Solar, Batteries and Other Related Topics - 2017

[pkveazey]

I mentioned to Ruth that I wanted to learn more about a solar power system. I know how it works and what I need, but since I plan to use Lithium batteries, I need to learn more about how to protect the battery system from short circuit explosion. I could get into why I plan to use Lithium batteries instead of Lead/Acid but that would just start a fight. I have already picked out which solar panel I want, which control panel/regulator I want, which batteries I want and what inverters to use. I just need to learn more about how to protect the batteries from extreme currant draw, such as a short circuit. Lithiums can go off like C4 if shorted. You mentioned that we have that info on here. Where do I look to get more info?

Edit: I moved this great topic to here as it was getting away from the subject line in the Ham Board. Carry on folks - JMc

[JohnyMac]

Pkveazey, I heard you on the net last night. Your transmission up here came in around a 5/6.

There is a lot of stuff on this site just use the archive to dig it out  Here is an example. Doesn't answer your specific question but it is a start. 

On another note: Lithium, lead/acid, or gel cell they all have their +/-'s. I have been using solar/engine charged house batteries for thirty years now. On the boat the best was gel for us. At the cabin we started with gel and due to the cold they did not last. So we went back to lead/acid which are fine as the battery shack does not rock in a seaway like a boat does. 

May I suggest Pkveazey, that you start a discussion on this subject so we can all learn and expand our knowledge.   

[Kbop]

I could get into why I plan to use Lithium batteries instead of Lead/Acid but that would just start a fight. I have already picked out which solar panel I want, which control panel/regulator I want, which batteries I want and what inverters to use. I just need to learn more about how to protect the batteries from extreme currant draw, such as a short circuit. Lithiums can go off like C4 if shorted. You mentioned that we have that info on here. Where do I look to get more info?

Lithium is better than lead acid   especially in a cold environment.  I want to build a battery bank but am hoping the cost per AHr comes down.  I have a 5KW panel array and am planning on a savonius VAWT to supplement.

I'm assuming you can get an inline - per battery - temperature sensor/current fuse or cutout.

[Jackalope]

Cost is the main reason why I don't use lithium batteries in my system.  I've been using deep cycle lead acid in my system over the decades.  I'm going to purchase some more this Spring, as my current set is about 10 years old, and it definitely doesn't have the capacity anymore.  I've been looking at prices, and it looks like, for me, that Sam's Club has the best prices for deep cycle batteries, and they're Duracell deep cycle batteries.  I've looked at pricing with other vendors, but when shipping is factored in that Sam's Club is the best, especially when I'll be going there for other purchases anyways.  This current set are Excide batteries and I'm very happy with them.  Prior to that I had a set of Trojan T-105's and they barely lasted 4 years.  Typically, I don't discharge my batteries more than 80%, and they're maintained on a monthly basis.  They're recharged with a 750 watt array and a 400 watt wind system.

      Does anyone have any experience with Edison batteries?  They may end up being my final battery bank purchase, since they're noted for their longevity.

[JohnyMac]

A few thoughts on buying deep cycle batteries.

Go to the store with a volt meter.

Back in 1987 when I was the store manager for the Marina del Rey West Marine store, I use to check all of the batteries that came in shipments. If they were below 12.8 volts I would refuse them. I also tried to pick up batteries within 1 volt of each other. For example if I found 3 batteries in the 12.10 volt range and the fourth one I needed was 12.8 volts on the shelf I would keep looking till I found one 12.09 12.10 or 12.11 volts.

What I described above was more important to me than a brand. I have owned Trojan, West Marine and Excide batteries and they all worked as designed if I did my part. I also prefer buying Group 31 size batteries instead of using a 4D or 8D battery that I used on my boat. The Group 31's are A LOT easier to move around.

Last, I found that batteries had to be exercised so I had no problem taking them down to 50%. A good thing to do is to take them down to 30% or so once a year and put a 120 volt battery charger on them to recharge. This  helps to keep the lead plates clean.

It costs me $108- for one Group 31 (105 Amps) battery For kicks and giggles I just looked up a lithium battery and it would cost me $5,700- for a 360 amp one - OUCH! I will stick with my lead/acid. Thank you.

[Kbop]

100Ah Lithium is down to 1,250 now - life cycle is 10X a lead acid.
getting pretty competitive.  assuming you don't discharge them too far every day - about 10 year lifespan.
-
cheapish lead acid battery is about 100 for a deep cycle. They last around 5 years in use - JM, let me know if that is off.

so cost per Ah/yr in a perfect world is
$1.25 for lithium
$0.20 for lead acid

Lithium still needs to come down for me to use them.

[Jackalope]

The longevity of lead acid batteries is mostly based upon how they're maintained.  But I suppose that's true with any type of battery.  PK has voiced one of my concerns regarding lithium batteries, the chance of them exploding while charging.  I do have a few lithium batteries for various electronics devices, but I'm very careful as to how they're charged, and I never let them charge while unattended.  I don't worry too much about my lead acid batteries, and I haven't had any issues with them in the 40 years that I've been using that type of battery.

    I can buy a Duracell GC2 (T-105) 6 volt battery for $85.00 each, which is less than I paid for them 10 years ago.  Not a bad deal if they'll last as long as my current set.

[JohnyMac]

Keep it mind what Jackalope is talking about is putting those golf cart batteries in series vs. parallel.

Most things in the solar world run off of 12 or 24 volts. Jackalope has cleverly taken those 6 volt golf cart batteries and put them in series. This gives him 210 AH for $170- vs. buying 2, 12 volt batteries for $216- and accomplishing the same end result. It is also generally believed that 6 volt golf cart batteries will out live 12 volt batteries. They do weigh a lot though so beware.   

I am only posting this clarification so a novice doesn't go out and buy a 6 volt golf battery expecting the battery to power 12 volt appliances.

All good stuff... Keep it coming...

[Jackalope]

Good point Johny.  Actually, I have series parallel set up for 12 volts, so it increases the total amp hours, but the total system voltage remains at 12 volts.  My small home is wired for both 110 VAC and 12 VDC.  I went with 12 volts rather than 24 or 48 volts because there are so many appliances and devices available that will run directly off of 12 volts, rather than going through a DC voltage converter or an inverter.  Most of my lighting also runs on 12 VDC.  For example, in my kitchen/dining area there are four Ikea pendant type light fixtures, two of them run on 110 volts AC and the other two on 12 VDC, the fixtures are identical except the bulbs.  The wiring consists of two strands of 00 wiring.  It's important to note that the house is small, so the voltage drop is not that significant.  All of the task lighting is 12 VDC, using a combination of 12 volt incandescent, fluorescent and LED lights, though I'm converting to LED's as finances allow. 

One of the task lights that I really like are called littlelites  http://www.littlite.com/   They are favored by musicians, and they come with a lifetime warranty.  These tiny lights are super bright, perfect for a reading lamp.  They're offered in incandescent, halogen and LED configurations.  Some other off-grid folks turned me on to them.  Lately I've been using some LED light strings, which are fine for general purpose or mood lighting.

     Getting back to the batteries, I maintain a number of solar powered radio repeaters, and we use lead acid batteries exclusively for our systems.  I tried some of the AGM batteries, but found they didn't last as long as conventional lead acid batteries.

[JohnyMac]

You got me thinking Jackalope (Scary) that my solar and battery living knowledge circles around living on a boat. I know NOTHING about land living solar & battery living so please, everybody, share with the group your favorite appliance companies. 

[Kbop]

JM - LED lighting.

I come at this from a mobile & remote operations point of view.
 LED lighting is - without a doubt - the best way to go with area and task lighting.
They can last for years.  no fragile filaments or glass bulbs to break.  no hot bulbs - low thermal signature.  you can get indoor or outdoor versions.  they work with AC mains or DC.  very efficient energy to light ratio -16 watts give as much light as the old incandescent 100 watt bulbs.  the light has an excellent CRI rating (you get to choose).  You can pick the color - so red/amber for night ops and high percentage blue light for close work.  they work with dimmers.  You can even get them in high PAR values for growing plants.
just be aware that most LED lighting (AC or DC) is susceptible to EMP and water damage.
the only drawback is price but it has plummeted in the last few years. 
LED lighting is now cheaper than incandescent including halogen or CFL.

[JohnyMac]

Thanks Kbop! Do you have a company link that you can recommend?

[Kbop]

@JM  the market is getting big enough to attract brand names.
in DC - LUXEON and CREE are good LEDs  the light is usually built around that.
in AC applications, try the usual suspects - like Philips, sylvania or GE.
most big box or local hardware stores carry them.  one suggestion, use what you have until they wear out and replace them a couple at a time - spreads the cost, adds to your learning curve.  if you have intensive lighting applications or are very aware of your power budget, you'll notice the difference.

most of you can educate me on flashlights - so i'll jump to house type lighting.   
here is a good site for window shopping AC bulbs. (A19) is the typical base for a US light bulb.
https://www.1000bulbs.com/category/led-light-bulbs/

[JohnyMac]

I have not seen any solar companies that you folks do business with for accessories, e.g. lights, bulbs, etc. Currently I am using www.westmarine.com for all of my accessories. I know there are better sources out there then paying top "boat" dollars.

My plan if needed*, to turn off the main breaker switch to my electrical box, plug into a 20 amp socket my 12 volt system. Then to swap out lights or bulbs with 12 Volt rated ones.

* I would not do this unless electric was off for a LONG time. For short stints I am happy with using kerosene lamps for light. My water
   system, Sirius radio, ham radio, etc are already being ran via 12 volt and my system. 

[Jackalope]

For the past several years I've been buying bulbs on eBay, mostly because they have the best selection and price, though not necessarily the best quality.  The last batch of LED bulbs that I've purchased have been good, no problems.  Prior to that I purchased some 12 VDC compact fluorescents and they lasted less than a month.  Anyways, I've started stocking up on the 12VDC LED bulbs because of their longevity.

[Jackalope]

   As a follow-up, I finally got around to replacing my solar system batteries this past weekend.  I'm using Duracell golf cart batteries (GC2) which are essentially the equivalent of the Trojan T-105 batteries.  These are 6 volt batteries, and they are quite heavy. 

  The old batteries were manufactured in November of 2005, so I definitely got my money's worth out of them.  Two of the batteries were not useable, but two of them still held a decent charge and I was still using them until they were replaced.  My solar system is used primarily for lighting, computers and radios.  The system can handle water pumping and refrigeration needs, if pressed.  Al in all, I'm quite pleased with the old batteries, and I hope the Duracells will be worthy successors. 

[JohnyMac]

Jackalope, would you share the price you paid for the battery's?

[Jackalope]

   Sure, they were $84.52 each with a $5.00 refundable core charge, plus our local sales tax. 

[JohnyMac]

For the archives...

What is the benefit of running two 6 volt batteries in series vs. running two 12 volt batteries in parallel?

[Jackalope]

   The biggest benefit is the longevity of the 6 volt batteries.  Six volt golf cart batteries, with their thicker plates, are able to endure long periods of deep discharging and recharging with less effect on their life span.  Even though both the 6 volt series battery bank, and the 12 volt parallel battery bank may have identical amp hour storage capacity, in the long run, the 6 volt battery system will be more economical, because the 6 volt bank doesn't need to be replaced as quickly.  My last battery bank is an excellent example of 6 volt longevity, lasting more than 11 years.  Most 12 volt batteries typically have a life span of 4-6 years.  You could go even further by using 2 volt batteries, which will easily last 10-15 years, if they're maintained properly.

[JohnyMac]

Jackalope is 100% correct.

Some cruisers (Folks who sail the oceans) use 6 volt in series for exactly what Jackalope wrote but do to their size and weight are limited to boats 45' or larger. Since you do not live on a boat the bigger 6 volts are very economical and will last a long time if properly maintained.