Battery Wiring

New to renewable energy? Have questions? Here's a great place to ask them and view information about wind and solar power basics.

Battery Wiring

Postby harry201 » Tue Nov 03, 2015 5:50 pm

Hi guys' it's been a few months since I was last on, been save up to buy some good batteries it was suggested.
Today we got our new 12 x 2v 1200ah batteries (long time coming). We unpacked them to find they have 4 post(terminals) rather than the usually 2 post. We have put them in series to end with 24v and end up with 2 pos/ 2 neg, do I run in and out (solar/invt) on 1 post or bridge, both have 24 (25.2)???
Appoint in the right direction would be great

Regards
Geoffrey
harry201
Solar Supporter
Solar Supporter
 
Posts: 22
Joined: Thu Nov 20, 2014 7:23 pm

Re: Battery Wiring

Postby Gordon-Loomberah » Tue Nov 03, 2015 6:45 pm

Many large capacity cells have 2 paralleled pairs of terminals, some even have 3 pairs.

I suggest using large cross-sectional area copper busbars to connect them, using all terminals.
http://gunagulla.com Loomberah weather and astronomy including live solar radiation intensity and UV + Gunagulla aquaponics, organic eggs and cherries
User avatar
Gordon-Loomberah
Community Moderator
 
Posts: 5763
Joined: Thu Sep 24, 2009 9:41 pm
Location: Loomberah NSW Australia

Re: Battery Wiring

Postby davidg » Tue Nov 03, 2015 7:21 pm

Gordon-Loomberah wrote:I suggest using large cross-sectional area copper busbars to connect them, using all terminals.

Definitely this one.

Can also use a AL as long as it's got a greater cross sectional area compared to copper and you must use "Aluminox" as well cleaning the contact surfaces.
SPS Standalone Power System/Hybrid specialist - Store the Sun!
SELECTRONIC SPMC482-AU, 8.2kW's of Arrays
Selectronic Certified AC-Coupled Fronius 8.2kW Inverter
1900Ah 48V Bank

An OTT Genset for a house.
PVOutput Stats

Sparkys light up your life :)
User avatar
davidg
Solar Crusader
Solar Crusader
 
Posts: 2102
Joined: Sat May 05, 2012 7:38 pm
Location: Dandenong VIC- *Really don't like Power Retailers at all.

Re: Battery Wiring

Postby harry201 » Tue Nov 03, 2015 7:51 pm

Thanks for that Gordon,
To make sure I've got it right connect 2 pos/neg with copper or brass bar size(25mm x 6mm x L), run 1 pos/neg
Wire back to a bus bar (250amp) where solar/wind/inverter are connected?
As you guest I'm know elect expert, a stick drawing would help heps.

Regards ;)
harry201
Solar Supporter
Solar Supporter
 
Posts: 22
Joined: Thu Nov 20, 2014 7:23 pm

Re: Battery Wiring

Postby Gordon-Loomberah » Tue Nov 03, 2015 8:52 pm

Apologies for the crappy diagram, but I find it impossible to draw with a mouse ;) Something like this is what you'll need, and you will definitely need a suitably rated HRC fuse/isolator between battery and bus bar/central connection point.

battery-connection.gif
battery-connection.gif (4.55 KiB) Viewed 4836 times
http://gunagulla.com Loomberah weather and astronomy including live solar radiation intensity and UV + Gunagulla aquaponics, organic eggs and cherries
User avatar
Gordon-Loomberah
Community Moderator
 
Posts: 5763
Joined: Thu Sep 24, 2009 9:41 pm
Location: Loomberah NSW Australia

Re: Battery Wiring

Postby harry201 » Wed Nov 04, 2015 9:18 am

Thanks again Gordon.
What size fuse? as I currently have a 80a in line fuse from battery to inverter.
harry201
Solar Supporter
Solar Supporter
 
Posts: 22
Joined: Thu Nov 20, 2014 7:23 pm

Re: Battery Wiring

Postby Gordon-Loomberah » Wed Nov 04, 2015 9:30 am

What size cable connects battery to bus bar? Too big a fuse for the cable is bad news. What is the max charging current and max load current? The fuse needs to be able to cater for that, + a bit more to avoid nuisance blows.
http://gunagulla.com Loomberah weather and astronomy including live solar radiation intensity and UV + Gunagulla aquaponics, organic eggs and cherries
User avatar
Gordon-Loomberah
Community Moderator
 
Posts: 5763
Joined: Thu Sep 24, 2009 9:41 pm
Location: Loomberah NSW Australia

Re: Battery Wiring

Postby harry201 » Wed Nov 04, 2015 4:47 pm

Hi, I'll try to answer the best i can
1. cable size from battery to basbar - 16mm2 ( orange )
IMG 9999999999.jpg
Solar controlers / busbar / battery connection / inline fuse

2. charge from current solar (so far more, to go up) 3 x strings (3 x 250w 8.64a each string)
- 3 x 26a (25.92) = 78amps. Another 5 strings to go up = 120amps - Total = 198amps solar
Wind - 2000w- 3phase- 24v- 84amps max ( most we have seen is 45 (storm) ).
3. Inverter - (6000W LF PURE SINE WAVE POWER INVERTER DC 24V TO AC 240V 50Hz with 100A BATTERY CHARGER ).
Batteries sit at max 27.7v
IMG 888888888.jpg
Battery reading, just connected :)


Is this what you are asking Gordon?

regards
geoffrey
harry201
Solar Supporter
Solar Supporter
 
Posts: 22
Joined: Thu Nov 20, 2014 7:23 pm

Re: Battery Wiring

Postby Gordon-Loomberah » Wed Nov 04, 2015 5:30 pm

Those cables are all going to get rather warm, melty even... and are completely inadequate for the current you will be sending through them. Get rid of that inline fuse (it looks like it might be in a length of 10mm^2 cable? but hard to tell in that pic, maybe it is just thinner insulation). Put a proper fuse mounted on the wall, you might want 250A + if that inverter really can output 6kW. A triple gang with HRC 100A fuses should do the trick - for battery isolation/fusing, and not blowing when it is sunny and windy

I'm not sure I quite understand your PV panel arrangement, when you say strings of 3 X 250W panels, do you mean 3 panels in series, or 3 in parallel (which would really be 3 strings)?
You are going to need proper isolation/protection between panels and charge controllers and charge controllers and bus bar... you really should employ someone qualified to design this properly, otherwise things could go very wrong.

Are you sure the batteries can handle that much charging power?
http://gunagulla.com Loomberah weather and astronomy including live solar radiation intensity and UV + Gunagulla aquaponics, organic eggs and cherries
User avatar
Gordon-Loomberah
Community Moderator
 
Posts: 5763
Joined: Thu Sep 24, 2009 9:41 pm
Location: Loomberah NSW Australia

Re: Battery Wiring

Postby harry201 » Wed Nov 04, 2015 6:38 pm

Thanks,
That would be nice to have someone qualified, we have had 2 'qualified' out to us and we are still wait for their return:(
We live in country Vic, where we rely on our self's .
As for the panel are 250w mono A grade 24v in parallel, the cabling is high quality truck battery cable.
As for the fuse you have got me confused, a 250A on the wall then a 100A HRC ???? I can send my email address if it would be easy for both us to communicate as getting onto this sit is not always easy for me.
harry201
Solar Supporter
Solar Supporter
 
Posts: 22
Joined: Thu Nov 20, 2014 7:23 pm

Next

Return to Q&A - wind and solar power basics

Who is online

Users browsing this forum: No registered users and 4 guests

new solar power specials
cron