RV batteries

RV batteries selection

RV battery selection

There are many questions regarding battery selection. 

• What type of RV batteries should I get?
• How long do they last? Lifespan?
• What are amp hours (AH)?
• Lithium, flooded or AGM?
• What does AGM mean?
• How can I mount them?
• What’s the lifespan of each?
• Is lithium worth the money?

All of these are valid questions and we are hoping this will help you figure what is the best solution for your RVing needs.

What RV batteries should I get?

This first question WE feel is the most important. Unfortunately you need to ask yourself first and foremost;

What does MY RV adventure look like?

The reason we feel this is the most important is if you’re not adventuring to the middle of nowhere and living completely off the grid. Or in other words your RVing is going from hook-up campground to hook-up campground, why would you spend thousands of your hard earned dollars for rv batteries that never get used for their intended purpose? 

In short get enough battery to enjoy your travels from site to site.

100AH flooded battery or 100AH absorbed glass mat (AGM) battery.  

These two options are the most inexpensive way to go. The flooded batteries require a lot of maintenance.

 For example;

• You need to check the water levels periodically (distilled water)
• Flooded type rv batteries need to be well vented 🤢
• Be sure not to discharge to deep 

With both flooded and AGM batteries you need to be conscious of your discharging. Basically you want to try not to discharge (DOD, depth of discharge) below 50% of the battery’s capacity. 

If you do, you can possibly create a memory of less than 100% as it recharges and will not charge fully.

Lifespan of my lead acid RV batteries

The typical lifespan is counted in cycles. The average cycles that lead acid batteries (flooded or AGM) is about 500-600 cycles or to put into years that’s about 3-5 years.

For the adventurous type

If you’re more of the get away from civilization type and want to live off the grid than there are the more advanced options. 

LITHIUM!

With lithium there is a serious monetary difference. You go from $200 to $800 minimum. 

This significant monetary difference does however gain you a better battery.

If only the DOD alone we feel is worth it for the off-grid adventurous type. 

 

Lifespan of my lithium rv batteries

The lifespan of a lithium battery is tremendously higher. About 10-11 years or about 2000 cycles. 

If you look at the cost of the lithium over the lifespan. In the end it does pay off.

 The downside to this is the upfront cost and extra concerns for the charging system type 

Next let’s talk about charging systems

When you go lithium simple things like your converter, which converts high AC voltage to low DC voltage while plugged in and also recharges your battery.

Most older converters are not designed for lithium rv batteries. They typically will only charge up to 80%.

WHY?

Where and what is the converter?

Your converter might be built into the power distribution panel.

In a sticks and bricks terminology, the breaker panel. Although you see in this panel both breakers for your AC distribution and fuses for the DC distribution.

Our panel has a specified breaker for the converter. Many plug into the panel somewhere, maybe in the back. I’ve seen them located in a storage compartment in the underbelly of a motorcoach and other various locations. 

The biggest issue is that most converters charge at a 13.6V rate whereas a converter that is rated for lithium use will be 14.4V.

That little difference is the difference between an 80% charge to an 100% charge to a lithium battery  

So what do I do?

• Get a smart charger or converter specifically rated for lithium batteries. 
  • NOTE: Replace the converter with similar amp size to assure proper wire sizing coming out of the converter. For example 35 amp replace with a 35 amp. Smaller is ok but larger is not so good. 35 amp wire size will be an 8 gage wire minimum and a 60 amp will need a minimum of 4 gage. All of this is dependent upon the length of the wire. 

• Supplement with a solar charge controller and solar panels also rated for lithium to top off the battery during daylight hours. 

Mounting

Mounting any battery needs some thought. 

• Space
  • Make sure you have enough room for the amount of batteries you intent to add to you system
• Temperature
  • Where you mount them the temperature rating for maximum performance may need to be considered
• Configuration
  • Accessibility for service 
  • Can you mount them sideways
  • Are the terminals free of obstructions
• Ventilation
  • Many sealed batteries do not need to be vented (AGM, lithium)
  • Flooded rv batteries should to be well vented 🤢
• Location in regards to accessories. 
  • If you are installing an inverter you will want your wire length as short as possible 
    • Keep the cost of the wire down. Longer the distance the larger the wire size
    • Convenience of overall wiring of both DC as well as AC needs

What are AH (amp hours)

So we have gotten this far without talking about the longevity of your system.

This can be defined by amp hours.

Simply put this is how many hours the devices will run or how many amps the battery will support for a given period of time. 

Analogy

Consider the battery is your bank account. If you had $100.00 (amp hours) and you use $10.00 (amps)  and do not put any money back into your account then you now have $90.00 (amp hours). It is really that simple.

UNTIL

Now you figure the battery. Lead acid, AGM can only handle a DOD of 50%. 

So your $90 is quickly $45. Or to sum up the analogy 45 amp hours.

Lithium on the other hand can handle about on the average of 80% DOD. So that $90 is $72 or 80% is yours to use verse only half of yours to use. 

Great video illustration of this analogy is here. Even though I consider myself very knowledgeable in electrical as well as teaching it for years. This is the first guy that explained it in the simplest of terms. 

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