Is anyone being forced to leave ladders up and secured in place for
inspectors? One jurisdiction in our neck of the woods is insisting that
we do this. I believe this is a serious risk to public safety, and I
won't be responsible for some homeowner or curious child getting injured
on or around a la
A letter from your insurance company may do the trick here. They
probably wouldn't be too happy about the homeowner, curious child, OR
inspector using your ladder even if you are on site watching it.
On 2011/9/1 7:45, Jason Szumlanski wrote:
Is anyone being forced to leave ladders up and secur
This issue came up for me as well.
I dont recall at the moment where it is written, perhaps it was OSHA, but
apparently the contractor (permit puller) is responsible for supplying access
and safety equip ie, fall protection (with exception of personal PPE, boots,
hat, glasses) for inspectors t
Ha – The roof we are dealing with today has 26’ high eaves and it is a steep
metal roof. There is no way they are actually getting up there. When we do
timed inspections in other jurisdictions they rarely step foot on a ladder.
Maybe it’s a testament to our reputation, but we are paying for the
I am looking for someone to install a PV solar and inverter/charger system in
an RV is Western Massachusetts. It is similar to an off grid system. Please
contact me off list if you can help.
Larry Crutcher
Starlight Solar Power Systems
11871 S Fortuna Road, #210
Yuma, AZ 85367
la...@starlightso
Friends:
Thanks for any referral for a customer. Please respond off-line.
Thanks,
William
William Miller
Miller Solar
Voice :805-438-5600
email: will...@millersolar.com
http://millersolar.com
License No. C-10-773985
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Hi gang. Just a reminder to **not** use this list to either find customers,
find installers, or to refer potential customer to others.
If you have any questions about this, please contact me off list.
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Hello wrenches,
I have a battery bank questions. I have an Oil & Gas client interested in
setting up an off-grid control system that has a various DC loads at 12VDC,
24 VDC and 48 VDC. My thought is to build a 48 V battery bank and tap off
the bank at various points to create a 12V bus, 24V bus
I always thought that a very small 12V or 24V tap relative to the total
capacity would be inconsequential. I was recently told otherwise by a battery
mfr rep, but that is not surprising. I suppose the real question is what
constitutes inconsequential. A 1A @ 12V fan on a 1000aH @48V battery bank
Mac,
Don't tap the battery. Bad idea. Uneven loading = unequal charge/discharge,
which leads to shortened battery life and other troubles.
Better idea: If you know the maximum load current, use high-efficiency DC-DC
supplies of adequate current and other ratings to step 48V down to 12 or 24V
mac,
Don't tap off various voltages. Use DC-DC converters for any voltage
other than nominal. Anything else will lead to uneven charging and
shortened life.
Allan
Allan Sindelar
al...@positiveenergysolar.com
NABCEP Certified Ph
I always thought small multi-voltage taps, for example a 12 volt
domestic water pressure pump center-tapped from a 24 volt battery bank,
would be no problem, too, but experience and troubleshooting calls have
proved otherwise. Even such a low-power intermittent use has caused
serious problems i
Dan,
What kind of efficiency level (%) can you get out of a DC-DC supply on a
small load, say <5A @ 12V with a 48V->12V converter? Is the efficiency
level highly variable depending on load as a percentage of the
converter's maximum capacity, or is it pretty constant?
I run into this once in
At 15:57 -0400 1/9/11, Jason Szumlanski wrote:
A 1A @ 12V fan on a 1000aH @48V battery bank can't make any real
difference. Correct me if I am wrong!
Yes that is wrong, because after 4 days you have removed 10% of the
nominal capacity or about 20% of the usable capacity.
Tapping off batt
Hi Jason,
Well designed off-the-shelf converters can achieve 90% efficiency, and as you
mention, this will vary a bit depending on the rated output current of the
converter vs. the actual load current.
I've designed and built 24V @ 25A to 12V @ 50A converters for my own use that
are in the 95
Mac
Don't do it! ...use a dc to dc converter to step down to each bus 12v 24v
etc. and then just hook up the equipment thru breakers to each bus
Tom Duffy
Systems Design Engineer
t...@thesolar.biz
575-539-2111 X 301
Although no trees were killed in the sending of this messa
Mac,
Never tap a battery bank off various voltages. This will result into unbalanced
battery units, thus confusing the charger, resulting into unbalance charge,
boiling ones and sulfating others occurring, killing the battery fast...
When facing various loads with various operating voltage 12V,
1a x 12V x 24hrs = 288 watt-hours on a 48,000 watt-hour battery. My math
shows 0.6% of the nominal capacity. And that assumes there is no
charging source present.
That being said, I would agree that avoiding it altogether is the wise
decision, but there has to be a level at which the tapped load i
> Jason - In my experience AHJs run the gamut on this issue, from refusing to
> get on the roof to requiring OSHA compliant access to all areas of the
> system supplied by the installer. In the latter case I would ALWAYS have
> someone on site, even if they had to wait all day (not uncommon). The
Glad I asked! Do these converters have a decent expected lifetime? If
anyone has any good DC-DC converters to peddle, please contact me off list.
Thanks for the help.
On Thu, Sep 1, 2011 at 2:48 PM, Jason Szumlanski wrote:
> 1a x 12V x 24hrs = 288 watt-hours on a 48,000 watt-hour battery. My m
I am both interested in the idle power, and the operating efficiency
This often comes up, but what does it require to allow a DC appliance to wait
and simply turn on when when necessary and not waste power when it is off?
Darryl
From: Exeltech
To: RE-wrenches
Sent: Thursday, September 1, 201
I would guess that it depends upon the use cycle, you always put more electrons
back in than you take out, If you are assuming a 90% recharge efficiency
recharging once every three days, a few percent of the recharge excess energy
could be used. BUT I strongly agree I have seen too many problem
At the risk of sounding sarcastic (and I assure this is not my intent) .. to
allow a DC appliance to wait and simply turn on when when necessary and not
waste power when it is off would take a battery .. internal or external to the
appliance.
Something has to keep the appliance powered. The b
At 16:48 -0400 1/9/11, Jason Szumlanski wrote:
1a x 12V x 24hrs = 288 watt-hours on a 48,000 watt-hour battery. My math
shows 0.6% of the nominal capacity. And that assumes there is no
charging source present.
Wrong again. Sorry.
You are taking out four times that percentage out of just one q
Sorry - I missed the 4 days part of your post. I'm not sure where you
came up with 4 days - sounds kind of arbitrary.
I'd be interested to know if it makes any difference at all if you tap a
12V load only when there is a 48V charging source present (assuming the
charging source current is signific
Or a switch...
At 03:14 PM 9/1/2011, you wrote:
.. to allow a DC appliance to wait and simply turn on when when
necessary and not waste power when it is off would take a battery
.. internal or external to the appliance.
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