Answers to questions:
The batteries are Discover EVL16A-A batteries. A single string of 8:
390AH @48V nominal. We had one fail last year, showing a significantly
raised internal resistance when tested under a load then under charge.
There is another one showing signs of weakness, but currently under a
30A draw it is only 0.12V lower than the highest battery in the mix,
and 0.05V from the average battery voltage. Readings were: 6.0, 5.88,
6.0, 5.93, 5.92, 5.91, 5.93, 5.94 using a 1500W space heater as a
constant load during the test.
There are more loads than just networking and security that the client
just recently disclosed. Gotta love the added loads to the design.
There is a satellite DVR, 2x4 camera webcam systems, cell modem,
simplisafe security system, chest freezer, 4 wifi range extenders to
serve the less reliable security camera system, and 26W LED dusk-dawn
light. I have already talked to them about thinking hard on what items
can be removed for the winter at least (DVR is going away, and one of
the camera systems too, likely the one requiring the wifi range
extenders). All other seasons the system is fine.
As for the DC converter(s) we would get a voltage specific converter
for any unique voltages, depending on the # of unique items, we would
likely abandon that approach if it got to bee too complicated. But
thank you to all that provided guidance there. The meanwell units
seemed to have the right specs to do the job if we go that route. We
would also install them using a LVD of some sort, set somewhere above
the standard low voltage cutoff of the rest of the system. We would
also only go this route if all AC loads could be removed by doing
this, allowing us to remove the 36w idle draw of the Outback.
With Regards,
Daniel Young,
NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90
Lead Systems Designer for:
<http://www.dovetailsolar.com/> www.dovetailsolar.com
Ph: 740-274-0139
We’ve completed nearly 400 renewable energy projects! Check out a
few in our photo gallery:
<http://www.dovetailsolar.com/Our-Work.aspx?path=commercial+-+solar+el
ectric>
http://www.dovetailsolar.com/Our-Work.aspx?path=commercial+-+solar+ele
ctric
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From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org]
On Behalf Of Starlight Solar Power Systems
Sent: Tuesday, January 16, 2018 11:08 AM
To: RE-wrenches <re-wrenches@lists.re-wrenches.org>
Subject: Re: [RE-wrenches] Off grid DC Loads: DC Converter
I too would like to know the make and model of batteries that are
loosing capacity. In the past 5 years we have experienced abnormally
high failures from 2 brands.
Larry
On Jan 15, 2018, at 2:00 PM, Jay <jay.pe...@gmail.com
<mailto:jay.pe...@gmail.com> > wrote:
Can you tell us:
Battery make,model and size?
Jay
Peltz power.
On Jan 15, 2018, at 12:32 PM, Daniel Young <
<mailto:dyo...@dovetailsolar.com> dyo...@dovetailsolar.com> wrote:
Hello Wrenches,
I have a client that is running into an issue with his off grid system.
The system is 3yrs old and they are starting to notice their AGM
battery bank is loosing capacity, in reality they are noticing the
generator is triggering more often. They want to try to lower the
frequency of the generator triggering if possible.
The system is not occupied during much of the winter (unconditioned,
which further hurts the battery bank capacity), but the client has a
security system with a cell modem installed and always on. This
fortunately allows Optics-RE access, but unfortunately based on the
FNDC shunt readings, is pulling a consistent 150w from the battery
bank. Currently the network and security equipment is powered from standard
wall-warts running on AC.
I’d like to help the client extend the time between generator cycles
by taking the network loads and powering them directly from the
battery bank (the loads are all 12Vdc). Does anyone have any
recommendations for a decent quality DC_DC converter that would be
applicable? Given inverter losses and the efficiency of the typical
wall-wart, I’d expect the running loads to be closer to 80-100w
rather than the 150w we see now. The intent is to then take the
inverter into search mode, or even switch it off, to remove the tare
losses there, and also to take all the wasted power from the standard
wall-warts and go to a single, more efficient dc power supply.
Any recommendations on a good DC_DC converter are appreciated.
With Regards,
Daniel Young,
NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90
Dovetail Solar and Wind
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