Batteries! Ugh!

[jimplumley]

It's that time. We've got to replace a 5-year old marine battery. We NE-VER boondock, so we don't need an $895 premium, platinum, 10000Ah, ultra-deep cycle, zippidy-do-dah battery. I've done the research, which makes me lean toward lithium iron phosphate. But again, we don't need an expensive, huge capacity battery. 100Ah? 50Ah? 8Ah? I also like the gel batteries. Each type has its advantages. So, what advice can anyone give me?

[profdant139]

If you never boondock or dry camp, and you always have short power available, then you don't need much of a battery. An ordinary flooded lead acid battery will do the job.

For what it's worth, I do a lot of boondocking, and all I have is a group 31 deep cycle battery from Napa. It has 110 amp hours. (I use a portable solar panel to recharge it.)

So if that cheap ($150) battery is good enough for me, it should be more than good enough in your situation.

Lithium is nice, except that I have heard that they can't be charged below 32 degrees. Does that mean you can't go camping in freezing weather? I don't know.

[jimplumley]

Originally Posted by profdant139

If you never boondock or dry camp, and you always have short power available, then you don't need much of a battery. An ordinary flooded lead acid battery will do the job.

For what it's worth, I do a lot of boondocking, and all I have is a group 31 deep cycle battery from Napa. It has 110 amp hours. (I use a portable solar panel to recharge it.)

So if that cheap ($150) battery is good enough for me, it should be more than good enough in your situation.

Lithium is nice, except that I have heard that they can't be charged below 32 degrees. Does that mean you can't go camping in freezing weather? I don't know.

That lithium charging temperature info is super good to know. The reasons I'm swayed toward the lithiums or gels are size and weight. As a rule we don't camp much below 40-50 degrees; below that and the battery gets pulled and goes into the cellar. So now I just need to figure out is whether a 20-30Ah battery is sufficient to properly complete our system.

[twinster2]

Just so you know, charging a LiFe battery (or any Lithium based battery) takes a special type of charger therefore are not compatible with most trailer converter/charging systems. Also, even though LiFe chemistry is one of the safer types of Lithium batteries you can use, the can still catch fire if charged incorrectly. IMHO, I would just stick with a flooded lead acid deep cycle battery. I been using a group 29 Everstart Maxx Deep Cycle battery from Walmart. I think they are around $130.

[profdant139]

jim, 20 or 30 amp hours would be a pretty small battery -- you could take a chance, but why not move up to at least a group 29? That would give you the flexibility to (for example) stay overnight at a rest stop when a snowstorm forces you to stop.

[jimplumley]

Upon the advice of seasoned campers, along with further research, I've decided that lithium batteries are out, due to the most likely incompatibility with my stock charging system and cold weather charging quirks. And more good advice suggests that I should be prepared for the odd emergency by having a battery large enough to supply our needs for at least overnight. I'm also wondering if anyone knows how to connect my truck so it charges the trailer battery while on the road. Can't tell y'all how much I appreciate your experience.

[JimboFunFinder]

The problem with normal lead acid Maintenance Free car batteries is that they do not tolerate a complete discharge even if they are only in storage. Devices such as your monoxide detector are often wired to be always ON and will eventually discharge a battery. If you keep a trickle charger on the battery during storage then you should be fine, otherwise a larger gel cell or deep cycle (Marine) battery is a better choice.
Like you we have generally camped where there is shore power but on almost every trip we have hit campgrounds where power is temporarily shutoff for repairs.

[jimplumley]

Originally Posted by JimboFunFinder

The problem with normal lead acid Maintenance Free car batteries is that they do not tolerate a complete discharge even if they are only in storage. Devices such as your monoxide detector are often wired to be always ON and will eventually discharge a battery. If you keep a trickle charger on the battery during storage then you should be fine, otherwise a larger gel cell or deep cycle (Marine) battery is a better choice.
Like you we have generally camped where there is shore power but on almost every trip we have hit campgrounds where power is temporarily shutoff for repairs.

I've been looking at both AGM and gel batteries, but it looks as though I'd have to modify the wire terminals to connect to the different style battery posts.

[profdant139]

I agree with Jimbo that deep cycle batteries should not be discharged lower than 12.1 volts (50 percent state of charge). That's why I keep them on a trickle charger.

And Jim, your ordinary seven pin connector usually enables your truck to recharge your battery while you are driving. But it is a slow charge. After you hook up the truck and the trailer, measure the voltage of the battery while the truck is running.

It will probably read something like 14 volts, more or less.

But that does not mean that your battery is fully charged. If your battery starts out at (let's say) 12.2 volts, it will take a few hours of driving until your battery is fully charged.

In order to measure how much juice is really in the battery, you have to measure the battery at rest (not under load). Some folks say that you have to let it rest for 24 hours to get an accurate reading.

I disagree -- I have done a simple experiment where I test the voltage of a resting battery at 15 minutes, half an hour, an hour, five hours, ten hours, and overnight. The curve flattens out after 15 minutes, So even just letting it rest for 15 min will get you the info that you need.

[dustyone]

I'm also wondering if anyone knows how to connect my truck so it charges the trailer battery while on the road. Can't tell y'all how much I appreciate your experience.

You should already have this ability. When you plug in the trailer it is already connected.

[RipVan]

We also NEVER boondock (on purpose) and generally try to camp where Full Hookups are available. We will settle for electric only as many/most of the WI state parks are set up that way. We've had the camper for nearly ten years now. When the battery of the previous owner required replacement, I bought an EverStart MAXX Deep Cycle/Marine battery (and subsequent one) from WalMart. The current one was purchased in the Spring of 2018. I plan to start this season with it but at 4 years old, I'm prepared to replace it if necessary. I kept it on a "Smart Charger" all Winter long and have had good luck with longevity doing so. We'll see in a few weeks when I take the camper out of storage.
RE: the question about charging while hooked to the tow vehicle, I'm not exactly sure but believe that the camper battery charges while the truck motor is running. Not so sure if there is a current draw on the truck battery when the motor isn't running tho. If that's the case, there could could be the possibility of a dead battery in the tow vehicle if there was no "shore power" and the camper remained hooked to the truck while camping. I need to check that out.

[LJAZ]

IIRC the battery line from the tow vehicle runs through the ignition so unless the key is on there's no battery power to the connector.

[dustyone]

Originally Posted by LJAZ

IIRC the battery line from the tow vehicle runs through the ignition so unless the key is on there's no battery power to the connector.

This depends on vehicle. My Chevy truck the battery in truck was connected all the time. My ford was only while ignition was on.

[twinster2]

How I wired my TV, I have a dedicated positive wire running directly from the battery to the 7 pin plug for trailer battery charging. Also had a dedicated negatve ground wire from plug to battery.

[LJAZ]

Originally Posted by dustyone

This depends on vehicle. My Chevy truck the battery in truck was connected all the time. My ford was only while ignition was on.

Interesting. My Chevy is wired through the ignition.

[gator]

Originally Posted by jimplumley

I've been looking at both AGM and gel batteries, but it looks as though I'd have to modify the wire terminals to connect to the different style battery posts.

My AGMs have the same posts. Look for some that do. AGMs last very long. My starter battery on my truck was 14 years old when replaced. I replaced the ones on my trailer after 9 years.

Make sure you have a good quality 4 stage charger for them. I personally don't use the converter. I charge mine via solar and have done so for the last 6 plus years. I never plug in.

[Rocky Mtn marmot]

I boondock alot and I use two Trojan deep cycle motive scs225 AH batteries. I prefer the Trojan brand as I feel they know the most about deep cycle batteries since many golf courses use their batteries in golf carts. They are expensive tho! FYI...The life of a battery is directly proportional to the number of discharge/charge cycles and proper maintenance. Alot of good battery information here: https://www.trojanbattery.com/tech-support/