which kit and bank configuration?

nyarelathodep · October 2014

Hey all, finally getting ready to order the system for my off grid house and looking at two possible choices, both somewhat similar for between 7-8k range. Any input into pros and cons between the two from the solar sages here would be great!
Both kits include everything but the bank and the conduit and wire from combiner box to the controller aparently.

The choice is mainly between the ez panel makes. One is the FlexPower 1 3524 (or 3648... which leads to my second question following the inverter choice), and the other is the Magnasine 4024 -or 48- with midnite solar 150 and the magnum remote.

The supplied panels are 8 245 watt canadian solar polys.

Any comments on the strengths and weaknesses of either? I don't forsee needing split phase but i suppose it could hurt. The total power requirements are pretty modest, 1200 daily watts , excluding 1/3hp submersible goulds in a shallow well (for which i have an 80 gallon pressure tank), and i wouldn't mind the ability to run some heat tape on my water pipe of possible (maybe with excess peak power).

The other question: my bank will be 8 215ah GCs (6v)... is it less than ideal to configure this for 48v? From what I've read, the 48v versions tend to have less issues overall? And are easier to expand and work with? With that array and those controllers, well the batteries be recharged at a desirable rate?

Cariboocoot · October 2014

Re: which kit and bank configuration?

Size of battery bank depends on amount of power needed. 48 Volt systems have some advantage over 24, but also some disadvantage.

http://forum.solar-electric.com/showthread.php?15989-Battery-System-Voltages-and-equivalent-power

215 Amp hours @ 48 Volts is roughly 5kW hours of stored power. So is 430 Amp hours @ 24 Volts. The difference is a single string or two parallel strings, and the current involved for a given amount of power.

Your 1960 Watt array would provide about 63 Amps @ 24 Volts or 32.5 @ 48 Volts. In either case well above the 10% median target. The 24 Volt system should have an 80 Amp controller whereas the 48 would only need a 60 Amp unit. In fact you could down-size the array to six 245 Watt panels and use a MidNite Kid 30 Amp controller on the 48 Volt system and still have enough power for 215 Amp hours.

If you power needs are really only 1200 Watt hours per day you would not need such a large battery bank. In fact 215 Amp hours @ 24 Volts would be enough to supply that and you'd only need half as many of those panels (or even smaller ones as you're at about 670 Watts minimum then) and the 30 Amp Kid controller.

In my opinion the Outback is a better inverter than the Magnum.

nyarelathodep · October 2014

Re: which kit and bank configuration?

Outstanding, 'Coot. That link explained a lot of what i wanted to know. I also did happen to find what looks line a good deal over at Renogy for an 1800w kit of 6 300w monos with the MS200 controller and combiner box, cables, and rack mounts... all for 3k delivered. Any thoughts on their panels/products in general? Seems like a pretty darn decent deal. I wanted to go with the OB over the magnum, but was having difficulty finding the vfx series prewired with the MS controller... If it were my intent to get this kit and then the prewired FP1, does the classic get along well with the OB set up if i swapped the fm 80 out and kept as a backup, or is there an easier/cheaper easy to do that?

Cariboocoot · October 2014

Re: which kit and bank configuration?

Several forum members have Renogy panels and are quite satisfied with them. I have no experience with their products myself.

The MidNite controllers work fine with Outback inverters. They do not 'communicate' with each other, but that really isn't necessary. (I have OB controller & inverter and they're not connected and mine is one of the best working systems you'd ever find.) MidNite will also sell you pre-wired E-panel (get the larger one) for connecting a VFX and a Classic. http://www.solar-electric.com/installation-parts-and-equipment/midnite/misoe/epaforouin.html

You do not need the Classic 200 unless your array Voc is likely to exceed 200 Volts in cold temps. Not really a good idea to configure high Voltage array unless you have long wiring distances to deal with.

nyarelathodep · October 2014

Re: which kit and bank configuration?

Is that to say that, aside from the expense, you can have too big a cc? I wasn't even considering one that big until i saw that deal, which doesn't seem to be offered with any of the MS smaller units. I wound think that the 150 would have more than been sufficient to cover any upgrades i would possibly do in the future. My total wire run is no greater than 30 feet, at any rate.

Cariboocoot · October 2014

Re: which kit and bank configuration?

nyarelathodep wrote: »

Is that to say that, aside from the expense, you can have too big a cc? I wasn't even considering one that big until i saw that deal, which doesn't seem to be offered with any of the MS smaller units. I wound think that the 150 would have more than been sufficient to cover any upgrades i would possibly do in the future. My total wire run is no greater than 30 feet, at any rate.

There's not really a difference in current capacity between the 150 and the 200: the numbers in this case relate to the maximum input Voltage. In fact the 200's current capacity is slightly less for a given system Voltage than the 150.

nyarelathodep · October 2014

Re: which kit and bank configuration?

Good to know then. So what model MS cc would you choose for such an array, which could handle an eventual upgrade of a few more panels should I ever find I need them? Assuming 24v bank.

Cariboocoot · October 2014

Re: which kit and bank configuration?

nyarelathodep wrote: »

Good to know then. So what model MS cc would you choose for such an array, which could handle an eventual upgrade of a few more panels should I ever find I need them?

That's a pretty broad range of possibles.

The full eight 245 Watt panels on a 48 Volt system would be about 31 Amps and could be handled by a Kid. On a 24 Volt system it would be around 62 Amps and you'd need at least an Outback FM60 or MidNite Classic 150.

How far up the scale will you go?
The Classic 150 on a 48 Volt system can handle 83 Amps which would be a fairly large battery bank (like 19kW hours stored power) and quite a big array: 5175 Watts.

You have to know how much expansion is planned before you can pick equipment that will work with the expansion. Settling on a system Voltage (so you don't have to change the inverter) is a good start. Then you can increase the available Amp hours by adding more panel and changing the battery bank fairly easily. Just beware of going with multiple parallel battery strings. Getting into sizes that require multiple parallel charge controllers offers challenges too, but you can run two Kids without any trouble and several Classics; MidNite controllers parallel better than any other brand. They also have the WhizBang Jr. shunt monitor which saves on having a separate battery monitor and can give you more accurate control of charging.

nyarelathodep · October 2014

Re: which kit and bank configuration?

I believe that answers my question, coot. The 150 for the 24v...i don't forsee going above 2.5 to 3kw range in any event. I believe four batteries at 215ah 24v will cover my needs fairly well, but having the option to double that is a desirable one.

which kit and bank configuration?

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