If you are never going to do any boondocking and always on shore power then 1 group 24 deep cell battery will fit your needs. Odds are that is what you have now.
This post is assuming your are going to stay with lead acid batteries. There are higher end ones, EMAN here has the AGM’s but his rig is setup special beyond most any of us here. He has the ultimate solar off the grid package….
If you want to invest in the future where you might want to try boondocking then 2 batteries is a good place to start. Especially since you have a slide as the slide eats up power going in and out. Now here upgrading in size from the standard Group 24 helps when boondocking. If you are staying in the 12 volt battery method to do this, group 27 or group 29 have more capacity over the group 24. I myself have 2 group 27’s. We fall boondock which means the furnace runs I also upgraded most all inside lights to LED’s over the last 2 years. And I deactivated any excess draw in the camper. Bascially I became a power mizer. Part of boondocking is eliminating the wasted use of power.
However… upgrading from the Group 24 size you have to deal with the battery tray on the front of the camper. They only hold group 24 unless your is a special. When I upgraded I made a larger rack that dropped in the Sunline rack and had to buy 2 new battery boxes.
There is nothing wrong with adding a 2 Group 24 batteries, they will fit your rack if you do not want to deal with making the rack bigger. You will just have less capacity.
While my Group 27’s do everything I throw at them right now, I also do daily genny recharges for 5 hours a day. When ever these 2 batteries die I will upgrade to group 29’s or may even go the 6 volt route. I wish I had realized all I know now when I did the group 27’s The cost is so little more to jump right to group 29’s from 24 that it would have been well worth it just to have the extra reserve. Or go the 6 volt route.
Now like Paul stated, some folks just carry extra batteries. Like 2 or more group 24’s. They charge them up at home and come with all 2 or 3 charged. When one gets down to 50% state of charge, they just unhook that used one and put a fresh full charged one in it’s place. And keep going. This is about the cheapest way to go and works. Since only one is used at a time, you can have old and new ones. Just hook them up 1 at a time when needed.
As far as brand. For sure make sure the battery is a Deep Cycle. Do not get a Starter battery. They make a combo Starter/Deep Cycle which is not as perfect as a true Deep cycle but not bad and may even be what you have now from your dealer.
After researching a few years ago I thought I read there are only 3 battery manufactures in the US. And they private label for everyone else I believe Or there are divisions of the top 3 some how. I think they are Exide, Johnson Controls and some one else. Do not know this to be 100% accurate on the 3 manufactures maybe some one else can confirm or deny it. I can’t find the links to where I found that right now.
As far as brand, I really do not know. I have one Deka and one Walmart made by Johnson Controls. I figured I would spend the higher $$ when I go the higher amperage upgrade some year. I’m not a brand wizard and admit that.
What I do know is that proper maintaining on the batteries makes a lot of difference regardless of brand. It may even revive the one you have now.
- Keeping the water up over the cells is a must.
- Next is maintaining them and desulfating them.
After every camping trip I hook up one of these to my TT batteries. It keeps them at 100% state of charge and desulfates them. This give the best life they can have regardless of brand. BatteryMINDer® Plus 12 Volt 1.33 Amp Charger-Maintainer-Conditioner (Desulfator) | All | Battery Chargers by BatteryMINDers.com
You can find them on the web for between $39 and $42.00 and one will do up to 5 batteries. I'm not hung up on the VDC as Cerka make one and so does someone else that uses the pulse technology to desulfate with. Key is make sure it has the desfulfate mode as well as a float charger. There are many float chargers which are good to, hey just do not desulfate.
Hope this helps and good luck