Newbie Fuse and Controller question...

[bproulx12]

Purchased Renogy 4 X 100W Monocrystalline panels and MPPT Controller which I will place onto of my RV rough, it came with 10 awg MP4 solar cable, do not know if I will go with a larger wire size, 8 or 6 maybe.

http://www.renogy-store.com/400W-Premium-Kit-p/kit-premium400d.htm

I inadvertently got a fancy combiner box off ebay which is fused. it holds 4 10x38 fuses as pictured

http://www.ebay.com/itm/131232900049?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I plan to wire up the panels in parallel, if I understand it, so if one panel gets shaded it does not affect the entire system.

The panel specifications are:

Maximum Powe rat STC (Pmax) 100 W
Optimum Operating Voltage (Vmp) 18.9 V
Optimum Operating Current (Imp) 5.29A
Open-Circuit Voltage (Voc) 22.5 V
Short-Circuit Current (Isc) 5.75 A
Maximum System Voltage 600VDC

Question #1. What amp and VDC fuse would I use? my best guess 10 amp 600VDC?

Question #2. Since I would be only running 400 Watts at the moment, would a MPPT Controller be overkill? I was thinking of going to a Tristar 45

Question #3. From the Controller to the battery using probably 6 or 4 awg wire, would a 60 amp fuse be appropriate?

Thanks

[inetdog]

Purchased Renogy 4 X 100W Monocrystalline panels and MPPT Controller which I will place onto of my RV rough, it came with 10 awg MP4 solar cable, do not know if I will go with a larger wire size, 8 or 6 maybe.

http://www.renogy-store.com/400W-Premium-Kit-p/kit-premium400d.htm

I inadvertently got a fancy combiner box off ebay which is fused. it holds 4 10x38 fuses as pictured

http://www.ebay.com/itm/131232900049?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I plan to wire up the panels in parallel, if I understand it, so if one panel gets shaded it does not affect the entire system.

The panel specifications are:

Maximum Powe rat STC (Pmax) 100 W
Optimum Operating Voltage (Vmp) 18.9 V
Optimum Operating Current (Imp) 5.29A
Open-Circuit Voltage (Voc) 22.5 V
Short-Circuit Current (Isc) 5.75 A
Maximum System Voltage 600VDC

Question #1. What amp and VDC fuse would I use? my best guess 10 amp 600VDC?

Question #2. Since I would be only running 400 Watts at the moment, would a MPPT Controller be overkill? I was thinking of going to a Tristar 45

Question #3. From the Controller to the battery using probably 6 or 4 awg wire, would a 60 amp fuse be appropriate?

Thanks

If you put the four panels in series, you will need a fuse that can handle 100V (4x22.5 plus some). The 600V specification is basically how high off ground you can float one of the panels. I.E. the maximum string voltage, which would take about 20 of those panels in series. If you keep them in parallel, you will need at least a 30V fuse. And make sure that it is rated for 30V DC, not just 30+ VAC.

An MPPT controller would not be overkill, but you need to compare the added cost of that CC against the 33% of the panel power that you would lose if you go with just
a PWM CC.

The maximum output you will get from a PWM CC will be 5.3 x 4 = 21.2A. You should get at least a 20A CC.
The maximum output you will get from an MPPT CC will be 400/12 = 33A. You should get at least a 30A CC.

You have not mentioned what size and type battery you will use, and that will also determine how large a CC you can use in the first place.
If you feed 30A to the battery and it is FLA, you will need about 240AH of 12V battery.
With a PWM CC you will need at least 160AH.

If you use an AGM battery bank you could use a smaller battery, but the extra cost and reduced life of AGM will probably not be a good deal for you.

PS: Welcome to Solar Panel Talk!

[Sunking]

If you put the four panels in series, you will need a fuse that can handle 100V (4x22.5 plus some).

If he puts 4 panels in series there is no requirement or need for an OCPD.

690.9 Overcurrent Protection

(A) Circuits and Equipment. Photovoltaic source circuit,
photovoltaic output circuit, inverter output circuit, and storage
battery circuit conductors and equipment shall be protected
in accordance with the requirements of Article 240.
Circuits connected to more than one electrical source shall
have overcurrent devices located so as to provide overcurrent
protection from all sources.


Exception: An overcurrent device shall not be required for
PV modules or PV source circuit conductors sized in accordance
with 690.8(B) where one of the following applies:


(a) There are no external sources such as parallel-connected
source circuits, batteries, or backfeed from inverters.


(b) The short-circuit currents from all sources do not exceed
the ampacity of the conductors or the maximum
overcurrent protective device size specified on the PV
module nameplate.

[inetdog]

Good point, Dereck!

[Mike90250]

The OP's question was about putting the panels in parallel to reduce /solve shade issues.

So in parallel, the 18V panels will NEED fuses (4 of them) in the Combiner Box. A 10A fuse is sort of high, I'd go with a 7 or an 8 amp, depending what you can get easily. Some panels have a series fuse value in the data sticker.

at 18.9V, a MPPT controller will have minimal benefit, BUT, if you plan on expanding later, maybe buying one now saves you having a spare $100 PWM controller sitting in a crate next year.

Controller to battery will only be about 20amps, so a 30A fuse would work. you will seldom see max output from an array.
Just be sure you use wire that is safe at 30 amps, at least 10 gauge, 8ga would be better.

[bproulx12]

You have not mentioned what size and type battery you will use, and that will also determine how large a CC you can use in the first place.
If you feed 30A to the battery and it is FLA, you will need about 240AH of 12V battery.
With a PWM CC you will need at least 160AH.

I will be using 4 t105 for starters.

[inetdog]

I will be using 4 t105 for starters.

Even as a starter, putting four 6V batteries in series-parallel to make a 12V system is a bad idea, although two strings of two batteries in parallel can be made to work with some care and monitoring. Adding more 12V strings to increase the storage capacity in the future is a worse idea.
Depending on what your planned loads are, you would probably be better off selecting different (lower voltage) batteries or putting them in a simple series connection to make a 24V system.