Took the bus out a few times now, and my inverter must be pulling more juice as the summer heats up because the insulation on the negative terminal (plastic sleeve) is melting.
Now the odd thing is, the positive side is ambient temp. I use 1/0 gauge wire (thick as my thumb)
Below (attached graphic) is how I have my battery setup with my house batteries / alternator/ etc
I'm considering adding an additional ground near the inverter.. or not even grounding near the coach battery at all, just using a chassis ground near the inverter.
A bad connection at terminal or crimp could cause the heat.
I should check my crimp, the connection is solid at the terminal end though.
I might get out the touch and solder it all. (terminal to wire)
On my Magnum it said to not ground the batteries directly to the frame etc. but to put a ground wire from the inverter to the frame or metal body etc. It had a screw terminal on the end of the inverter and I connected it to the frame with a 10 gauge wire as per instructions. Also have a 300 Amp fuse breaker on the Positive wire and a breaker also on the negative from batteries to inverter.
I have never heard anyone use 300 amp and 10 Ga wire in the same sentence.
Quote from: Jon on July 28, 2017, 03:19:23 AM
I have never heard anyone use 300 amp and 10 Ga wire in the same sentence.
I believe he was referring to the chassis ground lug on the inverter case, which is different than the main inverter battery ground lug.
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Quote from: Jon on July 28, 2017, 03:19:23 AM
I have never heard anyone use 300 amp and 10 Ga wire in the same sentence.
Actually, he used the terms in two different sentences. He was referring to the chassis ground when discussing the 10 ga wire. He was referring to the battery positive connection when referring to the 300 amp fuse. Everything he said was correct, though I question the instruction about not grounding the batteries to chassis.
Yes as mentioned the magnum is calling it equipment ground. The terminal can handle ( i believe it said ) 14gauge through 2. Sorry i closed out the pdf
The magnum manual illustrations im seeing are cables running straight to inverter, no stops unless optional dc shunt kit is installed on neg cable. The fuse and switch could be on pos cable like Dave was saying.
I guess the key here is what your inverter instalation describes. I mighta missed it in one of the videos, sorry. But hey its Friday
Good day there
Floyd
Grounding At Inverter not battery
This makes sense because the electron flow would need to go another hop. from inverter to battery negative then to ground / chassis.
Picked the bus up from the glass shop (thanks Glass Today in Minneapolis) and warmed it up, turned on the AC and smelled something while checking tire pressure (I'm super paranoid about PSI on my tires), I opened the battery door and the end was now smoking, felt super warm. I did leave my inverter on while it was at the shop to keep the fridge cool. So I'm thinking the battery banks were a bit low and everything was sucking lots of juice.
I think I'm going to shorten that cable up and ground at the chassis, because that's essentially what happens now, just after a longer run. Yes it's 1/0 cable, but I figure I'll double up my grounds and shorten the cables. I shot some video, I'll post it up soon.
If your thinking is having one ground path. Some interesting pages i seen in link.
I wanted to mention this because of a few designs in grounding the magnum.
The wiring plan chosen assigns a size of ground wire one can use. Im sure some others can easily describe this better than me.
In the meantime a nice page i found in a link below, though this is for a MS series Magnum so again it depends on our brand and i been looking at this one lately. Anyway on page 35 i believe it starts, and are ground wire designs and show a great deal on sizing with chosen design. hth
Floyd
http://pdf.donrowe.com/ms_series_owners_guide.pdf (http://pdf.donrowe.com/ms_series_owners_guide.pdf)
Is anyone else wondering why there's so much power going down a plain chassis ground during normal operation?????
First guess would be a ground loop. do you have neutral tied to ground / frame anywhere other than your inverter?
When the engine is running? when the generator is running? or all the time?
Melting insulation on a connector says the connector is faulty, unless the whole wire is hot the whole length of it. The resistance is what causes the heat, and the fault can be between the cable and the connector, the connector and the battery/inverter, or can be internal to the battery or the equipment. It's perfectly permissable to use the chassis as a major conductor path - all the the bus electrical system does, and pushes up to 6000 watts from the alternator, and much more than that when the starter motor is operating. Unlike a neutral connection, many ground connects are permissable and recommended. You can ground everything, and unless a fault condition exists all of the grounds will be at the same potential.
You say you were running one AC unit when you found the hot connector. That is around 1800 watts on the 120VAC side, maybe 2000 watts on the DC side, your picture suggest 28 volts so around 75 amps. Well within the acceptable range for 1/0 cable. I personally don't like soldered connectors, and prefer properly crimped ends. Usually replacing the cable end and cleaning and using correct grease on the connection clears these issues up. Sometimes the cable corrodes internally and needs to be replaced. I know it's not the ultimate cable for the application but I use welding cable, and up-size the cable vs the rated ampacity. I like the flexibility of welding cable, and it's very weather-proof.
Interesting situation. Excellent input given. Ground loop? Proper Crimping concerns? Insufficient cable diameter? Run length? Has anybody considered a dedicated house ground?
I also would be curious as to what is causing the hot inverter ground wire. Very heavy fine over size stranded mining cable does come to mind also. Is the inverter running hot?
Inverter is running fine..
I'm 95% sure I just have a bad crimp. I'll trim , recrimp and solder it.
Quote from: Jon on July 28, 2017, 03:19:23 AM
I have never heard anyone use 300 amp and 10 Ga wire in the same sentence.
Nope !!! 10 gage is usually around 30 amps
Solder may not be recommended here. Consider a proper crimp done with the mother of all 6 foot crimping tool, then heat shrink plastic coverings.
Jon and Red I didn't say 10 gauge and 300 AMPS in the same statement. if you re read it above guys. I said 300 Amp breaker on the cable from the Magnum 4024 inverter charger Hybrid to the Batteries on the positive cable as per instructions. The ground wire I used 10 gauge wire from the inverters ground clamp to the frame again as per instructions. Sorry for any misunderstanding. Please re read. ;D
Dave
HB this ht I did the first time. I made a good dozen crimps brrwwrrwn rwhrw battery bank and other cables, this is the only one giving me trouble.
Quote from: neoneddy on July 27, 2017, 12:25:50 PM
Took the bus out a few times now, and my inverter must be pulling more juice as the summer heats up because the insulation on the negative terminal (plastic sleeve) is melting.
Now the odd thing is, the positive side is ambient temp. I use 1/0 gauge wire (thick as my thumb)
I see your profile says you are in Ham Lake, MN. I also live in Ham Lake. I would happy to stop by and see if I can help with your electrical issue. You can send me a PM if you are interested
Quote from: HB of CJ on July 28, 2017, 04:21:36 PM
Solder may not be recommended here. Consider a proper crimp done with the mother of all 6 foot crimping tool, then heat shrink plastic coverings.
It doesn't need to be quite that long! My FTZ 94284 crimper has handles about 3 feet long, and with its adjustable dies makes "gas-tight" crimps on 4/0 cables with no problem. I cut one crimp apart to see how it looked inside, and all the cable's individual strands had fused into a solid mass of copper and were also fused to the lug. For me that's plenty good enough. I checked the temperature of one of my starter cable's lugs immediately after starting, and it wasn't even warm. I think the FTZ is as good a crimper as any busnut will ever need for occasional DIY cable-making. Don't forget also having a good cable cutter - if the cutter mashes the strands or makes a mess of the cable, it won't help having a good crimper.
John
Did you take an amp reading of the wire? A ground wire shouldn't have (much) current. A DC clamp-on amp meter is a great tool to have.
Quote from: Brassman on July 29, 2017, 10:30:56 PM
Did you take an amp reading of the wire? A ground wire shouldn't have (much) current. A DC clamp-on amp meter is a great tool to have.
I've never been able to find a DC clamp-on amp meter. Only AC.
Quote from: Brassman on July 29, 2017, 10:30:56 PMDid you take an amp reading of the wire? A ground wire shouldn't have (much) current. A DC clamp-on amp meter is a great tool to have.
Quote from: gumpy on July 30, 2017, 06:16:22 AMI've never been able to find a DC clamp-on amp meter. Only AC.
Shouldn't the amps going through a ground wire be well within the range of a "disconnect it and put the meter in line to check the amps" multimeter???? As I mentioned above, it concerns me that a plain chassis ground wire is carrying enough load to heat up the ground wire/terminal connectors.
Quote from: gumpy on July 30, 2017, 06:16:22 AM
I've never been able to find a DC clamp-on amp meter. Only AC.
Craig,a friend sent me a clamp on DC amp meter he found on Amazon
Quote from: Oonrahnjay on July 30, 2017, 06:29:07 AM
Shouldn't the amps going through a ground wire be well within the range of a "disconnect it and put the meter in line to check the amps" multimeter???? As I mentioned above, it concerns me that a plain chassis ground wire is carrying enough load to heat up the ground wire/terminal connectors.
Yep. Should be. Something's wrong if there's more.
Quote from: luvrbus on July 30, 2017, 06:33:48 AM
Craig,a friend sent me a clamp on DC amp meter he found on Amazon
Tell your friend I'll be his friend, too! :D
AC/DC clamp on meters are almost the norm nowadays, different from only a few years ago. Or so it seems. They seem to be second or third tier of expensive, running around $200 vs under $100 for AC only. I may ask for on for Christmas... :D
Brian, Merry Christmas
https://www.amazon.com/Uni-T-B4Q094-UT210E-Current-Capacitance/dp/B00O1Q2HOQ/ref=sr_1_1/143-7664851-2034502?ie=UTF8&qid=1501451524&sr=8-1&keywords=dc+clamp+on+ammeter (https://www.amazon.com/Uni-T-B4Q094-UT210E-Current-Capacitance/dp/B00O1Q2HOQ/ref=sr_1_1/143-7664851-2034502?ie=UTF8&qid=1501451524&sr=8-1&keywords=dc+clamp+on+ammeter)
Quote from: Oonrahnjay on July 30, 2017, 06:29:07 AM
Shouldn't the amps going through a ground wire be well within the range of a "disconnect it and put the meter in line to check the amps" multimeter???? As I mentioned above, it concerns me that a plain chassis ground wire is carrying enough load to heat up the ground wire/terminal connectors.
I stopped by his house yesterday since I live in the same city. The cable is the negative cable direct from the battery to the inverter. No connection to chassis ground. I didn't see any issues with anything, but the insulation was melted. He is planning to crimp on a new connector.
I ran a quick voltage drop calculation today and the 1/0 cable seems like it is big enough.
I've found lots of clamp-on DC ammeters that read up to about 400 amps, but that may not be enough to read starting current for a big diesel. Craftsman has (had?) their so-called Professional series 800 amp AC and DC ammeter, model 73756, but its actually an Extech EX730 with the Craftsman name on it. When I bought mine it was missing its thermocouple probe, so Sears had Extech send me a replacement! I don't know if it's still available, but I paid less than $100 for mine. I haven't had a chance yet to measure any high-amp DC currents with it, but it seems like a decent inexpensive meter for occasional use. Obviously a Fluke would be nice, but for the little I'll ever use mine I'm happy with it.
John
I noticed in your diagram you have your batteries linked by a daisy chain, Is your inverter also a charger? If so, I read a number articles last year that recommended all cables be the same length with all the positive cables going to a common post and all the negative cables doing the same. I have four 250ah 8D deep cycle gel cells. I made a large bus bar with two 3/16" x 1.25" x 10" copper bars screwed to a 4" x 6" x 12" block of wood that all the cables bolt to. From there I have one positive and one negative going to the inverter/charger. All are 0000 cables of equal length. The bus bar is enclosed! The point of the articles was that each battery further down the chain gets a little less voltage and the reverse is true when pulling energy from the batteries, shortening the life of the batteries. I have a 400 amp fuse between the batteries and the inverter. I'm not a professional electrician, but I thought it made sense assuming that the batteries closest to the charger don't modulate the voltage for the next battery down the line. Just thought I'd throw this out since I haven't posted anything in a year or so.
I think his main problem, aside from the possible bad crimp, is he's pulling a big overload when he tries to start that old AC unit. Dropping output voltage from the inverter to 70 volts indicates a massive overload. I am surprised the inverter is still working, I had an AIM inverter that ate it's output MOSFETS for lunch when I had an over-current situation. No warranty, no possible repair, all they would offer was swap the unit for full retail. I bought the Magnum.
re:bevans6 , the smoking / hot end was happening when the AC was running fine, normal current loads. Aims LCD would show 50-60% usage of the 3000 watt capacity.
Going to pickup the new AC Today will report back on the AC / Inverter thread.
QuoteI had an AIM inverter that ate it's output MOSFETS for lunch when I had an over-current situation.
All this overloading of inverters is making me poop my pants. Don't even the most basic inverters have quick acting fuses/breakers to prevent damage when feed too much of a load?
I'm guessing the folks intent on running A/Cs through inverters are not concerned about the long term damage, but instead are looking for ways to do what even the inverter manufacturers cannot recommend.
Regardless of the inverter rating the newer styles are not intended for the handling of the starting current.
Quote from: neoneddy on July 31, 2017, 10:24:26 AM... Aims LCD would show 50-60% usage ...
Yeah, AIMS inverter. You're not the first ...
Sounds like we nee to do an Inverter round up. Have some litmus tests we cna all run and measure.
Eventually I hope to go full Victron
Quote from: neoneddy on July 31, 2017, 01:30:07 PM
Sounds like we nee to do an Inverter round up. Have some litmus tests we cna all run and measure.
Eventually I hope to go full Victron
Yeah, me too (although as savvy as the Technomadia folks are, they have struggled a bit because, as they put it, Victron is more oriented toward home/off-grid systems and not mobile/vehicle/boat systems and they've had some issues with not-optomized-for-vehicle problems that Victron didn't seem to care about. Maybe Victron's customer support has gotten better.)
First to finalize my initial issue.
I was testing my new Mach 3 Plus AC setup and noticed my battery was draining, even with the bus running my bank read 23-24v .. not good. (under 90 or so amps of load). I checked the coach battery / alternator output.. it was good at 28-29 ... the house battery bank ground was completely hosed.
I crimped a new cable and grounded to the frame from the inverter / battery common ground point. I think I'll add a secondary as a backup, similar to how home electrical systems have 2 grounds, goof enough for me.
Additionally I use a small butane torch, flux and solder to make an even stronger connection. I do realize that if the terminal gets hot enough like before the solder would melt, but it only got that hot because of a poor crimp connection. This is crimped and soldered now. Cool as can be.
Re: Technomadia / Victron - Do you know what threads they talked about their troubles? I followed their youtube channel and didn't catch much negatives. Chief's Prevost youtube also used Victron, kinda figured it was the gold standard. What I liked most is how it all works together with the Color Control LCD panel and it shows power coming from batteries , solar and shore or generator power. Even shows what you used, etc.
QuoteWhat I liked most is how it all works together with the Color Control LCD panel and it shows power coming from batteries , solar and shore or generator power.
I believe most MPPT charge controllers have advanced features such as this; I do not believe it is unique to Victron units.
Quote from: neoneddy on August 01, 2017, 01:44:25 PM... Re: Technomadia / Victron - Do you know what threads they talked about their troubles? I followed their youtube channel and didn't catch much negatives. Chief's Prevost youtube also used Victron, kinda figured it was the gold standard. What I liked most is how it all works together with the Color Control LCD panel and it shows power coming from batteries , solar and shore or generator power. Even shows what you used, etc.
ISTR it was the "solar" postings. Don't get me wrong, they talk about a LOT that's right with the Victron, but there were a *few* aspects. And I seem to remember that those posts were from about 2013, only a year or so into their lithium experiment. And yeah, the color panel display is total drool candy. (BTW, they've bought a boat now too -- I guess they wanted to spread their money pits out!!)
In this video I show my new ground location and the grid tie inverter in action.
https://youtu.be/11c1enwgk6g
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