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Post by Deleted on Dec 18, 2020 18:25:59 GMT
The more perspicacious among our forum members (no, it doesn't mean sweaty) will have noticed that in the last few weeks, there have been one or two comments made relating to lithium batteries. It has become quite a topic.
As part of trying to find out more about battery wiring (and taking a break from chipmunk videos), I came across a video in which the presenter stated that on most boats he's looked at (electrically), the batteries are not wired for optimum lifespan.
His suggested wiring is pictured at 2 mins 40 secs:
He recommends a very specific way of wiring batteries based on his knowledge and experience as an electrical engineer, but there are also people with very good knowledge and experience on this forum, and I'm curious to know - is there is a single widely accepted or 'industry standard' method for wiring? Or are all boats slightly different?
In my usual simplistic way, I had imagined there were only series and parallel as the available options- but clearly there are different ways of parallel wiring.
So how many people have their batteries wired in this 'optimum' way that this chap suggests? Can the majority of boats really be wired wrongly, as he suggests?
And do you even care?
I care, because I have new batteries being wired in on Monday (in theory), and I'm wondering whether to show this diagram to the electrician and see what she thinks of its merits.
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Post by Telemachus on Dec 18, 2020 18:36:01 GMT
The more perspicacious among our forum members (no, it doesn't mean sweaty) will have noticed that in the last few weeks, there have been one or two comments made relating to lithium batteries. It has become quite a topic. As part of trying to find out more about battery wiring (and taking a break from chipmunk videos), I came across a video in which the presenter stated that on most boats he's looked at (electrically), the batteries are not wired for optimum lifespan. His suggested wiring is pictured at 2 mins 40 secs: He recommends a very specific way of wiring batteries based on his knowledge and experience as an electrical engineer, but there are also people with very good knowledge and experience on this forum, and I'm curious to know - is there is a single widely accepted or 'industry standard' method for wiring? Or are all boats slightly different? In my usual simplistic way, I had imagined there were only series and parallel as the available options- but clearly there are different ways of parallel wiring. So how many people have their batteries wired in this 'optimum' way that this chap suggests? Can the majority of boats really be wired wrongly, as he suggests? And do you even care? I care, because I have new batteries being wired in on Monday (in theory), and I'm wondering whether to show this diagram to the electrician and see what she thinks of its merits. This is something that Gibbo, on the other channel, used to go on about. And he has a lot of stuff on his website, some of which is good. He has this to say about battery wiring smartgauge.co.uk/batt_con.htmlHowever in my opinion the issue is overrated provided the battery interconnects are chunky. We have 70mm^2 and our batteries are wired “incorrectly”. I tried to find any tiny voltage difference between the paralleled batteries under heavy current, but failed to find anything greater than the resolution of the meter, a few millivolts. If your bank is wired up with corroded skanky 25mm^2 cables then maybe, but I think having clean and chunky connections is more important than having all current paths the same length etc. I also measured the currents in the various different legs of the interconnect wiring, again under heavy loads (200A) but could not find any differences within the accuracy of the clamp meter (which of course isn’t great).
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Post by Deleted on Dec 18, 2020 18:45:50 GMT
This is something that Gibbo, on the other channel, used to go on about. And he has a lot of stuff on his website, some of which is good. He has this to say about battery wiring smartgauge.co.uk/batt_con.htmlHowever in my opinion the issue is overrated provided the battery interconnects are chunky. We have 70mm^2 and our batteries are wired “incorrectly”. I tried to find any tiny voltage difference between the paralleled batteries under heavy current, but failed to find anything greater than the resolution of the meter, a few millivolts. If your bank is wired up with corroded skanky 25mm^2 cables then maybe, but I think having clean and chunky connections is more important than having all current paths the same length etc. I also measured the currents in the various different legs of the interconnect wiring, again under heavy loads (200A) but could find any differences within the accuracy of the clamp meter (which of course isn’t great). Cheers Nick, should have known it wasn't that big a deal. I think I'd best stick to the chipmunk videos.
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Post by Jim on Dec 18, 2020 20:20:02 GMT
My 4 LA batteries are wired using + and - busbars with equal length leads to each battery.
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Post by Telemachus on Dec 18, 2020 20:25:58 GMT
My 4 LA batteries are wired using + and - busbars with equal length leads to each battery. Very commendable, if slightly pointless.
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Post by Deleted on Dec 18, 2020 20:41:22 GMT
Mine three are wired opposite corners (method 2) a good compromise, its better than wiring from one end and not as complicated as some other ways. Parglena was wired as in method 4 in Gibbo's page but was 24v so series/parallel so had added diagonal links I tend to go with Gibbo as he has slightly more experience than any one on here.
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Post by Deleted on Dec 18, 2020 20:42:22 GMT
I'm definitely not wired right but this is not battery related.
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Post by Telemachus on Dec 18, 2020 20:48:12 GMT
Mine three are wired opposite corners (method 2) a good compromise, its better than wiring from one end and not as complicated as some other ways. Parglena was wired as in method 4 in Gibbo's page but was 24v so series/parallel so had added diagonal links I tend to go with Gibbo as he has slightly more experience than any one on here. However, like most people, he was right about some stuff and wrong about some stuff. In the end I pinned him down on the subject (after I’d done my own research) and he admitted that it only mattered if the connections were a bit dodgy (too thin, corroded etc). He was definitely very wrong about Peukert, big time.
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Post by Deleted on Dec 18, 2020 20:50:49 GMT
I remember the old Peukert discussions Chris W v Gibbo on canalworld.
If you could sell discussion forum threads they would be Gold, or even Palladium.
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Post by Deleted on Dec 18, 2020 20:54:55 GMT
I would guess that over 40% of boats fit into the smallwire/corroded bracket. But not all of us (overkill is my middle name)
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Post by Telemachus on Dec 18, 2020 21:00:01 GMT
I would guess that over 40% of boats fit into the smallwire/corroded bracket. But not all of us (overkill is my middle name) Yes lots do. But IMO the solution is to fix that rather than worrying too much about equal conductor lengths.
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Post by JohnV on Dec 18, 2020 21:40:34 GMT
I would guess that over 40% of boats fit into the smallwire/corroded bracket. But not all of us (overkill is my middle name) Yes lots do. But IMO the solution is to fix that rather than worrying too much about equal conductor lengths. I completely agree.
It can only be a problem if the cables are of inordinate length or very undersized.
There is a hell of a lot in all these "boat battery bibles" that is theoretically correct ......... and completely pointless in a practical installation.
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Post by Gone on Dec 18, 2020 22:09:53 GMT
I would guess that over 40% of boats fit into the smallwire/corroded bracket. But not all of us (overkill is my middle name) So in summary, for best battery life I need equally crappy connections to each battery and grossly but equally undersized wire to each crappy connection. Alternatively I could have good chunky cables and clean connections and not worry about it.
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Post by brummieboy on Dec 19, 2020 14:46:32 GMT
When your battery compartment holds 4 batteries, but only in rows of 2, and one is the starter battery, then the only way of complying is to have to 'lose' 14" of cable on the short connections. I'm glad that all these theories weren't in circulation 32years ago. I wouldhave lost a lot more sleep than I do now.
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Post by peterboat on Dec 19, 2020 19:06:37 GMT
I have 36 batteries.................................. no matter what way I wire them its going to be wrong, on the plus side I am using Valance interconnects which are the business to say the least
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