Good Sam Club Open Roads Forum: Lithium battery charging in FW of truck
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 Tech Issues

Open Roads Forum  >  Tech Issues

 > Lithium battery charging in FW of truck

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

USA

Senior Member

Joined: 01/16/2011

View Profile



Good Sam RV Club Member

Offline
Posted: 05/08/21 07:05am Link  |  Quote  |  Print  |  Notify Moderator

Can someone please explain. 2015 F350 alternator 200-220A, wire to rear of truck not clear on gage but about 20’, wire from plug to FW batteries 15’ or more supposedly protected by 30A fuse. I se people say batteries can draw power and fry alternator, and are installing dc to dc charger in FW to limit the charging. Also people are installing dc to dc chargers because of voltage drop in wire and smart alternators not supplying sufficiently. So how is all this happening,or is it. Please be gentle as I am no electric genus.
Thanks Frank.


Frank
2012 F250 XLT
4x4 Super Cab
8' Tray 6.2lt, 3.7 Diff.

BFL13

Victoria, BC

Senior Member

Joined: 02/15/2006

View Profile



Posted: 05/08/21 09:23am Link  |  Quote  |  Print  |  Notify Moderator

If you don't really need alternator charging via 7-pin, which is low amps and so not much use, you can avoid the whole question.

With solar on the roof of the trailer, it can do a better job than the 7-pin

Just "turn off" the 12v on pin #4 of the 7-pin (yank its fuse is one way). The signal lights etc still work from the rest of the pins.

If you do want alternator charging, then as you note, it gets complicated! [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.

Lwiddis

Williams AZ area

Senior Member

Joined: 08/12/2016

View Profile



Good Sam RV Club Member

Offline
Posted: 05/08/21 09:41am Link  |  Quote  |  Print  |  Notify Moderator

If you get an adequate solar system you’ll never look back. That’s all you need.


Winnebago 2101DS TT & 2020 Chevy Silverado 1500 LTZ Z71, 300 watt solar-parallel & MPPT, Trojan T-125s. TALL flag pole. Prefer boondocking, USFS, COE, BLM, NPS, TVA, state camps. Bicyclist14 yr. Army vet-11B40 then 11A - (MOS 1542 & 1560) IOBC & IOAC grad


Slownsy

USA

Senior Member

Joined: 01/16/2011

View Profile



Good Sam RV Club Member

Offline
Posted: 05/08/21 03:28pm Link  |  Quote  |  Print  |  Notify Moderator

Thanks so far, I do have 600w on the roof, but am a kind off belt and braises person. And would really like to understand how if possible for batteries to draw that much A true a small wire. Also Renogy recommendations for power to there dc to dc chargers are rather large for a long run. I do actually have 00 cable from batteries to rear drawbar but that is for my winch.
Thanks Frank.

BFL13

Victoria, BC

Senior Member

Joined: 02/15/2006

View Profile



Posted: 05/08/21 04:07pm Link  |  Quote  |  Print  |  Notify Moderator

May not be what you are looking for, but I have the Renogy 20 amp DC-DC in the truck camper and use that instead of 7-pin charging. The 7-pin 12v wire in the truck has a 40 amp fuse, so that indicates what the wire can stand.

I made the 7-pin 12v wire in the camper the pos input to the Renogy instead of having it on the battery as usual. It does a steady 20 amps no matter what the alternator voltage is, and pulls maybe 30 amps from the truck, so that is within that wire's ampacity and 40 amp fuse. Much better amps than using the 7-pin itself.

You can add the 20 amps to whatever solar amps you get if you set the Renogy DC-DC to the same voltage (it has some choices) as your solar controller's set Vabs.

You have a bigger alternator than in my truck so in theory, you could get the bigger amp DC-DC than the 20, but then you run into wiring ampacity issues where the 40 amper (output) will pull 60 amps input from the truck.

You could do something clever with the winch wiring so it is powered without turning on the winch.

I used a 12v connection in the camper instead of using the truck ignition method to turn the DC-DC on/off. Be same in the 5er. You want the DC-DC near the house batts, so it would not go in the truck like they would have it in a MH.

theoldwizard1

SE MI

Senior Member

Joined: 09/07/2010

View Profile


Offline
Posted: 05/08/21 04:20pm Link  |  Quote  |  Print  |  Notify Moderator

Slownsy wrote:

Also people are installing dc to dc chargers because of voltage drop in wire and smart alternators not supplying sufficiently. So how is all this happening,or is it. Please be gentle as I am no electric genus.

A DC-DC charger is the BEST solution for charging ANY auxillary battery ! A good DC-DC charger will properly charge the battery through all of the stages of charging, regardless of the voltage coming in (minimum about 10V) and prevent excessive draw drove the vehicle charging system.

pianotuna

Regina, SK, Canada

Senior Member

Joined: 12/18/2004

View Profile


Offline
Posted: 05/08/21 04:24pm Link  |  Quote  |  Print  |  Notify Moderator

Slownsy wrote:

And would really like to understand how if possible for batteries to draw that much A true a small wire. Also Renogy recommendations for power to there dc to dc chargers are rather large for a long run. I do actually have 00 cable from batteries to rear drawbar but that is for my winch.
Thanks Frank.


It is more about getting a constant voltage to the Li Batteries.

My OEM charging was fused at 60 amps. I did blow the fuse 3 times before I replaced it with an auto reset 50 amp breaker. I did double up on the charging path and have seen over 70 amps (How much over I do not know as my ammeter stops at 70 and starts flashing).


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, soon to have SiO2 batteries, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

theoldwizard1

SE MI

Senior Member

Joined: 09/07/2010

View Profile


Offline
Posted: 05/08/21 04:36pm Link  |  Quote  |  Print  |  Notify Moderator

Slownsy wrote:

Also Renogy recommendations for power to there dc to dc chargers are rather large for a long run

Reading the installation instructions for the Renogy 60A DC-DC charger they recommend 4 AWG and a 90A fuse for lengths up to 30'.

This seems like over kill me !

Many trucks wired with 7 pin trailer harness use a 50A fuse a 10 AWG wire for B+ in the factory wire harness. I would be comfortable leaving that as is for a 40A DC-DC charger.

BFL13

Victoria, BC

Senior Member

Joined: 02/15/2006

View Profile



Posted: 05/08/21 04:47pm Link  |  Quote  |  Print  |  Notify Moderator

"Many trucks wired with 7 pin trailer harness use a 50A fuse a 10 AWG wire for B+ in the factory wire harness. I would be comfortable leaving that as is for a 40A DC-DC charger."

Depends in real life, but they indicate the input can be 50% more than the output, so the 40 amper can be expected to pull 60 amps.

It is all about how long the alternator can run at the high amp draw before getting too hot. His 200 amp alternator may not be the heavy duty police/ambulance type.

Slownsy

USA

Senior Member

Joined: 01/16/2011

View Profile



Good Sam RV Club Member

Offline
Posted: 05/09/21 04:52pm Link  |  Quote  |  Print  |  Notify Moderator

Ok thanks all. It appears that I have better disconnect charging from truck or get a dc to dc charger. According to Fords window sticker it is the heavy duty alternator, there are 3 set ups that I am aware of , standard, heavy duty, and dual, don’t know what is used in Ambulance.
Frank.

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

Open Roads Forum  >  Tech Issues

 > Lithium battery charging in FW of truck
Search:   Advanced Search

Search only in Tech Issues


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.