Advice Needed - Breaker specifications

[mcsarge]

Hi,

Our current system replaced an old solar system using a SolarBoost 50 and 3 sets of panels in 3 set of pairs. We replaced them with 6 panels and a Midnite Classic 150, breakers, WhizBangJr, etc. I have repurposed the old system using a single set of 2 panels and the old Solar Controller. I have mounted the panels in such a way that they are under the eaves of the cabin protected from snowfall but still gets some sun a few hours each day. This setup helps keep the batter pack charged even when the main panels are covered in snow.

My question is the following, what breakers should be used between the panel and the Solar Controller? Here is the setup:
2 x Sharp NE-80EJEA 80watt (in series) --[ BREAKER?]---> SolarBoost 50 MPPT ---->[Large DC Breaker] ---> WBJr---> 24V Battery Pack

In the original system there was no breaker between the panels and the Solar Controller, that is wrong and I would like to fix that. Can anyone tell me the specifics of the breaker I need?

- Matt

[Vic]

Hi Matt,

In the following Data Sheet,   the max Fuse Size is shown as 10 A:
https://content.abt.com/documents/24117/NE80EJEA.pdf

So,  an MNEPV-10 Amp breaker should be OK.   All MN DC breakers,   have been rated for continuous DC current at the "handle" rating.   This is a DIN Rail-mount breaker.  These breakers can fit into a MN Baby Box,  or the MN Big Baby box,   both are Din breaker-compatible.
Breaker:
https://www.solar-electric.com/midnite-solar-mnepv-10-amps-circuit-breaker.html
Baby Boxes:
https://www.solar-electric.com/baby-box.html
https://www.solar-electric.com/misobigbabox.html

The MNEDC-10 breaker is a Panel Mount  --  1/4-20 studs on rear,  and mounts to panel with two front screws.
Breaker:
https://www.solar-electric.com/midnite-solar-150-volts-10-amps-dc-panel-mount-circuit-breaker.html

MN DCQUAD (a box that holds up to four MNEDC breakers):
https://www.solar-electric.com/mnedc-quad.html

EDIT:   It looks like you have been running strings of two PVs in series on your 24V FLA battery,  in the past.   And,  am unfamiliar with the Solar Boost CC,   but,   technically the string Vmp of two of those PVs may be a little bit low,  to reach a temp comped charge voltage,   depending upon just what you want that voltage to be,   and weather that CC has a temp sensor,   and so on   ...   FWIW.

Thanks for all of your work on DIY programming,  and questions (as well as to ALL of the other programmers and testers) !!...       73  Vic

[mcsarge]

Vic,

Thanks for the information!

The 2 panels in series do charge the batteries but not really well. It is temperature compensated but as you say, they may not have enough headroom to really charge much. Also they are old so even under the best conditions they would never come close to the rated watts (or the rated watts for our latitude). The original system was put in years ago but a guy of dubious knowledge.

I think a baby box and a breaker will work great. Thanks! I will make an order before Spring open up (if we ever allowed in Canada again).

Matt

Hi Matt,

In the following Data Sheet,   the max Fuse Size is shown as 10 A:
https://content.abt.com/documents/24117/NE80EJEA.pdf

So,  an MNEPV-10 Amp breaker should be OK.   All MN DC breakers,   have been rated for continuous DC current at the "handle" rating.   This is a DIN Rail-mount breaker.  These breakers can fit into a MN Baby Box,  or the MN Big Baby box,   both are Din breaker-compatible.
Breaker:
https://www.solar-electric.com/midnite-solar-mnepv-10-amps-circuit-breaker.html
Baby Boxes:
https://www.solar-electric.com/baby-box.html
https://www.solar-electric.com/misobigbabox.html

The MNEDC-10 breaker is a Panel Mount  --  1/4-20 studs on rear,  and mounts to panel with two front screws.
Breaker:
https://www.solar-electric.com/midnite-solar-150-volts-10-amps-dc-panel-mount-circuit-breaker.html

MN DCQUAD (a box that holds up to four MNEDC breakers):
https://www.solar-electric.com/mnedc-quad.html

EDIT:   It looks like you have been running strings of two PVs in series on your 24V FLA battery,  in the past.   And,  am unfamiliar with the Solar Boost CC,   but,   technically the string Vmp of two of those PVs may be a little bit low,  to reach a temp comped charge voltage,   depending upon just what you want that voltage to be,   and weather that CC has a temp sensor,   and so on   ...   FWIW.

Thanks for all of your work on DIY programming,  and questions (as well as to ALL of the other programmers and testers) !!...       73  Vic