RV.Net Open Roads Forum: Truck Campers: Moving LiFePo4, Rewire or run Long Extensions?

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 Posting Help and Support  |  Contact  

Search:   Advanced Search

Search only in Truck Campers

Open Roads Forum  >  Truck Campers

 > Moving LiFePo4, Rewire or run Long Extensions?

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 4  
Prev  |  Next
Sponsored By:
RickLight

Washington

Senior Member

Joined: 01/22/2017

View Profile



Good Sam RV Club Member

Offline
Posted: 12/27/20 09:59am Link  |  Quote  |  Print  |  Notify Moderator

Yeah we can get off track easily.

Sounds like the big question is how much better will the solar be with shorter wires? Longer 120 is not a factor under 50'.

Plan exclusively for the future 400W system. Then do your voltage drop calculations for both ways. https://www.southwire.com/calculator-vdrop At 10' 6AWG is probably good, but 4 will be half the loss. What can't be calculated is the value of your cash and sweat.

Moving LI batteries inside is a no brainer for me, if you plan on any cool temps. I've been snowed on in mid summer! There are heaters for batteries but that takes time with the truck noise, fuel and fuss.


Rick,

2019 Grand Design Reflection 150 273MK
2015 Ford F350 CC SB Lariat Powerstroke
PullRite Superglide

BFL13

Victoria, BC

Senior Member

Joined: 02/15/2006

View Profile



Posted: 12/27/20 09:59am Link  |  Quote  |  Print  |  Notify Moderator

In the OP, the object was to do more "off-season" camping. So adding more solar won't do any good in the dark half of the year.

You need more AH for the "off season". IMO your calculations of needing fewer AH next year will only help in the sunny, warmer half of the year.

You can add more batteries or charge what you have more often, twice a day even - most likely need to do both. Alternative is to wait for the "season" to use the TC. Just how it is. You are not the first to wake up to a dead battery at night when first trying to RV in the "off-season". So it is "go big or go home" basically. [emoticon]


1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
See Profile for Electronic set-ups for 1. and 2.

Grit dog

Black Diamond, WA

Senior Member

Joined: 05/06/2013

View Profile


Offline
Posted: 12/27/20 10:22am Link  |  Quote  |  Print  |  Notify Moderator

Except your battery will only stay warm if the furnace is running....


2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29

PastorCharlie

NC

Senior Member

Joined: 03/28/2004

View Profile





Offline
Posted: 12/27/20 11:20am Link  |  Quote  |  Print  |  Notify Moderator

When installing my system I used 4/0 welding cable with equal runs connecting 4 batteries ( 450 ah ) and a 2,000 watt Magnum inverter. Fuse the + at battery. All terminals are both crimped and soldered. Estimate your needed run and buy the cable in one piece and cut to desired lengths. Simple and minimizes loss.

phemens

Montreal, Canada

Senior Member

Joined: 09/18/2006

View Profile


Offline
Posted: 12/27/20 02:51pm Link  |  Quote  |  Print  |  Notify Moderator

adamis wrote:

Thanks for the comments and suggestions. I think I need to clarify a few things as a few of the suggestions seemed to focus on the wrong issue in my opinion. What is unique about this camping experience is our twin baby girls that required us to heat their bottles multiple times a day and to keep the furnace running at night because at their age you can't cover them in blankets.

The bottle warmer pulls ~300w for 10 minutes 4 times a day. The wife's coffee was ~700w for about 4 minutes each morning. Finally, we have running the furnace in the evening which was ~100w for about 5 minutes but cycling probably one to two times an hour from midnight till 6am. The 200w of solar is usually fine for our "pre-baby" camping needs during the summer but with these new needs and less sunlight in the winter months, just was not enough to get the battery topped off each day.

Next year we won't be doing bottles or need to run the furnace as aggressively so those factors will go away. The coffee pot we can run the genset for if really necessary though I think without the other two factors, the coffee pot isn't going to be an issue.

The point of my post however is that what I did discover is that the LiFiPo4 battery when it gets cold will limit it's charge rate. This was a bit of a head scratcher the one morning when we ended up with a dead battery so I started the truck around 6am (~20 degrees outside) in order to be able to run the furnace and put some charge back into the battery. I found the battery was only charging around 3 amps when I have a 20amp DC to DC charger. It took me a while to realize it was the BMS on the battery limiting the charge because of the temperature.

Moving the battery inside is just a project I am considering because I have a pretty optimal location for it that would eliminate the cold factor. In normal use I don't think I really need to add more battery capacity but will eventually add another 200w (for 400w) total of solar power. I might also replace the furnace with a more efficient two speed unit as well.


Just FYI, there's an active thread on heating pads for LiFePO2 batteries to keep them in the 'green' zone for cold weather charging. This presumes you might consider keeping your batteries 'outside'.


2012 Dutchman Denali 324LBS behind a 2006 Ford F-250 V10 out of Montreal
1 DW, 1 DD, 1 DS, 2 HD (Hyper Dogs)
1200w solar, 600AH LIFePO4, Yamaha EF2000 gen, Samlex 3000w Inverter

Bradymydog

Western MA

New Member

Joined: 03/26/2019

View Profile


Offline
Posted: 12/27/20 03:47pm Link  |  Quote  |  Print  |  Notify Moderator

Hello Adamis,

I also have a Bigfoot Camper 25c 9.4 and am going through the process of gathering all the information I can regarding Lithium Batteries. On my camper the "Battery Box" enclosure is a plastic box with a vented metal door on the outside of the camper. The BB is located directly under and behind the sink cabinet with an open (at the top) partition separating the two.

Here are my suggestions for your situations.

1. Insulate the access metal door with poly iso foam board - cheap at R 6.5-7/in. fit it very tight. Now it will be inside you conditioned space.

2. Keep cabinet doors open during the night to allow heat to circulate into the cabinet area. If your set up Is similar, remove the partition to allow more air to circulate around the BB.

3. Only use the inverter portion of the inverter/charger during times you need to warm baby bottles or make coffee, avoid using the converter for convince i.e., microwave, AC outlets, etc. Note: baby bottles have been warmed on the (propane) stove in water and tested on the wrist for decades, use an accurate digital thermometer if you want to go hi-tech.

With the above low cost measures, you should be able to: have more usable Ah in the battery and keep the Battery warm for very little time and expense.

Congrats on the baby girls. Enjoy and safe travels.

Grit dog

Black Diamond, WA

Senior Member

Joined: 05/06/2013

View Profile


Offline
Posted: 12/27/20 04:19pm Link  |  Quote  |  Print  |  Notify Moderator

PastorCharlie wrote:

When installing my system I used 4/0 welding cable with equal runs connecting 4 batteries ( 450 ah ) and a 2,000 watt Magnum inverter. Fuse the + at battery. All terminals are both crimped and soldered. Estimate your needed run and buy the cable in one piece and cut to desired lengths. Simple and minimizes loss.

4/0? OMG, why?
Presume you had it laying around and then thus more economical than buying adequate but much smaller cable?

StirCrazy

Kamloops, BC, Canada

Senior Member

Joined: 07/16/2003

View Profile



Posted: 12/28/20 09:30am Link  |  Quote  |  Print  |  Notify Moderator

I would move your battery inside and add another. double your AH availble. even next year when your not doing bottles that would still let you go longer between generator use, and even though your not going to be warming bottles you'll probably be still running the furnace more than you did.

if it was me I would get up to about 650 watts of solar also, if you have the room to do it. this might eliminate your need to even use the gen. but you would still have it if there was a week of overcast or somthing like that.

Steve


2014 F350 6.7 Platinum
2016 Cougar 330RBK

phemens

Montreal, Canada

Senior Member

Joined: 09/18/2006

View Profile


Offline
Posted: 12/28/20 10:10am Link  |  Quote  |  Print  |  Notify Moderator

Grit dog wrote:

PastorCharlie wrote:

When installing my system I used 4/0 welding cable with equal runs connecting 4 batteries ( 450 ah ) and a 2,000 watt Magnum inverter. Fuse the + at battery. All terminals are both crimped and soldered. Estimate your needed run and buy the cable in one piece and cut to desired lengths. Simple and minimizes loss.

4/0? OMG, why?
Presume you had it laying around and then thus more economical than buying adequate but much smaller cable?


Mine is wired the same way, and nope, didn't have 4/0 just lying around. Depending on the draw (microwave, etc), you can pull several hundred amps off the batteries in short bursts - I've seen in excess of 300. Much smaller wire will not be up to the task.

Grit dog

Black Diamond, WA

Senior Member

Joined: 05/06/2013

View Profile


Offline
Posted: 12/28/20 11:26am Link  |  Quote  |  Print  |  Notify Moderator

My mistake, by much smaller, I meant couple sizes (which is considerably smaller diameter and cost).
A 2000W inverter will draw approx 200A at full load.
I also assumed a relatively short wire run, under 10’. With that 1/0 would be more than sufficient and 2/0 would be conservative.
No harm in overkill on wire size. ( Just like pickup trucks, right? Lol). Just not necessary for the load from a 2000W inverter unless it’s a long run. Which would make no sense as it’s far more efficient to have the DC load close to the power source and distribute with AC current to AC loads.

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 4  
Prev  |  Next

Open Roads Forum  >  Truck Campers

 > Moving LiFePo4, Rewire or run Long Extensions?
Search:   Advanced Search

Search only in Truck Campers


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

Adjust text size:




© 2021 CWI, Inc. © 2021 Good Sam Enterprises, LLC. All Rights Reserved.