The gauge going from batteries to my house panel looks to be around 8, possibly 6. From the batteries to the panel there is a relay (so I can disconnect the entire panel), and then the house fuse block. I'm not sure what to check at those junctions-- I mean, it seems like it's either connected or not.
8ga should be good for 30A up to 15 feet. I like to upsize one wire size for a little elbow room and to accomodate resistance due to connections etc, so 6ga would be even better. Thats assuming 30A is your largest combined load, including in-rush current.
This battery isolation relay, is it normally closed? Using a relay in this capacity seems like an odd choice to me. Either it always needs power to be connected, or it needs power to be disconnected.
I usually use a marine circuit breaker or battery selector switch for that purpose, they are manually actuated but use no power to be open or closed.
For testing your connections, do a voltage drop check.
Test battery voltage at the battery and compare it to the voltage measured between the positive battery post and the positive connection on your lift actuators, with the actuators commanded to lift. Ideally there will be no difference, but the world is not ideal.
Use that method to find the wire or connection with the largest voltage drop and address it, if necessary.
I have used that method many times to find faulty components, inadequate connections and undersized or corroded wires. I like to keep voltage drops down to 0.10v or less. Resistance testing can find blatant issues, but doesn't help identifying loss due to amp draw.
For testing your connections, do a voltage drop check.
Test battery voltage at the battery and compare it to the voltage measured between the positive battery post and the positive connection on your lift actuators, with the actuators commanded to lift. Ideally there will be no difference, but the world is not ideal.
Use that method to find the wire or connection with the largest voltage drop and address it, if necessary.
I have used that method many times to find faulty components, inadequate connections and undersized or corroded wires. I like to keep voltage drops down to 0.10v or less. Resistance testing can find blatant issues, but doesn't help identifying loss due to amp draw.
Great info and tip @kbeefy . I'll do that. My van is a ground-up homebrew, with help from a few different shops at different times, so things are a little "interesting" as I learn what everybody did (I've been mostly impressed and happy). When I installed the Lithium, I discovered that the relay actuator is powered by the house batteries themselves. (i.e. an independent wire run back to my relay switch on my panel, and then everything else on my panel powered by the main 8 or 6 gauge run from the switched side of the relay). I think I asked for this when I wanted absolute certainty the batteries were isolated from loads. In retrospect, a manual switch might have been better.
I'll do the testing that you and Ray recommended, and see if there are any drops between the batteries and the pop-top motors. Overall I'm super happy with the Lithiums, and the BMS that comes with them.
When I installed the Lithium, I discovered that the relay actuator is powered by the house batteries themselves. (i.e. an independent wire run back to my relay switch on my panel, and then everything else on my panel powered by the main 8 or 6 gauge run from the switched side of the relay). I think I asked for this when I wanted absolute certainty the batteries were isolated from loads.
I used to, and sometimes still do this to isolate the starting battery and charging system from the house side when the engine is off. It's automatic, and as long as your starting battery is charged pretty safe.
If your relying on an electrically actuated relay to maintain power to your house panel, it is an extra parasitic draw and it will eventually fail.
30A seems like a pretty high draw for the pop top, I am gonna have to check my CCV top when I get a minute. I will check it on the shunt and then hook up my Fluke and see if I get a comparable result.
Maybe I just got lucky, my top raises real happy off of just my Renogy 100AH lithium house battery. 4GA from the battery to the distribution block and then whatever CCV uses from there. Maybe 12 gauge? Its an intermittant load so they can get away without giant wires I suppose. Its not too weighted down, RB (so short) and just a Maxxair and 2x Renogy panels on aluminum rails. No baskets or boxes or things of that nature.
I did have issues with my Maxxair fan as wired from CCV. The original install used spade terminals and had enough resistance that the Maxxair would trip out for under voltage. Spade connectors suck, I was surprised they were used. I re-terminated it in high amp Weatherpaks and have had zero issues with my fan randomly dieing when running on high. I use my fan to suck the canvas in on my top when I lower it, and it works great for that now that I fixed the harness connections,.
One of the most helpful tools I've found when solving automotive electrical mysteries is a small D.C. clamp-on ammeter. They're uncommon, but they actually do exist! The one I use most often is the Model 316 Mini AC/DC Clamp Meter from B&K Precision. (Please see the picture below.)
You can buy these meters from Amazon for about $200, but I've seen them elsewhere for around $150 sometimes. Just beware of the prices you see on Ebay for these, as some of those vendors are asking more than $400 (i.e. they're just looking for a fool with money).
If you don't already have one of these meters (or its equivalent), then $150-$200 for such an unusual tool may seem like a lot, but I believe "it's only expensive if you never use it" - and I use mine all the time.
The jaws will clamp around single conductors with an O.D. of up to 12.5 mm (≈1/2"). Mind you, this isn't a "lab-quality" instrument, but in my experience it's "usably" accurate down to 50 mA or so on the 10 Amp scale. It also has a 100-amp scale (it's auto-ranging) that would work well for checking the actual current draw of your pop-top motors.
Checking the actual current draw at each motor can tip you off to mechanical issues in d.c. electric motor-driven applications.
Makes for a useful "sanity check" sometimes . . .
Good luck!
Timerider
P.S. I also have a Fluke 337 that reads up to 1000 Amps, but I use it less often, because the jaws are much larger, and therefore harder to clamp around individual conductors in a wiring harness without undoing the zip-ties. My 337 also does less well in reading d.c. currents much smaller than one Ampere.
__________________
"Silver Kitten": 2002 E-350 7.3 RB-50 SMB Quigley 4x4, Agile RIP-kit
"My Metal Mistress": 1982 Cessna T182 - "Sleeps 0, but leaps tall mountains in a single bound."
I'd suggest looking into "fuse buddy" testing tools offered by Electronic Specialties, Inc: https://www.esitest.com/C/17/FuseBuddy If you have the typical bladed fuses mounted in a block those might be more affordable for infrequent testing.
I have several of the fuse buddy's. I made up an adapter out of a fuse holder to easily attach alligator clips to it.
There are a few different models. The 'heavy duty' model says 30A max, but works fine with a 40A fuse. Not sure beyond that.
For diagnosing parasitic draws, that model is to course, it only measures to .1A. The 'standard duty' one measures to .01A, and works fine with a 30A fuse in it.
One of the most helpful tools I've found when solving automotive electrical mysteries is a small D.C. clamp-on ammeter. They're uncommon, but they actually do exist! The one I use most often is the Model 316 Mini AC/DC Clamp Meter from B&K Precision. (Please see the picture below.)
Thanks @Timerider . This is a great tip-- I gave up and assumed there was no such thing as a non-contact tester for DC current, after spending a long time searching but only finding AC. I'm always up for buying a new tool that I *think* I'll use a lot-- and if I spend enough on it, it may work its magic to ensure I never have another electrical problem to use it on . (...looks hard at 6 gauge terminal crimpers)
. (...looks hard at 6 gauge terminal crimpers)
Linear Mode
