Questions for setting up a solar system

[rvpopeye]

Spiff and Bob really said it all.....I can't add much to that.
I loved the comic relief on the last two posts too! Thanks given guys.
I prefer the 2x6v plan but 2x12v AGMs are an option too ,depends on your space and weight situation.
(AND wallet size.)

 

[Seraphim]

While I obviously can't speak for Bob, keep in mind that with 200W of PV panel (which is what Bob recommended), a 225Ah battery bank is more likely to suffer from chronic undercharging than is a 100Ah battery bank.

That depends on how many amps he uses on a daily basis.  Regardless of the total capacity of the batteries, if he used only 50ah  before recharging, it matters not if the system has 100 or 225 ah.  

 

[akrvbob]

No problems or issues with unvented batteries in my rig.
Bob

 

[Seraphim]

No problems or issues with unvented batteries in my rig.
Bob

I found that if I keep charging the batteries on shore power without using them, and no open vents in the unit, my propane alarm goes off.  Took me quite a while to track down the source of the sudden alarms, especially when the propane tank had been disconnected. Lots of experimentation proved the batteries overcharging was the only possible cause  Hasn't happened since I properly sealed up the vent boxes. There were also times, before I sealed the battery boxes, I'd wake up with a scratchy throat.  Just mentioning this for safety sake. Take it as you wish...

 

[Optimistic Paranoid]

Wasn't there a women here a year or two ago who reported that she had to dump an FLA and replace it with an AGM because it was setting off her allergy issues?  Laverne, maybe?  Blogged as The Complete Flake, or some such?

Regards
John

 

[GotSmart]

The subject of battery gasses is one of critical importance.  

Here is a link about the safety and dangers of gasses 

http://batteryuniversity.com/learn/article/health_concerns




[font=Arial, Helvetica, sans-serif]Charging batteries in living quarters should be safe. This also applies to lead acid. Ventilate the dwellings regularly as you would a kitchen when cooking. Lead acid produces some hydrogen gas but the amount is minimal when charged correctly. Hydrogen gas becomes explosive at a concentration of 4 percent. This would only be achieved if large lead acid batteries were charged in a sealed room.[/font]



[font=Arial, Helvetica, sans-serif]Over-charging a lead acid battery can produce hydrogen-sulfide. The gas is colorless, very poisonous, flammable and has the odor of rotten eggs. Hydrogen sulfate also occurs naturally during the breakdown of organic matter in swamps and sewers; it is also present in volcanic gases, natural gas, and some well waters. Being heavier than air, the gas accumulates at the bottom of poorly ventilated spaces. Although noticeable at first, the sense of smell deadens with time and potential victims may be unaware of its presence.[/font]


As a simple guideline, hydrogen sulfide becomes harmful to human life if the odor is noticeable. Turn off the charger, vent the facility and stay outside until the odor disappears. (To learn about potential hazards when incorrectly charging Li-ion, see http://batteryuniversity.com/learn/article/safety_concerns_with_li_ionLithium Safety Concerns.)




In a nutshell, If you can smell gasses, there is a problem.  Most times charging happens during the day when the van is open. In this situation the gasses do not concentrate and you can not tell.

I had my van shut up for a week, and when I opened it I could smell Hydrogen Sulfate.  I left the door open, opened the vent  and within three minutes no more odor. I now leave the windows and vent cracked.

In Bobs situation with the batteries in his van, the doors are open enough to never have any gas buildup.  So he will never have a problem with the hydrogen sulfate. The same goes for 99% of the members of this forum. 

If however there is a problem with the battery, it is possible to have the battery vent a large amount of gas into the living space.  The odds of it being bad enough to cause health problems is miniscule.  There is a much greater potential of a problem from the batteries not being bolted down.  

 

[Sabatical]

Two quick thoughts on this... A 12v battery is roughly the same size as a 6v battery. The 12v will have more plates in it (each cell is 2v). I have read that the plates are thinner and will therefore not last as long. If you're gonna spend that kind of money you probably want the longevity that comes from more robust components.
Second, if you decide to go with an mppt controller, you might look at the midnite kid with the whiz bang jr. accessory. This pkg is more cost effective than a decent pwm and the trimetric battery monitor that is so popular. The whiz bang jr gives all the info you will need to take proper care of your batteries and it's shown right on the charge controller lcd screen. I am using this setup and it works extremely well, so well that I bought another one for a different system.

 

[akrvbob]

Bear in mind, I only charge from solar, if I charged from shore power it would be a very different story!! Even then I'd never be over 20 amps so I don't think that would matter either.

Yes, I have a friend with sever breathing issues and she bought a pair of Trojan T105s and half way home her throat started closing up--and they weren't even connected yet!

She turned around and went back and exchanged them for AGMs and has never had a problem since.

If you have breathing issues, you ONLY WANT AGMS!!!!
Bob

 

[ccbreder]

It is understood some people have allergies and respiratory issues. They know they do and need to take extra caution. My long time shop experience has seen two batteries explode. Both were being "fast charged" and subjected to a ignition source. One was under the hood and one was in the back seat area. In both cases, the battery cell exploded, not the vehicle. I would be concerned with a battery sealed in a box before one vented in my van. The danger is confined gases, and the acid mist from high charge rates. And a note about hydrogen sulfide, if you smell it there is not enough, higher concentrations shut off the odor receptors and then you die.

 

[GotSmart]

If you smell it, there is a problem.

 

[mariasman]

This might sound obvious, as more energy is required to return a more depleted battery back to full charge, but while a battery cycled to 80% might need 105% the energy taken from it to return to 100% state of charge, the battery depleted to 50%  might require 125% of the energy returned into it before the  specific gravity rises as high as it can go.  These percentages stated are not set in stone, and they will change as the battery ages too.

http://www.otherpower.com/images/scimages/7427/Lead_Acid_Battery_Efficiency.pdf

 

[Spaceman Spiff]

It is understood some people have allergies and respiratory issues. They know they do and need to take extra caution. ...

And a note about hydrogen sulfide, if you smell it there is not enough, higher concentrations shut off the odor receptors and then you die.

I have two problems with your first statement:
1. most people don't know they are allergic to something until they are exposed to it and react.
2. a persons sensitivity to something changes with age, medical condition, length of exposure, etc.

The only information I have on what levels of hydrogen sulfide is considered medically problematic is from 'Battery University' linked to in an above post, to wit: "hydrogen sulfide becomes harmful to humans if the odor is noticeable".

-- Spiff