*Understanding* Battery Management and good FWC customizing from ExpoPortal

[pvstoy]

White Dog over at Expedition Portal created a post that documented some changes. But what he had posted about his battery management is a good read. So here is the link and youtube. Cheers.

Fourwheel Camper Personalization


And here is his quote saying...

...I was afraid I was going to have to start into a long description about why this isn't a very good approach. Fortunately, a few days ago, Andrew St. Pierre White at 4XOverland posted a video that describes the problem much better than I can (4XOverland Battery Discussion)....

 

[klahanie]

I think White Dog is being far too modest - I found the video hard to get though...

Agree the charger should suite the battery - I think that was the message. Though I wonder sometimes just how we all made it this far.

Have never driven to Cairo but I did drive home from our last trip. House batts were ~12V the morning (rested) before we broke camp, maybe a little under. Stock alternator charged, and powering the fridge en route, they were at 12.78 the morning after we got home. Couple days later they are at 12.76. For wet cell ACDelco (like the house batt in the video ?) I'm thinking they've been fully charged. Could be wrong tho.

One difference is the little "pipe" he's describes between the truck and house batts, I used large gauge, controlled with a marine switch. Not for everyone but then, nothing is.

 

[Vic Harder]

Agreed Klahanie. White Dog did oversimplify, but some folks need that to get the point. I also can charge my camper batteries from the alternator. But then I don't think either of us drive Toyota's, and we both have fat wires running from alternator to camper.

 

[craig333]

I like the marine switch myself. I've actually had more occasions to use the camper to charge the truck batteries than the other way around.

 

[smlobx]

Agreed Klahanie. White Dog did oversimplify, but some folks need that to get the point. I also can charge my camper batteries from the alternator. But then I don't think either of us drive Toyota's, and we both have fat wires running from alternator to camper.

I must confess electrical issues are somewhat of a black box to me...

So having said that my question Vic can you explain the wiring from your alternator to your camper?

When I bought my new truck I had our local truck accessory dealer to install a 7 pin switch in the left front side of the bed which is what Hallmark did on our original installation. I have no idea what gauge wire they used or where they ran the wire to..

Any insight would be appreciated....

 

[Beach]

Good video, good explanation for the layman.

 

[Vic Harder]

I must confess electrical issues are somewhat of a black box to me...

So having said that my question Vic can you explain the wiring from your alternator to your camper?

When I bought my new truck I had our local truck accessory dealer to install a 7 pin switch in the left front side of the bed which is what Hallmark did on our original installation. I have no idea what gauge wire they used or where they ran the wire to..

Any insight would be appreciated....

Sure. There is a pretty detailed thread on my solar/alternator charging build up here
http://www.wanderthewest.com/forum/topic/13230-i-need-more-power-scotty/

But to answer your question, I ran #2 AWG welding cable from the alternator back to the camper. It goes through 100A breakers at both ends, with Anderson Power Pole connectors at the camper/truck bed connection. I needed 52 feet of this stuff, which isn't cheap.

I also added all kinds of monitoring capability in the cab, so I can see what's going on. In this pic the switch is selected to measure the voltage at the truck battery, and the current flow from the alternator to the camper batteries.

 

[pvstoy]

Like Vic I ran 4 gauge welding wire from the alternator to the camper batteries with Anderson power pole connector at the camper interface.. 80 amp breakers on each end. And Blue seas 7622 battery separator at the camper battery. I have the auto switch to "off" as with my solar it has not been necessary yet to use the trucks alternator to provide charge to the camper batteries.

 

[Vic Harder]

Like Vic I ran 4 gauge welding wire from the alternator to the camper batteries with Anderson power pole connector at the camper interface.. 80 amp breakers on each end. And Blue seas 7622 battery separator at the camper battery. I have the auto switch to "off" as with my solar it has not been necessary yet to use the trucks alternator to provide charge to the camper batteries.

I've forgotten how much solar you have? I have 265W on the roof, and 200w of portable (never used that yet). I always let the solar "finish" the job as it has the best algorithm and understanding of what my batteries need, but will connect the 7622 from the cab of my truck while driving to let the alternator do the bulk charging.

I have 250AH of battery, and rarely get below 85% SOC. Installed a heater this summer and plan on doing some winter camping, so I may run the batteries down more, and they won't charge much from the sun up here in Alberta.

 

[pvstoy]

Vic I have the Victron 100/50 smart MPPT charger bought that first thinking I was going to wire in series, cheaper to keep it and use it than returning it.

Solar I have "3" Overland 160 Watt Semi-flexible Sunpower Gen 3 panels on the roof. 480 watts wired in parallel. The Hawk flat bed has a huge roof space to put three across between the roof vents.
https://overlandsolar.com/products/145-watt-semi-flexible-sunpower-gen-3-panel?yotpo_token=045a61d279ae838980099f7c0b008ad13f6cd7b3&utm_source=yotpo&utm_medium=email&utm_campaign=map&ref=yotpo_8

Batteries have "2" of the original 2015 Fiamia 80 amphr that came with the camper.

 

[Advmoto18]

I must confess electrical issues are somewhat of a black box to me...

So having said that my question Vic can you explain the wiring from your alternator to your camper?

When I bought my new truck I had our local truck accessory dealer to install a 7 pin switch in the left front side of the bed which is what Hallmark did on our original installation. I have no idea what gauge wire they used or where they ran the wire to..

Any insight would be appreciated....

Eddie...

Since we have near identical trucks...

I ran 2 AWG from Pos/Neg terminals of the LH battery, through a breaker for Red, back to camper bed. I used Anderson PowerPole on truck bed side to camper side. Camper side, Red cable ran through the Blue Sea 7622 separator, the other to the Blue Sea 500A shunt.

The heavier the cable you use, the more amps that can be pushed to the camper batteries from the alternator,

Once "bulk" charging is complete, it becomes a much slower process for Volts to push Amps into the batteries through absorption. The bigger diameter the wire the better.

I used tinned crimped 3/8" fittings on the end of the welding cable for terminal connections.

Go with welding cable!!!! More, thinner strands of copper means more flexibility in the wire and more amps being pushed through the wire.

Bill

 

[Vic Harder]

480W, wowza... that's great! I'd like to see a picture of your roof and how you laid that out.

 

[klahanie]

Agreed Klahanie. White Dog did oversimplify, but some folks need that to get the point.

To be clear I think White Dog could have done at least as well in 20 mins, from what I've read of his postings anyway.

The most intriguing part of that vid was the idea of using another regular SLI battery. It was stated the alternator would charge it but it wouldn't last as long as a more conventional house battery (might). Which brings to mind the wonder that is oem charging system.

After all, who among the tens of millions of private vehicle owners check their battery condition-ever; or put it on a tender when away for holiday; or drive enough to recharge after each engine start or stereo listening. Or, frankly, even know what side of the engine compartment it's on. And some units last a very long time, 10yrs is not unheard of.

Granted oem alternators, power controls and SLI batteries are not the same in the past, they have evolved. Makes generalising less accurate, but still just as fun...

Compare that to house batteries. Just look at Craig's thread with all the links to read, all the products and techniques that can be employed vs the humble oem SLI where no knowledge is required until time of replacement. Then it's just vehicle make, model and year of mfr.

Yeah, I know, different horses for different courses. The battery uses are different etc. But the oem system performing so well was the underlying idea behind me using heavy ga. Make the truck charging think the house batt is part of it's system, part of it's battery bank really, because it does such a good job charging and maintaining on it's own.

my .02

 

[Advmoto18]

As Vic hashed out (and quite well done and thought provoking) in his epic "I need more Power Scotty" thread...

IMH (humble) O, the issue will never be how can I get more power to suit my consumption needs, but rather, how do I conserve what power (stored energy) I have to meet my needs for "x" number of days. More power is like have having more space to pack stuff. If you have the space, you will pack more stuff. Likewise, if you have more stored power, you will use more stored energy. And enough will never be enough IMH (humble) O.

Each one of us has a different life style with our own unique quirks that require energy from our camper batteries.

While I admire the person who designs a solar system to run a microwave, TV with DirectTV, Mr Coffeemaker and whatever, frankly, that's not me. The only reason I have a FWC camper is so the wife will go on adventures with me. Solo on my motorcycle, I'm tickled pink sleeping on the ground in my Hilleberg 1 person tent. Cooking with twigs in my Solo Stove. But, L (wife) prefers sleeping in a bed, in her pjs, on nice sheets under a down comforter, with LED reading lights...and a gas fired furnace for when its below 60F...so I have a FWC Hawk and enjoy the heck out of it with L along for the ride.

So again, IMH (humble) O, figure out the energy you need to be HAPPY and design accordingly.

 

[smlobx]

Bill-
Thanks for the info. Email sent..
BTW, my wife is cut from the same cloth....