Yes LFP - the grid is only on a few hours in the morning and a few hours
in the evening and even that is not reliable. Diesel is to be avoided
as much as possible as diesel prices are volatile now that Venezuela is
closing the tap and local maintenance is iffy. So I'm looking at
buffering with as many batteries as financing will allow. So PS and
battery need to be sized above power consumption. It's a small hospital
so consumption varies quite a bit daily - the more they have the more
they use and can serve. Solar roof space is limited to about 16 KW - so
grid opportunity charging could make all the difference for them. We are
in the 24 KW (5 sec) peak, 8 KW typical, 60-100 KWHrs/day range. Doing
more data logging to pin that down more. Thanks for your input!
Jeff Clearwater
Village Power Design
Starlight Solar Power Systems wrote on 3/16/20 10:05 AM:
Did you mean to say LFP? It depends on who made the battery. LFP
batteries can be charged using CC/CV. Some, like the Elite PS/GBS
battery packages can accept a simple CV power supply of 3.65 Vpc.
The inverter is always on and isolated from the grid so it’s not
affected by poor power quality unless you allow ripple or spikes to
the battery system. That should be protected at the AC input of your
charger/PS and PS filtering.
What is the daily power consumption? If the battery and PS are sized
to meet your loads, then it won’t matter when the grid is available.
Grid Outages longer than you design for can be backed up with a
generator.
Larry Crutcher
Starlight Solar Power Systems
On Mar 13, 2020, at 6:09 PM, Jeff Clearwater
<[email protected] <mailto:[email protected]>>
wrote:
Thanks All,
Mick and Tump - I'll look into the Victron - good suggestion - Thanks!
Chris - I'm not sure a transformer will buffer the spikes and
frequency but just pass them on - others?
Larry and Jerry - If I were to go with the separate battery charger/PS
approach - what specific 48 V LFeP battery Charger/PS might you
recommend and how to protect it with what sort of surge and LV
equipment? If either the inverter or PS/Charger is protected within
too narrow a range then it might defeat the purpose - wanting to
maximize pulling in as much opportunity charging as we can get.
Seems to me like there might be a market for a highly tolerant battery
charger between 160-260 VAC and frequency tolerant as well - something
bulletproof we could put on these systems - perhaps that is the
Victron - but I'd rather have it in a separate beefy battery charger
then risk the inverters - especially if we are going to buffer the
customer from the grid with the battery/inverter system.
For instance we have a hospital that can only use the available grid
for the office but they can't risk it for their hospital equipment.
But If I could pull the grid into batteries safely and always power
their loads with the high reliability battery/inverter system - now we
are talking.
So specific 48V battery chargers that can take it? Any equipment out
there anyone is aware of?
Thanks!
Jeff
Tump wrote on 3/13/20 2:47 PM:
Check out the Victron line of Chargers as well as the inverter
charger units. AC in 187-265 45-65 Hz. for the inverters 230V/50Hz,
inverter.
Please feel free to e mail me 4 additional info. Great BT support /
internet access. well thought out product.
On Mar 13, 2020, at 5:11 PM, Jerry Shafer <[email protected]
<mailto:[email protected]>> wrote:
Jeff
I have been there too in most cases we have programmed in the VAC
max/mins with tighter setting so as the grid starts to go we just
disconnect. I did just do a charger instead of the inverter because
the grid was generally low on frequency but the charger just charged
and l see it on optics when that happens
Jerry
On Fri, Mar 13, 2020, 12:03 PM Jeff Clearwater
<[email protected] <mailto:[email protected]>>
wrote:
Good Day Esteemed Wrenchers,
So we are doing more work in developing countries where the grid
is super unreliable but on for some hours almost daily.
So let's say we have a grid that's on 9 AM - 11 AM and 4 PM - 7
PM each day but often browns-out during those hours and comes on
and off during those hours. 230 VAC voltage can drop to 160-180
periodically or go above 260 in spikes.
The present practice in many of these situations is for battery
based system designers/installers is to set up an off-grid
system in parallel to the mains but not relying on them - so the
grid AC IN is not connected. They just install a transfer
switch and manually switch or they wire a critical loads panel
to the solar.
This avoids constant switching and nuisance shut-downs from the
battery inverter and protects it from burning out trying to
handle the grid.
MY QUESTION:
I'm wondering what we can do to use the grid when it is up for
opportunity charging of the batteries while at the same time not
subjecting our nice new battery inverters to constant brown-out
tripping and possibly long term damage.
So question #1 - Is anyone using existing battery inverters but
succesfully navigating such a grid variablity settings such that
you are able to take advantage of the grid even if browning out
often?
or question #2 - Can we add some sort of high Voltage and
Frequency tolerant battery charger to the system - keep the
battery inverter/charger off grid - but charge the batteries
from something able to handle the wonky grid without constantly
nuisance charging or burning itself up?
Your thoughts and wisdom I await!!!
Best,
Jeff
--
~~~~~~~~~~~
Jeff Clearwater
Village Power Design
linkedin <https://www.linkedin.com/in/jeff-clearwater-0622a312/>
www.villagepowerdesign.com <http://www.villagepowerdesign.com/>
cell - 413-559-9763
~~~~~~~~~~~~~~~~~~~~~~~
--
~~~~~~~~~~~
Jeff Clearwater
Village Power Design
linkedin <https://www.linkedin.com/in/jeff-clearwater-0622a312/>
www.villagepowerdesign.com <http://www.villagepowerdesign.com>
cell - 413-559-9763
~~~~~~~~~~~~~~~~~~~~~~~
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