Energize Your Battery Knowledge: Compare The Types

If you like to camp in an RV, especially off-grid, you know that your camping experience is all about the battery. The central part of your electrical system stores the energy you will be using throughout your boondocking experience. So learning what you can about the types of batteries and how they are used is essential to an enjoyable camp trip.

Here’s a breakdown of the three types of deep cell batteries that have proven themselves in the RV world:

Lithium

The cream of the crop, lithium batteries can be extremely expensive. The number of “positives” they have going for them is worth the investment. Lithium batteries create a charge when electrons move through lithium salts from anode to cathode. 

They can be almost entirely depleted before recharging with little effect and they recharge much faster than other battery types. The one “negative” to a lithium battery is that it doesn’t do well charging in cold temperatures.

AGM

This stands for Absorbed Glass Mat batteries, which have fiberglass plates between their cells. Their price is mid-range, as they are maintenance-free, can be depleted by 60% to 80% before being recharged, and their recharge rate is faster than a lead-acid battery but slower than a lithium one.

Lead Acid

This is the standard, least expensive battery that uses distilled water for electrolytes to move around in. These batteries require maintenance about once a month when the cells need to be topped off with distilled water, but they hold a charge well. 

A drawback is that a lead-acid battery can only be used to half of its charge before requiring recharging. The rate of recharge is the slowest of all three battery types.

Pricing Breakdown

Because RV coach batteries should be deep cell ones, you will not need to purchase batteries with a high number of CCA (cold cranking amps).  Instead look for batteries with higher AH (amp hours) that will give you long, continuous power during use.  Here’s a general idea of how much you will pay for comparable batteries with 100 amp hours:

• Lithium batteries can run up to almost $1,000 each. However, they can last you 10 years.  And keep in mind that the price also includes a built-in battery maintenance system.  
• AGM batteries can cost between $160 to $290.
• Lead-acid batteries will run between $80 and $180.

Differences

Each battery type has pros and cons to its usage.  Make yourself familiar with these terms and how they will affect your energy consumption before shopping for a battery:

1. Cycle Life – all rechargeable batteries have a fixed number of cycles, meaning the number of times they can be fully recharged.
2. Depth of Discharge – this term described how much of the energy stored in a battery can be used before it needs to be recharged.  Most lead-acid batteries only allow 50% of their charge to be utilized, AGMs allow 60% to 80% depth of discharge. Lithium batteries can be discharged 80% to 100% before needing a recharge.
3. Efficiency – refers to how much charge the battery produces after being charged to 100%.  In other words, does it lose any charge through heat or while it is not being used?  This is measured as a ratio of the amount of power discharged by the battery divided by the amount of power delivered to the battery. 
4. Charge Rate – this measurement tells users how many hours the battery will take to fully charge.
5. Energy Density – measuring the amount of energy that can be stored in a battery is listed in “watt-hours per kilogram” or W-h/kg.

Which Should You Choose

When deciding which type of battery would be best for your RV, you need to assess what your camping style will be.

1. Full-Time Off-Grid Residence – if boondocking is your idea of real camping and you will be making a lifestyle of it, consider investing in lithium batteries with a solar setup.  With several batteries in a bank, several hundred watts of solar panels, a controller, and an inverter, you can live completely off-grid for as long as your water, black and gray tanks can hold up!
2. Part-Time Off Grid – for part-time boondockers, a solar system with lithium batteries may not be worth the investment.  A couple of AGM batteries may be just the right equation to help you enjoy off-grid camping on random weekends, and with a generator as a backup power source, you should be able to boondock whenever the feeling strikes you.
3. Battery Backup System – even if you camp periodically and don’t want to invest in expensive power components, having a bank of batteries is a good practice.  Even 2 batteries connected give you confidence in having more power available when you need it.  You can wire these systems based on the type of voltage your batteries have:
   1. 12-volt deep cycle batteries should be wired in parallel. This will still produce only 12 volts of power, but will double the amp hours on the batteries.
   2. 6-volt deep cycle batteries should be wired in series. This will double the voltage to the requisite 12 volts that your RV system requires. The amp hours on the two batteries does not double (in other words, 2 100ah 6 volt batteries will still only have 100ah). 

Considerations

You should be ready to purchase batteries now. Here is a checklist of the considerations you will need to navigate in buying RV batteries to fit your own personal camping application:

• Weight – will the weight of the battery be important?  If so, lithium batteries are the lightest and lead-acid the heaviest, by far.
• Cost – if the cost is a consideration, lead-acid batteries will be your cheapest upfront investment. Lithium will be cheaper over the long term.
• Useable energy – if you want to discharge your batteries almost completely before you will be able to recharge them, then lithium is your only option.
• Charge efficiency – which batteries will hold a higher percentage of charge before you use them?  Again, lithium wins this race.
• Temperature – will you be traveling in cold regions for some time?  Lead-acid works best in varying temperatures, but if you are set on adding lithium batteries, many companies now offer “battery heaters” to avoid any cold temperature problems.
• Power delivery – which batteries will give you steady and strong energy without any problems?  Once again, lithium is your best bet here. 
• Charging time – how long will it take to get your batteries back up to 100% capacity?
• Storage – which batteries can sit unused without losing their charge or needing a battery tender?
• Installation – how difficult are the batteries you select to install?  Lead-acid and AGM batteries just require attachment to their posts. Lithium requires its own battery management system (many times built into the battery itself).

Now that you have a thorough understanding of battery types and their benefits, it’s time to head to the store!  You are ready to begin building the most important RV system to your own specifications. What RV batteries do we recommend? Check out our battery buyer’s guide.