my cheapo off grid system

[almac]

have 3 x 24v sets in parallel for now, these batteries are less than a year old can put the fuse posts for the charge controllers and inverter on any 3 of the terminalsDSCN0020.JPG

[jflorey2]

have 3 x 24v sets in parallel for now, these batteries are less than a year old can put the fuse posts for the charge controllers and inverter on any 3 of the terminals[ATTACH=CONFIG]n305225[/ATTACH]

From here:

1) GET A BATTERY BOX. That is one critical thing you have to do before you drop a soda can on the bank and cover yourself with acid. Try here:http://solar-catalog.com/battery_racks.html. Then vent it to the outside.

2) Fuses. I'd recommend putting an appropriately rated fuse (i.e. will carry inverter loads) on each + and - terminal of any battery string. i.e. not on the black wires in your diagram, but on every other terminal. Then run appropriately rated wire to your inverter. Then get a fuse rated for your charge sources and connect that to the + terminal of the inverter. Then connect the charge sources to the other side. The negative side doesn't need a fuse at that point. That's a minimum of 7 fuses - six fuses around 100-200 amps, and one fuse around 20 amps.

3) Mounting. In your picture, all it would take is someone knocking against that table and you'd have your charge controllers and/or inverter falling onto the battery bank with the usual smoke/fires/explosions etc. Get a sheet of plywood, paint it and then attach it to the wall studs. Then mount the inverters/CC's on that. Use conduit if possible, or at the very least anchor the wires somehow so they don't flop around.

[SunEagle]

Another item would be to use the same size wire throughout your battery system.

That black wire looks a lot smaller then the blue or red which creates different resistance paths and uneven charging/discharging.

[Sunking]

Almac I beg you and others to stop, until he can prove he will be safe and can preform acceptable workmanship. . Almac what you are showing us is extremely dangerous. Open batteries, no OCPD, poor workmanship, on or near wood is just plain foolish.

What we are seeing here is like a Heroin Addict shooting up dope saying: " I can handle it and know what I am doing". What you have is 3rd grade science fair project nightmare. For God's sake do you not value your life and property?

[almac]

Another item would be to use the same size wire throughout your battery system.

That black wire looks a lot smaller then the blue or red which creates different resistance paths and uneven charging/discharging.

hi thanks for the reply, thats an optical illusion, the black wire is the same as the red wire, both 140 amp. although the blue wire is thicker

[almac]

Almac I beg you and others to stop, until he can prove he will be safe and can preform acceptable workmanship. . Almac what you are showing us is extremely dangerous. Open batteries, no OCPD, poor workmanship, on or near wood is just plain foolish.

What we are seeing here is like a Heroin Addict shooting up dope saying: " I can handle it and know what I am doing". What you have is 3rd grade science fair project nightmare. For God's sake do you not value your life and property?

thanks for the reply, the reason i put up these pics is for the feedback so i can make it right. so far you have explained the fusing, ie inverter needs 100 amp at +ve and negative post. although wouldnt just the +ve post suffice? the charge controllers need 30 amp fuse at the +ve and neg post but would just the +ve suffice? ok battery box to protect exposed battery terminals, thanks jflorey2. iv already asked you sunking what is the go with wood when you pointed this out earlier? of the few members that actually post pics some put their batteries on open wooden pallets. no mention on that posting about exposed batteries on the floor on a pallet. do you expect me to know what OCPD means? im guessing it has something to do with wire ratings, fusing .. just a guess...

[inetdog]

Sorry about the jargon. OCPD stands for OverCurrent Protection Device. Which could be either fuses or circuit breakers. Most circuit breakers are not rated for high current DC, nor are most commonly available fuses, so you have to be a little more careful just what kind you get.

[almac]

Sorry about the jargon. OCPD stands for OverCurrent Protection Device. Which could be either fuses or circuit breakers. Most circuit breakers are not rated for high current DC, nor are most commonly available fuses, so you have to be a little more careful just what kind you get.

thanks for the reply, so something like this? http://www.ebay.com.au/itm/Battery-F...wAAOxyg7xSYfT5

[inetdog]

thanks for the reply, so something like this? http://www.ebay.com.au/itm/Battery-F...wAAOxyg7xSYfT5

Yes. I cannot comment on what is being sold in that particular ad, but that looks like the kind of battery-terminal-mounted fuse that would do the job.

[jflorey2]

iv already asked you sunking what is the go with wood when you pointed this out earlier? of the few members that actually post pics some put their batteries on open wooden pallets. no mention on that posting about exposed batteries on the floor on a pallet.

I once did an off-grid design for an airport. They just asked for the electrical design, which I did for them; I told them to build a battery box. They did a reasonable job with cheap plywood, but did not paint or finish the interior. It included an exhaust fan that exhausted to the outside.

The batteries were standard flooded T-105's because that's what the local supplier had. The airport had someone who did a reasonable job of keeping them topped off.

The system lasted about six years before they got sick of the maintenance (watering the batteries mainly.) When they disassembled it I took a look at the inside of the box. The plywood on the bottom had turned black, and acid had eaten through the floor, through the carpet beneath the box, and through the plywood under the carpeting. The fan had disintegrated from the acid.

So think about whether or not you want that in your living room.

[almac]

Yes. I cannot comment on what is being sold in that particular ad, but that looks like the kind of battery-terminal-mounted fuse that would do the job.

thanks, one more question, sunking says both neg and +ve terminals need to be fused. why is this? i would have thought in an overload event the +ve fuse would break the circuit so why do we need another fuse at the neg terminal

[almac]

I once did an off-grid design for an airport. They just asked for the electrical design, which I did for them; I told them to build a battery box. They did a reasonable job with cheap plywood, but did not paint or finish the interior. It included an exhaust fan that exhausted to the outside.

The batteries were standard flooded T-105's because that's what the local supplier had. The airport had someone who did a reasonable job of keeping them topped off.

The system lasted about six years before they got sick of the maintenance (watering the batteries mainly.) When they disassembled it I took a look at the inside of the box. The plywood on the bottom had turned black, and acid had eaten through the floor, through the carpet beneath the box, and through the plywood under the carpeting. The fan had disintegrated from the acid.

So think about whether or not you want that in your living room.

sounds like more a case of neglect than a wood problem. i check my batteries daily, how did so much acid get into the floor?

[Sunking]

sounds like more a case of neglect than a wood problem. i check my batteries daily, how did so much acid get into the floor?

No not neglect, that is what happens when you have wood near batteries. You cannot stop it. Every thing around the batteries needs to be an inert material that does not react with corrosives be it alkaline or acidic. Any acid or alkaline is going to react with anything organic. In some cases a very strong reaction as mixing acids with organic material is the recipe of high explosives.

[almac]

No not neglect, that is what happens when you have wood near batteries. You cannot stop it. Every thing around the batteries needs to be an inert material that does not react with corrosives be it alkaline or acidic. Any acid or alkaline is going to react with anything organic. In some cases a very strong reaction as mixing acids with organic material is the recipe of high explosives.

ok, these batteries have been on this floor for nearly a year no acid in the wood so far.. maybe the airport maintanance guy was overfilling these t105s jflorey2 was talking about

[cebury]

No not neglect, that is what happens when you have wood near batteries. You cannot stop it. Every thing around the batteries needs to be an inert material that does not react with corrosives be it alkaline or acidic. Any acid or alkaline is going to react with anything organic. In some cases a very strong reaction as mixing acids with organic material is the recipe of high explosives.

So is it from micro droplets of acid in the air that cannot be prevented when rfilling? It would seem so given the evidence of th exhaust fan damage as well.