[RE-wrenches] heating any battery bank
Dana
dana at solarwork.com
Tue Feb 27 12:01:45 EST 2018
At a couple of remote systems, I have housed the battery bank as follows.
It is not cheap [$2,000 for pump, controller, & collector, plus the slab] but works very well:
Flat plate Solar thermal collector installed at 60+°, pumped directly to a 6” insulated slab dedicated to the battery bank or the power room slab. Well insulated slab is the key word here.
If you are interested contact me off list, it is a lengthy conversation & it helps if you have some radiant heat installation experience. I have a 900 sqft building floating at 46-54°F currently at 5,600 ft in South Central Idaho with no heat back up to the slab.
The temps would be higher if the collector orientation was more S-SW VS the SE orientation due to the canyon & building orientation. We floated our home in CO at 70-74° with the same system & a boiler backup.
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Dana Orzel Great Solar Works, Inc.
C - 208.721.7003 dana at solarwork.com
Idaho Contractor - # 028765 Idaho PV # 028374
NABCEP # 051112-136 <http://www.solarwork.biz> www.solarwork.biz
"Responsible Technologies for Responsible People since 1988"
P Please consider the environment before printing this email.
From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Ken Schaal
Sent: Tuesday, February 27, 2018 9:01 AM
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Subject: Re: [RE-wrenches] heating a lithium battery bank
Have u considered, or is it possible, to set the batteries several ft. into the earth? 50 or so year round.
Works for livestock water, earth sheltered houses, caves.....
On Feb 27, 2018 10:29 AM, "Starlight Solar Power Systems" <larry at starlightsolar.com <mailto:larry at starlightsolar.com> > wrote:
Hi Drake,
I agree. Li-ion batteries, like lead batteries, should always have a human overseer. This is a difficult reality to convey in our set-it-forget it, automated world.
One function of a Li-ion battery EMS or BMS is to prevent over discharge. Once any battery cell reaches the lower limit, the battery will turn off. For many systems, once charge current is again detected, the battery will turn on. Some will not and require a user to turn the battery back on. You can also install an external LVD device to stop power use at a higher SoC.
As wrenches, its our responsibility to know our product and educate the customer. Too often, this does not happen.
Larry Crutcher
Starlight Solar Power Systems
On Feb 27, 2018, at 7:11 AM, drake.chamberlin at redwoodalliance.org <mailto:drake.chamberlin at redwoodalliance.org> wrote:
Snow on the array could be a very big problem with the heater load, inverter idle current and anything else that might be left on. Extended periods of heavy clouds can reduce power generation to be less than system's internal losses. It seems like a pretty big gamble to leave an expensive battery bank unattended, that can not go below freezing, and is dependent on array power to prevent freezing.
If AGMs survive in this application, it might be better to stay with this technology.
----- Original Message -----
From:
offgridsolar at sti.net <mailto:offgridsolar at sti.net> "RE-wrenches" <re-wrenches at lists.re-wrenches.org <mailto:re-wrenches at lists.re-wrenches.org> >
To:
"RE-wrenches" <re-wrenches at lists.re-wrenches.org <mailto:re-wrenches at lists.re-wrenches.org> >
Cc:
Sent:
Mon, 26 Feb 2018 10:36:29 -0800 (PST)
Subject:
Re: [RE-wrenches] heating a lithium battery bank
Hello Daniel,
I will give this some thought. What lithium make? The ones I have looked
at log the temperature for warranty so that might negate the value a bit.
The high temp is just as bad in your case here.
Since this has been working well I am assuming snow on the panels is not
an issue?
Building a battery box that was cooled (small fan) from conditioned space
is what I have done. The wall between the garage and living space is
perfect. This won't help when the house is cold (unattended) much. It
won't help if the house is allowed to get hot either.
Some of the Lion batteries are actually listed for living space. The LG
is. I don't do that with mine though. Hmmm
Dave Angelini Offgrid Solar
"we go where powerlines don't"
http://members.sti.net/offgridsolar/
e-mail offgridsolar at sti.net <mailto:offgridsolar at sti.net>
text 209 813 0060 <tel:(209)%20813-0060>
> Hello Wrenches, here is a fun one for you all.
>
>
>
> The client you all helped me with earlier this year is now considering
> changing out their AGM off grid bank with a lithium battery bank before
> the
> next winter. I looked into this, as we have been eying the various lithium
> options for 2+yrs now, but not bit the bullet and really designed a bank
> into a system.
>
>
>
> The main issue I am trying to consider is this. The cabin is not occupied
> during most of the winter, and the batteries are in the unconditioned, but
> attached, garage. They drain the plumbing system and shut off all breakers
> except the ones that power the internet, chest freezer, and security
> system.
> As such, the battery bank has routinely gotten below freezing, sometimes
> staying there for 1-2 weeks. This is not an issue with AGM's, within
> reason.
> The battery bank has never gotten below 20F over the last 2 winters, where
> the site has seen below zero temps for brief periods. But the AGMs likely
> produce more heat during a charge than lithium's, and they have
> significantly more thermal mass to ride through the really cold nights.
>
>
>
> Lithium batteries, to the best of my knowledge, can be below freezing
> during
> storage. But to safely charge, they must be above 32F. So the thought was
> to
> provide an insulated battery box, and design in some small heating system
> that is set to 40-45F. The first thought was a low power fiberglass
> heating
> pad like is sometimes used for livestock to give them a slightly warmed
> place to lay down. Then tie that to a thermostat with a sensor on the
> battery bank. I would of course need to try to account for the extra load
> in
> the battery bank sizing. They array is more than is needed right now so I
> do
> not worry about it's ability to compensate when the sun is shining.
>
>
>
> In theory this could be ok, but I worry about the summer. Will the
> insulated
> enclosure cause the opposite issue during the summer, the batteries
> getting
> too hot? I have seen the AGM bank go to 110F at one point in Aug 2016. But
> with the lower internal resistance of the lithium's, maybe this is less
> likely to be an issue. Do any of you wrenches have any experience with
> this
> unconditioned setup?
>
>
>
> With Regards,
>
>
>
> Daniel Young,
>
> NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90
>
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Dave Angelini Offgrid Solar
"we go where powerlines don't"
http://members.sti.net/offgridsolar/
e-mail offgridsolar at sti.net <mailto:offgridsolar at sti.net>
text 209 813 0060 <tel:(209)%20813-0060>
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