Deep Cycle batteries | are they half the power?

[Deleted User]

Let me rephrase my original question:  I am picking up my 2020 T@B 320 Boondock lite next week.  I called and asked my dealer about putting a deep cycle battery (AGM) into my T@B 320 2020. He said it would only give me half the power of the 12V battery that he put in there (I don’t know what that is so if I should ask for a specific type let me know). It sounds like the only way to use AGM is you have to have 2 of them if you want the same or better performance than one 12V.  I don't think there is room for two in the 2020 320-S but I may be wrong.  I’ll be doing a lot of dry camping.  I have purchased a Honda EU2200i generator. Has anyone put 2 AGM in a T@B 320? 

gspdx

Well - I will tell you what I think I know!

I don't have a T@B 320 so I don't' know what the standard battery is.  My T@b 400 came with two 6 VDC AGM batteries.  I believe they were 235ah batteries.  Wired in series they created a 12 VDC 235ah system.

I can only assume the dealer means you should only discharge to 50% for max battery life.  If you are regularly discharging lower that 50% you will start to shorten the battery life.  That is not to say they have half the power.  If you are out and need to run your batteries down farther you can.  

So I had about 117 ah available to use without causing degradation of the batteries.

Do you know the specs on your battery?

pthomas745

What battery is in your trailer now?  If you are subbing a smaller battery, then it may well be "half the power". 

Be specific:  how many amp hours and what size are the batteries you are trying to replace.  What are you trying to replace it with?  And,  are you trying to install the battery inside the trailer?

I have one battery, because that is all I need.  There is no "right way", it all depends on your needs.

Keep this battery FAQ handy.  Use it to compare and examine all the battery advice you get!

https://www.solar-electric.com/learning-center/deep-cycle-battery-faq.html/

[Deleted User]

I watched some videos, which I should have done before posting.  I think the issue is I need 2.  Now I'm checking to see if 2 will fit. 

N7SHG_Ham

All lead acid chemistries batteries be they flooded, AGM (maybe even gel) all have about 50% usable power if you want the battery to have any lifespan at all. So if you have 100ah rated battery, then you have 50ah usable at a 5ah (C/20) discharge rate, less usable at higher rates.

Either the dealer doesn't know what he is talking about OR they are talking of replacing your current battery with a single smaller capacity AGM.

The only way to get more than the 50% usable is the change chemistry of the battery, LiFePo4 is the go to choice currently, big up front cost but assuming they really will last 10 years like the warranty says, then cheaper per usable AH in long run. That allows conservatively 80% discharge and some say up to 100% discharge, no ill affects from big loads, no maintenance, faster charging, lighter weight, etc.

pthomas745

Why do you think you need 2? 

GatorEgg

You need to get the numbers (amp hrs, model, part #)off your current battery so you have something to compare.  Then we can help you.

Sharon_is_SAM

@Missstsomewhere, you are smart to plan for a large battery capacity if you plan to dry camp a lot.  There are members who have placed 2 wet cell 6v batteries in the tub, but I do not know of anyone who has placed 2 6v AGMS in the tub.  Several members have placed their AGMS inside under the driver side bench or in the closet of a clamshell.  We have a single 150 amp AGM in the plastic tub, but it required the tub to be moved forward to accommodate the footprint.  To fit the 6v x 2, you may need to move the LPG framing and/or downsize your LPG tank.  Just some ideas.  The good thing about AGMS is they can be placed on their side or on their ends to free up space as necessary.

Sharon_is_SAM

Some more info.

https://tab-rv.vanillacommunity.com/discussion/comment/103456#Comment_103456

Info about fitting a 150 amp Group 31 here:

https://tab-rv.vanillacommunity.com/discussion/3346/agm-filliment-question-for-outback-model/p1

[Deleted User]

I am not going down the modification road right now.  Too new/inexperienced.  According to NuCamp, I can fit a Group 27 deep cycle battery in the space provided in the 2020 T@B 320-S boondock. If there are any specific battery manufacturer/type recommendations for that, love to hear them. If I can't do 2 6V AGM (without mods), I at least want the very best I can get that will fit.  

dCliffhanger

My dealer, Jerry's in Monona Wi, put me onto a relatively new form of lead acid battery that was patented by the Caterpillar Co about ten years ago. It's branded the Firefly, a Carbon Foam battery which has the ability to be drawn down to near zero % routinely without suffering the extreme sulfating that degrades other lead acid batteries. They, literally, wedged a Grp31 115 ah battery into my T@B 320S tub. They are more than double the cost of standard deep cycle and hard to get. But, they are projected to give 3-4x the life even when routinely drawn down low or even left discharged for up to two years. The military and world sailors are finding them to be terrific in their applications. I've only begun to take mine on the road, but I'm convinced this battery will give me more usable power storage in my 320's limited space, and last longer, given the deep discharging demands I'm likely need when off grid. It's going to be, almost, like having two batteries. Check them out:  http://fireflyenergy.com/products/12v-g31-battery/  There are getting to be quite a few actual experienced based reviews out there.  Oh, and they are much cheaper than lithium and not sensitive to cold like lithium.  Sounding perfect for the off grid RV'r.