170 Watt PV System

[Mike90250]

John P - you need to get a clue about safety with large power sources like batteries. Often a fuse CAN help, and sometimes something is done so stupidly even a single battery can blow up. If the plastic nut holding the + terminal (or the - term) on the inverter loosened, cracked or melted (all 3 are very possible things, they are not remote) and the cable FELL off the inverter, and landed on the opposite battery terminal, there will be a mess. When the cable touches, it can / will arcweld itself, and sit there till something melts, boils, or explodes.
A friend of mine at work, is missing a ring finger, his wedding ring completed the circuit on his motorcycle a little motorcycle battery arcwelded the ring to cable and chassis, cooking his finger off in the process.

Till you are party to a mishap, it's easy to say, oh that will never happen, or just a few sparks, or nobody would ever do that by mistake.

I keep my 12v system battery, in a marine battery box, with the lid, just to keep random tools and things from falling onto it. At the very least, Perry needs his battery in a container with a lid of some sort, to contain spills (you must have never had a battery leak or spill) and cover the terminals.

[Trickster]

I would keep the battery covered, like a marine battery box. Those exposed terminals make me nervous.

I also agree with fuses, they just might save you in those OMG moments.

I had a few of those OMG moments with my battery killing Wind Genny.

I vote fuses are good.

[Sunking]

Sunking We all think you need glasses as you seem to have a vision problem ..

You must have a mouse in your pocket when you say "WE".

You need to move to a country where they place value on human life and safety. Philippines values will not cut the cake here in the USA.

[john p]

Sunking by we I ment we as I have shown this to others at work that includes technicians and engineers. they all agreed basicly with my findings not yours.. and they still cant understand how you cant see the differences in AC into a rectifier and DC into a rectifier and you get same output..They all wondering about your credability.
My values are not based on Philippine values but Australian values.
And we have hundreds of various types of batteries here at work and God knows how many inverters and charge controllers in various states of working (8 of the inverters not working due to my attempts so far not totally successful of trying to get then to work with grid tied inverters. hmm lost one of them too)Yes I know you can get ones designed for that purpose.But what fun is that I wont learn anything? .and not working and no one seems to have problems with exposed battery terminals.In fact we avoid fuses wherever possible.. mabe we just careful??most of us at work are old time workers .. gee im really way past retirement age..no one has lost fingers ,toes or noses.by doing things the way we do.

Thread :Electrical engineers

[Sunking]

cant understand how you cant see the differences in AC into a rectifier and DC into a rectifier and you get same output..They all wondering about your credability.

FU John, I know the difference, I missed the DC input to the rectifiers. I design the darn things for Pete sake.

[john p]

Sunking well if you knew the differences why you just went on and on and on giving wrong answers and then trying to tell me im on crack and only made up the story about putting DC into a rectifier..Then if you noticed it much later why you not just say it was just another mistake you made in those postings???No you never admitted you made a mistake and not saw it because as you said you dont proof read and dont check even when you told you have given wrong answer..you just made me look like and idiot that knew nothing and Perry ended up believing all your wrong statements..
Everyone expects better than that from you.. As everyione knows you have a wealth of electrical knowledge . but sometimes you just very wrong but you just dont like to admit it. And thats not the first time ive proved you wrong but you never apologize , one other time I kept telling you were wrong but you just made me look stupid and then when another person you had it wrong you only said "my bad " to them. nothing to me..
Mabe learn to proof read and if someone says you are wrong mabe it good idea if you go back and CAREFULLY check what the original question or post was before just telling the person they are smoking dope or on crack,, it would save a lot of bad arguments and bad posts.

[Sunking]

Sunking well if you knew the differences why you just went on and on and on giving wrong answers and then trying to tell me im on crack and only made up the story about putting DC into a rectifier..Then if you noticed it much later why you not just say it was just another mistake you made in those postings???

John you need to quit making things up. I told you I missed the DC input. What I hammered you on is you were wrong with AC input, you cannot get 17 volts DC out with 12 VRMS AC input with a loaded full or half wave rectifier as it defies physics. I advise you to drop this right now and never bring it up again.

FWIW I do not apologize to anyone on a forum, I do not know them or being paid. i will admit when I am wrong, but never appologise for it. I am a busy man with my own company and most of the time I am on here is when I am at work. So yeah sometimes I read to quick and miss things. That is life, but the advice is free. But I would never intentionally give irresponsible advice. In fact I go out of my way to not respond to hands on details to DIY's, They do not even know what questions to ask. I don't want to be responsible for harming anyone. Like a doctor I have a sworn oath to do no harm to the public. That is what the PE means.

[Mike90250]

John P & Sunking - both of you are "Solar Fanatics" according to your aviatars, and both are really smart.

Can we (you) chalk this up to some misunderstanding, and not pick each others nits so much ??


Mike (with hand in pocket)

[john p]

sorry to everyone that has read all my posts.and found them to appear like personal attacks on Sunking..
I dont want bad between us.
I think if anything good can be gained from all of this we have to be careful with statements as most people will only read the first answer given and wont come back to see if there was a mistake in the answer given

[Perry]

For the record, this PV system is to be used to temporarily power this spec house I am building from logs I cut & sawed on my sawmill....



Well I finally got the whole house wired and hooked up to the 100 amp service panel. Since I will not be on the grid (with this house) any time soon, I hooked up the 1250/2500 watt inverter to the panel and now I have power running thorough the whole house. Sure is nice to get rid of the maze of extension cords running everywhere. Supposed to receive the PV panels and the charge controller on March 7. The modified sine wave sure makes those GFI's humm.

[Steve]

Hey, I can put the fuses in if they are necessary. Here's the smaller of the two inverters I use. (800W/1600W)



You really think I need a fuse here?

I mean I can understand if I have 20 batteries or something....

I'm firmly behind Sunking on this. Fuses need to be located directly at the source of power.

There is an endless list of "What if's"- such as what if some of the terminals on the input (DC) side of your inverter was exposed and the spring on your clamp-on utility failed and it swung to short them out?
What if there was a freak manufacturing defect within your inverter (Such as an erroneous screw lodged underneath the fuse sockets) which caused a non-fused short?

The number of batteries is really irrelevant. I guarantee if you were to short your inverter input that single battery would light those wires like the inside of your toaster until something burns in half. The vinyl wire coating would likely catch fire, likely catching your wood mounting board and there you go.
Chances are you wouldn't know it was happening at the time.

Personally, I'd cut off the large DC clips and use a copper lug to avoid accidents at the battery itself, or at least cover them up with an insulator (Even an old plastic spray paint can cover).

There's thousands of possibilities.... I bet anyone who has suffered accident will tell you it was a freak occurance. And those freak accidents happen all the time.

[Sunking]

Perry FWIW and piece of mind, go to a golf cart shop and buy a battery post fuse or circuit breaker. Any golf cart shop will have them, or you can order one on the web. In fact since your system is not grounded, get two of them one for each battery post.

Judging from the size of your inverter and wire size put 20 amp fuses in them. You will sleep better OK?