Adding an AC charger to 12V System

dudedogvan

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Mar 10, 2022
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Its not just the starter battery its all the loads that run off the chassis alternator.
Ok, so to test current output of the alternator I need to rev the engine up to 1500-2000 rpm, turn a/c fan on high, coldest a/c setting to run compressor at max, turn radio on, and shine my brights (to simulate the maximum load the alternator is already powering) and clamp a DC amp clamp around the positive lead coming out of the alternator. Is this correct? I'm pretty sure it is.
SO, I don't have a dc amp clamp (or dc amp meter of any kind). I don't want to have to spend the $100-$200 to buy one to measure DC current one time (maybe I'll want one later when I fool with building a bigger system, but that's on down the line). SO, I figure I can borrow one, it's going to take less than 5 minutes to get this reading and move on. Not so easy. I have talked to: the HVAC dude down the road (had a clamp, it reads AC amperage), a classic car tinkerer in my neighborhood (no), auto part stores that loans tools and do free battery tests and all that jazz (no, they can measure voltage), a small engine repair shop (no), I've only talked to one electrician (no, and really they're trying to land jobs, not fool with some weird request from a guy they don't know). I have learned: ok, this is a special piece of equipment. I know this is long-winded and anyone reading this probably thinks I'm crazy. 🤪 I already know I'm a nut, but today I think I got a little nuttier! 🤣 I just want to express my steadfast effort and diligence to do what was advised by the advisors and tell y'all about my little adventure seeking out the elusive "DC amp clamp".
 
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Ok, so to test current output of the alternator I need to rev the engine up to 1500-2000 rpm, turn a/c fan on high, coldest a/c setting to run compressor at max, turn radio on, and shine my brights (to simulate the maximum load the alternator is already powering) and clamp a DC amp clamp around the positive lead coming out of the alternator. Is this correct? I'm pretty sure it is.
You should also test at idle.
As soon as the IGN wire is energized the dc2dc charger is going to pull current.
 
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Another thing to consider is the "big three" upgrade.

1: engine to frame
2: frame to battery
3: battery to alternator
 

Zwy

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My gut says its crap.
I think it would be OK for some applications. I actually would buy one for my boat, however it only has settings for FLA, AGM, and GEL. The AGM setting would probably work OK when using LFP, however the absorption can't be turned off. For what I need, the 1000W inverter would probably be just fine.

Ya, I know we discussed inverter/chargers before and I still haven't bought one yet.
 
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I think it would be OK for some applications. I actually would buy one for my boat, however it only has settings for FLA, AGM, and GEL. The AGM setting would probably work OK when using LFP, however the absorption can't be turned off. For what I need, the 1000W inverter would probably be just fine.

Ya, I know we discussed inverter/chargers before and I still haven't bought one yet.
The one you were looking IMO is a different quality level.
My gut says CRAP but on the other hand its really inexpensive.

The low voltage disconnect doesn't suck "Under voltage shutdown: 11.8 Vdc"
I agree that the AGM charge profile is kinda promising.
Also the company has been known to return phone calls.

The little ground screw is just ugly but that should be easily solved with a pigtail and a Wago lever-nut.
That is assuming that it has a relay that bonds neutral to ground when the unit is in inverter mode.
Its not suitable for the mobile use case if it doesn't do that.
 

camelCase

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Apr 24, 2021
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Plus one on doing a "big three upgrade." Put a fuse on the alternator to battery wire if you do it. Highly recommended if you use the frame as a grounding point anywhere in your system with alternator charging and it helps keep voltage drops to a minimum so actual amps drawn from the alternator for the amount of current are less.
 

coreyzev

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Sep 18, 2021
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Comparing inverter/chargers and all_in_ones from each company based on my best guess for quality regardless of price.
Based on the excellent judgment of my diaphanous friend and his Sherpa.
FWIW, i ended up going (nearly) full Victron. just wanted the reliability.
 

12VoltInstalls

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don't want to have to spend the $100-$200 to buy one to measure DC current one time
My Klein was like $75 and it is great.
It has other functions and will prove a useful tool.

I skipped a chapter 😳 but regarding 400W: at the price of panels I’d do 600W myself. 800W makes for real usable power. Flat panels lose quite a bit at higher latitudes and I think 600W will mask some of that pretty good.
 

dudedogvan

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My Klein was like $75 and it is great.
It has other functions and will prove a useful tool.

I skipped a chapter 😳 but regarding 400W: at the price of panels I’d do 600W myself. 800W makes for real usable power. Flat panels lose quite a bit at higher latitudes and I think 600W will mask some of that pretty good.
After mulling it all over and rereading some of the threads, I went back on the roof of the van to see if I could fit the 600 watts of panels with my rack design and I can!! I liked Mike's point he posted days ago saying solar should be considered my primary charging source. I plan to wire the 3X 200w panels in series with a victron 100/50 smartsolar mppt to charge the 206ah SOK. This will simplify the system and save on other charging components, fuses, and wire. Also another discovery I found to be super slick that I plan to implement: mount the panels attached to gas struts so when I'm parked I can tilt the panels, harvesting the most wattage possible! I'm working on the wiring diagram.
 

Zwy

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After mulling it all over and rereading some of the threads, I went back on the roof of the van to see if I could fit the 600 watts of panels with my rack design and I can!! I liked Mike's point he posted days ago saying solar should be considered my primary charging source. I plan to wire the 3X 200w panels in series with a victron 100/50 smartsolar mppt to charge the 206ah SOK. This will simplify the system and save on other charging components, fuses, and wire. Also another discovery I found to be super slick that I plan to implement: mount the panels attached to gas struts so when I'm parked I can tilt the panels, harvesting the most wattage possible! I'm working on the wiring diagram.
Much easier to have power tilt. Automatically locks in place, I'm too lazy to crawl up there. Actuator pulls the rod forward to unlock, then when lowering once the bracket hits the saddle it pulls the stainless rod to the rear and locks it down. Actuator on each side. Tilting solar panel mechanism.jpgTilting solar panels.jpg Once the mini split is installed, the roof air is coming off and I will have 4 panels that tilt instead of 2.
 
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