Community Forums

WoodGlue · 11-03-2012, 04:16 AM

I'd like to string 3 batteries together if this is possible. I haven't done it yet, but I'd like to eventually string together 3 12v AGM Deep Cycle Marine Batteries.

Possible?

Upsides?

Downsides?

Opinions?

Thanks,

WoodGlue

nightriderrv · 11-03-2012, 05:00 AM

You can do it as long they are wired POS to POS and NEG to NEG then it will stay at 12V don't do it the other way or you will end up with 36V in the end. I don't know the amp hr math but there are some here that do and I'm sure they will chime in but it will allow you to run longer for boondocking.

GWinger · 11-03-2012, 05:31 AM

WoodGlue,
You didn't state your objective but what nightriderrv said is correct. The 'parallel' connection, as he suggested would give you three times the capacity... assuming all the batteries are the same size as they should be.
GWinger

WoodGlue · 11-03-2012, 05:38 AM

It would be for boondocking/camping at State Parks and such. I'm the type of person to sleep with a light or to on, the fan going and maybe fall asleep with the TV on.

I didn't think about the 36v mistake! Thanks!

This is the battery I'd like to link together:

http://www.sears.com/shc/s/p_10153_12605_02850134000P

TXiceman · 11-03-2012, 06:00 AM

Wow, that is one EXPENSIVE battery. It you have room for 4 batteries, I would go with four 6 volt batteries. Wire 2 batteries in series to get 12 volt, wire the other two in series and then wire the two pairs in parallel to get 12 volts and more amps.

Ken

nightriderrv · 11-03-2012, 06:09 AM

WOW!!!! that is pricey but you get what you pay for they look good and should work fine now if you leave every light on they won't last as long but just be sparingly on your lights and I guess the TV is 12V and 120V also but you are on the right track. Led lights don't use a lot of power to run people been changing them out to save power and they run cooler too

az bound · 11-03-2012, 06:11 AM

Quote:

Originally Posted by WoodGlue

I'd like to string 3 batteries together if this is possible. I haven't done it yet, but I'd like to eventually string together 3 12v AGM Deep Cycle Marine Batteries.

Possible?

Upsides?

Downsides?

Opinions?

Thanks,

WoodGlue

Installing them in parallel will triple the storage capacity.

Maintenance free. Will not freeze even if fully discharged. Only loose 1-2% of charge each month in storage, no need for a maintainer. They have less internal resistance than wet cell so they will accept a charge faster at a higher rate. No stratification or corrosion issues, no gass off.

I would say the only downside is price.

My opinion is

clyon51 · 11-03-2012, 06:12 AM

DO NOT use any battery that says "marine" on it. Also DO NOT use any battery which is rated in CCA (Cold Cranking Amps). These are starting batteries and will soon fail in an RV house battery enviroment.

You want true DEEP CYCLE batteries. These are rated in Amp Hours (AH). If anywhere in the rating it states CCA, do not buy them.

The below link is a must read for you. Also read the second part, the link is on the bottom of that page.

http://www.marxrv.com/12volt/12volt.htm

Tha_Rooster · 11-03-2012, 06:17 AM

I run 4 Agms with no problems so 3 should be fine if you have a place for them. A twelve volt fan no problem a 32 inch LCD tv all night on a inverter maybe. You did not say what group size that make a difference also.

WoodGlue · 11-03-2012, 07:43 AM

Yikes! Now I'm confused! No marine battery?

I guess I'm most concerned about 3 things:

1) Keeping at least 1 interior light on in the evening hours (turn off at bedtime)
2) My TV is 12v - 24" (2 hours in the evening)
3) My laptop will be on 24/7 (Due to work - The laptop is a HP dm1z-4100) The laptop will be run by a 12v adapter obviously!

The battery is a group 34.

Thanks for all the info so far! I'm learning!!

I currently have a 145 watt solar panel

J Birder · 11-03-2012, 08:29 AM

Quote:

Originally Posted by clyon51

DO NOT use any battery that says "marine" on it. Also DO NOT use any battery which is rated in CCA (Cold Cranking Amps). These are starting batteries and will soon fail in an RV house battery enviroment.

You want true DEEP CYCLE batteries. These are rated in Amp Hours (AH). If anywhere in the rating it states CCA, do not buy them.

The below link is a must read for you. Also read the second part, the link is on the bottom of that page.

The 12volt Side of Life (Part 1)

This is good advice. There are true deep cycle batteries with really thick plates and there are starting batteries with much thinner plates. The marine deep cycly batteries are a hybrid about half way inbetween.

Joel

monkey · 11-03-2012, 08:54 AM

Quote:

Originally Posted by J Birder

This is good advice. There are true deep cycle batteries with really thick plates and there are starting batteries with much thinner plates. The marine deep cycly batteries are a hybrid about half way inbetween.

Joel

Good to know... Our mh came with both chassis and coach batteries fairly new. The coach battery is a marine battery,, it seems to do fine, but we don't boondock,, so I'll (try) remember this when it comes time to replace them...

Ed-Sommers · 11-03-2012, 10:14 AM

That Battery is listed at only 68 Amp Hours, very low for boondocking purposes. Three would get you to only around 200 Amp Hours, lower than only two REAL deep cycle golf cart style batteries like Trojans!

Ed

wa8yxm · 11-03-2012, 10:49 AM

Comments: RV's have two 12 volt batteries in them (Most any way, there are a very few exceptions) Those are the "House" or Aux battery and the "Main" or chassis battery used to start the truck part of the motor home.

Some also have a 3rd Generator, and in some cases the "Chassis" may be other than 12 volt.

We will thus stick with the House battery:

It can be one piece, 2, 3, 4,5,6,7,8,9 many. It matters not Electrically it is still ONE battery.

So assuming you have one now, you parallel an indentical battery, you now have one battery consisting of 12 cells, you add a 3rd you now have one 18 cell battery.

So the answer to your question is: YES, it can be done, no problem, I'm doing it.

Now,,, Some other comments:

You spoke of AGM DEEP CYCLE batteries,, I'm glad to see you choosing Deep Cycle, Those are best for house use as they do not object to being run down a bit where as starting batteries, including Marine/Deep cycle, are a lot less tollerant of that.

AGM however, In most cases is overkill, They are very expensive, and their main advantage over maintenance free is the lack of a "This side up" sticker IN a very few cases there may be other advantages to a Motor home owner, but frankly those are few and far between (Lifeline AGM's. specific brand, can accept a much faster recharge).

Lifeline are also more rugged than liquid types and Optima (A special case of lifelien) Still more rugged (Physically) but if you are driving your motor home in a manner whree this makes a difference batteries are not going to be a problem for you.

Finding a very big dustpan (Front end loader) and broom (Seeepwer) to sweep up what's left of your motor home.. That will be the problem.