question

bleon avatar image
bleon asked

Use car starting cable for setup

Hello,

I'm about to refresh my solar setup for various reasons.

I'm gonna use 25mm2 from the battery to bus bars and inverters. This size of cable is quite expensive (around 8€/m) and while doing some search, I found that you can get car charging cable of 3,5M 25mm2 for only 13€ at my local dealer.

The idea would be to cut the ending clip to put proper terminals of course.

Do you see any strong argument against it ? Usually battery starting cable ar flexible, so I guess they are multistrand too.

Thanks

wiring
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5 Answers
nickdb avatar image
nickdb answered ·

Don't guess. Be sure. The internet is full of bad ideas mixed with good ones.

What inverter/charger, what battery? What Voltage?

Does the cable publish its full specification? What is its heat tolerance?

There is no better way to waste money than trying to cut a corner that you aren't sure about.

As a victron community we need to encourage buying good spec components from competent suppliers.






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phoenix avatar image phoenix commented ·
I agree. The problem with using a so-called 25mm2 cable is heat. Heat coupled with unknown insulation could cause serious damage. Cheap fuses create a similar problem.

If you have a welding supplies outlet near you, you may find they have high quality cable.

I love a bargain, but for electrical stuff I budget from a wholesaler.

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ejrossouw avatar image
ejrossouw answered ·

@bleon Spend the money on decent, welding cable as it is often known, to ensure it is properly insulated and can handle the required currents when charging/discharging over extended periods of time. Cutting corners now may cost you dearly later. I cannot comment on the actual AWG without knowing a lmore about the system components.

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JohnC avatar image
JohnC answered ·

@bleon

Cables aren't created equal. Some guidelines here.. https://www.victronenergy.com/media/pg/The_Wiring_Unlimited_book/en/dc-wiring.html

I like the ones with tinned stranding, they resist corrosion where copper will blacken over time. Choose well..



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bleon avatar image
bleon answered ·

Thanks all for your inputs.

Given the overall price its true that cutting corners in the end doesn't make much sense, especially when you decided to go the Victron way initially, which is not the cheapest one but guaranty good building quality.

I'll go for H07V-K cabling (https://elec44.fr/fils-souples-ho7-vk-de-15-a-25-mm/108852-fil-h07-v-k-souple-25-mm-coupe-au-metre-rouge-ref-ho7-vk25rouge.html) which I found for around 5€/m. Single way length should not exceed 1.5m.

The system is pretty simple, the main power eater is a Phoenix 12/800 inverter which does accept 25mm2 maximum anymay. Fuse on that line will be ANL 100A.

When I was doing my search still, I found it hard to find a proper source of "truth" about what cables can take. For my 25mm2, it goes from 80A to 180A, and the HO7-VK (what you find in France) is rated at 96A sustained current.

If somebody has link to proper table, I would be glad to get it.

Thanks again.




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kevgermany avatar image kevgermany ♦♦ commented ·
Install the Victron toolbox. It has a cable calculator.

There isn't really a single truth. It depends on how the cables are mounted, cable type, insulation temp rating, ventilation as well as current (especially sustained current). In addition your inverter has cable size recommendations.


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derrick thomas avatar image
derrick thomas answered ·

When buying DC cable, avoid 'copper clad aluminum'. It may have it's place, but this isn't it. Q

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