Questions and comments for the DIY solar hive mind

[Badgerz]

1st let me say on the resource that Will Prowse started here, Will has performed "Yeoman Service" here due to his general enthusiasm and his experience with this and other technologies. Thank you.

Comments:
My dealing with solar related manufacturers, marketing and documentation that go along with them correlates with my over 40 year experience with technology manufacturers, tech support and suppliers in general. The trend is less and inaccurate documentation, exaggeration of capabilities, promises of future improvements, longer waits for tech support , and the language barrier ect. It is what it is.

Some of my experiences in the DIY solar area:
The misunderstanding of Low and High frequency inverters. I "thought" i researched sufficiently the purchase of a Low Frequency inverter, For me it was down to Sigineer M6048D and MPP LVX6048, i chose the LVX6048 due to the higher solar voltage input (450 vs 250), turns out the LVX6048 is a high frequency inverter with an auto transformer. all marketing materials seemed to indicate low frequency. after purchase and contacting contacting tech support for this unit it was stated "The surge capacity on all our inverters is 2X for 5 sec, but this is the result of testing with “resistive load” in the laboratory. Therefore, we always advise the customer to only use “the nominal maximum continuous power” referring to the inverter, which is 6000W in this case. It’s the best way to avoid the risk of overloading your inverter." I wanted a Low frequency inverter that could handle at least 15KW surge load. Another issue with this inverter - parallel mode, I was preparing to connect 2 of these units in parallel however looking at others and their experiences, i am hesitant to do so now, just look at the threads on the topic. Any comments on parallel experience with the MPP LVX6048 is welcome.

Another experience is with Seplos BMS , stated on the distributor web site it has "heater function", after installing these units and attempting to use this feature i was informed by the distributor that the "heater function is a future feature not yet available". I chose this BMS for the heater function which was plainly on the distributor site and still is. so there you go.

Another issue is Integration, specifically between inverters and BMS , my experience integrating other systems specifically PBX phone systems and Property Management systems via RS232, its not easy sometimes for the 2 systems to talk with each other, they need to have "common language" and different manufacturers have different ideas on what they want and don't want to see come across the link. In a conversation with a battery supplier recommended on this site, his statement was "the battery system has an interface but does not recommend using it" I personally cant see the real need to have the inverter and BMS talk to each other, given the risks, because think about it "what could go wrong????"

Talking with someone who has years of experience with inverters and MPPT, his comment was that " most of the failures and problems come from Surges, overloads, sudden interruption of feed or loads or heavy loads in general". given that manufacturers are not completely honest with the specs and/or they dont apply to the real world, i wouldn't go the the rated capacity so make sure you have plenty of headroom for anticipated surges, and don't disconnect under heavy loads. ect

I would NOT recommend generally that people install a system unless they have experience with electrical, electronics and common sense and are VERY careful and focused. one small mistake can destroy components and this stuff is Dangerous and LETHAL !!! Have someone install it who knows what they are doing, let them take the risk and danger if you can afford it.

Questions:
Anyone know of a AFCI or AFCI/GFCI arc-fault interrupt for the panel side that operates at approx 500vdc and 20 amps? I searched and really cant seem to find any, i am not referring to disconnects, although if one does both i would be interested in those. i have 40 used panels from SanTan solar in Arizona which i want to make sure have good protection from arc-faults due to age (still a great deal for the watts).

Anyone have a FIRM grasp on grounding and lightning protection? I have one inverter 300 feet away from the 240 main service, 10 feet away from the panels and 20 feet away from a 450 foot deep well with steel casing which the submerged pump is connected to the 240 output of the inverter. How would you do it? any suggestions?
another inverter is inside a CON-EX approx 150' from the house/main 240 service which is connected to the inverter input, 20' from the panels running at around 300vdc, and output approx 150' back to the house on a sub panel feeding certain circuits within the house. any suggestions?
I used to think grounding was easy. i was informed by a surge suppressor manufacturer in Florida some years ago, lightning can come back up the ground to get into equipment and that the ground should also be protected which they sold a low voltage protector (Phone line) that protected the ground from being used to come back into the system PBX.

For future reference does anyone have experience on lightning damage and what is common and gets the most damage? I am not talking about direct hits, more like close with static build ups/discharges? Do panels take alot of damage? ect.

Anyone know the proper fuse holder for the VICfuse included with the MPP LVX6048? even went to the mfg site and couldn't find the fuse holder for that fuse

Of course if we want the best equipment and the best and accurate documentation we have to pay more, a lot more. This is why this forum is such a wonderful resource for the capable and experienced DIY crowd, who either just like to "tinker", probably OCD, maybe a bit on the autistic spectrum, cannot afford the best or some sort of combination of those.

Through this "hive mind" we can learn from others who have experience with this line of equipment , manufacturers and dealers.
Thank you

 

[Darren67-72]

Wow, my help here on this forum, is to offer advice. THEN, someone will chim in, that thinks they know everything, and the ideas will come from every direction... it's a process, but you will get some very helpful advice from this.
I'll start with grounding (it always gets people wound up) starting with one ground, and only one! Then, people will tell you to add grounding rods all over your property. I will say; use your original ground source, and connect it to your well casing. This will be your "one ground source" there are several clamps available to do this. My experience is, they are all good but, I prefer a bronze clamp.
As far as, lighting protection..... there are a hundred arguments from very knowledgable "experts" on this issue. But, long story short..... it depends on YOUR situation. You need to look at all your factors and decide for yourself. Your area, wire, conduit, length of runs, inverter, solar, adv. ground water level, amount of metal in the immediate area, soil type, and which "lighting" you want to protect your equipment from.
I'm not trying to be a smart a$$ either. It is a complicated endeavor and NOBODY knows the true power of lighting..... period
Ok, it's a start. Good luck!!!!

 

[OffGridForGood]

Maybe better to post the questions individually, as too long a post usually doesn't get clear responses. Just an idea.

 

[RoadTurtle]

I think I'm reasonably intelligent and competent. Maybe it's dunning krueger, maybe it's not.
.
Learning what and how to get my RV properly set up was a very deep learning rabbit hole and I really appreciate this forum and Will's videos and book.

Some of the highlights of my learning curve

• Wire size, I never knew DC circuits require you to calculate round trip
• Bad crimps are not only bad for performance, but potentially dangerous, Where this was especially revealing to me, my RV mfg had done such a bad crimp job on multiple wires, several were at best slip fit.
• Panel performance is severely reduced in winter, and rated output only happens in the lab environment
• LFP are warm weather batteries
• VOC isn't the last number one needs to look, the temperature compensation chart too.
• Some of the crazier controverseries
  • Over paneling, boy does this get some people worked up. I had an installer go on an ad homenien attack because I clearly didn't understand you should never ever over panel
  • releasing clamps on 120v wire retainer on MP before inserting 120v wires. Victron's own docs add to the confusion, because they tell you to have a 2.5mm screwdriver, but never tell you why.
  • Ferrules. there are several reports that people have been told by Victron to use ferrules, but I don't recall seeing it in any of their docs
  • One controller vs two controllers
  • Shadows, this one was especially important to me, because my intermediate installation, shadows were a big issue. But even so called experts completely dismiss the impact of shadows.
• Buss bar capacity. I struggled with this one, as I initially bought a 250a buss bar, and then began to understand the cheaper amazon bars couldn't handle the wire and fuse size.
• Wire vs buss bar battery interconnect.
• Initially undersizing for capacity. This is what sent me down the learning path. I increased capacity from the factory system, and wasted time and money doing it halfway.
• Dual wires vs single wires. It's interesting that Europe has a preference for dual wires. I struggled with this one too, as one bigger wire was better, but given my installation, dual smaller wire made installation much smoother. Company I used to make the wires also told me that some customers had complained MP II 2x wouldn't accept his 4/0 ring terminals, as they were too large.

Thanks to this forum, both for expanding my knowledge, putting a check on my expectations, and guiding me to a successful build. The system has exceeded all of my expectations. The only change I'm making in my "2nd" attempt, is I am going from 400 --> 600ah in battery. My potential use was just pushing a little too hard on the batteries. This should provide a little bit more overhead for those multiple days in a row with no sun.

 

[JJJJ]

There is a wide range of experience on this site. Over time as you sift through advice you learn who does installations and/or those who share information about their build in their signature.

There are a wide variety of components and voltages available and this comes down to a personal choice.

As indicated above and in other threads there are non negotiable truths such as wire sizes, breakers and fuses and proper connections for your particular build.