[RE-wrenches] PWM Controllers in parallel

[Dan Fink]

Andrew - I've had no trouble running multiple Trace C-series PWM
controllers in parallel in the distant past. You just have to carefully
adjust (with a multimeter) the bulk/absorb/float/EQ pots of both units so
they don't interfere with each other and pull each other into the wrong
mode for current sun and battery SOC conditions. One should have all
setpoints slightly lower than the other so the first C60 gracefully bows
out of each mode into the next, and the second C60 follows a few minutes
later and does the same.

We have even added a third C60 set by the jumpers to Diversion mode for a
wind turbine, and again just a matter of the voltage/mode setpoint pots.

These are not fancy digital setpoints on a display screen, so some trial
and error on your part will be involved getting all the C60s to play nice,
but it's very do-able and back in the pre-MPPT and pre-Cat5 data cable days
this was the only way to go for larger PV systems at 12 or 24 volts nominal
battery bank. And with some recent experiences with fancy digital MPPT
charge setpoints...the internal voltage accuracy on some recent fancy MPPT
equipment I've dealt with has been abysmal.

Your tiny screwdriver and Fluke 87 won't let you down with the legacy
C-series gear. To avoid multiple truck rolls, I advise adjusting the
settings on a sunny day, starting with a 100% SOC battery bank, so you can
turn big loads and PV input on and off to bring everything down to bulk,
then play with absorb and float setpoints as SOC rises.

Dan Fink
Owner, Buckville Energy Consulting LLC
IREC Certified Instructor for PV and Small Wind Installation
NABCEP Certified PV System Inspector
NABCEP PV Associate
d <dan.fink at greendustrialtraining.com>anbob88 at gmail.com
970-672-4342




On Tue, May 7, 2024 at 10:25 AM Andrew Perkins via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Hello Wrenches,
>                     I have a client who has a large 2000 watt 12v array
> that he said used to be hooked into an internal solar charger on his old
> trace. Never seen a trace with one of those in it but he claims it could do
> 200a. This internal charger has now died and needs a replacement. He is
> refusing to rewire his panels into a new configuration and their aren't
> many options for him out there. I did get him a Coleman Aire 400a Charge
> controller but it is more of a load controller and wants to be able to
> properly absorb is batteries off the sun. He currently has a c60 running
> only part of the array and now he is asking about running another c60 in
> parallel. Not quite sure if this would work or not but my gut feeling says
> no and there will be problems.
>
> If anyone knows of any controllers that would fit that or if running those
> in parallel works your advice would be greatly appreciated.
>
> Andrew Perkins
>
> Greenwired
>
> P: 707-923-2001 ext. 100
>
> 1150 #1 Evergreen Rd
>
> Redway, CA 95560
> www.greenwired.com
>
>
>
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