Wiring a Solar panel array.
The plan is to fit 3 or 4 80 watt panels to the roof of the van, each panel will be connected individually to bus bars 1 each for positive and negative, what size wire from each panel to the bus bar ? Depending on the location of each panel i would expect the longest cable run to be about 3 meters, cables will run inside conduit.
The bus bars will be mounted in a waterproof junction box above the entry point through the roof, what size cable should I use from the bus bar to the solar controller considering the cable run will be less than 1 meter and again what size cable from the controller to the batteries, cable run no more than 2 meters.
Excluding type and brand of solar controller, what size controller would you suggest for 240 to 320 watts of solar panels, and what is the max amount of AH said system could supply, I have 1x105ah 1x 95ah and 1x110ah batteries
PeterD said
11:59 PM Nov 17, 2015
What are these bus bars? If you get 8 gauge cable you can run it right through from the panels to the battery.
Phillipn said
09:22 AM Nov 18, 2015
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 said
12:43 PM Nov 18, 2015
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 said
11:46 PM Nov 19, 2015
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 said
07:02 AM Nov 20, 2015
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 said
08:07 AM Nov 20, 2015
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 said
08:29 PM Nov 21, 2015
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:
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
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
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
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.
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
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