Solar Charing not popular with CPF?

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KITROBASKIN

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For that price, I could buy another deep-cycle battery, which would give me the equivalent energy that the solar setup would provide in about a week of charging.

So the break-even point seems to be about a week without power. Shorter than that, and it makes better economic sense to just buy another battery and keep it charged. Longer than that (or for use in a remote site where you don't have mains power), the solar setup makes more sense.

Not sure how you determined a 'week without power', but deep discharging your battery will shorten its life. Also, I bought my first BP Solar 75 watt panel in 1996 (something like US $4.50/watt back then) and it is still going strong. The other one is about 2-3 years younger. Even though I take care of my Trojan batteries, they do not survive nearly that long. The first set required that I refill the electrolyte more and more often as they aged. We'll see how the AGM's do. We do get a lot of sun here. Solar power is not perfect and there are environmental costs associated with their manufacture, but I am so glad to have my system.
 

KITROBASKIN

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For me, solar charging takes too long.

That's like saying your AAA batteries don't have enough capacity. Simply put, a larger panel size allows faster charging. My stationary system can charge just as fast as the coal-fired powerpole electricity. And since I don't let my 18650's discharge deeply, the little 15 watt is not that bad either. It is hard to remember to use the sun here at the house though.
 

KITROBASKIN

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Not really. I can carry spare AAAs on me and in my Work/Get home bag. And actually, that's what I do.

Can't do that with solar charging.

Different strokes...

The only alkalines we use in flashlights are from devices that have already utilized most of the energy. Our (almost) 5 year old can use his torch and learn from his mistakes, while our used-for-one-year 9 volt batteries last 'forever' snapped to a Pak-Lite in the master bedroom.


Personal attack deleted - Norm
 
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Norm

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Please drop the battery Chemistry chit chat and get back to the thread topic. Six off topic posts have been deleted, there are plenty of existing threads where you can discuss battery chemistry. - Norm
 
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IonicBond

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Solar can be done, but it is usually confusing and frustrating because many people do it backwards. And yes, when you consider that a long-term installation requires battery replacement in a few years, the overall cost is about 10 times what you get from your local power company.

Still, there are other reasons to do it. But to do it properly one follows these steps in order:

1) Find out how much power you plan to run, and for how long (hours). You can use a multimeter, and something like a P3-International Kill-A-Watt meter. For example, with the kill-a-watt, you could plug in your Maha, and find out how much power you draw charging up 4 eneloops. Add up all the other power you plan to draw, and multiply that by time of use.

2) Knowing how much power you need daily, for a typical deep-cycle lead-acid battery, you then DOUBLE the ah requirement, since most plan to go no deeper than 50% DOD to get any sort of cycle life out of them.

3) Now you figure out how much panel wattage you need to replenish MORE than 50%, since recharging is not perfectly efficient. Simple pwm solar controllers do ok, but mppt types do it much more efficiently, and allow for "GTI" or grid-tie panels that are cheaper and usually come in much larger wattages.

4) This is a BIGGIE. Even if the 3 steps above are calculated, you have to know your solar-insolation hours for the area you live. The most common mistake is to calculate based on sunrise-to-sunset. WRONG. Early morning and late afternoon hours, although having plenty of visible light, don't really count in the calculations. What one wants to do is consult a SOLAR INSOLATION chart to see if the panel wattage calculated in step 3 will jive with the actual solar-insolation hours available. Depending on where you live, and since you want to use the worst-case scenario of winter months, you may need MUCH more panel power than originally calculated.

5) If you are doing more than just powering an RV or an experimental system, do not paint yourself into a 12v corner! Ie, an off-grid cabin that uses quite a bit of power would actually end up being dangerous at 12v and super high currents. Far better to start out with a 24 or 48v system, where cable losses are low, and wiring runs can be much longer.

A quick glance at your solar insolation hours can be found here:
http://www.solar-electric.com/solar-insolation-maps.html/

What you are looking for is the "kWh per square meters per day" value in hours. In Seattle in the winter, that would be 0 to 2 hours. Albequerque might be 5 or 6 hours in winter! Again, these are NOT sunrise-to-sunset hours. You can see that in Seattle, you may have to adopt HUGE panel arrays, and special agm batteries that can be recharged VERY quickly, adding greatly to the overall cost.

You can see that just winging-it by buying stuff first, is the most expensive way to go and is the backwards approach.

A couple sites that might be very helpful:

http://forum.solar-electric.com/forum.php
and
http://www.solarpaneltalk.com/forum.php

These may help guide you.
 
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SemiMan

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If you do what the last poster suggested you will have dead batteries and quickly killed batteries.

Arm chair experts should not make recommendations on expensive battery backed solar systems .

Isolation sizes panels ... With lots of degradation factors or you will not have enough.

Blindly sizing batteries for 50% load usage works in summer .... Most of the year even in normally sunny places you need far more storage.

AGM is only for unattended systems and/or where cold temps or highest efficiency is needed. Flooded batteries of proper design will last longer and are more abuse tolerant.
 

KITROBASKIN

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Here is the Original Post:

Aside a few threads on solar charging, I'm not seeing threads on this topic. Why isn't solar charging popular on here especially for emergency/prepping? I don't know much about solar charging but I'd like to learn what brands, models and tech is to rave for in 2014? I want one system that can charge 18650s or Eneloops or radios that run on either lithium or NiMh. Are we there yet where solar chargers can handle 18650s size lithium? With the best setup, how many hours of charging are we talking about and how many 18650 or eneloops can solar chargers handle at once with today's tech?
 

WalkIntoTheLight

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AGM is only for unattended systems and/or where cold temps or highest efficiency is needed. Flooded batteries of proper design will last longer and are more abuse tolerant.

Really? I've read that AGM is better for deep-cycle batteries, whereas the flooded batteries are usually for car-battery applications (lots of current, but don't drain them). Doesn't AGM use thicker plates, which allows you to drain them more?
 

SemiMan

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AGM stands for absorbed glass mat and it describes how the electrolyte is held not how the plates are made.

The longest lasting lead acid are flooded ... But need to be maintained.
 

KITROBASKIN

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AGM stands for absorbed glass mat and it describes how the electrolyte is held not how the plates are made.

The longest lasting lead acid are flooded ... But need to be maintained.

AGM is more expensive given the same capacity, I believe. The charge cycle is different, is it not? I chose AGM for my second set of batteries because of the indoor location and the sounds and smells of flooded lead acid.

Let's start a thread called Going Solar, that will have more wide ranging information and beliefs/experiences
 

SemiMan

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Different voltages not necessarily different cycle.

AGM is expensive.

Often people will pipe any fumes from flooded outside and just good practice during charging. Most electrical codes have mandatory venting requirements.
 

WalkIntoTheLight

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The AGM batteries I use are just the car-battery-size deep cycle marine batteries. I have no first-hand experience with household off-the-grid systems, but I assumed they would also use AGM. I guess not. Is AGM too expensive for a large system like that, or is flooded really a better solution?
 

Norm

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What do we need to do to keep the topic away from battery chemist?
Please drop the battery Chemistry chit chat and get back to the thread topic. Six off topic posts have been deleted, there are plenty of existing threads where you can discuss battery chemistry. - Norm
 
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ChrisGarrett

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Hi Norm,

Either keep deleting (pain) or lock it down.

Maybe this thread has run it's course?

I first thought that this thread was about smaller, solar charging systems, like you and I have put together.

Chris
 

SemiMan

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Norm, your micromanaging of this thread is over the top. There was some unprofessional chat but that's done. If you are talking solar charging then you need to talk chemistry as that is a big part of it.

Moderation means directing not forcing just because you don't like the direction personally.
 
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ChrisGarrett

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Norm, your micromanaging of this thread is over the top. There was some unprofessional chat but that's done. If you are talking solar charging then you need to talk chemistry as that is a big part of it.

Moderation means directing not forcing just because you don't like the direction personally.

Actually, here's the OP:

"Aside a few threads on solar charging, I'm not seeing threads on this topic. Why isn't solar charging popular on here especially for emergency/prepping? I don't know much about solar charging but I'd like to learn what brands, models and tech is to rave for in 2014? I want one system that can charge 18650s or Eneloops or radios that run on either lithium or NiMh. Are we there yet where solar chargers can handle 18650s size lithium? With the best setup, how many hours of charging are we talking about and how many 18650 or eneloops can solar chargers handle at once with today's tech?"

As you can no doubt see, 'battery chemistries' don't even enter into the OP's questions, he's focusing on solar panel type chargers to charge up his rechargeable gadget batteries/cells.

Now, we do have AGM/SLA deep cycle batteries which most of us probably use, we have old style 'flooded' LA batteries (do they still even make these?) and we have the new lighter LiFePO4 'motorcycle' jobbies which people can use as a 'mother battery,' if they want to add one to their solar charging rigs, but that's an easily discussed topic not really worthy of the nuances and hairs that some in this thread want to split.

Anyhow, if you want to discuss different LA batteries, start a new thread.

It's funny, but with your vast knowledge of solar charging systems, you didn't share one iota of 'solar panel' advice with the OP, lol. You went on about something he didn't even ask about in his OP.

Finally, while often times an OP topic veers off on tangents in sometimes a good way, that doesn't mean that a moderator isn't correct in steering the topic back on point.

Just because I try and stay on point, here's some free 'pron:'

SystemRear.jpg


Here's the top view of Norm's elegant 'drink cooler' box that he made:

11849641854_2d0c4e3c31_o.jpg


Chris
 

Norm

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Norm, your micromanaging of this thread is over the top. There was some unprofessional chat but that's done. If you are talking solar charging then you need to talk chemistry as that is a big part of it.

Moderation means directing not forcing just because you don't like the direction personally.

I suggest you read rule 8.

Norm
 

StorminMatt

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I think that the practicity of solar charging depends ALOT on where you live. Here in Northern California, you're lucky if you get 10 overcast days between mid May and mid October. Bright sunny days are largely something that can be counted on here from late spring to early fall. So solar charging actually makes sense. Given that a small, portable monocrystalline USB solar charger can charge a smartphone as fast as a wall outlet, it is actually better from even a weight standpoint to carry a solar charger on a backpacking trip than it is to carry a bunch of extra batteries. A solar charger is even better for car camping since you don't need to worry about running your car periodically, discharging your battery, or needing to charge gadgets or batteries in your car. Hell, a solar charger even makes sense if you want to chill in a far corner of your backyard or city park and use your phone or tablet. Granted, the same may not be true in most other parts of the country (or the world). But when sunny days are practically a given for over half the year, solar just makes sense.
 
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