What size solar?

[VallAndMo]

Hi,

 

You will definitely need more battery capacity.

Agreed, from what I've learned 2 6V GC2 batteries in series are about the minimum for a really usable system, and they can be had for not too much money.

 

I paid $1000 for 4 $255 watt panels, $700 for charge controller, $1800 for inverter and just spent $2700 for LiFeMnP04 battery bank.

We're in the initial stages of planning for our system and would really like to use LFP batteries, but are having a hard time finding a cost-effective and tested setup. Specially regarding charge controllers that will work well with them. Do you have your setup posted somewhere? Would love to learn from your experience.

 

Cheers,

--

Vall.

[A_K_Chesnut]

Loads of fantastic info. I'm working on a more accurate sheet of power usage. The setup I get will definitely be determined by cost, especially after adding batteries and a good monitor/meter. Whatever I do I'll be sure to allow for panel addition down the road.

[Jack Mayer]

Hi,

 

 

Agreed, from what I've learned 2 6V GC2 batteries in series are about the minimum for a really usable system, and they can be had for not too much money.

 

 

We're in the initial stages of planning for our system and would really like to use LFP batteries, but are having a hard time finding a cost-effective and tested setup. Specially regarding charge controllers that will work well with them. Do you have your setup posted somewhere? Would love to learn from your experience.

 

Cheers,

--

Vall.

Check with Larry at Starlight Solar in Yuma.

[Ronbo]

Val I don't remember what brand of panels I have. My batteries are at 100% by 11 am every day. Mine are all parallel so I am not affected by a shadow if dirt. Recently we had tree and bird drippings all,over the roof. All but one panel was totally covered. I was still able to charge system by 11. It was so bad I bought a pressure washer to clean it all off. My point about larger is better was that he only has a 23 ft rv. He doesn't have a lot of real estate. A 200 watt panel is not much larger than a 120 watt and by going larger capacity, he could add another one down the line without having to replace the current panel. I love discussing solar systems and am becoming educated on LiFe batteries now. I will be spending a little bit of time with an engineer discussing some of my ideas in a couple weeks.

[Daveh]

Val as far as charge controller and inverter/charger for lithium the key is to look for one that allows the user to input the settings.

[Yarome]

The setup I get will definitely be determined by cost.

 

If it's kosher to ask.. what type of budget did you have in mind? It might help us make price appropriate suggestions.

[A_K_Chesnut]

 

If it's kosher to ask.. what type of budget did you have in mind? It might help us make price appropriate suggestions.

Certainly! I need to keep the battery and solar setup under $2k. Ideally I'd like to spend $1k or so with the ability to add more panels down the road.

[bruce t]

Size doesn't matter when it comes to panels. Well it does but it's not critical. Not all panels are created equal. We had Uni-solar bi directional/parallel units and they worked fine under trees etc.

 

regards

[Yarome]

Certainly! I need to keep the battery and solar setup under $2k. Ideally I'd like to spend $1k or so with the ability to add more panels down the road.

 

You're right on track and can put together a nice little system for under 2k. Just some ballparks:

 

Trimetric meter 150

Battery/ies 150-180 :(Costco/Sam's) Trojan class would be more in the 270-300 range.

Controller 90-350 :Depends on PWM, MPPT, and amp output.

Display 70-190 :Depends on controller.

Shunt 35-50

Temp sensor 25-40 :Optional but highly recommend it if your controller is capable of temp compensation.

Misc hardware/wiring/fuses/switches/etc. 200-300

 

Panel x2 300-450

 

You'll note that laying the core components is where the majority of your money goes. Adding additional panels is really not all that costly. Ie., another 300-450 and your capacity is doubled with no additional equipment required. Even at the "high end" it should still put you well shy of 2k.

 

As a side note it wouldn't be a bad idea to go ahead with the battery meter now. It would help you tremendously in your energy audit since you can simply turn on a device and get actual consumption readings immediately.

[VallAndMo]

Hi Ron and Dave,

 

Val I don't remember what brand of panels I have. My batteries are at 100% by 11 am every day. Mine are all parallel so I am not affected by a shadow if dirt. Recently we had tree and bird drippings all,over the roof. All but one panel was totally covered. I was still able to charge system by 11. It was so bad I bought a pressure washer to clean it all off. My point about larger is better was that he only has a 23 ft rv. He doesn't have a lot of real estate. A 200 watt panel is not much larger than a 120 watt and by going larger capacity, he could add another one down the line without having to replace the current panel. I love discussing solar systems and am becoming educated on LiFe batteries now. I will be spending a little bit of time with an engineer discussing some of my ideas in a couple weeks.

 

Thanks for the explanations! If you can, please keep us posted on what you learn from the engineer.

 

 

Val as far as charge controller and inverter/charger for lithium the key is to look for one that allows the user to input the settings.

 

I noticed but it's really difficult to determine that just from their descriptions and even manuals (when those area available)... :-/

 

Cheers,

--

Vall.

[Ronbo]

I don't think you need an inverter/charger. Get a smaller inverter, about 1000 watt. Get a solar charge controller and only use solar to charge the batteries. If they get too low you can use the converter or stand alone charger to top off the batteries.

[A_K_Chesnut]

I don't think you need an inverter/charger. Get a smaller inverter, about 1000 watt. Get a solar charge controller and only use solar to charge the batteries. If they get too low you can use the converter or stand alone charger to top off the batteries.

Confused. I agree an inverter is not something we are going to invest in at this point. Can always add later. But then you say to get a 1k watt inverter?

[Ronbo]

Here is an example and there are cheaper ones. http://www.theinverterstore.com/1500-watt-pure-sine-inverter.html

[A_K_Chesnut]

I think for now we're going to hold off on an inverter and stick to 12v stuff plus adding a charging panel from the battery (via a fuse block). The only thing I have that would really require an inverter is my laptop which I won't need to charge often. An inverter is something we can always add later.

[Ronbo]

You can add a couple 12 volt recepticle said and use the smaller 150 watt inverters.

[bruce t]

For every solar user there is a different setup and requirement. Start off simple and let it grow as you figure it out. BUT be careful not to waste money on items that you MAY have to replace later on.

 

regards

[A_K_Chesnut]

Yes I agree. I think a too small inverter could definitely be one of those things. Will wait to see what we need down the road.

[Jack Mayer]

If you are only charging your laptop with 120 volt power and do not need it for anything else then you can start without an inverter. Ron was referring to an inverter/charger - where the inverter and high quality battery charger are combined into one large unit. I agree, you do not need this, at least at this point. And probably never, from the way you describe your usage.

 

What I would do would be to run a heavy 12 volt line to a central point in your rig (lets say a #2 cable). The build a charging and 12-volt loadcenter around that, for your power needs. Then use a 12-volt adapter (car adapter) to charge your laptop. Add a USB charging center to charge your other items. Later, if needed you can top this 12 volt loadcenter for a SMALL inverter. Not sure what you would use the inverter for, though.