Battery Charging With Outback System

 

Hi.

I have an Outback 2-inverter (VFX3648) system connected in what I think they
call the Outback Series configuration along with the autotransformer (X240)
and charge controller (MX60).  I don't have any solar panels yet.  I am
charging a bank of twenty-four 225 Ah 6 volt batteries configured for 48
volts.  The problem I am having is that if I want to run a big load (well
pump, washing machine etc.) I need to manually turn off battery charging or
the inverters will drop the AC-In connection and my well pump, which has a
bunch of protection circuits, kept turning off and on (I stopped it rather
quickly).  My cheap Chinese 5500 watt generator got toasted when I had the
charging rates set to about 19 aac on each port: I turned it off because it
sounded like it was struggling and I failed to disconnect it first.  It
flipped both breakers when I shut it down and apparently fried the diodes.
I am now using my old Honda-powered/Italian 5000 watt genset but I reduced
the charge rate to 15 aac on each port.  The "meter" shows about 2300 watts
but it sure seems like a lot more than that.  I think I need a big, fat
ammeter connected to the batteries because I cannot determine anything for
certain with the info from the Outback system.  Also, if I have a small
generator (2000 watts) connected the output voltage drops quite a bit below
what the generator would normally produce if not connected to the inverters.
Consequently there is very little power available when the generator is on
and such things as a microwave oven won't really work at all and clocks and
fans run slow.  With whatever generator is connected I am restricted to the
output of the generator minus whatever is getting sucked up by the Outback
system.  So, my question is:

    Why is it better to use transfer switches to switch to generator power
instead of simply using one of the battery chargers to charge the batteries
and continue running everything from the inverters?  I would have 7200 watts
available, the wave output would (should) be a consistant, good quality sine
wave, my appliances would all run normally, and my clocks would keep the
right time.  I would not have to go push a bunch of buttons every time I
want to run a compressor or well pump etc.

    If I decide it would be better to charge the batteries directly and keep
the inverters online then what would be the best way to achieve this?  It
seems that I already have three 3-stage chargers including the MX60 charge
controller.  Anyone know if there is a way to bypass the transfer switches?
Also, since the MX60 can handle up to 141 VDC input I was thinking it might
not be too difficult to build a power supply by running the AC output from a
generator through a full-wave bridge rectifier along with a smoothing
capacitor but as yet I don't know if the MX60 can be set to a lower charging
rate (they gave me a LOT of stuff to read) and I don't want to overload any
generators or ruin the charge controller.  They discuss solar panels as the
*only* DC input for the controller but as long as the DC is faily pure why
would it care?  Or should I buy another 48 volt battery charger?  Any
recommendations?

    BTW I tried emailing Outback twice and got no response and I'm waiting
to be blessed with access to their forums.  They don't seem to have a
toll-free number.  And yet I've read many times that their customer support
is far superior to Trace/Xantrex.  What's the best way to get ahold of them?

Thanks.

 

On Fri, 18 May 2007 09:13:33 -0700, "Ulysses"


Most pump protection devices in that size range have a calibration
routine that may need to be reset to match your setup. They have to be
pretty sensitive in order to catch the current drop when the pump runs
dry, so the calibration routine sometimes has to be repeated to get it
right. For example - if the well is such that it will draw down, then
the calibration is best done when the water level is low. Also,
ideally you'd have the pump on a timer so that it comes on when it's
best for the system, as opposed to just letting it cycle whenever the
tank level drops.


You should add a proper battery monitor on that setup. If you have the
Outback panel the shunt is probably already in there. I've tried both
the Emeter (Link 10 now) and the TriMetric. I prefer the Emeter by
quite a bit.


Sounds like it might be overloaded. You could set inverter battery
charging to zero and see if that changes things.


Once the inverters sync to the generator, they pass the generator
power straight through to the loads, and use whatever's left over (if
any) to charge the batteries. As you add loads, the charger must dial
back to compensate. Meanwhile the loads are seeing whatever surges and
fluctuations are caused by any lag in the inverter's sensing and
generator's governor. Partly because of that, I switched to DC
charging so that the inverters would always be in invert mode. I lost
the nice charge control functionality, but I never finish charge with
a generator anyway so the only control I need is a time limit.


You should probably get on the phone with Outback and do whatever fine
tuning they suggest before trying to reinvent the wheel. It would be
nice to have either the Emeter before that, or at least an AC-DC clamp
meter on hand. A Fluke 336A would be nice. $275 delivered
http://www.testequipmentdepot.com/fluke/currentclamps/330series.htm .
There are many cheaper models as well. I have a 337, and have made
good use of the DC current and inrush capture features.


A friend with a similar issue (washing machine was causing generator
breaker to trip) told me she got Outback on the phone, and was told to
remove the limit on the generator input. I couldn't tell from the
story if she may have misunderstood.

Have you tried limiting the max charging rate? I would think you'd
want to set the generator input limit to somewhat less than what
starts to bog the generator down, and then set the charging rate to
say, 1500W below that.

Wayne

 


Might even want to try the TM-500; there's a few features in there
that I like, over the Link10.



It's not. You just don't have your inverter programmed optimally.


Don't plug anything but PV into an MX-60; it'd likely damage the
controller or the source unit. They're nice rigs, but not that rugged
when you start coloring outside the lines...


As you can imagine, it's a busy time of the year for those of us in
this business. But your question finally made it into the forums, and
there are a bunch of answers there now (some even from me).


It's partial, yeah. Depends on what you want the inverter to do if it
encounters problems. On a big genset (say, 30a AC 120v), bumping up
the gen input limit is good. On a small genset, you have to bump the
AC IN *down* to near the charging rate, so it turns the charger off if
there's a load.

DJ

 



diodes.

reduced

I have a new TriMetric in the box but it says it needs a shunt.  For all
they money they didn't send me a shunt?

What in particular do you like better about the Emeter?


inverters.

Well, it *says* it's charging at about 1000 watts on one port but with my
5000 watt genny it *says* 2.2-2.4 kW but I'm sure the genny is running at
near full capacity.  I just don't have any way to prove it.

Meanwhile I've made my old eu2000 with the dead engine into a belt-drive
generator head so I should be finding out soon if the high quality output
from the eu2000 improves things.

is very little power available when the generator is on

Outback

batteries

How are you charging with DC?


charging

waiting

support

It's way below what the generator should be able to handle and the genny
sounds well-loaded.

 

On Fri, 25 May 2007 16:11:41 -0700, "Ulysses"



If you have the PS2DC breaker panel it has a shunt inside. If not,
then you need the shunt, *and* a 48V adapter
http://www.bogartengineering.com/48VadaptInstruct-VA.pdf . Same thing
with the Emeter. It mostly ships as a meter-shunt package but still
requires a "prescaler" for 48V.


It's been a while, I can't remember most of it. The main differences
are that the TM doesn't have a graphic display and has 3 main displays
instead of the Emeter's 4. Fewer customization options as well as I
recall. They both do the job though and I'm sure that some would
prefer the TM. It's made to fit in standard double gang box for
instance while the Emeter was made to snap into a dashboard hole.


I built a custom generator -  electric-start lawn tractor type engine
running at about 2/3 normal rpm with a small throttle opening. Belt
drives a converted vehicle alternator with an external rectifier and
field controller. Many convenience features including timers to delay
field cut-in during warm up, and to delay engine stop for an unloaded
cool down period.

Your Outback inverters are reputed to be more efficient at charging
than the SWs and should be more efficient than my DC generator as
well. I don't need much generator backup so convenience is more
important to me than efficiency.

Wayne