12 volt 900 AH solar system so far

[zman7458]

So this is what I (actually it should be we, because I've had alot of help from some techies on another rv forum I'm in) have come up with so far. now I'm not going to get into the actual equipment brand names because I've found that that is a subject were folx have problems being objective. I know my budget and what will fit into it, so even though I will admit that a Ferrari is far superior to my Camaro. I don't want to get beat up because I can't afford one. There are two sheets I'm uploading one is a schematic of the system the other is a layout sheet drawn to scale (aside from shunts, switches, disconnects and wire). the bay I am putting this in is 40" wide by 30" tall by 20" deep so that is what this layout sheet is designed to fit. Anyhow take a look if you will and feel free to critique or make suggestions as you see fit. This isn't written in stone until I submit the order (probably next week) Thanks for the extra sets of eyes y'all.

[scrubjaysnest]

Your solar looks about right for a 900aH battery bank but you might want to check out SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank for the bank wiring to achieve best performance. Also a good explanation of why.

[zman7458]

Originally Posted by scrubjaysnest

Your solar looks about right for a 900aH battery bank but you might want to check out SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank for the bank wiring to achieve best performance. Also a good explanation of why.

That was very cool, I had never thought of that in those terms before. unfortunately I'm wired series parallel and that was a strictly parallel install, but I could still apply it to my parallel section if it wasn't for the fact that 4/0 copper wire is so stinking expensive! lol. thanks for that though it was very informative.

[zman7458]

Originally Posted by scrubjaysnest

Your solar looks about right for a 900aH battery bank but you might want to check out SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank for the bank wiring to achieve best performance. Also a good explanation of why.

It does just so happen that the way my batteries are located in the bay with my electronics directly above them that I will be pulling my feeds from the middle of the bank rather than the ends ( because 4/0 copper is so stinking expensive) so I will be a little more balanced than pulling from one end or the other.

[zman7458]

I'm just buying 25' of red 4/0 and 25' of black, so if I add a couple 4 pole busses I might be able to pull off method #3 with the wire I will have. Thanks scrubjaysnest I think you may have just saved me from myself on this one.

[zman7458]

so this would be a crude sketch of my perfectly balanced battery bank. Thanks scrubjaysnest, good looking out.

[Camper2016]

Where is the flux capacitor??!!!

[Chance]

Originally Posted by zman7458

....cut.... the bay I am putting this in is 40" wide by 30" tall by 20" deep so that is what this layout sheet is designed to fit. Anyhow take a look if you will and feel free to critique or make suggestions as you see fit. ....cut.....

My only suggestion is to keep in mind that you will have approximately 500 pounds of batteries, so take care supporting that much weight. When you pick up batteries individually at 60 to 65 pounds each, it's easy to forget that together they weigh more than two generator sets, or the V8 engine in some motorhomes. Most cargo bays I've seen didn't look beefy enough to handle that much weight.


Regarding your wiring to make them identical, it's an excellent idea to do your best, but in the end not all your batteries will have the same exact internal resistance which is one reason many "experts" also recommend having fewer than 4 strings in parallel. This may become more of an issue as your batteries age, making them less balanced (notice most identical RV batteries don't fail at same time). Having too many strings in parallel also makes troubleshooting more difficult.

I really like what you're doing, and look forward to following your progress. I've looked at having the capacity of 8 batteries but haven't found a practical way to make it work for me. Please keep us informed.

[zman7458]

Originally Posted by Chance

My only suggestion is to keep in mind that you will have approximately 500 pounds of batteries, so take care supporting that much weight. When you pick up batteries individually at 60 to 65 pounds each, it's easy to forget that together they weigh more than two generator sets, or the V8 engine in some motorhomes. Most cargo bays I've seen didn't look beefy enough to handle that much weight.


Regarding your wiring to make them identical, it's an excellent idea to do your best, but in the end not all your batteries will have the same exact internal resistance which is one reason many "experts" also recommend having fewer than 4 strings in parallel. This may become more of an issue as your batteries age, making them less balanced (notice most identical RV batteries don't fail at same time). Having too many strings in parallel also makes troubleshooting more difficult.

I really like what you're doing, and look forward to following your progress. I've looked at having the capacity of 8 batteries but haven't found a practical way to make it work for me. Please keep us informed.

yup when I was racing electric R/C cars if you had a good repoire with your hobby shop owner he would let you check the individual batteries you were buying from him so you could build a balanced battery pack and run cooler.

[zman7458]

Originally Posted by Camper2016

Where is the flux capacitor??!!!

I think that goes between the spacely sprocket and the cogswell cog .

[Forest Grump]

Why not use a larger battery and reduce the number of batteries required? You can get 5 Trojan 215 ah 12 volts, J185H or 6 360 ah Trojan 6v? I've used both. The 12v are 7 years old and going strong, new owner, and the 6v are in my ACE going on their 3rd year and also going strong. These batteries have a size 27 footprint but are taller 18" and 14" if I remember right.

When I designed my solar I went for a quick recharge with a smaller battery bank. This allows the batteries to receive a full and complete adsorption phase after each use which is important for battery longevity. I only use a max of 40 amps per day, normally. I have 2 6v 360 ah batteries with 480 watts of solar. I can inflate my pontoon boat - 22 amp draw from available solar and dry camp 7 days without the need for running the generator. This is when parked in partial shade.

Then again I only travel and camp when there is sun, no clouds of any type are allowed.

[Forest Grump]

Why not use a larger battery and reduce the number of batteries required? You can get 5 Trojan 215 ah 12 volts, J185H or 6 360 ah Trojan 6v? I've used both. The 12v are 7 years old and going strong, new owner, and the 6v are in my ACE going on their 3rd year and also going strong. These batteries have a size 27 footprint but are taller 18" and 14" if I remember right.

When I designed my solar I went for a quick recharge with a smaller battery bank. This allows the batteries to receive a full and complete adsorption phase after each use which is important for battery longevity. I only use a max of 40 amps per day, normally. I have 2 6v 360 ah batteries with 480 watts of solar. I can inflate my pontoon boat - 22 amp draw from available solar and dry camp 7 days without the need for running the generator. This is when parked in partial shade.

Then again I only travel and camp when there is sun, no clouds of any type are allowed.

[zman7458]

Originally Posted by Forest Grump

Why not use a larger battery and reduce the number of batteries required? You can get 5 Trojan 215 ah 12 volts, J185H or 6 360 ah Trojan 6v? I've used both. The 12v are 7 years old and going strong, new owner, and the 6v are in my ACE going on their 3rd year and also going strong. These batteries have a size 27 footprint but are taller 18" and 14" if I remember right.

When I designed my solar I went for a quick recharge with a smaller battery bank. This allows the batteries to receive a full and complete adsorption phase after each use which is important for battery longevity. I only use a max of 40 amps per day, normally. I have 2 6v 360 ah batteries with 480 watts of solar. I can inflate my pontoon boat - 22 amp draw from available solar and dry camp 7 days without the need for running the generator. This is when parked in partial shade.

Then again I only travel and camp when there is sun, no clouds of any type are allowed.

The things I considered when deciding which batteries to use were size (both electrical and physical), price, availability and user ratings. Not necessarily in that order. I could have went many different ways with this, but since the batteries will be here tomorrow I'm pretty firm on which ones I will use (grin). Thanks for looking out though. Phil

[Chance]

Originally Posted by zman7458

The things I considered when deciding which batteries to use were size (both electrical and physical), price, availability and user ratings. Not necessarily in that order. I could have went many different ways with this, but since the batteries will be here tomorrow I'm pretty firm on which ones I will use (grin). Thanks for looking out though. Phil

Phil, will you share more info on batteries? That's a large part of total cost for any system. Model, cost, supplier, etc.? I'm also curious if you got a better deal by buying 8 of them.

[Forest Grump]

Were you aware that larger size 6v existed? They are used in fork lifts and floor machines, pretty common.

[zman7458]

Originally Posted by Chance

Phil, will you share more info on batteries? That's a large part of total cost for any system. Model, cost, supplier, etc.? I'm also curious if you got a better deal by buying 8 of them.

Here you go Chance,https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I've already bought them, they'll be here tomorrow. so the Trojans are out of the question

[Chance]

Originally Posted by zman7458

Here you go Chance,https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I've already bought them, they'll be here tomorrow. so the Trojans are out of the question

Thanks Phil, very nice. I see AD that buying 4 would cost $1,000, so you do get a break by buying 8 of them.

Those 8 batteries should be able to easily run a small air conditioner overnight, making my long-term plan viable. And being AGMs instead of flooded makes it practical to install under RV if needed.

[zman7458]

Originally Posted by Chance

Thanks Phil, very nice. I see AD that buying 4 would cost $1,000, so you do get a break by buying 8 of them.

Those 8 batteries should be able to easily run a small air conditioner overnight, making my long-term plan viable. And being AGMs instead of flooded makes it practical to install under RV if needed.

Yes Sir you are correct on all counts. Glad I could help.
p.s. 8 of them weighs 650 lbs. not to mention the free freight.

[zman7458]

I'm still waiting on my 4/0 wire and terminal ends to get here, but everything is in place and fitment is as I expected (close!). I've also received my PV panels and have them on their tilt mounts, but the system they sold me for tilting was going to be problematic at best so I'm reworking them before I goto the work of installing them. I'll post pics when I get them done.

[rlewis]

As I get closer to ordering my solar equipment for my project, I would be interested in a progress report. How did your install go? How are the VMAX AGM batteries working out?