Yesterday's Tractor Co.
Shop Now View Cart
   Allis Chalmers Case Farmall IH Ford 9N,2N,8N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   Traditional YT Forum ViewClassic View   RegisterRegister 
 ProfileProfile    Log inLog in 

Voltage drop

Goto page 1, 2, 3, 4  Next

 
Post new topic    
View previous topic :: View next topic  
Author Message
Charles in Aus.
Tractor Expert


Joined: 16 May 2011
Posts: 1941
Location: Victoria , Australia

Report to Moderator

PostPosted: Mon Oct 09, 2017 3:02 pm    Post subject: Voltage drop Reply to specific post Reply with quote

Could someone please help me out with a projected voltage drop calculation ?

I need to lay cable from the solar panels at my barn to the machine room that houses the battery bank .
The distance is 40 metres / 130 feet . I have two[ one positive one negative ] 25mm2 cables with cores of about 20 copper strands each and am hoping that these will be heavy enough to use over this span without compromising the charge current too much .
Output from the panels is aproximately 18.5 volts at full capacity , regulator charges at 13.5 v .
 
Back to top
View user's profile
JMOR
Tractor Guru


Joined: 13 Aug 2007
Posts: 22250


Report to Moderator

PostPosted: Mon Oct 09, 2017 3:16 pm    Post subject: Re: Voltage drop Reply to specific post Reply with quote

Charles in Aus. wrote:
(quoted from post at 19:02:36 10/09/17) Could someone please help me out with a projected voltage drop calculation ?

I need to lay cable from the solar panels at my barn to the machine room that houses the battery bank .
The distance is 40 metres / 130 feet . I have two[ one positive one negative ] 25mm2 cables with cores of about 20 copper strands each and am hoping that these will be heavy enough to use over this span without compromising the charge current too much .
Output from the panels is aproximately 18.5 volts at full capacity , regulator charges at 13.5 v .
don't care much about voltage, but need to know current. Also, is the 'copper' 25mm2?
 
Back to top
View user's profile
chuck2015
Long Time User


Joined: 11 Jul 2015
Posts: 661


Report to Moderator

PostPosted: Mon Oct 09, 2017 3:28 pm    Post subject: Re: Voltage drop Reply to specific post Reply with quote

Charles in Aus. wrote:
(quoted from post at 16:02:36 10/09/17) Could someone please help me out with a projected voltage drop calculation ?

I need to lay cable from the solar panels at my barn to the machine room that houses the battery bank .
The distance is 40 metres / 130 feet . I have two[ one positive one negative ] 25mm2 cables with cores of about 20 copper strands each and am hoping that these will be heavy enough to use over this span without compromising the charge current too much .
Output from the panels is aproximately 18.5 volts at full capacity , regulator charges at 13.5 v .

25mm2 is about 3awg gage wire.
 
Back to top
View user's profile
da.bees
Tractor Expert


Joined: 28 Mar 2012
Posts: 1725


Report to Moderator

PostPosted: Mon Oct 09, 2017 4:12 pm    Post subject: Re: Voltage drop Reply to specific post Reply with quote

Charles in Aus. wrote:
(quoted from post at 18:02:36 10/09/17) Could someone please help me out with a projected voltage drop calculation ?

I need to lay cable from the solar panels at my barn to the machine room that houses the battery bank .
The distance is 40 metres / 130 feet . I have two[ one positive one negative ] 25mm2 cables with cores of about 20 copper strands each and am hoping that these will be heavy enough to use over this span without compromising the charge current too much .
Output from the panels is aproximately 18.5 volts at full capacity , regulator charges at 13.5 v .

18.5 volts at 10 amps over a distance of 130 feet will have 17.99 volts at end under ideal conditions. 0.51v or 2.76% drop.
 
Back to top
View user's profile
jeffcat
Tractor Guru


Joined: 28 Sep 2004
Posts: 10558


Report to Moderator

PostPosted: Mon Oct 09, 2017 5:04 pm    Post subject: Re: Voltage drop Reply to specific post Reply with quote

I posted a little over a week ago about my scrap yard 12ga. extension
cords. They are very heavey and work great. Here is something that
suprised even me. I had my handy dandy harbor freight heat gun for the
shrink tubing. If I plugged the gun into the outlet it makes a sound
at this frequency. A certian pitch. You plug in the 100 footer and
then plug the gun back in to the end of that cord and it makes a
slightly lower pitch. Not even a half a note but it is different. I
was very suprised. You would never think a 100 foot 12ga. cable would
have any drop. That is why I wired my generator house input with 10 /
3 ga. Wire. I would say to go as big as you can afford. Also ask at
the electrical supply place and go one size bigger than they say. Just
my opinion. Since china slowed down two years ago the price of copper
really tanked. Almost 1/2 the price. Go get it.
 
Back to top
View user's profile
JDEM
Tractor Expert


Joined: 18 Mar 2016
Posts: 1751


Report to Moderator

PostPosted: Mon Oct 09, 2017 5:54 pm    Post subject: Re: Voltage drop Reply to specific post Reply with quote

You lost me with your wire-size designation. What is the total solar array wattage?

With a 130 foot run from the array to the controller at 18 volts . .

100 watts needs #4 AWG copper, .37" diameter
200 watts needs #2 AWG copper, .43" diameter
400 watts needs 2/0 AWG copper, .54" diameter
800 watts needs 250MCM copper, .79" diameter
1000 watts needs 300MCM copper, .84" diameter
 
Back to top
View user's profile
JGayman
Regular


Joined: 24 Jul 2011
Posts: 316


Report to Moderator

PostPosted: Mon Oct 09, 2017 7:51 pm    Post subject: Re: Voltage drop Reply to specific post Reply with quote

> You would never think a 100 foot 12ga. cable would have any drop.

All copper wire has resistance and voltage drop. There are voltage drop calculators available on-line. The HF 1500W heat gun draws 12.1A at full power. Assuming a 120V source, a 100FT 12Ga extension cord feeding 12.1A would have a voltage drop of 3.84V delivering 116.16V to the heat gun.

For comparison a 16Ga extension cord would have a 9.71 volt drop with the same load.
 
Back to top
View user's profile
Charles in Aus.
Tractor Expert


Joined: 16 May 2011
Posts: 1941
Location: Victoria , Australia

Report to Moderator

PostPosted: Tue Oct 10, 2017 3:39 am    Post subject: Re: Voltage drop Reply to specific post Reply with quote


Thanks all for the fast replies .
Two panels at 200 watts each planed for the moment with a possible third or fourth in the future depending on what I may power with it .
As far as I can tell 25 mm squared cable [ that refers to the copper core without insulation ] is a little larger than a no 4. AWG and smaller than a no. 3 AWG.
 
Back to top
View user's profile
Texasmark1
Tractor Guru


Joined: 22 Nov 2011
Posts: 7694


Report to Moderator

PostPosted: Tue Oct 10, 2017 3:47 am    Post subject: Re: Voltage drop Reply to specific post Reply with quote

The reference data book I use for line (voltage) drop calculations is printed by Sams Co.......the guys that used to do the Sams Photo Fax
(or something like that) TV schematics we used in the old days (1960s) for TV repairing. He uses 2% for line (voltage) drop when sizing
wire for a given current at a given distance. Considering the fact that our COOP runs our power lines at 124v we have a lot of lee-way in
things like marginal gauge extension cords for power tools.
 
Back to top
View user's profile
buickanddeere
Tractor Guru


Joined: 31 May 2003
Posts: 32083
Location: in front of computer

Report to Moderator

PostPosted: Tue Oct 10, 2017 4:43 am    Post subject: Re: Voltage drop Reply to specific post Reply with quote


A 48V PV system has less voltage drop concerns and 48V inverters handle more power for less $$$ than 12V equipmemt.
Is the plan to provide power for an home, farm, ranch , livestock watering pump or what? 200W of panels will be hard pressed to supply a few LED lights, a microwave oven and a TV set.
Calculate your batteries at 25% use, not 100% discharge . Otherwise the batteries will be ruined in a few months .
Using deep cycle golf cart or fork lift batteries ? Ordinary vehicle or tractor starting batteries are not a match to solar applications .
 
Back to top
View user's profile
JDEM
Tractor Expert


Joined: 18 Mar 2016
Posts: 1751


Report to Moderator

PostPosted: Tue Oct 10, 2017 5:35 am    Post subject: Re: Voltage drop Reply to specific post Reply with quote

RE . . your comment . . " Calculate your batteries at 25% use, not 100% discharge . Otherwise the batteries will be ruined in
a few months ."

Not true. Trojans can be discharged to 100% and survive 750 cycles. If done to 50% they survive 1600 cycles. If at 25% they
survive 3500 cycles. NO down side to a full discharge.

I will further note that in the solar off-grid world, Trojan T-105s are not considered true HD deep-cycle batteries. They are
a good compromise between cost and longevity. Some of the most durable batteries made for solar come from Canada (Rolls
Surette).

 
Back to top
View user's profile
JDEM
Tractor Expert


Joined: 18 Mar 2016
Posts: 1751


Report to Moderator

PostPosted: Tue Oct 10, 2017 5:47 am    Post subject: Re: Voltage drop Reply to specific post Reply with quote

Not really doable with 18 volts unless you want to invest a fortune in 300 MCM copper cable nearly 3/4" diameter. I'd go with
all the panels in series, for higher voltage. There are charge-controllers that can take up to 200 volts at the input and
output a lower 12, 24, or 48 volt charge for the battery bank. I have a 60 foot run from my 5400 watts of solar, to the
controller. I have the panels wired to make 100 volts and only need #6 copper cable. My battery bank is 48 volts with
Canadian batteries. When I did the install, USA batteries were not allowed due to lack of warranty. In retrospect, I wish I
had done the bank in 12 volts.
 
Back to top
View user's profile
jeffcat
Tractor Guru


Joined: 28 Sep 2004
Posts: 10558


Report to Moderator

PostPosted: Tue Oct 10, 2017 6:09 am    Post subject: Re: Voltage drop Reply to specific post Reply with quote

I still have a few of thr AR books for car radios. Great help bqck in the day when I used to do repairs.
 
Back to top
View user's profile
JMOR
Tractor Guru


Joined: 13 Aug 2007
Posts: 22250


Report to Moderator

PostPosted: Tue Oct 10, 2017 7:02 am    Post subject: Re: Voltage drop Reply to specific post Reply with quote

Charles in Aus. wrote:
(quoted from post at 19:02:36 10/09/17) Could someone please help me out with a projected voltage drop calculation ?

I need to lay cable from the solar panels at my barn to the machine room that houses the battery bank .
The distance is 40 metres / 130 feet . I have two[ one positive one negative ] 25mm2 cables with cores of about 20 copper strands each and am hoping that these will be heavy enough to use over this span without compromising the charge current too much .
Output from the panels is aproximately 18.5 volts at full capacity , regulator charges at 13.5 v .
Getting past all the "other info" you got here, you asked about voltage drop & got one answer close to what you asked & at that point he didn't know about your 400W number, so basically double his drop number. ANS.: is 1.1 volt drop. Can you tolerate that? JDEM wants you to have 0.437 volt drop. That is nice, but do you need that small a drop? Only you can answer that, knowing you own equipment.
 
Back to top
View user's profile
JDEM
Tractor Expert


Joined: 18 Mar 2016
Posts: 1751


Report to Moderator

PostPosted: Tue Oct 10, 2017 7:21 am    Post subject: Re: Voltage drop Reply to specific post Reply with quote

I figure any of my wiring with loss at around 3%. Certainly not uncommon. 1/2 volt in an 18 volt system is substantial loss.
Loss is just what it sounds like. Energy not being used for the intended purpose. Usually just takes a couple of extra bucks
to keep it to a minimum. All the figures I gave were with losses 2.2% to 3.1%.
 
Back to top
View user's profile
Display posts from previous:   
Post new topic    Yesterday's Tractors Forum Index -> Tool Talk All times are GMT - 8 Hours
Goto page 1, 2, 3, 4  Next
Page 1 of 4

 
Jump to:  

TRACTOR PARTS TRACTOR MANUALS
Fast Shipping!  Most of our stocked parts ship within 24 hours (M-Th). Expedited shipping available, just call! Most prices for parts and manuals are below our competitors. Compare our super low shipping rates! We have the parts you need to repair your tractor. We are a company you can trust and have generous return policies. Shop Online Today or call our friendly sales staff toll free (800) 853-2651. [ About Us ]

YT Home  |  Forums

Modern View Forum powered by phpBB © 2001, 2005 phpBB Group

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters