Can we mix batteries?

[adriacoral]

Hello peoples.

We currently have an 85ah gel battery and wish to add another, question is can we add a cheaper battery or does it have to be gel. Batteries are stored under seat in lounge area so probably need to be sealed at least. We can switch the charger to acid so is it better to swop both to lead, and what about AGM?. Apologies if this has been asked before, if so just direct me to the thread. Read many other opinions on other sites, what is general consensus on here?

 

[gordon]

you have to use gel with gel ect but it is not advisable to try and charge a old battery with a new one.

 

[adriacoral]

Current one is very good as we got 2 days off it, so presume ok?

 

[Deleted member 3011]

The three common types of batteries - flooded lead acid, Absorbed Glass Matt and Gel - do have different charging requirements. Normal and AGM are sufficiently similar but some Gel batteries require a lower end of charge voltage than the other two. Opinions vary though.

Of course you can mix them and you will end up with more capacity than if you kept just the one battery, BUT one of the batteries will not receive optimum care and may have reduced life. Whether this matters much will depend on your particular usage pattern.

After all, many RVers get years of service out of batteries yet have only a fixed-voltage converter floating the batteries at around 13.5V. Others have high-tec multistage chargers and manage to kill their batteries in 6 months.

If you really need the extra storage capacity and have deep enough pockets, then yes, it is better that they all be of the same type. Purists will demand that they also be EXACTLY the same brand, capacity AND AGE, and of course they are correct when considering things to the fifth decimal place, but in the real world ...

Some of your considerations will be whether you can safely house the batteries. It is true that Gel and AGM batteries are often chucked in anywhere on the (false) premise that they don't need venting while conventional flooded cell batteries certainly do need sealing from the living space and venting to the outside. They are also all equally heavy and need proper restraint.

 

[Kontiki]

You probably have the same Exide Gel battery I have in my Adria, like you I thought about another battery but having had my van for 2 years I find that the one is good enough. I have a solar panel that keeps it topped up & we wildcamp nearly all the time in Europe. I opted to stick with the one & if it needs to be replaced I would look at something larger at the time.
It does all depend on what you intend to run off the battery, this would then detmine how much capacity you would need.

Gel batteries aren't charged quite as high as a conventional lead acid so I don't know if linking them together might cause problems.

 

[maingate]

Hello peoples.

We currently have an 85ah gel battery and wish to add another, question is can we add a cheaper battery or does it have to be gel. Batteries are stored under seat in lounge area so probably need to be sealed at least. We can switch the charger to acid so is it better to swop both to lead, and what about AGM?. Apologies if this has been asked before, if so just direct me to the thread. Read many other opinions on other sites, what is general consensus on here?

My van has a switch for the type of batteries being used. One position is for gel and the second position for lead/acid and AGM.

So the short answer is no to your query. Unless your second battery is also gel.

 

[Firefox]

I'd say one or the other wouldn't get charged properly. My charger has different settings for different types.

But more importantly, don't mix older batteries with newer ones. One will drag down the performance of the other, so while it may work after a fashion, you won't be getting optimum performance.