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AGM Batteries

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Posted by Mark C.

Jul 17, 2018 at 8:22am

I have a 100ah renogy agm sealed battery. I have it in a small room in my house connected to the other necessary solar equipment.I have been reading that these batteries will emit hydrogen sulfide and/or hydrogen. My concern is about how much do these batteries really emit and how well should I be venting the room.Theres fans all around my house blowing anyway so I'm hoping the gas just mixes into the air and everything is fine.There is conflicting information on gas emmisions from these batteries.So, once and for all.Do they give off hydrogen sulfide or not? Also hydrogen sulfide is heavier than air so what's the concern with that?

Posted by Guest

Jul 17, 2018 at 9:11am

Valve regulated lead acid batteries only vent when over charged.
They are sealed to allow for the recombination of the H and O at some pressure. The valve vents anytime the pressure is too great.

Posted by jsb2000

Jul 18, 2018 at 4:19pm

It's always a good idea to vent the room when batteries are concerned. Hydrogen is an explosive gas and electronics do, at times, produce sparks.

Having said that, my deep cycle lead acid batteries are located in the same room I'm typing this reply from. The room is roughly 18 x 10 x 8. My Renogy Solar installation has been in service for just over 4 years now. Lots of electronics in here, too. And I haven't asphyxiated or gone boom yet.

I suspect you'll be just fine.

Posted by tattoo

Jul 18, 2018 at 7:14pm

jsb2000 Avatar

Jul 18, 2018 at 4:19pm jsb2000 said:

It's always a good idea to vent the room when batteries are concerned. Hydrogen is an explosive gas and electronics do, at times, produce sparks.

Having said that, my deep cycle lead acid batteries are located in the same room I'm typing this reply from. The room is roughly 18 x 10 x 8. My Renogy Solar installation has been in service for just over 4 years now. Lots of electronics in here, too. And I haven't asphyxiated or gone boom yet.

I suspect you'll be just fine.


Yes sir, My solar system and batteries are vented and in the room where I sleep and have been for over 1 and a 1/2 years....

Posted by Admin

Jul 22, 2018 at 6:16pm

When it comes to having an AGM battery installation, we readily recommend any kind of aired space that's bigger than a battery box, this should be fine. The AGM battery chemistry should actually be okay with ventilation and users don't have to worry about any potentially toxic fumes.

Posted by joyfulskip1

Jul 23, 2018 at 1:40pm

So, if one were to put 2 100ah AGM batteries in the interior of a truck camper to store solar energy in, what would be the needed amount of ventilation in there?  Or, where can I get an external battery cage of some sort to hold each of the batteries fastened against the underside of the Truck Camper frame in front of where the wheel wells of the truck would be?  I need to keep them attached to the camper and not the truck.  They would be up above the wheel wells in addition to being in front of the wheel wells to allow the camper to be loaded on and off.  

Thanks!

Posted by smokeys pipe dream

Jul 23, 2018 at 3:02pm

hi, ive turned my school bus into a rv (camp on wheels) and i have a mid size fridge and freezer 6 amps each off the top of someones head how many 250 amp hr batteries do i need to last a week without sun like in the winter i have a aims 4000 pure sine inverter and whats the best battery for the buck if they last pretty good i dont need the best going id rather go big to start with im thinking 12 of them @12 v 250ah id rather be a hair to big than to small so my discharge will be smaller so i can use cheaper batts to start does this sound reasonable?

Posted by Guest

Jul 23, 2018 at 4:51pm

inverters are DC appliances, seems I;ve read here or there that DC sucks! always a good laugh.

Posted by tattoo

Jul 24, 2018 at 6:44am


Jul 23, 2018 at 4:51pm Guest said:




inverters are DC appliances, seems I;ve read here or there that DC sucks! always a good laugh.


Yes sir I'm the one that says DC sucks Bird and what I've read about how well DC works I'm right... It has nothing to do with inverters it's the DC load side of a CC.....But when you only have solar lights on the walkway to your house I guess DC is just fine ain't that right bird?

Posted by Mark C.

Jul 24, 2018 at 4:17pm

So far so good.Battery has been charging heavily every day and I can't seem to notice any problem.

Posted by tattoo

Jul 24, 2018 at 5:32pm


Jul 24, 2018 at 4:17pm Mark C. said:


So far so good.Battery has been charging heavily every day and I can't seem to notice any problem.


Man that is awesome.... Solar works great when it's working like it should...

Posted by skyguy42s

Aug 28, 2018 at 6:51pm

I have two Renogy Deep-Cycle AGM6-260 (6V 260 Ah/20Hr) batteries connected in series for my RV 12V system. In the Renogy battery specification of 'Charge Voltage 25-DegC' for 'Cycle Use' applications I see a note "max charge current: 27A". Is this actually the maximum charge current (in constant current Bulk Charge Stage) which can safely be pumped into these [series-connected] batteries?  I thought Deep-Cycle AGM batteries tolerated high charging current rather well - yes? If so, then 27A seems well below another manufacturer's recommended AGM charge current of at least 52A (battery capacity 260Ah * 0.2) for repetitive deep cycling applications. Also, assuming that RV usage results in approx 50% DOD each day, it seems that daily charging at the low 27A or less (due to solar panels flat on roof and variable sun irradiation levels) may tend to risk an undercharge problem whereby the battery’s state of charge may gradually “walk down” as it is cycled over successive partially overcast days. If AGMs are subjected long term to under-charged cycling, wouldn't this eventually have negative affect on battery life? Am I missing something?

Posted by tattoo

Aug 28, 2018 at 8:04pm

skyguy42s Avatar

Aug 28, 2018 at 6:51pm skyguy42s said:

I have two Renogy Deep-Cycle AGM6-260 (6V 260 Ah/20Hr) batteries connected in series for my RV 12V system. In the Renogy battery specification of 'Charge Voltage 25-DegC' for 'Cycle Use' applications I see a note "max charge current: 27A". Is this actually the maximum charge current (in constant current Bulk Charge Stage) which can safely be pumped into these [series-connected] batteries?  I thought Deep-Cycle AGM batteries tolerated high charging current rather well - yes? If so, then 27A seems well below another manufacturer's recommended AGM charge current of at least 52A (battery capacity 260Ah * 0.2) for repetitive deep cycling applications. Also, assuming that RV usage results in approx 50% DOD each day, it seems that daily charging at the low 27A or less (due to solar panels flat on roof and variable sun irradiation levels) may tend to risk an undercharge problem whereby the battery’s state of charge may gradually “walk down” as it is cycled over successive partially overcast days. If AGMs are subjected long term to under-charged cycling, wouldn't this eventually have negative affect on battery life? Am I missing something?


Forget about Battery state of change SOC it means nothing and it shouldn't even be there....


Are your batteries going to float? What is your voltage in the morning and what is it at sun down?

Posted by grumpy

Aug 29, 2018 at 1:02pm

So with all this talk about AGM Batteries emitting dangerous or explosive gasses when the manufacturer of AGM Batteries (including Renogy) says that they can be mounted in any direction. Am I missing something? I was under the impression that AGM Batteries are completly sealed.

Posted by tattoo

Aug 29, 2018 at 1:12pm

grumpy Avatar

Aug 29, 2018 at 1:02pm grumpy said:

  Am I missing something? I was under the impression that AGM Batteries are completly sealed.


Me too..........

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Posted by bupkis

Aug 29, 2018 at 5:57pm

grumpy Avatar

Aug 29, 2018 at 1:02pm grumpy said:

So with all this talk about AGM Batteries emitting dangerous or explosive gasses when the manufacturer of AGM Batteries (including Renogy) says that they can be mounted in any direction. Am I missing something? I was under the impression that AGM Batteries are completly sealed.


valve-regulated lead-acid battery or VRLA

if overcharged or charged faster than the H and O can recombine they will vent if the pressure inside exceeds the what the valve is set to open.

Posted by v10

Aug 29, 2018 at 7:15pm

Volvo installs them (starting battery) under the back floor of the xc70....



Posted by Admin

Aug 30, 2018 at 5:09am

grumpy Avatar

Aug 29, 2018 at 1:02pm grumpy said:

So with all this talk about AGM Batteries emitting dangerous or explosive gasses when the manufacturer of AGM Batteries (including Renogy) says that they can be mounted in any direction. Am I missing something? I was under the impression that AGM Batteries are completly sealed.




AGM batteries are virtually completely sealed and can be mounted in different directions due to the mesh inside which prevents spills like in normal lead acid batteries. AGM charging abuse, while not immediately apparent, can and will pressurize internally, by which the the battery might buildup and have a one-way pop out valve to safely release or vent the fumes. The rate at which the fumes are released is heavily regulated due to the mesh inside the battery, so not near those dangerous amounts, at least not at one time. An un-ventilated battery can possibly (over time) have a buildup because the AGM battery might still need to vent if it is being abused. You can expect the battery to be irreversibly damaged. So while the fumes released are not at the rate for other batteries that leak acid, we still recommend some type of ventilation, even if small.

-Renogy Team

Posted by Admin

Aug 30, 2018 at 5:19am

skyguy42s Avatar

Aug 28, 2018 at 6:51pm skyguy42s said:

I have two Renogy Deep-Cycle AGM6-260 (6V 260 Ah/20Hr) batteries connected in series for my RV 12V system. In the Renogy battery specification of 'Charge Voltage 25-DegC' for 'Cycle Use' applications I see a note "max charge current: 27A". Is this actually the maximum charge current (in constant current Bulk Charge Stage) which can safely be pumped into these [series-connected] batteries?  I thought Deep-Cycle AGM batteries tolerated high charging current rather well - yes? If so, then 27A seems well below another manufacturer's recommended AGM charge current of at least 52A (battery capacity 260Ah * 0.2) for repetitive deep cycling applications. Also, assuming that RV usage results in approx 50% DOD each day, it seems that daily charging at the low 27A or less (due to solar panels flat on roof and variable sun irradiation levels) may tend to risk an undercharge problem whereby the battery’s state of charge may gradually “walk down” as it is cycled over successive partially overcast days. If AGMs are subjected long term to under-charged cycling, wouldn't this eventually have negative affect on battery life? Am I missing something?




For the time being, the recommendation stays the same. Some AGM batteries are capable of higher amperage charge and they can sometimes be up to 5x faster than flooded battery charging. However, at the same rate, charging a battery faster than can cause a buildup by which the batteries heat up and have to vent. Some manufacturers might recommend 0.2C for the battery, but this particular battery does not. We will look into this information and report if there is an update.

-Renogy Team

Posted by tropex21

Sep 25, 2019 at 4:10am

The original AGM battery in my Mercedes is still going strong at 9 years. The instrument cluster can give you the current voltage and it's been doing fine lately so I haven't bothered to replace it yet. Advance Auto typically has good coupon codes to take the price down about $50 so they're not too much more than regular batteries plus they last longer and you don't get the corrosion on the terminals you normally get on flooded batteries.

expertpickhub.com/

Posted by Admin

Oct 14, 2019 at 11:01am

grumpy Avatar

Aug 29, 2018 at 1:02pm grumpy said:

So with all this talk about AGM Batteries emitting dangerous or explosive gasses when the manufacturer of AGM Batteries (including Renogy) says that they can be mounted in any direction. Am I missing something? I was under the impression that AGM Batteries are completly sealed.




AGM and GEL batteries are designed to be Spill-proof through acid encapsulation in matting technology. This means you can mount them right side up, or on their sides. It is not recommended for them to be mounted upside down.

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