Keith Birchfield's posts

Posted by Keith Birchfield on Sep 14, 2009 06:57 pm

#1 -  Renewable Energy > Technical Discussion: Other > Re: Mixing pwm and mppt to same bank ok?
Thanks guys, its been a lot of fun to work on! I hope the site ends up helping someone get started in to the wonderful world of renewable energy.

Anyways, I'll probably squeak in that monitor install sometime in the next month or so.

I'm just a little bummed that the main project is pretty much finished, it was very satisfying while working on it and I'm enjoying the rewards, but it left me feeling like "huh, now what" once it was done.

 ... time to try hot water. :-)
 

Posted by Keith Birchfield on Sep 13, 2009 03:32 pm

#2 -  Renewable Energy > Technical Discussion: Other > Re: Mixing pwm and mppt to same bank ok?
Thomas,

I'm not sure how to tell if its working properly or well. But it is installed and running.

I updated my install story here:
http://solarinvirginia.com/Solar_Shed_To_Home_Story.php
It includes a mention of how the charger is in play, and the panel that it is connected to. It also includes links to all of the products I purchased here at AltE Store of course.

So far there have not been any noticeable problems. The battery bank is charging a little earlier every day, and the out from the MPPT controller is showing less output to the battery bank to get to float every day. And the loads have not changed. They are all pretty much 24x7 loads. With very little on/off loads.

I do have a Bogart trimetric setting in a drawer that needs to be installed. But I've put it off since I'll need to move my charging connections off of the battery and in to the disconnect enclosure first.

Some day I'll get around to it.

 

Posted by Keith Birchfield on Aug 25, 2009 06:35 am

#3 -  Renewable Energy > Technical Discussion: Other > Mixing pwm and mppt to same bank ok?
I have a MPPT charging a 12v bank and want to make sure its ok to add a pwm charge controller to the same bank.

This is the mppt controller:
http://www.altestore.com/store/Charge-Controllers/Solar-Charge-Controllers/MPPT-Solar-Charge-Controllers/Xantrex-MPPT-Charge-Controllers/Xantrex-XW-Solar-Charge-Controller-MPPT-865-1030/p5946/

This is the pwm controller:
http://www.altestore.com/store/Charge-Controllers/Solar-Charge-Controllers/Pwm-Type-Solar-Charge-Contollers/Morningstar-Charge-Controllers-Pwm/Morningstar-Sunsaver-Ss-10-10A-12V-Pwm-Chg-Cntrlr/p798/


 

Posted by Keith Birchfield on Aug 11, 2009 07:41 pm

#4 -  Renewable Energy > Technical Discussion: Other > Re: Can I tie these modules together? ES180 and SW100C
Thanks for the feedback, it has helped.
 

Posted by Keith Birchfield on Aug 11, 2009 07:40 pm

#5 -  Renewable Energy > Technical Discussion: Other > Re: Pole Mounting - Use the Pole as Ground?
... The OP's pole does not meet the requirements as a ground rod or a Ufer. ...

Thanks to all for the feedback.
 

Posted by Keith Birchfield on Aug 11, 2009 12:46 pm

#6 -  Renewable Energy > Technical Discussion: Other > Re: Can I tie these modules together? ES180 and SW100C
Excellent feedback, Thanks.

I'll need to consider the wind load, and see if I can find something that fixes the appearance, without causing problems.

One of my concerns was leaving the top of pole fully exposed ... allowing rain water to accumulate inside of pole.

Have you seen solutions for this?


 

Posted by Keith Birchfield on Aug 11, 2009 10:56 am

#7 -  Renewable Energy > Technical Discussion: Other > Re: Can I tie these modules together? ES180 and SW100C
putting the new panel on a new controller may work fine for this situation.

Question though ... since I'm doing this partially for cosmetics, I will have the single panel on the pole mount ... potentially going back to a new controller.

What happens if I decide to get, lets say, three more of these panels, and place them on a shed roof ... about 20 feet away .. will it still be safe to wire all four together, to the new controller?

second question, will the second controller work ok with the mppt? or do the contrllers need to be matched too?
 

Posted by Keith Birchfield on Aug 11, 2009 06:50 am

#8 -  Renewable Energy > Technical Discussion: Other > Can I tie these modules together? ES180 and SW100C
Are these two panels compatible?

Evergreen ES180 RL/SL 180W 18V Solar Panel
http://www.altestore.com/store/Solar-Panels/150-Watts-Up-Solar-Panels/Evergreen-ES180-RLSL-180W-18V-Solar-Panel/p4410/
and
SUNWIZE Solar Panels & Component SW100C 100W 18V Nominal Solar Panel
http://www.altestore.com/store/Solar-Panels/100-to-149-Watts-Solar-Panels/SUNWIZE-Solar-Panels-Component-SW100C-100W-18V-Nominal-Solar-Panel/p5882/

I have four evergreens, two per string, and want to add a 'skinny' panel to the pole in between the evergreens.

The panel needs to be 24-26 inches wide, at any length. This is to 'fill the center gap' ( in between 4 evergreens) on top of a pole mount.

and ideally would be able to tied in to one of the two evergreen strings.

Can the sunwize safely be included?

If not, what's a good way to use the new 'skinny' panel's output?
or
What's the cheapest way to to include it?

In case it matters .... I currently have an mppt 60 controller.



 

Posted by Keith Birchfield on Aug 8, 2009 01:09 pm

#9 -  Renewable Energy > Technical Discussion: Other > Pole Mounting - Use the Pole as Ground?
Can you use a steel ( 6 inch schedule 40 ), in 4 foot of concrete, as the system ground?
 

Posted by Keith Birchfield on Jul 17, 2009 05:44 pm

#10 -  Renewable Energy > Technical Discussion: Other > Re: More than 4 12v batteries in a Bank?
What does this statement mean:

Quote
"If you parallel more than three strings of batteries, you risk shortening battery life due to uneven charging1."

in this article:

http://howto.altestore.com/Articles-on-Renewable-Energy/Solar-Panel-System-or-PV-Systems/Solar-Batteries-Deep-Cycle-Batteries/How-to-Size-a-Battery-Bank/a94/


and it references this:

1A great article explaining the rationale behind this paralleled string limit is available in Home Power Magazine issue 114: “Top Ten Battery Blunders.”

http://www.homepower.com/article/?file=HP114_pg54_Dankoff]http://www.homepower.com/home/]http://www.homepower.com/article/?file=HP114_pg54_Dankoff

which mentions:
Quote
The problem is that when current splits between parallel strings, it’s never exactly equal. Often, a slightly weak cell or terminal corrosion will cause a whole battery string to receive less charge. It will degrade and fail long before other parallel strings.

But, help me out here ...

A 'string' is a set of batteries connected in a line ... positive to positive and negative to negative ... right?

So, If I have 8 batteries connected this way ... its only one string ... right?

And then to 'help' even out the draw and charge, just connect the positive to one end of the string, and the negative to the other end. ( or tie all positives together, and all negatives together )

Another reference to "no more than three:
http://www.wind-sun.com/ForumVB/showthread.php?t=3170
 

Posted by Keith Birchfield on Jul 16, 2009 10:01 pm

#11 -  Renewable Energy > Technical Discussion: Other > Re: More than 4 12v batteries in a Bank?
Excellent link ... Thanks!
 

Posted by Keith Birchfield on Jul 16, 2009 09:36 pm

#12 -  Renewable Energy > Technical Discussion: Other > Re: More than 4 12v batteries in a Bank?
The way you are doing it sounds like a good compromise, and I would think it would help even the stress out.

I don't have any links, just a couple of different people advised me not to do more than 4.

I have not been able to find any thing via google that supports it yet ... so I'm hoping this discussion will clarify the concern ... and the options.

how long has your 8 battery bank been live?

mine would be just about identical to yours ... I have 4 105ah 12v in place, and want to add 4 more of the same batteries, and either tie at the opposite ends or the centers of the two sets of 4.

 

Posted by Keith Birchfield on Jul 16, 2009 09:22 pm

#13 -  Renewable Energy > Technical Discussion: Other > Re: More than 4 12v batteries in a Bank?
I'm not sure .... but I've been advised not to do it.
something was said similar to this:

"... you don't want to have too many parallel strings. Four is the max. "

I'm guessing that it is to prevent too much power being pulled from the end of the string ... but wouldn't a bus bar or tying at a center point fix that?
 

Posted by Keith Birchfield on Jul 16, 2009 08:37 pm

#14 -  Renewable Energy > Technical Discussion: Other > More than 4 12v batteries in a Bank?
What prevents me from connecting more than 4 12v batteries, in one 12v bank?

I currently have 4 12v, in a 12v bank, and would like to connect either 2 or 4 more to the same bank ... keeping it at 12v.
 

Posted by Keith Birchfield on Apr 15, 2009 06:27 am

#15 -  Renewable Energy > Wanted > High School Needs Help - Solar Dog House Project
Georgette wrote:

Quote
I am a HS teacher trying to add alternative energy into a construction course. My students and I are looking to create a prototype for a passive and active combination solar dog house. We are looking for a solar panel to control a few things in the dog house. 1) a light that the dog could control by hitting a pad with it's paw 2) a bird feeder style heating system to keep the dog's water from freezing in the winter 3) a fan to circulate the air 4) (possibly) a temperature triggered venting system to keep the doghouse from getting too warm. We are hoping that you would have knowledge you could share with us about what we would need to try an accomplish these goals. We are also hoping that you might be interested in helping to sponsor the project - or know of a corporation who might be willing to fund our solar components. Thank you for doing what you do!
>
> Georgette Yakman
> Technology Education Teacher
> Pulaski High School
>
> Voicemail: (540) 643-0333/0476
>
>

 

Posted by Keith Birchfield on Apr 11, 2009 08:50 am

#16 -  Renewable Energy > Wanted > Re: want to purchase used solar pathfinder
John,
How much would you resell it for?

I was able to use a simple glass dome from a clock to get my rough ideas. Worked great ... I think.

I would love to use one of these things to confirm my early findings, but I do not want to spend anywhere near what they cost new.
 

Posted by Keith Birchfield on Mar 28, 2009 07:44 am

#17 -  Renewable Energy > RE General Discussion > Re: During Float Charge - How to use the extra PV power?
I am curious about the remark you made concerning "net metering." Does this mean you have a grid intertied system with batteries as a back up power supply?

Thomas,
No, This system is not tied to the grid right now. It has a constant light load ( internet, single light, sprinkler system, single phone ), and random short loads ( tools, lights, etc )

I would love to upgrade my inverter, and net meter back my extra power
... I've looked in to it, and it looks like it would cost anywhere between  2k and 5k to upgrade my system and get it certified for net metering.
... on a 700w array with only an hour or 3 of grid feedback, it would take a long time to get return on that!
... If I'm going to spend, I would rather spend on growing the system instead. My next goal would be to double the array and battery bank , but the budget is not there yet :-)

Maybe I do need to think about growing the battery bank?
 

Posted by Keith Birchfield on Mar 28, 2009 07:35 am

#18 -  Renewable Energy > RE General Discussion > Re: During Float Charge - How to use the extra PV power?
I would plug in anything that needed charging. ...

James, I think that is an excelent idea, except for my situtation ...

As an example:
I have a lot of rechargeable yard tools, so charging them off solar would be ideal, but
... I would only want them to re-up charge during float
... this means I could connect to a relayed circuit
... but, that would mean that while the circuit was inactive, the batteries would be connected to chargers that have no power
... which for some of my chargers, that would mean the batteries would drain the 'other 21 hours of the day'

I could also get more batteries and grow my bank
... collect additional power
... and then add additional load
... but my batteries are past the 1 year add on time
... and replacing is very expensive

so ... for now, I'm trying to figure out what I can actually run, instead of trying to store the energy.

 

Posted by Keith Birchfield on Mar 25, 2009 09:33 pm

#19 -  Renewable Energy > RE General Discussion > During Float Charge - How to use the extra PV power?
I have a 700w PV system that is putting my battery array in to float charge for a couple of hours a day.

Other than net metering, What is a good way to use the extra power?

I'm thinking about using the Auxilary Output on my MPPT to trigger a relay, during float charge, to turn on an external device.

But what device? What can I 'turn on' to use the wasted power. So that It gives me some value back?
 

Posted by Keith Birchfield on Dec 14, 2008 10:50 am

#20 -  Renewable Energy > Technical Discussion: Other > Re: Wiring solar panels together
For serial connection ( adds volts, keeps same amperage )

/--\            /--\
|PV|-(+)(-)-|PV|-----(+)
\--/            \--/
  |
 (-)
 (+)
  |
/--\            /--\
|PV|-(-)(+)-|PV|-----(-)
\--/            \--/

The above is an attempt to show what a typical 2x2 PV wiring could look like.

This means, that each PV feeds the next PV, where the first PV provides the + connection to your controller, and the last PV provides the - to your controller.

Here is another attempt a showing this same connection, but with each PV in a line ( 1x4 )

 (-)_[PV]_(+)(-)_[PV]_(+)(-)_[PV]_(+)(-)_[PV]_(+)
 
 

Posted by Keith Birchfield on Dec 5, 2008 07:52 pm

#21 -  Renewable Energy > Technical Discussion: Other > Re: Bogart Trimetric and MK 105ah AGM batteries
Andy,

Yes, my trimetric did come with a manual ... and its a pretty deep. I wish it had a few real world example diagrams, it would make things a lot clearer.

Anyways, yes ... I did send an email and received a very helpful response.

But, unfortuanately ... my monitor is still not working as it should. The readings do not appear to be tracking the battery bank very well at all.  As an example, Today .... I saw 0% full reading on the battery at 12.5 volts.

I'm pretty certain that part of the problem is that I don't have the Controller going through the shunt right now. After that, I may have a poor connection.

I guess I'm going to have take it out, re-study the wiring , and give it another shot.
 

Posted by Keith Birchfield on Dec 5, 2008 07:41 pm

#22 -  AltE > Announcements > Re: The Dec Renewable Rewards Winner
I used to say 'I never win anything' ... now I'm all smiles! :-)

Its pretty cool to be rewarded for reading and talking about something like alternative energy.

Thanks AltE !
 

Posted by Keith Birchfield on Nov 21, 2008 06:55 am

#23 -  Renewable Energy > Technical Discussion: Other > Re: Bogart Trimetric and MK 105ah AGM batteries
Thomas,
Thanks for the feedback.

I am hitting 14.4, or so, during absorb ... So it sounds like that should be my trigger top voltage.

And, I've been given the advice to set my trigger amps to 8.

So that when it goes up to or over 14.4 volts and the amps drop below 8 ... then it should have completed absorb.

And it sounds like you are recommending to put both the inverter and the charger on the outside of the shunt ... since I want to measure total state of the battery.

Something like this:

           Trimetric
                 |
Battery -> Shunt --> Inverter
                      +-> Charger

Also,
Does it sound 'ok' that on a day where I'm seeing it go in to absorb ... that I'm seeing 12.3 or 12.4 volts on the battery bank, after the charger cuts out? It would be under load, since the Inverter would still be running, but little to nothing else.

 

Posted by Keith Birchfield on Nov 18, 2008 08:33 pm

#24 -  Renewable Energy > Technical Discussion: Other > Bogart Trimetric and MK 105ah AGM batteries
Hello,

I have 4 105ah AGM batteries for a total of 420 amp hour capacity.

I also have a Trimetric TM-2020 Battery Monitor.

But, I'm having difficulty in trying to figure out how to configure the monitor to properly provide stats on the battery bank condition.

Can anyone tell me how the monitor should be configured?

Separately, Should both the inverter and the charger be connected to the shunt?

The monitor allows you to set the following:

VOLTS "Charged" setpoint voltage.
10.0 to 65.0 volts
( this I think should be somewhere around 14.4 ? )

AMPS "Charged" setpoint amps
1 to 100, amps or "OFF"
( this I believe should be off ? )

(AH)Amp hours
( this I believe should be 420 )
 

Posted by Keith Birchfield on Nov 1, 2008 09:44 am

#25 -  Renewable Energy > RE General Discussion > Solar Hot Water - Heat Exchangers
Do any of the retro fit heat exchangers push heat in to the existing tank continuously?

By continuously I mean, via a controller and heat differential settings of course.

It looks like many, or even most, only work by providing extra thermals to the incoming line. In other words, they are attached, in line, to the hot water tank incoming 'cold' line.

I would prefer an exchanger that is continuously heating the existing tank, via some sort of circulation.

Since most of my use is during early morning and late evening, and I've read that a huge portion of electric hot water heater consumption happens during stand-by. I'm very interested in finding the best method of getting heat in to my existing tank whenever it is available, and whenever the heating coils would have needed to turn on.

Anyways,
The Helio-Pak Pro exchanger looks very interesting to me ... mostly because of the wireless monitoring. I really like that idea.
But, Its not clear to me how and when it adds heat to the existing tank. Is it only on the input during consumption?

http://store.altenergystore.com/Solar-Water-Heaters/Heat-Exchangers/Heliodyne-HelioPak-Heat-Transfer-Appliance-HPAK-16/p6650/
 

Posted by Keith Birchfield on Oct 21, 2008 06:46 pm

#26 -  Renewable Energy > RE General Discussion > Re: Solar Hot Water and Solar Radiant - Costs - Why so much extra for Radiant?
Keith, you are comparing different size systems from different manufacturers.  ... We are working on getting more details of the kit from Heliodyne, we'll update the site as we get it.

Ah! Thanks for the extra info.
 

Posted by Keith Birchfield on Oct 20, 2008 01:28 pm

#27 -  Renewable Energy > RE General Discussion > Re: Solar Hot Water and Solar Radiant - Costs - Why so much extra for Radiant?
David, thanks for the extra info on the board and barrier. That does help explain at least some of the missing costs.
But, I can't tell if that is the whole difference or not.

Tom,
I absolutely believe as you do about buying local where it makes sense. And as you have suggested ... a lot of the supporting materials would ideally be purchased through a local plumber.

 

Posted by Keith Birchfield on Oct 19, 2008 08:12 pm

#28 -  Renewable Energy > RE General Discussion > Solar Hot Water and Solar Radiant - Costs - Why so much extra for Radiant?
Hello all,
I feel like I'm missing something.
Why do the kits for hot water + radiant heating cost so dramatically much more than hot water only kits?

For example:

Here is an example 'everything you need' for solar hot water
 that runs at about 3k
http://store.altenergystore.com/Solar-Water-Heaters/Climate-freezes-Closed-Loop-Systems/Closed-Loop-Systems-for-1-4-People/Closed-Loop-PV-Powered-w-Tank/AET-Alternate-Energy-Technologies-Ipv-80-40/p170/


Here is an example 'everything you need' for solar hot water + radiant heating that runs at about 9k

http://store.altenergystore.com/Solar-Water-Heaters/Climate-freezes-Closed-Loop-Systems/Combined-Solar-Hot-Water-Space-Heating/Heliodyne-Solar-Hot-Water-Space-Heat-1000-sqft/p6728/

I do understand that when doing both, you need to add an additional sqft of collector, and that you will also need a pump. The two combined might add 2k to the cost .. I think.

But why the additional 6k?

What am I missing?
 

Posted by Keith Birchfield on Sep 23, 2008 06:51 pm

#29 -  Renewable Energy > RE General Discussion > Re: Solar Thermal - Adding heat to crawl space
huh?
 

Posted by Keith Birchfield on Sep 22, 2008 09:00 pm

#30 -  Renewable Energy > RE General Discussion > Re: Evergreen Solar Panels
Thank James and David.

I've got a single 180w ordered to top off my 170s. :-)

That should complete my solar electric project for now ... time to focus on solar thermal for a bit.

 

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