Wednesday, November 19, 2014

Updating our Solar Power System - Modified Sine Wave and 12 Volts to Pure Sine Wave and 24 Volts

And now the circle is complete.  I have upgraded every single component in our original solar power system - so I have a second system in parts that I will likely try to put together on my future workshop.

As exciting as it is to join the big(ger) boys club with the new system, I did wake up this morning to realizing that the inverter had shut off our power due to low batteries - doubly annoying because yesterday was actually a pretty sunny day!

I will be the apologist for the batteries I guess...  It was sunny, but there was a constant haze that really prevented the batteries from quite getting to absorption.  We also ran the washing machine for a couple of loads, as well as the heating cable in the well, and the well pump for a good twenty minutes to half an hour (at about 30 amps).

Still, I think they should easily be able to handle the loads we are throwing at them overnight.  I could show you my math, but I don't think you're interested.

In any case, this was all an upgrade from the older, modified sine wave inverter courtesy of a Canadian Tire sale about three or four years ago.  I sure cannot complain about the use I got out of that one.  It's still going strong.  My only issues with it were the way it cut out at 15.5 volts (easily reached in winter, or while equalizing) and the low voltage/current alarm that was audible, and sounded every time our fridge compressor kicked in.  (Switching to 4/0 cables from the battery to the inverter mostly solved this problem.)

First I had to remove all the old wiring and setup.

Unfortunately, the inverter I ordered was delayed a week or two, so I temporarily wired back in our original one until it came.

With the old inverter, it had a few cheap built in circuit breakers, and outlets on the front.  I didn't bother wiring in a panel box or anything complicated like that.  I simply put a male end on each circuit and plugged that into the front of the inverter.

With the new setup, I had a distribution panel with three circuit breakers.  I wanted to include an outlet on the input side, so I could get power directly from the generator if the inverter ever failed.  I also wanted an outlet on one of the circuits so that I could plug in our router and modem close to where the lines came into the house from outside.

Finally the new inverter arrived.  I booked off the rest of the day to get it installed.  I screwed a pair of dollar store cookie sheets to the wall, as the inverter dictated that it shouldn't be directly mounted to a flammable surface.

With significant effort, Donna marked where the first few screws should go while I tried to hold the inverter up to the wall.  It weighs quite a bit actually.  Be prepared!



Finally I had it mounted, wired up with 4/0 cables in from the batteries and 10/2 out to my distribution panel.  I switched off everything, put on a single, Michael Jacksonesque glove, and mounted the fuse...

video
I didn't see the spark myself.  Donna managed to capture it though.

I was delighted to see a display on the remote indicating all was well.
Next I actually turned on the inverter, and then one breaker at a time.  The fridge started up as soon as it was in the circuit, and I was feeling great!

A few observations...  The new inverter is much louder than the cheap one was.  It hums constantly, sounding like a fridge or transformer box itself.  We're getting use to that.  I will hopefully someday soundproof it somewhat.

I no longer have a shunt, so we have to observe things based on the inverter's display of volts and amps out, versus the charge controller which shows volts and amps in from the panels.  It's something we'll be fine with I'm sure - just not as nice as the old display which simply showed whether we had a surplus or deficit of amps.  Someday in the future perhaps a new shunt will be in the budget.  But not for now.

The new inverter/charger allows us to charge the batteries a bit faster - it can push the amps and voltage higher than our old Iota.  It seems that the generator maxes out at pumping a little over 30 amps at 24 volts.  I think upgrading the wiring between the generator and the cabin would help with that.  It will be a project for the spring, as I am not thrilled with the notion of going under the sauna anytime soon.

Now if only I could find a way to make the batteries last through the night!

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