21 replies to this topic

[So Cal Adventurer]

Hey All

 

Question for the masses that have their FWC's wired to charge from the alternator while driving..

 

Obviously the #s will vary vehicle to vehicle, but has anyone actually measured how many amps their alternator is putting out to the FWC batteries while they're driving?

 

Example, using the Victron battery monitor app that shows real time #s, etc..

 

I'm working on something ill post up about when im done, but curious others opinions.

 

Thanks

[cwdtmmrs]

I don't have numbers nor do I have any way to get numbers, but I can say that my only charging has been from my alternator and I have never had a dead camper battery. I have a 120 amp alternator wired with 4 ga in addition to the 10 ga wires  feeding a 12 year old Optima yellow top battery. I do have a 3 way fridge and usually drive every day.

[ntsqd]

Similarly I don't have numbers either. No way to pull that data from our battery monitor system as it was not a data logging unit. Our old camper was wired and breakered to allow 80 amps with less than 3% voltage drop. We usually move every day to every other day and with only 100W on the roof we never had low batteries once we got undamaged batteries in the camper. The camper's original batteries must have been abused and took me a while to realize that I had a battery problem rather than a charging problem.

[rando]

I have looked at these numbers from my battery monitor.  

 

2016 Tacoma, 6AWG from engine bay to camper plug, stock wiring inside camper, 150Ah LiFePO4 battery.   

 

I got around 7-8A for the first few minutes after start up, dropping to 5-6A after that.    

 

I recently modified my wiring to allow my MPPT 100/20 to also act as a B2B charger, and I now get constant (programmable) 20A charge:

http://www.wanderthe...c-dc-cheap-b2b/

 

I primarily rely on solar, so the B2B was more out of interest to see if it would work than necessity. 

[So Cal Adventurer]

I have looked at these numbers from my battery monitor.

2016 Tacoma, 6AWG from engine bay to camper plug, stock wiring inside camper, 150Ah LiFePO4 battery.

I got around 7-8A for the first few minutes after start up, dropping to 5-6A after that.

I recently modified my wiring to allow my MPPT 100/20 to also act as a B2B charger, and I now get constant (programmable) 20A charge:
http://www.wanderthe...c-dc-cheap-b2b/

I primarily rely on solar, so the B2B was more out of interest to see if it would work than necessity.

That’s pretty slick sir

[alano]

I have a current sensor in the battery box reading the alternator feed. It's wired to a readout looking through the front window of the camper into the back window of the truck. Alas, the rear-view mirror's polarizing won't let me read it while driving and I have to turn around, so I only look at it when stopped though the wife checks it if we have concerns.

 

I was getting about 5 amps through the stock 10 AWG wiring most of the time. Had troubles and I think my separator went wrong so I added 4 AWG wire on a shorter path and hooked in a 40 amp DC to DC charger. On the first test run with the batteries brought down a bit (lost SOC info when wiring things up) we measured 24 amps at freeway speeds. Since most trips we drive most days, this should keep things topped off nicely when the 200W of solar on the roof can't keep up due to clouds, shadows or smoke.

 

Alan

[craig333]

I suppose I should check. I haven't needed to since the solar does all the work, so far. Also 6ga wire so I have no reason to think it won't work but I'd sure hate to find out I fubar'd something. Easy enough to check after I draw the batteries down a bit.

[So Cal Adventurer]

I’m asking because for over a year I never had an issue, living in SoCal I’m spoiled and my 275 watts of solar always keeps things tip top.

But after a trip north and a week of full clouds and rain, I couldn’t keep the batteries topped off.

I ran some tests and did some things but curious what others are getting and their setups before I finalize my “fix”

Thanks

[Oilbrnr]

I just recently finished hooking up my Hawk a couple of weeks ago. Ran 4 AWG (more from the fact I had it laying around) from the starter battery back to a couple of single post lugs that I mounted under the bed directly below where the Attwood trolling motor plug comes through the bed. The Attwood piece itself is not overly inspiring, but I went with it for now.

 

The rest of the wiring is stock with a Blue Sea 7611.

 

So far the highest I've seen on the Victron is 24 amps when the SOC was ~70%.

 

Speaking of Victron, their app is a hot mess. No single pain of glass for their products is kinda wack. And no clock. Every time I go in and out of my parking garage at work, starts a new day on their MPPT history. But I digress.

[So Cal Adventurer]

Speaking of Victron, their app is a hot mess. No single pain of glass for their products is kinda wack. And no clock. Every time I go in and out of my parking garage at work, starts a new day on their MPPT history. But I digress.

That’s bizarre and sounds like a glitch. Mines worked perfect for about 1.5 years and nothing like that with the app.