Victron Energy: Alternator/Solar Charging - LFP Battery System

dreadlocks

Well-known member
I just got back from Utah, Driest place in every possible way.. the little beer my wife did find the clerk made a big deal outta.. "Oah it must be a special occasion" the clerk smirked.. I dunno what was so special? the 12 hour anniversary of when I ran out of beer?

I shoulda stocked up in Arizona, and I knew better.. I just didnt realize I was running so low already..
 

Photobug

Active member
I just got back from Utah, Driest place in every possible way.. the little beer my wife did find the clerk made a big deal outta.. "Oah it must be a special occasion" the clerk smirked.. I dunno what was so special? the 12 hour anniversary of when I ran out of beer?

I shoulda stocked up in Arizona, and I knew better.. I just didnt realize I was running so low already..
I lived in Utah for a while. There is actually some good beer there but the church and government want to keep you from drinking it. Are you familiar with Epic Brewing? They started in SLC.

Just so I am not accused of thread drift: Victron.
 

dreadlocks

Well-known member
naw I got some Evolution Ale out of SLC, wife musta thought it funny.. :p

back on topic eh? So I found another reason to favor the Victron Ecosystem this last outing w/my Battleborn LFP.. Wife turned on Microwave w/Crockpot still on and instantly tripped the BMS over current protection.. and had the unfortunate effect of resetting my SOC to 0% since it also cut power to the BMV-712.. if I had a Victron LFP, SOC would be determined by the battery and any BMS protection would not cause this loss.

Until I got the battery fully charged to calibrate SOC, I was using the charge voltage and current to guesstimate SOC%..

This was one week camping in the south western canyon lands with ample sunshine all for the last day, with varying locations, terrain, environments.. 100AH LFP w/650W of Solar

Max Wattage Seen in a Day: 433W
Min Wattage Seen in a Day: 192W

Screenshot_20191020-155033.png

As you can see the output varies dramatically when your constantly on the move, really only 3 days I even saw a float charge.. I did have to use the generator twice.. but both for very short periods (1h max)

Rooftop solar was largely a bust this trip for daily camp loads, still needed portable pretty much every day unless we were straight desert.. though it did great recharging while driving and it even charged the LFP up one day WHILE running the crockpot w/some BBQ Pulled Pork simmering away all day.. was awesome setting up camp and eating such a good meal w/so little effort.. need to get seperate controllers for the panels so I can evaluate them individually instead of as a pair.. but right now it seems if I want to stave off the Generator the portable panel is going to be key for my needs (~51AH/day)
 
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Alloy

Active member
naw I got some Evolution Ale out of SLC, wife musta thought it funny.. :p

back on topic eh? So I found another reason to favor the Victron Ecosystem this last outing w/my Battleborn LFP.. Wife turned on Microwave w/Crockpot still on and instantly tripped the BMS over current protection.. and had the unfortunate effect of resetting my SOC to 0% since it also cut power to the BMV-712.. if I had a Victron LFP, SOC would be determined by the battery and any BMS protection would not cause this loss.

Until I got the battery fully charged to calibrate SOC, I was using the charge voltage and current to guesstimate SOC%..

This was one week camping in the south western canyon lands with ample sunshine all for the last day, with varying locations, terrain, environments.. 100AH LFP w/650W of Solar

Max Wattage Seen in a Day: 433W
Min Wattage Seen in a Day: 192W

View attachment 545843

As you can see the output varies dramatically when your constantly on the move, really only 3 days I even saw a float charge.. I did have to use the generator twice.. but both for very short periods (1h max)

Rooftop solar was largely a bust this trip for daily camp loads, still needed portable pretty much every day unless we were straight desert.. though it did great recharging while driving and it even charged the LFP up one day WHILE running the crockpot w/some BBQ Pulled Pork simmering away all day.. was awesome setting up camp and eating such a good meal w/so little effort.. need to get seperate controllers for the panels so I can evaluate them individually instead of as a pair.. but right now it seems if I want to stave off the Generator the portable panel is going to be key for my needs (~51AH/day)
How about another fixed panel? When there sun our fixed panels will bring our FLAs back up before noon.
 

dreadlocks

Well-known member
nah, these conditions wouldn't have helped.. old growth ponderosa forest dispersed camping.. sure there were plenty of sites I passed that had ample sunlight, but the not the one we got with the view we got.. then in bryce we showed up at 8am to get a walk-in, almost no choice on site.. again thick canopy over the fixed panel just had to find a break in trees looking south, plop portable down and hope for the best.
 

Alloy

Active member
nah, these conditions wouldn't have helped.. old growth ponderosa forest dispersed camping.. sure there were plenty of sites I passed that had ample sunlight, but the not the one we got with the view we got.. then in bryce we showed up at 8am to get a walk-in, almost no choice on site.. again thick canopy over the fixed panel just had to find a break in trees looking south, plop portable down and hope for the best.
Alternative would be to make the fixed portable.....saves buying a 2nd controller.
 

shade

Well-known member
That's why I added alternator charging. I'm not even sure I'll want or need a second panel for ground placement. A 100W or so is as large as would be practical for me to carry for a remote panel anyway. My effort may be better spent developing a tiltable mount for the 360W panel. Something simple, like this:


My plan is to start any extended time away from the truck with the battery at a high SoC, and let solar charging contribute to battery endurance. As long as I can park where there's a little light, I should be able to get several days out of 160Ah with whatever solar harvesting yields. Come to think of it, I probably wouldn't want to leave a panel on the ground while I'm away for days, so that makes it easy to skip one.
 
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Photobug

Active member
.. but right now it seems if I want to stave off the Generator the portable panel is going to be key for my needs (~51AH/day)
To me it seems key if you want to run a high electrical demand lifestyle, a generator is key. Especially if you are running lead acid batteries that benefit a full charging cycle once a week. As long as the generator runs consistently it seems to be the most reliable tool for independence. While a generator is loud, cost money and space, all other sources have their issues and costs. I am trying to see where a DC generator can fit in my rig.
 

dreadlocks

Well-known member
Yeah if you wanna go fully solar, it dont matter how many panels you got.. your going to have to start compromising on sites and picking them for their solar qualities over anything else.. and before long you'll be worshiping the sun with as much as you pay attention to it and always want to bask in its glory.

Having an engine of some sort to provide charge when sun is not cooperating, makes life less stressful..
 

Alloy

Active member
To me it seems key if you want to run a high electrical demand lifestyle, a generator is key. Especially if you are running lead acid batteries that benefit a full charging cycle once a week. As long as the generator runs consistently it seems to be the most reliable tool for independence. While a generator is loud, cost money and space, all other sources have their issues and costs. I am trying to see where a DC generator can fit in my rig.
We have FLA, solar and a generator and use around 70Ah from 6pm-6am. The FLA reach float on solar more often than on generator.

It would take 6 hours per day of burning fuel and noise for the generator to bring the FLA up to float.

A generator works better with Lithium.
 

dreadlocks

Well-known member
yeah Ive had my genny through both FLA and then w/LFP.. I hated it with FLA, running the engine for a few measly amps during absorb is a huge waste of fuel and takes forever.. at idle the genset is discarding a ton of energy.

With LFP I like it much more, just an hour is really all I need if I'm entirely engine dependent.. and there is no pressure to ever get it back to 100% (unless you loose SOC calibration lol).. with my ~50AH a day usage, and my 40A shore charger.. I only need an hour of runtime and I've got ~40AH back in.. if I run it for half an hour I get ~20AH back in.. If the sun is setting and I'm not where I want to be w/my SOC, its very minimal genny time to get me back to where I want to be.

For those going off an alternator w/LFP, just a half hour to an hour drive every day may be all you really need.. and IMO thats pretty easy to achieve unless you just like parking in one spot for weeks on end w/out moving an inch.
 

Alloy

Active member
Yeah if you wanna go fully solar, it dont matter how many panels you got.. your going to have to start compromising on sites and picking them for their solar qualities over anything else.. and before long you'll be worshiping the sun with as much as you pay attention to it and always want to bask in its glory.

Having an engine of some sort to provide charge when sun is not cooperating, makes life less stressful..
We camp in the trees, never chase the sun. The fixed panels do the job 90% of the time if not I bring out the portable.

Two weeks ago I ran the generator for the first time this year when it rained for 2 days. A friend with was plunged into our inverter because he screwed his batteries up using a WAFO converter.
 

dreadlocks

Well-known member
I went all summer w/out needing the portable panel.. then Labor day I needed it, then this last trip over half of the sites I needed it.. If I park on the north side of a big tree, I'm probably not getting enough sun on it to do much.. I think the reason I got by this summer so well was due to the angle of the summer sun, its able to penetrate a canopy easier when its higher in the sky.. here in October its too close to the horizon all day and wont ever get that high angle of attack I got closer to the summer solstice

Making my fixed portable is not happening, it was hard enough getting my 45lb panel 11ft in the air once w/out damaging it.. I'm not doing it again..

The solution would be enough battery capacity to ride out those sites and not need a daily charge of some sort.. but LFP is expensive compared to solar and even generators.. so until I can get the needed capacity without spending $3-4k more on batteries I'll make due w/the design I have now.
 

spressomon

Expedition Leader
For us and our 6500w LFP the plan is to upgrade both rig's alternators to higher output variants for when we're doing extended same-location camps along with a foldable panel, probably a Merlin, to augment when feasible.
 

shade

Well-known member
To me it seems key if you want to run a high electrical demand lifestyle, a generator is key. Especially if you are running lead acid batteries that benefit a full charging cycle once a week. As long as the generator runs consistently it seems to be the most reliable tool for independence. While a generator is loud, cost money and space, all other sources have their issues and costs. I am trying to see where a DC generator can fit in my rig.
If you're going to move your truck every 2-3 days anyway, you have a good DC generator under the hood. Run some wire for a DC-DC charger and you're done.

The solution would be enough battery capacity to ride out those sites and not need a daily charge of some sort.. but LFP is expensive compared to solar and even generators.. so until I can get the needed capacity without spending $3-4k more on batteries I'll make due w/the design I have now.
That's another reason I'm happy about gaining an additional 60Ah of capacity for so little. It's rare for me to spend several days camped at the same site. Either the truck is parked and unattended while I'm away camping elsewhere, or I'm driving every few days. I'd be more inclined to bring my generator along if I was camping in the truck for several days without moving it, but that's a rarity for me.
 
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