RV.Net Open Roads Forum: Switched to 6v setup, questions about care/feeding

RV Blog

  |  

RV Sales

  |  

Campgrounds

  |  

RV Parks

  |  

RV Club

  |  

RV Buyers Guide

  |  

Roadside Assistance

  |  

Extended Service Plan

  |  

RV Travel Assistance

  |  

RV Credit Card

  |  

RV Loans

Open Roads Forum Already a member? Login here.   If not, Register Today!  |  Help

Newest  |  Active  |  Popular  |  RVing FAQ Forum Rules  |  Forum Help and Support  |  Contact

Search:   Advanced Search

Search only in Class A Motorhomes

Open Roads Forum  >  Class A Motorhomes

 > Switched to 6v setup, questions about care/feeding

This Topic Is Closed  |  Print Topic  |  Post New Topic  | 
Page of 7  
Prev  |  Next
Sponsored By:
jrcmlc

Illinois

New Member

Joined: 04/12/2012

View Profile


Offline
Posted: 04/14/12 02:23pm Link  |  Print  |  Notify Moderator

I don't necessarily want or need to hear it's fine as is, I'm just saying that I've been told by xantrex which cable to use and how long of a run was ok, so I did that. If that's not right, I can replace the cable I guess, but I cannot imagine that there is a significant difference in voltage drop from thick-strand cable and fine-strand over only about 13 feet.

There are charts that demonstrate voltage drop over a known distance, and in the xantrex manual it says that the voltage drop per foot for 1/0 cable is .020 per foot, and in another place on xantrex' website, it says that anything under .25 total drop is good. at 13ft, including the connections, I'd say I'm just over the .25total drop. I need to just pull the inverter out and hook it up right at the battery and find out if it'll work that way, to be sure.

JC

crah

Las Vegas

Senior Member

Joined: 11/19/2008

View Profile


Offline
Posted: 04/14/12 02:28pm Link  |  Print  |  Notify Moderator

At what voltage does that xantrex supposed to cut out? .25v drop is large for a 12 volt system.


2003 Holiday Rambler Scepter 36PST 3 Slide
Cummins ISC 350/Side Radiator
Banks System
2011 Buick Enclave Towed
Ready Brute/Ready Brake/Blue Ox

jrcmlc

Illinois

New Member

Joined: 04/12/2012

View Profile


Offline
Posted: 04/14/12 02:32pm Link  |  Print  |  Notify Moderator

10.5 volts I think.

Looks like I should have maybe used 4/0 and been done with it, but at that size it's so friggen hard to work with, it's almost unmanagable.

The cable we used came from mcmaster carr and is labeled as battery cable, not welding cable, also.

JC

crah

Las Vegas

Senior Member

Joined: 11/19/2008

View Profile


Offline
Posted: 04/14/12 02:45pm Link  |  Print  |  Notify Moderator

If you use welding cable, it will be like working with rope. Easy to work with but expensive. Besides voltage drop from the cable itself, a hard draw like the microwave, etc. will cause a big voltage drop from the battery even if you are close. When I had my 2 6 volts, I could use my coffee maker down to about 12.2 volts before I would get the low voltage alarm. It's been a while so I don't remember exactly. A while back Piano Tuna mentioned either high draw or voltage drop. I think he was right on. Unfortunately I think you will have to replace your wires which I'm sure will be a pain. Any chance you can mount the inverter closer to the battery and then extend the AC side to the transfer switch? Even if you do that, I would upsize the wires and go with a fine stranded type.

pianotuna

Regina, SK, Canada

Senior Member

Joined: 12/18/2004

View Profile


Offline
Posted: 04/14/12 07:00pm Link  |  Print  |  Notify Moderator

Hi,

My Dometic microwave draws 1591 watts. It is the item that gives my 2500 watt inverter the most trouble.

To measure voltage drop.

Set up volt meter at the battery bank. Turn on coffee pot. Take a reading at the battery bank.

Then repeat the above measuring at the DC inverter terminals.

I do not know what the inrush on a microwave is--but on occasion I have to add a small 100 load to my inverter *before* I turn on the microwave. It has not happened for a while.

There was a case of a gentleman here with four six volt batteries who had great problems trying to run high draw items. The six volt batteries just don't appreciate heavy loads, so the voltage drops internally.

It may be that the battery bank will need to be doubled in size (four six volts) or that 12 volt jars wired in a balanced manner may be needed.


Regards, Don
Kustom Koach Class C 28'5" 256 watts Unisolar, 875 amp hours in two battery banks 12 volt batteries, 2500 MSW watt inverter.

jrcmlc

Illinois

New Member

Joined: 04/12/2012

View Profile


Offline
Posted: 04/14/12 07:05pm Link  |  Print  |  Notify Moderator

This is also a dometic microwave, but it's very small. Perhaps I will pull it out to get the model # and see if that's the issue.

I wonder if a 10-20 Farad capacitor on the DC side would help to make up for the inrush that causes the initial low voltage?

JC

pianotuna

Regina, SK, Canada

Senior Member

Joined: 12/18/2004

View Profile


Offline
Posted: 04/14/12 08:07pm Link  |  Print  |  Notify Moderator

Hi JC,

Farad's and capacitors are beyond my pay grade unfortunately.

jrcmlc

Illinois

New Member

Joined: 04/12/2012

View Profile


Offline
Posted: 04/14/12 08:19pm Link  |  Print  |  Notify Moderator

LOL, beyond mine also. Time to talk to my engineer friend and see if _THAT_ pay grade gets it.

JC

jrcmlc

Illinois

New Member

Joined: 04/12/2012

View Profile


Offline
Posted: 04/17/12 11:24am Link  |  Print  |  Notify Moderator

Not to beat this thread to death any longer, but I thought I'd give another update.

I checked and the jumper wire, the one that was loose, is also smaller than the other wires I'm using, so temporarily I made up a larger jumper between the 2 batteries and it helped a _little_ more. Still not everything I wanted, but good enough for me, I think. (although I have an LED flickering issue I'm going to post about in a minute).

Thanks for all the help guys.

JC

BigRabbitMan

Dixon, CA

Senior Member

Joined: 07/02/2005

View Profile



Good Sam RV Club Member

Offline
Posted: 04/17/12 07:59pm Link  |  Print  |  Notify Moderator

Good to hear the "rest of the story".


BigRabbitMan & DiamondGal
Diatomaceous Earth for health
76 FMC #1046, Gas Pusher W/Chrysler 440-I
Edelbrock MPI fuel injection, Allison 545
Toad: Red '87 4x4 Subaru Brat, '95 Honda Accord
DataStorm Satellite internet / I am here-click to see


This Topic Is Closed  |  Print Topic  |  Post New Topic  | 
Page of 7  
Prev  |  Next

Open Roads Forum  >  Class A Motorhomes

 > Switched to 6v setup, questions about care/feeding
Search:   Advanced Search

Search only in Class A Motorhomes


New posts No new posts
Closed, new posts Closed, no new posts
Moved, new posts Moved, no new posts

Adjust text size:

© 2013 RV.Net | Terms & Conditions | PRIVACY POLICY | YOUR PRIVACY RIGHTS