only way just it works for me and is a cheap way to do it without ever having to talk to my batteries or top them up!!

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1 minute ago, mrsmelly said:

Nope, every other autumn. They last two years the way I use them minimum. Probably longer this time as I am plugged in again this winter. I am not saying its the only way just it works for me and is a cheap way to do it without ever having to talk to my batteries or top them up!!

 

Ah yeah, I forgot. These days when not plugged in, you run your engine 26 hours a day don't you? This compensates for not spending 26 hours a day obsessing over them like I do. 

 

:giggles:

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Just now, Mike the Boilerman said:

 

Ah yeah, I forgot. These days when not plugged in, you run your engine 26 hours a day don't you? This compensates for not spending 26 hours a day obsessing over them like I do. 

 

:giggles:

Yep, as you and I both know there is no perfect or cheap way. I used my engine a lot all this summer cruising which kept my batts in good order, had I been working and moored up I would have charged the hell out of them whilst moored up thus putting hours and oil changes in to the equasion. Im plugged in at the moment and its for bloody peanuts. People who live in houses should be made to pay more for their bloomin cheap electric to subsidise us poor boaters even more ?

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I did an audit today, assuming I might one day have BOAT ! thanks to Bimble solar calculator

No washing machine

Its kinda a fix on winter usage, though I'd likely turn the fridge off if I was short of power in winter. 

Winter

quote:

Item Quant Watts Hours Watt Hours
fridge X 1 50 W 12 Hrs 600 Wh
lighting X 5 10 W 10 Hrs 500 Wh
wi fi X 1 6 W 20 Hrs 120 Wh
radio/cd X 1 2 W 24 Hrs 48 Wh
laptop X 1 60 W 12 Hrs 720 Wh
eberspacher X 1 16 W 4.0 Hrs 64 Wh
Total Watt Hours
2,052 Wh
Amp Hrs of Batteries
222 Ah to 
445 Ah @ 12v
Solar Panels - Watts
445 W
Solar Panels - Kw
0.44 Kw


name: Lady G

SECOND ESTIMATE 

More of a summer one, with added water pumps and showers, I've assumed less draw by laptop but as that may have to be fed through the invertor there will be more inefficiencies, so that is one factor, I expect the fridge will run more and the lights less in high summer, but of course higher solar input.

Spring/summer

Item Quant Watts Hours Watt Hours
fridge X 1 50 W 12 Hrs 600 Wh
lighting X 4 10 W 10 Hrs 400 Wh
water/shower/gulper X 3 40 W 0.25 Hrs 30 Wh
laptop X 1 20 W 12 Hrs 240 Wh
radio/CD X 1 2 W 10 Hrs 20 Wh
eberspacher X 1 20 W 4 Hrs 80 Wh
wi fi X 1 6 W 15 Hrs 90 Wh
Total Watt Hours
1,460 Wh
 
 
Total Watt Hours
1,460 Wh
Amp Hrs of Batteries
158 Ah to 
316 Ah @ 12v
Solar Panels - Watts
380 W
Solar Panels - Kw
0.38 Kw
 
CONCLUSION
To liveaboard, I'd need 375 watt solar panel and about 440 ah battery capacity, I'd expect to be in a marina in winter, depending on circumstances, if not for months, then for a few days every now and then.
 

 

Edited by LadyG
NEW CALCULATION
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6 minutes ago, LadyG said:

I did an audit today, assuming I might one day have BOAT ! thanks to Bimble solar calculator

No washing machine

Its kinda a fix on winter usage, though I'd likely turn the fridge off if I was short of power in winter. 

Summer solar

quote:

Item Quant Watts Hours Watt Hours
fridge X 1 50 W 12 Hrs 600 Wh
lighting X 5 10 W 10 Hrs 500 Wh
wi fi X 1 6 W 20 Hrs 120 Wh
radio/cd X 1 2 W 24 Hrs 48 Wh
laptop X 1 60 W 12 Hrs 720 Wh
eberspacher X 1 16 W 4.0 Hrs 64 Wh
Total Watt Hours
2,052 Wh
Amp Hrs of Batteries
222 Ah to 
445 Ah @ 12v
Solar Panels - Watts
445 W
Solar Panels - Kw
0.44 Kw


name: Lady G

Less laptoping for you LadyG

 

Or a less power hungry one.

Lighting looks high too

Edited by rusty69
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16 minutes ago, TheBiscuits said:

16W sounds low for an eversplutter.  Where did you get that figure?

 

 

My cheapo Chinese air heater sips the leccy like a boss! 3.0a running at full chat (40w) and 0.3a at tickover. 4W.  So 26w could be correct, although I doubt it.  

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1 minute ago, Mike the Boilerman said:

 

My cheapo Chinese air heater sips the leccy like a boss! 3.0a running at full chat (40w) and 0.3a at tickover. 4W.  So 26w could be correct, although I doubt it.  

What does it draw on startup?  Some can draw 10 or 12 amps during their startup phase.

 

( I won't say for how long to avoid confusion!)

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