Keith Birchfield's posts

Excellent,
Thanks for the idea.
now, its a matter of whether or not I can make it appealing enough for my wife 'to allow'. :-)

Tom,
Yes. The "solar wand" looks very much like what I was hoping to find ... now I just need to find it for sale. Homepower points to butler sun solutions, so I guess it should be safe from them.

Its a shame that AltE doesn't carry this or other lower cost exchangers. Does AltE carry products by request?


This also makes me wonder how hard a "solar wind" :-) would be to find.

Take the wand principle, but instead of inserting it in to a heater ... fan it out and blow air across it for solar heated air. this way you can use a glycol based close loop system to deliver the energy, and then dump it via air in to whatever space you like ...

Anyways, that's a different project.

David,
Thanks for the excellent info.

I think I get it, mostly. :-)

So, to see if I'm understanding ...

In simple laymen's terms ... the string is limited by its weakest link.

If I were to get two 180w instead, then I could run them in parallel .. right from the get-go, and should still be safe on my mppt controller? Since I'm only going up to 16ish amps ...with little change in voltage?

and

But for now, I'm buying more than I can use, by getting a single 180w.

A shame, but ok. I really like buying american made, and the 170w panels I have ... have performed fairly well.

But, getting a 170w would be better. They are currently listed here as 'Call for Availability' ... and I think they are no longer manufactured, in favor of other 'sizes'.

Anyone know how to get one?

And a 'B' module has some minor defect ... right? Where can I find them?

Tom,

I like your suggestion more and more, but I trying to visualize the best way to get the hot air in to the crawl space ... from the 'green-house/collector'

Am I close with this description ...

Would there be a large pipe near the apex of the structure, going in to the crawl space?
Where the apex of the structure is at the same height as the top of the crawl space.
 
And then a same size pipe going from the crawl space / near the base ... and in to the base of the structure.

And if so, I'm guessing some sort of flow valve to keep it all going one way.

And finally ... A small solar powered fan to pull the hot air flow in to crawl space. This would force the passive flow control valve to only open when the sun is shinning enough to power the fan ... and assumingly heat the structure air space.

the pipes should be insulated and flexible and detachable for summer break down of the structure?


... in my case this means a 3 foot tall collector structure. which leads me to thinking 3 foot wide and 6 feet long. for a 3x6 concrete base. In case it factors in, My foundation is brick covered concrete block, and the house is vinyl sided.

Would the structure need to be glass covered? Or could it be plastic instead? For easier break down and storage during warm to hot months.



also, with all that said ... do you think the simple black pad contact with the foundation be enough of a heat transfer that air movement not even be necessary?

Would using a heat exchanger on an existing tank still work well?

for example, the one used in this kit:
http://store.altenergystore.com/Solar-Water-Heating/Climate-freezes-Closed-Loop-Systems/Closed-Loop-Systems-for-1-4-People/Closed-Loop-AC-No-Tank/Heliodyne-DHW-System-for-1-2-People/p6756/

Is there a less expensive method?

Ignoring labor for the moment ...

I would love to do something that included 1 panel and a heat exchanger that could be dropped directly on my existing tank. Which is what I think the above is ... sort-of. But my budget may not allow quite that much spent on the parts.

Hello,
I currently have two Evergreen 170w panels connected directly together in series.
http://store.altenergystore.com/Solar-Panels/150-Watts-Up-Solar-Panels/Evergreen-ES170-RLSL-170W-18V-Solar-Panel/p4409/

Is it safe or appropriate to connect either:

- 1 or 2 Evergreen 180w panels in series with the current 170w
http://store.altenergystore.com/Solar-Panels/150-Watts-Up-Solar-Panels/Evergreen-ES180-RLSL-180W-18V-Solar-Panel/p4410/


- 1 or 2 Evergreen 190w panels in series with the current 170w
http://store.altenergystore.com/Solar-Panels/150-Watts-Up-Solar-Panels/Evergreen-ES190-RLSL-190W-18V-Solar-Panel/p4411/

- 1 or 2 Evergreen 195w panels in series with the current 170w
http://store.altenergystore.com/Solar-Panels/150-Watts-Up-Solar-Panels/Evergreen-ES195-RLSL-Solar-Panel-195W-18V-MC/p6826/


I think that they are all fully compatible, but wanted to make sure before investing.

thanks in advance for any advice.

Tom,
This sounds very interesting ... do you know of any links that show details of this method?

In particular, I'm very interested in anything that can be more aesthetically appealing ... it may help sell it to my wife!! :-)

Mary,
Thanks for the additional tip ... I'll check our provider's site out and see if they offer any incentives.

Also, thanks for the info about insulation ... but I'm thinking about doing something a little different with the attic ... using a radiant barrier to channel the hot air down to the crawl space in the winter ... and out the vents in the summer. Still thinking about this one.

Tom,
Thanks for the encouraging words about tanks being able to 'hold the heat' .... that's wonderful to hear!  I would love to use solar thermal instead!

I would especially love to consider a retro-fit, where an exchanger is used.

So, would this hold true for using a heat exchanger to 'heat up' the water in an existing electric tank too? Would a 10 year old tank perform well in keeping the heated water over night?

Mary,

Many thanks for your reply and sharing your experience!

Even though I know that gas can be greener than electric ... I'm hoping to completely avoid gas ... I'm very slowly working towards a 'no burn lifestyle' ... trying to 'just say no to gas' ... yes, i know about much of electric coming from coal burning ... working that angle with RE too :-)

Anyways, I'm curious about your comment on 120 watts to run the heater ... did you mean amps? I hope not ... that would be horrendous! Did that heater really burn so much that you had to upgrade your 20 amp service?

Thanks again!

I have a crawl space on a house built about 10 years ago.

It is in excellent condition, with very little moisture concern ... and only needs a little minor touch up on the ground cover/ moisture barrier and entry door.

I am considering doing roughly this:
1. Re-do floor moisture barrier ... lay down new 4-8mil plastic, well overlapped
2. Replace entry door with something fairly air tight
3. Close off cross ventillation during winter months
4. Add some thermal mass below main living room ( large rocks? )
5. Pump in Solar heat in to this space

I believe that this, plus some passive solar heating , will greatly reduce my heat pump's load.

I'm hoping to find a path to 100% Solar Heating ... but would be very happy with 50% with this start

I want to use a ground mount collector, for flexibility ... and I do not want it mounted on the house directly.


So, am I on the right track? Suggestions?

Looking for advice and help deciding on how to proceed.

We currently use an electric hot water heater, to provide hot water to 4 distinct locations.

1 location uses almost no hot water ( spare bath )

1 location is the clothes washer, and rarely uses hot water

1 location is kitchen sink used daily ... mostly in the late evening + dishwasher ... which is used about twice a month

1 location is master bath for two people with average use of only a couple of showers per day. the showers are almost always in the early a.m. ... long before sunshine. :-)

So, our use is relatively light.

The hot water heater in the crawl space ( which is a different project ... making air tight and solar heating )

Access to the pipes to each location is fairly clear and easy.

So ...

If my largest hot water consumption happens in the early a.m. ... It feels like I'm not going to take advantage of the 'best' hot water that a solar hot water system can provide.

First question ... is this true? Do i understand correctly, that solar hot water systems will not keep their heat  ( without other energy source help ) overnight, very well?

And is it true that I should expect to pay around 3k total for the components and installation ( by local,who charges very reasonable hourly rates )

This leads me to think about tankless hot water heaters ... 1 for each of the 4 locations. and getting completely rid of the current electric hot water heater. This way I should save a tremendous amount of energy from standby heating ... and heat loss from transporting through the pipes.

Question 2 ... is this true?

Is it also true that the tankless will end up costing less to purchase and install? Less than 2k?

Allen, do you have a website with email contact for your Roanoke Solar business? I'm in Bedford-Lynchburg Area ( Goode ) and may want to talk to you about later projects.

Ok, and thanks.
I believe my b&d chargers are going to be a problem. Bummer.

So, do I understand that I could use something like the DLS charger to charge off the shelf 18v b&d batteries? How would you do this, with alligator clamps? More than one battery at a time? Even though they would be at different charge levels?

This seems like a complicated solution, but its starting to sound like my options are severely limited for these 'cheep' 18v chargers.

John,
Thanks, but I'm not certain I understand.

I'm looking for a way to lessen the impact of keeping my yard tools charged ... and household batteries like double As etc ...

How would your recommended charger work with my riobi and black and decker tools?

These tool chargers will be connected to a solar powered circuit that already is in place ... and that has a pretty good mppt charge controller on it. and a relatively good true-sine inverter.

Thanks,

Since a couple of these are simple off the shelf black and decker chargers ... I wouldn't expect them to be expensively made.

So, how do I determine if I have 'good chargers'?

Goal: Reduce total net consumption for a very specific set of devices. ( primarily battery chargers for tools )

Question: Is it possible to connect a power strip to an a/c timer, and set the timer to only run during specific hours during the day ( peek pv production times )

Here is part of what I have ...

I have 5 battery chargers that draw roughly between 6 watts and 30 watts during standby, trickle charge and full charge modes.

I want to put these chargers on a solar+battery powered circuit.

But, the chargers running 24x7, put quite a net load on the power supply. ( mostly phantom / standby power draw ).

So, my thoughts are that If I can find a timer that draws very little to none during standby, and then have it turn on while the solar panels are generating at near peak ( about 4 hrs per day ) ... then I would put the least possible load on the supply, while, hopefully, keeping the batteries charged and ready to go.

My worry is that any 'good' timer would end up drawing just as much power in standby as the chargers ... but I'm having a lot of trouble seeing that kind of specs associated with the timers for sale online.

Anyways ... Any comments or suggestions would be greatly appreciated.

Thanks for the feedback, it is very much appreciated. I'm sort of doing it that way now. Instead of a drop cord for emergencies.... I'm wiring two receptacles in my living/working space.

And I hear you on the learning by doing comment. I'm learning a lot more by putting hands on, then I could have ever learned by just reading. I've still got a long ways to go though. :-)

Yes, My home is all electric ... including heat pump, electric heat, hot water heater ... several computers running 24x7 ... large entertainment center with tons of 'phantom load'.

The 1200kwh, is from before I started looking at it, and trying to change my consumption ... with changing life style.

So far, the only thing I've done to improve consumption, is changing (almost) all of my light bulbs.

I definitely need help, and need to learn more about how to reduce consumption ... again, without changing life style.

I too would love to take my home completely off grid, but due to the high costs of doing that as is ... I'm trying to work it a step at a time. With the goal of getting everything except ( heating, cooling, dryer, oven ) on to RE.

I would love comments and suggestions about what follows:

I'm thinking about and trying to approach it this way:

1. I'm installing a standalone, off grid circuit. ( its not yet complete) That will power my shed, back yard, garage, and two receptacles in my living room ( which doubles as my home office ) This first Array and Bank will provide around 2kwh per day. It might not sound like much, but it meets the needs of this isolated circuit.

- This will give me emergency power when needed, and the opportunity to use some green energy right away ... Reducing my  grid consumption.

2. I'm replacing every light bulb on the property with CFL's where possible and lower wattage elsewhere.

- This reduces my energy needs, and reduces the heat in my home during the summer.


3. I'm replacing my gas powered yard tools with electric versions.

- This reduces my gas consumption,, and carbon foot print. It also gives me a place to put some of the collected solar power ... in to the batteries of the tools. This is not really house-off-grid related, but it is a feel good extra step.

4. Since half the goal of being able to go off grid is to reduce power needs ... I'm looking at;
  a. Solar Hot Water Heating add on
  b. South Side Window utilization;
     i. opening in winter with heat collecting mass added to floor
     11. closing in summer with extra shading
  c. Additional attic ventilation for summer
  d. Pulling solar heated air in to home during winter
  e. Putting hot water heater on timer, to prevent heating while sleeping
  f. Reduce phantom/stand by loads. This one is tough, not sure how to fix this.

- These things help reduce the needs of the RE, and therefore the cost of the system required. So, If you skip the big energy eaters like Heat Pumps and other heating/cooling type of devices ... Your actual energy requirements can drop quite a bit.

5. Add additional PV and possibly Wind Power ... repeat until complete.

Anyways, I would love to hear comments, and also hope this helps and gives Gary some more to think about. I know I'm still trying to wrap my head around a good path to get these things done in an affordable manor.

I guess the question becomes ....

What things can be done to get your energy requirements down ( without changing life style) to where it is affordable to go off grid?

Here is an attempt at the whole house off grid needs.

My usage has traditionally run at about 1200kwh per month.

Thats about 40 kwh per day.

To cover this usage, I would need to consider roghly this:

Solar Panels / PV:

an example: 170w panels over 4 net hours of peak performance = 680 watt hours 40000/680 = 59 panels needed!

so, 60 panels at about 800$ each = 48,000$ !!!
Batteries :

an example: 100ah 12v = 1200 watt hours deliverable max at full discharge
To stay in the top 20% ( for longevity and give a couple of days when sun is poor ) = 1200*.2 = 240 watt hours per battery
40000/240 = 167 batteries needed !

so, 168 batteries at 200$ each = 33,000$ !!!
 
....

81k Ouch.

Jason,

I'm no expert, but I'll toss in a bit until you get better answers.

in general, the PV's will go to a charge controller first, sol you want to match your pv output voltage to the capability of the charge controller.

if you get a mppt controller, then you will have a great deal of flexibility in your pv configuration ... plus you will get better usage of the pv generated power. Any 'good' controller should have this flexibility, so the mppt mostly buys you efficiency.

next the charge controller output must be capable of matching your battery voltage. again, an mppt or other better controller will be able to match most any battery bank.

finally, and i think this tends to be the most restrictive worry ... the input of the inverter must be compatible with the battery bank.

So, an example could be like this:

18v pv  -> mppt controller
mppt controller -> 12v batteries
12v batteries -> 12v inverter

It may be most important to choose a higher voltage pv, if you will need longer cable runs from your pv to your controller.


I hope this helps?

Would something like the

MPPT60

http://store.altenergystore.com/Charge-Controllers/Solar-Charge-Controllers/MPPT-Solar-Charge-Controllers/Xantrex-MPPT-Charge-Controllers/Xantrex-XW-Solar-Charge-Controller-MPPT-865-1030/p5946/

work?

It includes a configurable auxiliary port, that allows you to trigger and clear on max or min voltages ...
This could be used to trip relays or similar ... resulting in an effective diversion load controller.

I have one of these, but have not used the auxiliary port yet ... but I am hoping to do so at a future point.

Anyways, Would this work for what Travis wants to do?
( by the way ... I love this controller, and am very thankful the Alt-E staff recommended it )

I have a top of pole rack that I have not yet done a permanent install
http://store.altenergystore.com/Solar-Trackers-Solar-Panel-Mounts/Top-Of-Pole/Two-Seas-Top-Of-Pole-Mounts/Two-Seas-Uni-Tp06-Doubletier-TopPole-70-Sppt/p1866/

It basically requires a nice straight 6" schedule 40 pipe to set on.

For the moment it only has one panel on it, but I want to get it installed, and then get three additional ( roughly 3'x5' ) panels

My questions are,

Is there an alternative to using such a large, heavy and difficult to install pipe?

Is there an easy way to get the proper hole dug?

If I get a 12' 6" schedule 40 pipe ... how big/deep should the hole be. 3' deep and 12" wide?

Any suggestions or advice would be appreciated.

More research repeats the manufacturing literature that I received with the batteries, stating that the sealed agm does not vent, and is sealed and pressurized.


And this appears to address the question of can it vent, and how to store:


So, it appears the manufacturer says roughly:
1. Put the batteries in a battery enclosure that includes venting. ( for overcharging instances )
2. The batteries do not vent under normal use.

Dennis,
Thanks for the answer and feedback.

But, I am still left confused.

If a sealed AGM battery does vent hydrogen during normal use ... then that hydrogen surely comes from the water(fluid) in the battery ... which should result in lower fluid levels ... which should require replenishment.

But, I thought that sealed AGM batteries never required water to be added.

And, some reference to AGM batteries mention not needing to be vented as an advantage.

All of this left me believing that sealed agm batteries were designed not to generate hydrogen/oxygen. But, at the same time it seams unlikely that some H is not split with all that energy being moved.

I feel like I'm missing a piece of understanding here.

Anyways, can anyone give final confirmation that this battery:
http://store.altenergystore.com/Batteries/Batteries-Sealed-Agm/MK-8A31-AGM-105-Ah-20-Hr-AGM-Battery/p769/
does indeed require ventilation.

Thanks to all for your help and patience with my 'thick-headed-ness' :-)

John,
Thanks for the reply and reference link.
My question, or at least the part about 'boom', was at least 50% tongue in cheek.

But, I really do want to know ...

Do they vent during normal use?

From what I can tell, they do not. They may vent in a bad over-charge .. or similar. But in general, normal use AGM's do not vent hydrogen oxygen or other gases .

I'm just trying to get someone to confirm.

Thanks in advance,

Do AGM Batteries vent?

I'm mostly worried about the fact that I am going to have 4 105ah batteries within a few feet of a riding lawn mower ... inside a shed. ( But inside an enclosure ) And that the mower will be cranked and moved out of the shed ... again only a few feet away from the batteries.

Since they are enclosed ...Can they or their emissions ignite?

I'm I gonna go boom? :-)

James,
Thanks for the reply.

It sounds like our math ends up with the same answer! :-)

Yes, I have a mppt controller, and I've been avoiding talking about the load portion ... just so I can focus on and try to understand the battery charing portion.

in actuality, my boot strap system ( not optimized! ) is generating about 700 watt hours per day on average and at an average peak of about 145watts  ... over maybe 6 to 10 total hours of (semi)active charging ... from  a pitiful 4 watts in the morning up to a high of 145-170watts and then back down ...

the mppt controller is doing a wonderful job !

i was using the simple 170watts*4hrs ... to keep it simple and to have a similar net result.

anyways, back to the battery charging piece ...

your formula looks like it may be something like:

(battery_volts*battery_amphrs) / (pv_watts*sun_hrs)

is this correct?

Thanks Thomas,
It does help. I'm trying to get a handle on my current and planned loads.
At this point I think my test load is coming close to fully draining my battery, and my PV is barely keeping up.
So, this exercise is helping me quite a bit to figure out my  real needs.
Anyways, for the moment, I'm trying to focus on how to predict my battery charging capability . ... as a piece of the puzzle.

My math ends up looking like this:
(battery_amp_hrs / ( (PV_Watts/Battery_Volts) * Sun_Hrs ) )

so, using my 105ah battery on a 170w PV with 4hrs per day ...

(105 / ( (170/12) * 4 ) ) )

(105 / ( (14.17) * 4 ) ) )

(105 / ( 56.67 ))

(105 / 56.67 )

( 1.85 ) days to charge a single 105amp hour battery using

my earlier result was
57amphrs of a 105ah battery

so
57/105 =  .54 batteries per day
or
1/.54 = 1.85 days per battery

I hope the experts can chime in to make sure this is correct.