100 amp breaker / disconnect

[microage97]

Hello all - What can I use for a classic 150 charge controller disconnect? I am pushing about 90-ish amps to the bank. 12- 245w 24v panels - 12 gc2 bats - 3 parallel strings. I have a bbe with only one breaker in it. Thanks!

[Westbranch]

Uh, can you flesh that description a bit more...  a full description of  string output,  the Vmp, Voc, Imp etc, Epanel? Battery config ... what the string calculator recommended...

[microage97]

Yes I have 4 strings of panels, each string is composed of 3 panels in series. The strings come into a midnite combiner and then to the classic and then to the bank. The bank is composed of 6 volt golf cart batts wired in series for 24v a string with 3 stings paralleled to give me 696 ah.

[Westbranch]

OK so you have about 735 W per string of 3 and 2940W total.

Each string of 3 will be outputting ~8.19 (8.2) A    4Strings = ~32.8A
Each string of 3 is outputting ~89.7Vmp                4 Strings =~ 89.7V

You should be using an Epanel as it has both breakers needed for the controller, 1 for the input and 1 for the output  to the bank...

[microage97]

ya that would have been nice, but I am out here in the middle of the ocean and availability ect are very lacking some times. ;-( I  have breakers for the input side. What can I go with for the classic to the bank side?

[Westbranch]

do you have access to Square D or other major brands of electrical supplies?

[Vic]

Hello all -    ...    I have a bbe with only one breaker in it. Thanks!

Sure do not know what is a " bbe " .   Doubt that it is a MN Big Baby (box) ...  What is a "  bbe  "?

MidNite offers several large circuit breaker families.  The MNEPV series has a 100 Amp breaker available.  It occupies two DIN rail positions:
http://www.solar-electric.com/installation-parts-and-equipment/midnite/cipr1/stfubr1/misomn150vdc.html

There are MNEDC breakers -- Panel Mount types.  These are also offered at 100 Amp maximum ratings:
http://www.solar-electric.com/installation-parts-and-equipment/midnite/cipr1/stfubr1/pamodccibr.html

The MNEPV and MNEDC breakers are rated for continuous rated current flow without tripping.

Then there are the larger Inverter type breakers,  with ratings starting at 125 Ams,  IIRC:
http://www.solar-electric.com/installation-parts-and-equipment/midnite/cipr1/high-amperage-inverter-breakers/mnedc125.html

You will want a quality breaker that is rated for DC current.  AND,  you will want to make certain that the cables that connect the Classic output to the breaker and the battery connections are rated for the maximum current that will be flowing in them.

FWIW,   Good Luck,  Vic

[microage97]

do you have access to Square D or other major brands of electrical supplies?

Yes I do. Thanks!

[microage97]

Hello all -    ...    I have a bbe with only one breaker in it. Thanks!

Sure do not know what is a " bbe " .   Doubt that it is a MN Big Baby (box) ...  What is a "  bbe  "?

MidNite offers several large circuit breaker families.  The MNEPV series has a 100 Amp breaker available.  It occupies two DIN rail positions:
http://www.solar-electric.com/installation-parts-and-equipment/midnite/cipr1/stfubr1/misomn150vdc.html

There are MNEDC breakers -- Panel Mount types.  These are also offered at 100 Amp maximum ratings:
http://www.solar-electric.com/installation-parts-and-equipment/midnite/cipr1/stfubr1/pamodccibr.html

The MNEPV and MNEDC breakers are rated for continuous rated current flow without tripping.

Then there are the larger Inverter type breakers,  with ratings starting at 125 Ams,  IIRC:
http://www.solar-electric.com/installation-parts-and-equipment/midnite/cipr1/high-amperage-inverter-breakers/mnedc125.html

You will want a quality breaker that is rated for DC current.  AND,  you will want to make certain that the cables that connect the Classic output to the breaker and the battery connections are rated for the maximum current that will be flowing in them.

FWIW,   Good Luck,  Vic

Thanks Vic! yes I meant the MN Baby box but I see it is only rated for 63 amp breakers.

[Vic]

Hi microage97,

Thanks for the Baby Box clarification.  Yep,  the BB is very small.  There is very little room to route cables in the box.  It is good that you have looked at the specs on it.   The Big Baby has more room,  and believe that it will accommodate larger conduit fittings,   if you need those.

The MidNite DC Quad box is nice,   as it will use the Panel Mount breakers -- MNEDCs.   These breakers mount form the front with two screws,  and are very solid,  and the largest breaker is 100 amps,  but still occupies only breaker position.   The MNEDC breakers have studs for connections,  so one must (generally)  crimp lugs for connections.  The DIN - rail breakers can be a bit more convenient,  as they have clamping terminals,  so no lugs are required.

The MNEPV breakers appear to have a higher current interrupt ratings than the MNEDCs,  so there are tradeoffs,  especially for your large CC to battery breaker.

All FWIW,  from the Center Of Nowhere in CA.   Good Luck,   Vic

[microage97]

Thanks Vic! I will look into my options. Oh I am on the Big Island in lower puna.....amazon prime take 7 - 10 days.... sigh

[Westbranch]

the reason I asked about Square D is that their QO breakers are DC rated to 48Volts, and others  above that, http://www.schneider-electric.com/products/ca/en/4200-power-circuit-breakers-switches/4280-direct-current-dc-rated-circuit-breakers/7218-dual-rated-ac-dc-circuit-breakers/
so you can use a small distr. box for the CC to battery disconnect, and make a combiner to meet the specs for your PV output.  If you do it right it might all fit in one box, depending on what you can get locally...

[Vic]

Hi Wb,

Thought that this was what you mentioned before.  BUT,  the specs for DC operation stop at a 70 Amp rating.

In general,  QO  breakers are DC rated to 48.00 Volts as I read it.   So they would not be appropriate for systems that have a 48 V nominal battery voltage,  as an aside (IMO).

microage97's system voltage is 24 V,  so that part would be fine with QO breakers,  but believe that a 100A rated breaker would best suit his requirements.

Did not look at your link,  today,  but in the past,  70 A was the last stop on that bus,  and at that,  bet that a 70 amp breaker would be a bit hard to find.   And,  generally  the SQ-D QOs are about the same price as the MN,  REAL DC breakers +/--  a bit.

All FWIW,  Opinions  from   Vic

[Vic]

And Wb,

That Link that you provided is Broken (for me) -- it is often very hard to link to Schneider.

Here is Grainger's Link to the SQ-D  QO breakers:
http://www.grainger.com/ec/pdf/QO-QOB-Miniature-Breakers-Catalog-2008.pdf

FWIW,  so on,   Vic

[Westbranch]

Ya I just tried it too  I searched forr " square d qo breakers dc rating'  and got the link straight off...??

took me to the page :

: Home > Products > Power Circuit breakers & Switches > Direct Current (dc-rated) Circuit Breakers > Dual Rated AC/DC Circuit Breakers

the page has  a new statement that surprised me

QO/QOB â€" Available with dc voltage ratings from 48 Vdc to 125 Vdc.
    QOU â€" Available with dc voltage ratings from 48 Vdc to 125 Vdc   

I only included the Sq D  as he said he was isolated and in the middle of the Pacifc Ocean