2200 watts of solar on the roof?

luthj

Engineer In Residence
I would pick the panels which allow you to fit the maximum amount of solar, within reason at least. Its possible to use two different panel sizes/types. You may need more than one solar controller anyways. Or if you go with more than one panel per string, you would just make the strings symmetrical.

As @dreadlocks indicates, for $/cycle, its hard to beat flooded GC2 batteries in the lead category. Cheap, easy to source, very reliable.

You need to sit down and work out your power needs. Do an energy budget to determine how much storage you need. With a 2kw array, you will probably want at least 12kw-hr of battery capacity (lead). Possibly more depending on your needs. That will give you about 6-8kw-hr of routinely usable capacity, which corresponds to about 6 hours of good sun. That leaves a little extra for the long absorb charge you will need a few times a week which lead needs to survive long term daily cycling.

If you don't need lots of power reserve: For example you only plan to run your high power loads during the day, and you don't need a big reserve for cloudy days. Then you could get buy with a smaller lithium pack. 3-6kw-hr for example.

It all depends on your usage case. In some situations its actually cheaper to go with a larger lithium pack, and actually reduce your total solar array size. Because the lithium packs can charge quickly and don't need long absorb times, they are effective at carrying short term peaks and maximizing solar harvest in between.
 

dreadlocks

Well-known member
yeah if your like me with alot of solar and a little bank, it charges so damn quick that a full long summer day of sun results in most of the captured energy being disposed of, that could be done w/lesser solar much more efficiently.

however my design philosophy was plan for the worst and hope for the best, it does awesome when I only get a little bit of sunlight, more than enough power for basics.. and when im basking in sun all day long then I can turn like everything on at once and not even think about it, its what afforded me to get stuff like a crockpot, ice maker and microwave.. and at his scale, possibly an air conditioner.. I'm looking at an electric dirt bike or something frivolous like that I can dump excess energy into when the sun gods are rewarding me w/a bounty of photons.

Nobody ever complained about having too much solar.. except perhaps whoever is incharge of the finances.
 

Alloy

Well-known member
One of the failings (but not Lithium) of FLA and AGM is the loooonnng (Bulk/Absorb/Float) charge cycle. A large solar array is advantageous to make sure the FLA/AGM batteries are brought into float (zero chemical reaction) at least twice a week.
 

67cj5

Man On a Mission
If your going to run 2200w on a 24v system then I would be adding between 600/1200Ah of batteries to collect all that wattage, Around a 1000Ah would be nice, But I would split the panels and the battery bank so if it one got to 50% I could then switch over to the other bank and let the first one charge, But if you have the space why not go bigger and go for around 2000Ah, A 6000w inverter @ 24v will pull about 234.37Ah so I would go for 2000Ah of battery power. (y)
 

Simons

Adventurer
The only real advantage to AGM’s over FLA’s is where you can mount them and the orientation. They come in a variety of dimensions and can be mounted in almost any orientation, and don’t need to be vented so you can put them anywhere inside if you like, which can be very helpful when designing in smaller spaces.
Considering your rig though, you likely have tons of exterior space between your frame rails (or along them) for mounting a whole whack of 6v FLA’s!


Sent from my iPad using Tapatalk
 

luthj

Engineer In Residence
If you don't understand the issues with large multi battery banks, it's probably best to educate yourself.
 

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dreadlocks

Well-known member
You can install a simple disconnect relay like a battery protect and have it drop loads with some capacity in reserve, then wire up an override switch and you always have backup power.. thats what I do.. I drop my loads at 20% SOC on my LFP, and the LVD drops everything at 5% SOC.. so if I over-ride my 20% drop out, I got about 15% in reserve, which is more than enough to keep the heat on at night.
 

67cj5

Man On a Mission
If you don't understand the issues with large multi battery banks, it's probably best to educate yourself.
I understand about equalizing large banks which is another problem which is why I said about running two banks,

Personally I don't see it as a problem, like all things they have to be maintained,

But that still does not answer my question.
 

67cj5

Man On a Mission
You can install a simple disconnect relay like a battery protect and have it drop loads with some capacity in reserve, then wire up an override switch and you always have backup power.. thats what I do.. I drop my loads at 20% SOC on my LFP, and the LVD drops everything at 5% SOC.. so if I over-ride my 20% drop out, I got about 15% in reserve, which is more than enough to keep the heat on at night.
Thanks for that, It does seem the better way to go,

I would rather do that that run just one system because if One system develops a fault then you still have power while you fix the other system.

Well done, (y)
 

luthj

Engineer In Residence
How about giving us a few pointers. A brief education ?
Its not like we are a bunch of electro-dipshitz who could never understand so dont bother offering an explaination for.
Your attempt at snark is noted. I think it's slightly ironic given how fond you are of doing the same.

I don't see any reason to regurgitate several thousand words that barely covers the basics. Feel free to do so if you like.

If the OP needs/wants specific questions answered that's a different matter.
 

67cj5

Man On a Mission
I have several systems that I am using and I am installing one or 2 SLA deep cycle battery/s ?

I have the Vans own AGM Starting battery with nothing added to is or being run from it,

I have a Tiny Lithium self contained box that runs 2 LED lights and can be used to charge small things like Phones etc,

And I have the 2 Dometic PLB-40's for running my small fridge or even the ARB when needed

The PLB's can be charged from either the foldup 120w solar panel or the Cigar socket or via a Generator or AC,

The little Lithium setup can be charged by AC or it's own Solar panel,

The Lead Acid Deep cycle batteries I can charged from Solar or the 38A AC Charger run from the generator,
 

rayra

Expedition Leader
yeah if your like me with alot of solar and a little bank, it charges so damn quick that a full long summer day of sun results in most of the captured energy being disposed of, that could be done w/lesser solar much more efficiently.

however my design philosophy was plan for the worst and hope for the best, it does awesome when I only get a little bit of sunlight, more than enough power for basics.. and when im basking in sun all day long then I can turn like everything on at once and not even think about it, its what afforded me to get stuff like a crockpot, ice maker and microwave.. and at his scale, possibly an air conditioner.. I'm looking at an electric dirt bike or something frivolous like that I can dump excess energy into when the sun gods are rewarding me w/a bounty of photons.

Nobody ever complained about having too much solar.. except perhaps whoever is incharge of the finances.
... and you can add battery capacity later as fund allow or better battery tech becomes affordable.
 
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