MX60 self-protection?

Discussion about the MX60 Charge Controller

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drstrip
Forum Guru
Posts: 111
Joined: Mon Jan 08, 2007 12:32 pm
My RE system: 18 x 160W BP3160 modules
2 x VFX3524
2 x MX 60
Mate/Hub/Trimetric
HUP SolarOne batteries SO-6-85-33/23 - 1690AH@24V http://www.hupsolarone.com/
Kohler 15RYG backup
Location: New Mexico - The land of enchantment and 76% of possible sunshine

MX60 self-protection?

Post by drstrip »

My system currently has 18 x 160W panels feeding into two MX60s. The controllers never come close to their rated output capacity. Now that panels cost about 15% of what they did when I built the system I'd like to either add new panels or completely replace the existing ones to better utilize the charging capacity. Is the MX60 smart enough to not blow itself up if the max power point would exceed it's output limits? Would it seek the the power point that reaches peak capacity, or would it seek the peak power point and burn itself out if the input capacity is too high?
Mike Curran
Forum Emperor
Posts: 1893
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof:
- 8 (2x4) Evergreen 180's into one FM80 (2007/2020 - replaced MX60)
- 6 (2×3) ALEO S79-300's into one FM80 (2017)
[***2 grid-tied GVFX3524's classic stacked for 120/240VAC (2007-2020)]
- 2 grid-tied VFXR3524A-01's series stacked, ***replaced GVFX's (2020)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy ES maximizers on each PV module.

Westinghouse Solar - Barn roof: (2012)
- 30 (2x15) 235W panels with Enphase M215 microinverters, grid-tied

Outback Skybox - Barn roof: (2019)
- 14 Talesun 275W in series (DC array input to SB inverter/charger)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: MX60 self-protection?

Post by Mike Curran »

I saved a Q&A article from Home Power issue #104, December 2004-January 2005 for my own MX60 system commissioned in 2007. In it, Christopher Freitas, an OB power rep, stated:
The MX60 is rated at 60A continuous. There is a setting for continuous output as, which can be set as high as 70A without any problems. This is running the equipment above its listing, which may not be acceptable to your inspector.

The MX60 is also rated for 100% continuous duty, as are the OB OBDC60 and OBDC70 circuit breakers. The adjustable current limit is provided to prevent tripping the circuit breakers when the PV array is producing more than normal - such as during an edge of cloud event, or when snow reflection and cold temperatures are present.

The maximum PV array size is primarily dependent on the battery bank voltage, as follows:
- 48VDC×60A= 2880watts DC
- 48VDC×70A= 3360watts DC

The same calculations apply for a 24 volt system.

Our recommendations for maximum nameplate wattage rating is as follows:
- Colder climates - 48VDC: 3,000 watts DC
- 24 VDC: 1,500 watts DC
- Warmer locations - 48VDC: 3,500 watts DC
- 24VDC: 1,750 watts DC
There's more, but I think the key is having properly rated circuit breakers between the MX60 and your battery bank. This will prevent overcurrent that might damage your MX60s.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221
drstrip
Forum Guru
Posts: 111
Joined: Mon Jan 08, 2007 12:32 pm
My RE system: 18 x 160W BP3160 modules
2 x VFX3524
2 x MX 60
Mate/Hub/Trimetric
HUP SolarOne batteries SO-6-85-33/23 - 1690AH@24V http://www.hupsolarone.com/
Kohler 15RYG backup
Location: New Mexico - The land of enchantment and 76% of possible sunshine

Re: MX60 self-protection?

Post by drstrip »

As a followup -
do the newer charge controllers (or any from non-Outback vendors) limit the output current regardless of the peak power point?
SandyP
Forum Guru
Posts: 433
Joined: Tue Jun 21, 2011 4:44 am
My RE system: 8 x 190W 24V Suntech panels (4 strings of 2) July 2011
4 x 325W 24V Suntech panels (2 strings of 2) added Sept2018
Mate2
Outback FM60 MPPT (max output lowered to 55amps)
12 x 2V Hoppecke GEL 612 Ah C24 - 24V System
Outback VFX3024 Inverter/Charger
Victron BMV-602s
Honda 5.5kW Genset
Location: Victoria, Australia

Re: MX60 self-protection?

Post by SandyP »

drstrip wrote: Tue Nov 17, 2020 8:19 pm As a followup -
do the newer charge controllers (or any from non-Outback vendors) limit the output current regardless of the peak power point?
With the FM charge controllers (and probably the MX) you can set the desired maximum current output of the charge controller below the maximum rated output for the unit however (as stated in the previous post) "sudden" effects such as cloud edge etc. does briefly result in the output exceeding the manually entered limit.
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