wiring sizes

Gundog · Guru

wiring sizes

PeterD · Guru

What are these bus bars? If you get 8 gauge cable you can run it right through from the panels to the battery.

Phillipn · Guru

PeterD wrote:
What are these bus bars? If you get 8 gauge cable you can run it right through from the panels to the battery.

PeterD, do you mean 8 B&S cable?

I changed the wire on my folding panels to 8 B&S, to reduce the voltage loss.

Bus bars, who knows, new jargon to me.

-- Edited by Phillipn on Wednesday 18th of November 2015 10:08:42 PM

Vince · Senior Member

Gundog I have 4 x 80 watt panels on the van roof and all run to bus bars + & - in junction box with 6B&S cable.

Then 6B&S cable to the solar controller (40amp controller)

3 x 100AH Panasonic batteries

Then 6B&S cable to battery 1 positive terminal -- battery 3 negative terminal

On a good day at peak they will get 27Ah to 30Ah

Average on a sunny day 24Ah

Best I can expect would be 33.4Ah

I have never discharged the batteries through everyday / night use as yet to date although a real test would be longer than 2 weeks

Cheers
Vince

PeterD · Guru

Phillipn wrote:
Bus bars, who knows, new jargon to me.

Phill, to me bus bars are something like the 25 x 3 mm or larger coper bars they run around telephone exchanges to carry the current from their huge battery banks. They are used in lieu of cables. I was wondering why you were running these from the roof to your batteries. They would would be a bit of overkill to me.

If you are using the cable you say you have purchased then you can run this through a waterproof entry point at the top of the van straight to your controller.

-- Edited by PeterD on Thursday 19th of November 2015 11:49:15 PM

Phillipn · Guru

PeterD wrote:
Phillipn wrote:
Bus bars, who knows, new jargon to me.
Phill, to me bus bars are something like the 25 x 3 mm or larger coper bars they run around telephone exchanges to carry the current from their huge battery banks. They are used in lieu of cables. I was wondering why you were running these from the roof to your batteries. They would would be a bit of overkill to me.
If you are using the cable you say you have purchased then you can run this through a waterproof entry point at the top of the van straight to your controller.

-- Edited by PeterD on Thursday 19th of November 2015 11:49:15 PM

PeterD, thanks for the answer what Bus bars are. No, I am not the one who is using them from the roof to the batteries.

Gundog · Guru

A busbar is an insulated terminal block which allows you to bring a number of wires together into one. in my plan you would have the 4 positive wires eg 8B&S from the 4 solar panels joining together at the busbar and a single larger wire eg 6B&S to the solar controlar, like wise for the negative wires. The idea behind wiring this way each solar panel is operating independently, so if one or more panels are effected by shade or are under performing they dont effect the output of the other panels.

Jaahn · Guru

Hi Gundog,

I believe we are talking about different things here. No problem except we may answer the question incorrectly for you. I would call what you described a terminal or terminal block.

What you propose sounds good. The panels should have reverse blocking diodes fitted in the junction box, if not fit them, so the under performing panels do not bleed current back.

Cheers Jaahn

Wickipedia has this for bus bars and that is my idea of them:

(abreviated)In electrical power distribution, a busbar is a metallic strip or bar (typically copper, brass or aluminium) that conducts electricity within a switchboard, distribution board, substation, battery bank, or other electrical apparatus. -----

Busbars are produced in a variety of shapes such as flat strips, solid bars and rods, solid or hollow tubes, and braided wire.

My experience has been the flat copper bar type in DC systems inside the distribution/switching cabinets. Dangerous places at 180Volts DC and plenty of amps available.

-- Edited by Jaahn on Sunday 22nd of November 2015 01:01:49 PM

Baz421 · Guru

See attached for cable size and length/size.

http://www.engineeringtoolbox.com/amps-wire-gauge-d_730.html

-- Edited by Baz421 on Sunday 22nd of November 2015 10:28:01 PM