From Solar off-grid to Solar (main)+ grid – From generator back-up to grid as back-up (ME-ARC)

mburellemburelle Registered Users Posts: 2
Hi, first time here. Hope this section is appropriate for my posting.

My set-up up to last week

3Kw of solar panels / Combiner box / Solar Charge controller EP solar 60A / 48v Battery bank (Crown  430 AH) / Magnum MS4448PAE inverter-charger / AGS module / Generator: onan 6500w propane.

 

Until  recently all was pretty well working.  Here in Quebec , Canada, November and December months are the worst of the year. You can’t count only on Solar because the days aren’t long enough and cloudy most of the time. Something to do with the Great Lakes until they freeze over).

So around this time of year the generator kicks in more frequently and go through a complete charge cycle when required. From Bulk to float with runtime of 3,5hr.

Now here is my issue….Earlier this year utility became available at our door step and we decided to take advantage of it.  Since we had already invested so much money in original set-up, only 4 years old, we wanted to continue to operate as usual but simply replace the Generator , as back-up , by Utility as back up. We are not interactive with the grid. All existing equipment is compatible with this to the exception of the ME-RC remote. Following info received from Magnum we bought the ME-ARC remote which can handle setting-up for the grid input.

Done everything as indicated. But the damn grid comes in for only sometimes 0.3hrs or 0.6hrs. Definitely not going in float. After some emails exchange with Magnum the rep latest comment was it is normal as the grid is used only to bring the battery to a certain voltage and then let the main solar system take care of the rest. Eeeeehhh, what? (not to mention some other error message but for later discussion)

Did I mentioned the solar can’t keep up, most of the time,  at this time of year anyway? And why the ME-ARC manual goes extensively about choosing the multistage charging and setting up the absorb time to 1.5-2hrs, etc…Why isn’t it working as the AGS/generator combo?

 

Did anybody experienced something alike? Can’t I get my charger do a full charge cycle  when needed?


Marco

3kw solar array (flat roof installed); Combiner box; Ep Solar 60A charge controller; 48v Battery bank (Crown 430ah); Magnum PAE4448 charger/inverter w/ME-ARC50 remote; and since November 2017: grid connected as back up instead of generator+ags.

Comments

  • EstragonEstragon Registered Users Posts: 1,545 ✭✭✭✭
    I don't know Magnum stuff, so can't help there.

    As a general proposition, the Magnum rep is right. You would normally want to use the generator to get to a point where available solar can finish charging batteries. I assume the inverter is dropping grid on transition to absorb, which occurs at a settable voltage. If you want to have grid charge more than it currently does, you may want to check the absorb voltage setting for the inverter. Setting the inverter absorb voltage higher, by (eg) 0.1v increments should result in the inverter continuing to draw grid power for longer, if my assumptions are correct.

    In absorb, there could be an issue of different readings or settings between the charge controller and the inverter. If the inverter thinks the voltage is good or high for absorb, but the charge controller thinks the voltage is low, the inverter will wait for the voltage to drop, while the controller does what it can to provide current. Sun comes out, pv increases voltage, inverter/charger sleeps, rinse, repeat.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mburellemburelle Registered Users Posts: 2
    Thanks Estragon. Will check the details over the week-end. Will  having only partial charging repetitively during couple of days  cause problem to the batteries? Isn't it better that they go full charge each time they need to? That was my understanding.
    3kw solar array (flat roof installed); Combiner box; Ep Solar 60A charge controller; 48v Battery bank (Crown 430ah); Magnum PAE4448 charger/inverter w/ME-ARC50 remote; and since November 2017: grid connected as back up instead of generator+ags.
  • EstragonEstragon Registered Users Posts: 1,545 ✭✭✭✭
    Leaving the batteries at low SOC (eg. 50%) for long periods (days to weeks) is definitely bad for LA batteries, especially if they're warm. As long as they get up to ~85% most days, and a full charge once or twice a week, they should be ok.

    Getting to "full" every day can actually be harder on the battery than just getting up to a reasonable but not quite full SOC. The last 5-10% of charging is relatively inefficient, with much of the current going to heat and gassing. It does need to be done regularly, but not necessarily daily.

    I set my controllers to skip the bulk/absorb for 2-4 days, so they go straight to float unless they've been drawn down enough to trigger a cycle on skip days.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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