Re: [electricboats] Electric Drive Update - end of season inspection

I did ask, and I really appreciate the information, Dave.

Very helpful!!

MC

On Fri, Jan 14, 2022 at 10:52 PM Dave Yamakuchi via groups.io <dyamakuchi=yahoo.com@groups.io> wrote:

Chris, well, you asked bud :-)

They don't tin the harnesses on cars because: cost.  I'd bet if you pulled apart a Bentley's wiring harness, you find it, but cheap cars drive many years on salted roads and along coasts without failures.  Tinning's not the be all end all, it's just another of the million variables.  The connections are _way_ more important.  Tinning costs a few bucks.  On a lot of wire, that can add significant cost.

Stranding is another variable.  The same gage conductors can have almost an infinite variety of stranding options.  Especially with big wires.  The tiny strands fail by corrosion much faster than the larger ones.  That evil green chews right through small strands.  Yet, there's a lot more of them, the extra surface area reduces inductance, and they're more flexible too, so they'll also last _longer_ against repeated flexing.  

There's no one right answer. A simple, 'design' perspective might be:  Corrosion is an exposed surface area phenomenon.

As a practical matter, catastrophic failures are maybe 80-90% _connection_ failures, at least re: corrosion. With essentially all types of electrical systems.  Maybe even 95%. Depending. I'm estimating, obviously.  

'Ageing' of the conductors themselves is the one wire sales people talk about naturally, but that's the 5%, not the 90%.

There's crazy factors too if you really want extreme, extreme.  For instance: if you temperature cycle widely far below zero C, particularly, but not exclusively, in a vacuum, then tin pest is a big problem, and tinning will likely have you needing to place physical barriers, like conformal coating, like shrinkwrap in such a way as to prevent it.  Thank NASA for figuring that one out.  The tin 'grows tin whiskers,' which is just like it sounds.  Not what you want conductors doing.  But mostly only on satellites, and at the poles.

If you want to eliminate most of the downside of having bare copper wire vs. tinned:

1) Mechanically connect good, watertight terminals to the bare copper wire.  Crimp, screw, whatever they gotta do.  You want a good mechanical grip on the copper somehow.  First.

2)  Then, get a big enough iron and solder the connections. If you're not good at soldering then get help. You _must_ connect them, without solder, first though.  I cannot stress this enough.  Connections can get very hot at high current.  Yes, hot enough to melt solder.  Mechanical connection is essential.

3) Clean the connections after soldering with isopropyl alcohol really, really good. Rosin flux is somewhat corrosive, but soulble in iso. (An old toothbrush is helpful for this.). Do not use acid core.  That's bad.

4) Make sure you shrinkwrap those suckers afterwards.  Keeping the moisture/environment away from the bare  is the key.  Shrink tube helps.

That said, usually most insulation is pretty much completely watertight at least until it's got even so much as a pinhole.  So, protect your conductors well, like for instance in a conduit, and the moisture can only get in through the ends, and would then still have to migrate past your tinned area first.

I hope this helps!

On Thu, Jan 13, 2022 at 12:26 PM, Chris Hill

<m.chris.hill@gmail.com> wrote:

Ah, yeah - mine does, too: "#4 SAE COPPER 105 CENTIGRADE."   I took off the heat shrink and discovered that it isn't tinned copper, so it will fail sooner.

Here is an article I found on a quick search:

https://www.westmarine.com/WestAdvisor/Marine-Wire-Terminal-Tech-Specs

Technically, SAE (Society of Automotive Engineering) cable would work, but it is not the most appropriate solution. 

I'd be interested in any other input on this issue. I'm a bit concerned that these components are being sold as solutions for aquatic/marine environments.

-MC

On Thu, Jan 13, 2022 at 10:55 AM Jorge Anchia <sv.calypsocat@gmail.com> wrote:

MC

I've checked and the jacket says copper. 

Jorge 

-------- Original message --------

From: Chris Hill <m.chris.hill@gmail.com>

Date: 1/12/22 21:52 (GMT-05:00)

To: electricboats@groups.io

Subject: Re: [electricboats] Electric Drive Update - end of season inspection

Hey Jorge --

I am also doing a conversion with a kit from Thunderstruck.

Did you happen to check the  cables they sent to see if it's tinned copper or just copper?

Thanks!

MC

On Tue, Jan 4, 2022 at 9:00 AM Jorge Anchia <sv.calypsocat@gmail.com> wrote:

Dan, thanks for the post. The details are very helpful indeed. I'm in the process of doing a diesel to electric conversion using the 10kw Thunderstruck sail boat kit.

I have a question for you what length and gage wire are you using for the connection from batteries to controller. 

Thanks,  Jorge 

-------- Original message --------

From: Dan Pfeiffer <dan@pfeiffer.net>

Date: 12/31/21 01:37 (GMT-05:00)

To: electricboats@groups.io

Subject: Re: [electricboats] Electric Drive Update - end of season inspection

Thanks for the comments.  Happy to give back a little of what I have gotten from this group. 

I spent some time this evening adding more info and photos.  I'll likely split this all into smaller pages but for now it all starts here:
http://dan.pfeiffer.net/10m/electric_drive.htm



Dan Pfeiffer

On 2021-12-30 4:58 pm, Günter Wöckener wrote:

Dan, thank you very much for information and data.

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