Since absolutely everything you run in your RV operates through your RV battery, you’re going to need to know how to keep it topped up and living a healthy life for as long as possible. This means regular charging, proper maintenance, and knowing how to safely and healthily use batteries in parallel. But how do you do all of these things? And where can you buy good RV batteries?
In this post, we will take you through all you these the answers to these questions and more to help you get the most out of RV batteries and all of your RV accessories too. Check out our ‘RV batteries near me’ tool below to find trusted sellers:
Table of Contents
- How to charge RV batteries
- How to hook up solar panels to RV batteries
- How to charge RV batteries in parallel
- How long do RV batteries last?
- How to maintain RV batteries
How to charge RV batteries
So, how do you charge RV batteries? Whether you want to know how to charge RV batteries with generator or how to hook up solar panels to RV batteries, here are 8 easy steps that will make charging your RV battery a breeze and remind you to keep your battery well maintained and in good health at all times:
#1 Turn off the RV
Whenever you want to charge your RV battery, you’re going to need to switch off the RV! Also, be sure to pull that emergency brake on nice and tight so you don’t get any nasty surprises when removing your battery.
#2 Find your RV battery/batteries
As the location of batteries varies on RVs and larger vehicles have more than one main battery, you will need to check out your user manual to locate where your RV battery is.
#3 Remove battery cables with a wrench
You should always wear heavy and thick gloves when removing your battery cables. Moreover, ALWAYS REMOVE THE BLACK CABLE FIRST, this is the negative side and is an important safety consideration. For example, if you remove the positive side first and your wrench makes contact with anywhere on the RV you will short-circuit your system. Removing the negative side first disconnects the battery from the RV chassis.
Once the black cable has been detached with the wrench, you can then detach the red cable with the wrench to fully disconnect the battery from your RV.
#4 Clean the battery connections
Using your battery can lead to corrosive substances forming on the battery connections. With the battery removed from your RV, now is a great time to maintain your battery so you can extend its lifetime every time you plan to recharge it. Fortunately, to clean off this corrosive formation all you need is some water and baking soda mixed into a paste, a wire brush, and an old rag.
3 tablespoons baking soda and enough water to make a reasonably thick paste is enough for a single battery. You can then apply this paste to the battery connections and scrub off the corrosive material using the wire brush. You then want to completely clean the battery of this paste using your old rag. For optimum use, you should also apply petroleum jelly to the connections once cleaned. This helps prevent corrosion from happening in the future.
#5 Check battery water levels
Checking the water level in lead-acid batteries can help extend RV battery life. It is important you check this regularly since the more you use and charge a battery, the quicker water starts to evaporate from the battery’s cells. Generally speaking, you should only add water when the battery is fully charged, as this is when you can read water levels most accurately. However, if you notice the water level is below the plates, you should top it up to the line.
Top tip: when topping up water (topping up the electrolyte level) you should only use distilled water.
#6 Attach the battery to your charger
Make sure your generator has enough fuel to fully charge your RV battery, be that propane, gas or diesel. Attach the battery cables to the battery charger for your generator – this time connect the positive cable (red cable) first. Then, connect the black connector or clamp to the negative connection on the battery charger. Then, plug in the charger and allow it to fully charge the battery. An indicator light will show when the charge is complete.
#7 Unplug your charger
Remove all the connections, making sure to remove the negative cable first.
#8 Reconnect your fully charged battery
Now, you have maintained and charged your battery it is ready to be reconnected. Remember, when you are reconnecting it you need to connect the red cable first (the positive). Make sure this is tightened securely with a wrench. Then, you’re ready to reattach the negative side – again, tightly with a wrench.
How to hook up solar panels to RV batteries
If you wish to use solar power to charge your battery you can either use it to trickle charge your battery or hook it up in the same way you would a generator. Either way, when using solar power you are going to need an amp controller (sometimes known as a charge controller). This ensures your device doesn’t overcharge. You can use either a pulse width modulation (PWM) charge controller, or you can use a maximum power point tracking (MPPT) charge controller.
MPPT’s are more efficient but cost more. Whichever you choose, you’ll need a charge controller that can cope with more amps than your combined solar panels produce. Ideally, choose a 15 amp charge controller as this will give you room to expand your solar production and provide ample energy to charge your 12 volt RV batteries. Here are 6 quick steps to guide you through how to charge RV batteries with solar (once first having completed steps 1-5 from above):
#1 Mount your charge controller somewhere safe
This needs to be somewhere protected from the weather as you don’t find weatherproof charge controllers very often. This means you should not install your charge controller on the outside of your RV. It should also be grounded and preferably attached to a material that is non-conductive. PVC or wood paneling is perfect for mounting your charge controller – metal is a no-no.
#2 Connect positive & negative wires to your battery
Some batteries already come with wiring built-in, if this is the case, then there is no need for you to do this step. If your battery does not have these wires use wiring with ring connectors that fit over your battery connectors. Ideally, you should use red wiring on the positive side and black wiring on the negative side.
#3 Connect the wires to your charge controller
You will need just stripped down wiring at the end of the cables which go into the charge controller. Simply attach the bare wires into the charge controller in their designated spots and tighten the screws to keep them securely fastened in place. Make sure the positive connects to the positive port and the negative connects to the negative port. For 12 volt batteries, you should use at least 10-gauge wire.
#4 Connect the charge controller to your solar panel
Solar panels tend to be fitted with MC4 connectors. These have a ‘male’ and a ‘female’ side. You will need to fit MC4 connectors to your charge controller to make sure you connect these safely. These can be attached to the charge controller in the same way as the 10-gauge wire, with one end stripped bare and the outer end offering the MC4 connections.
You can now hook up the solar panels to your charge controller – male to female and female to male. For example, attach the female MC4 cable from your solar panel to the male MC4 cable on the charge controller. Always double check your positive and negative cables are lined up correctly.
#5 Check charge controller output
Charge controllers come with a digital screen indicating energy flow to your battery. If it is reading 0 then you need to check your connections are right. Higher-end charge controllers can also be linked to an app on your phone making it easier to monitor how much output is flowing into your battery.
#6 Leave the battery charging until fully charged
Again, you should always aim to fully charge your battery if you can when re-charging to prolong your battery’s life.
Once you have completed these steps you can follow steps 7 and 8 above to reattach your battery/batteries to your RV. Solar power has so much to offer whether you’re interested in saving the environment or saving yourself money on energy bills. If you use your RV a lot, solar power is definitely the best way to go.
How to charge RV batteries in parallel
Charging your RV batteries in parallel is easy but it is also easy to make a simple mistake that will lead to you shortening all of your batteries’ lives. If you run an RV, you’ll likely be running more than just two batteries in parallel when charging. This means simply connecting the positive to positive and negative to negative from your charger to your first battery, through to your final battery. However, this causes unbalanced charging, that gets more extreme the more batteries you add to your system.
Fortunately, this can be easily corrected, at least partially, by attaching the positive cable to the positive connector on battery 1, and connecting the negative to the final battery in the circuit, say battery 4. However, even this fix sees batteries 2 and 3 receiving different charge to batteries 1 and 4. For perfectly balanced charging in parallel, you will need multiple connectors. These should all be the same gauge wires. The differences are displayed in the images below:
How long do RV batteries last?
When properly maintained, RV batteries can last a good 6 years, sometimes even more. On the downside, if you don’t look after your battery properly, then you can see it go kaput in under 2 years. This means it is important to maintain your batteries well. Following the charging instructions above, including the routine maintenance, will go a long way to extending your battery life but how can you take it to the next level and push your battery beyond the 6 year mark?
How to maintain RV batteries
If you want to extend your battery life to its maximum potential, then you also need to consider (at least) three further maintenance requirements:
#1 Don’t drain your battery more than 50%
Whilst deep cycles can cope with being completely drained, it still does them some damage. For maximum lifespan, don’t let it drop below 80%.
Note: a 12-volt battery will actually have 12.7 volts when completely charged. When a voltmeter reads 12-volts, this indicates the battery is 50% drained.
#2 Check water level more frequently in tougher conditions
When the weather is hot, or if you are using lots of devices, you put your battery under more strain. If you’re using lead acid batteries, make sure to check the water levels more often during these times. Remember, if you drain a battery to 20% every use, it will last half the time of a battery you only drain to 50% every use.
#3 Charge your battery properly
As mentioned above, there is a wrong way, an okay way, and the right way to charge batteries in parallel. However, even if you are not charging batteries in parallel, you need to put some thought into charging them properly. This typically requires a charge controller with at least 3 stages: the bulk charge phase (which charges your battery to 90% within a couple of hours); an absorption charge phase (completes the charge more slowly to prevent loss in water or battery gassing), and; a float charge phase (to help maintain full charge).
Running batteries in an RV is easy but keeping them in perfect shape requires a little more love, care, and attention. Follow the tips and step by step guides above to help you get the best out of your RV battery. Don’t forget to check out the RV battery sellers near me tool above to find trusted sellers near you.