2nd Leisure battery

I fitted a second leisure battery to our MH this spring. The original leisure battery is under the garage at the back while the engine battery is under the driver’s seat. There are enough room under the seat to fit a second leisure battery. I used 35mm cables ( size of little finger) to join the terminals together. I fitted a mega block fuse, rated 150 amp between the two positive terminals, in case the cable became frayed and shorted.
When joining the 2 earth terminals together, I noticed that the earth from the orginal leisure battery to the chassis was in a poor condition so I compensated it by linking the the earth of the new leisure battery to the chassis at the same point as the engine battery.
In all it is quite straightforward, link all the positives poles together and then link all the earth poles together. This it true for 2 batteries or 10 batteries.
The cable size is the most important element, 35mm cable from my local motor factors was priced at 8 euro a metre but I used a set of long jump leads instead because they were cheaper. I cut off the clamps and crimpled on new eyelids.
I think the thread you are looking for could be under ally solar panels.

The question about matching batteries has sparked great debate here before. My orginal leisure battery was banjax so I had to purchase two batteries. My local supplier got me 2 batteries, one 90Ah and one 110 Ah. His advice was because each battery is the same make and age, the capacity issue doesn't arise.
However this could be disputed.
I forgot to say earlier that the cables linking the batteries together were routed under the van in the chassis, so it save me interfering with internal structures.

It's under the seat but it 5 metre run to the other leisure battery. Yes the seat will probaly have to be removed.
Most garages or auto electrical place can test your existing battery with a duty cycle tester ( its name has escaped me) and the results gives you the capacity of your battery. This is completely different to sticking a volt meter across the terminals.
When both batteries are connected properly the charge and discharge is spread evenly between them.
Another thing to check especially on old vans is the charging capacity of your alternator. Most of them are 150 amp rating which is adequate to recharge the system. This is also why the connecting cables are as big as I quoted

No problem you can send photos to me if you want.

forum/topic.php?t=13735

Try this one. There are a few videos too.

Just a matter of interest. When you say on page 4, I have only 2. If you go to your control panel and settings, you can scroll down and change the posts per page to up to 40. This saves on having to load the next page each time, especially if you are set to a quite low post per page setting.

If you are going to do it . Then go .
Same size , same age , as close together as you can get them . all leads the same length.
Then you are on s winner.
But you're right first check do you really need to go down that road.

LTS fitted a 2nd leisure battery for me last week. I assumed that I would need to replace the existing battery two but they said it was in good condition - likely because of the solar panel in the roof. They were able to keep the batteries very close to was having other so minimal cable needed. I don't know what diameter of wire they used. I would not feel confident tackling a job like this so I let them at it while doing a habitation check & some other work. Great to know Ivan go a long time without need for hook up if any need at all.

12V-24V-Inline-Auto-Waterproof-Circuit-Breaker-150-AMP-Manual-Reset-Switch.
HPC150 Circuit Breaker (150 Amps, Manual reset)

• Circuit breaker

• 150A

• Manual reset

•12v

•Waterproof
Malcolm,
is this the right type of circuit block to use.

great, thanks malcolm