Fitting extra leisure battery

Hello everyone,
Since having solar panels fitted to my 2015 Warwick XL last summer I have been thinking about fitting an extra leisure battery
 to improve our off grid capability.
I have a spare battery identical to the one currently fitted in the vehicle, and although neither battery is new they both give similar readings on my battery testing device.
I've got two queries really,  1: Is it ok to do this as described rather than use brand new batteries ? 2: Would it affect the readings on the panel above the door showing leisure battery battery status?
The solar panels are controlled by a smart device which is independent of the factory fitted unit.
I'm not really clued up on this sort of thing so any advice would be most welcome,
Thanks very much everyone in anticipation!

Best wishes 
Michael O'Hara

More battery capacity can be a bit of a double-edged sword, because if you spend most of your time off-hookup you have to bear in mind that double the battery capacity will take twice the time to recharge the batteries. It probably won;t be an issue on properly sunny days, but if you get a run of dull days you may find that the batteries spend a longer than desirable amount of time heavily discharged.

It's not an easy balancing act, but I think the general consensus here is that, unless you already have huge panels, more solar capacity is probably going to be better than more batteries. But of course it does depend on exactly what your pattern of electricity use is. We've had people here who run CPAP machines overnight and in that case you may really need the highest capacity of both solar and battery.

Fixer wrote:My view is that an extra battery is like having a bigger fuel tank and more solar is having the fuel stations nearer so a bigger battery is more useful off grid.

Charging may be a problem.

In my opinion, just get a decent portable power station. It will do everything you need and the added bonus of being used elsewhere. Also a bonus with additional sockets usb's and other "extras". Not to mention, not having to put any addition strain on the current solar set-up or the hassle with a hardwired installation.

Hello.

I have just had an extra battery on my warwick and a dc to dc charger fitted. Makes a big difference to your power capacity..

Regards

Thanks for your comments everyone, they've given me food for thought regarding 
doubling up on my battery capacity,
Roll on spring!

Best regards and thanks again,
Michael O'Hara

Fixer wrote:
Not as much as a flat battery though.
It’s the ability to last more days when solar isn’t available when battery capacity will win every time.

we have 130w solar and a 110Ah LB
We rarely, if ever use EHU
We have all the usual toys, led lighting, TV, phones tablets even Mifi all needing power.
Never even once ever been short of power......IMHO solar is only not available after dark!!

Simplicity and minimalism wins every time!!!