Second leisure battery installation (1 Viewer)

[Jands]

First diy job on my MH.
Want to fit a second Leisure battery.
The leisure battery fits under the dining bench seat, enough room for a second battery.
The battery is strapped down inside an open plastic box.
The leads look just long enough for that battery.
Need advice on obtaining and fitting.
Need some hold down straps and brackets from where?
The original battery box is open at the top, do I need a covered box?
Second battery needs to be similar design and amp/hour to the original.
Wiring, read advisable connecting MH positive to one battery and negative to the other, if not enough MH wire to do this is it that important?
Don't want to do a rewiring job, just connect the second battery.
Fuses for new battery, read that it should be outside to battery storage. Also as I expect I will just be connecting the second battery in parallel by joining at the terminals is a fuse important, the original fuse will protect both batteries.
Are battery problems commonplace or quite rare?
Any good advice would be useful. As I said know the preferred theory of a fuse for each battery and split electrical cables but easily adjusting original wiring might be difficult.

 

[pappajohn]

Batteries DONT need to be similar/same ah.... Just the same age & type.. Lead acid, AGM etc

not critical to wire MH pos to one and neg to other when only two installed.
Preferable if a large inverter is used to balance the load.

If batteries are vented to outside (they should be) then no problem fusing close to batteries.
A fuse at BOTH ends of the Pos wire is preferable rated at the maximum current you are likely to draw..... 30amp should be adequate.

 

[Lenny HB]

For battery boxes and straps eBay is your best bet. Most modern batteries are sealed or semi sealed so not important to have a top on the box however a lid makes it neater and prevents you dropping tools on the terminals and having a bit flash bang wallop.

You will probably need to vent the 2nd battery should be able to "T" into the vent tube on the 1 st battery.

Assuming your batteries are standard flooded wet cells and the original battery is only around a year old it's OK to add a second battery if much older it is better to fit 2 new batteries.
The size of the second battery is not that important but does need to be the same type.

As you are installing the second battery cose to the original battery there is no need to fuse it separately.

Use cables of at least 16 mm sq you can buy them already terminated on eBay. Yes with 2 batteries just connect in parallel.

Are battery problems commonplace or quite rare?
The answer is like how long is a piece of string.
Biggest cause of batteries failing is miss-use, over discharging them lower than 50% for wet cells, 80% for Gels & 70% for AGM, not giving them a proper charge with a multi stage charger.
Good quality wet cells are fairly reliable, cheap ones not very good.
Gell's very reliable often lasting up to 10 years.
AGM biggest hype ever, IMO a load of rubbish, designed for stop/start cars not leisure use, even the car manufacturers are dropping them due to reliability problems.

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[Jake Royd]

This article is useful for making up the connections.
https://caravanchronicles.com/guides/how-to-connect-two-batteries-in-parallel-part-2/

 

[Lenny HB]

This article is useful for making up the connections.
https://caravanchronicles.com/guides/how-to-connect-two-batteries-in-parallel-part-2/

For two batteries next to each other not necessary.

 

[autorouter]

Wiring, read advisable connecting MH positive to one battery and negative to the other, if not enough MH wire to do this is it that important?

The reason for this is to equalise any voltage drops along the battery wiring and connections. This wiring pattern is one solution to the problem, but there are others if that one is not convenient.

For example, the positive wire will no doubt go from the battery positive to a fuse or isolator switch. You could connect the second battery positive to the same fuse or isolator terminal with a wire of about the same length and thickness.

On the negative side, it's not so easy. Maybe the negative wire goes to a nearby chassis point, and you could connect the second battery negative to the same chassis point.

Otherwise just use very thick wires, and tight connections, so that any voltage drops are very small.

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[Jands]

Will have a good look at the installation on Monday to see what is achievable.
Expect though will just put it in a box, strap it down and do short direct connections to the original.
I can see making it too complicated and changing the original fit too much would increase the chances of building in problems.

 

[laurieash]

First diy job on my MH.
Want to fit a second Leisure battery.
The leisure battery fits under the dining bench seat, enough room for a second battery.
The battery is strapped down inside an open plastic box.
The leads look just long enough for that battery.
Need advice on obtaining and fitting.
Need some hold down straps and brackets from where?
The original battery box is open at the top, do I need a covered box?
Second battery needs to be similar design and amp/hour to the original.
Wiring, read advisable connecting MH positive to one battery and negative to the other, if not enough MH wire to do this is it that important?
Don't want to do a rewiring job, just connect the second battery.
Fuses for new battery, read that it should be outside to battery storage. Also as I expect I will just be connecting the second battery in parallel by joining at the terminals is a fuse important, the original fuse will protect both batteries.
Are battery problems commonplace or quite rare?
Any good advice would be useful. As I said know the preferred theory of a fuse for each battery and split electrical cables but easily adjusting original wiring might be difficult.

What sort of vehicle is it. As Autotrail there is a just a plug in socket.

 

[Lenny HB]

What sort of vehicle is it. As Autotrail there is a just a plug in socket.

With tiny little undersized wires that aren't suitable for the job.

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[laurieash]

Same size wires that run the first hab battery.

 

[Jands]

It's a Pilote.
Only a few weeks old, used it for the first week then been away since then so not been on her.
Going to Norwich for a few days on Monday so will open the battery area up and have a better look.
Might be easy to do a proper job, although it sounds a bit over the top.
Failing that 2 short thick cables will do the job.

 

[daveandsan]

Will have a good look at the installation on Monday to see what is achievable.
Expect though will just put it in a box, strap it down and do short direct connections to the original.
I can see making it too complicated and changing the original fit too much would increase the chances of building in problems.

Hi @Jands does your battery compartment look like this by any chance.
I have only had a quick look at mine with a view to fitting another battery, but as the battery is already a year old i will probably wait now until the spring to fit another and then just drop two new Gell ones in as they are in the living area.
We are away in ours tomorrow, but i may try to see how much spare cable there is. The floor the battery is sat on is a false floor so it may be possible to bring the + or - up through the floor.i
let me know how you get on.

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[Blue Knight]

Pilote P740 with twin habs:

 

[Reallyretired]

All the wires in the pictures are too thin if you're using an inverter. Ours are as thick as a finger and fused at 300A which is in line with the maximum draw from, the inverter (3Kw)

 

[Blue Knight]

All the wires in the pictures are too thin if you're using an inverter. Ours are as thick as a finger and fused at 300A which is in line with the maximum draw from, the inverter (3Kw)

That's a very good point you make. We're not fitting one but your tip-top advice will be great for @Jands

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[Lenny HB]

In the photos from @daveandsan & @Blue Knight the cabling to the batteries looks way undersize, main battery cable to avoid volt drop should be 16 mm sq, if either of those vans were mine I would be rewiring the batteries.

 

[Blue Knight]

In the photos from @daveandsan & @Blue Knight the cabling to the batteries looks way undersize, main battery cable to avoid volt drop should be 16 mm sq, if either of those vans were mine I would be rewiring the batteries.

That's not good Lenny - I paid the dealer a big wedge of cash for that setup. I think I'll be having a word with them at the NEC.

 

[Lenny HB]

I had to restrain myself from you giving a Funny.

While I'm at it those QR battery terminals are naff they are only plated steel can't beat the cheap old fashioned solid brass ones.

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[Blue Knight]

While I'm at it those QR battery terminals are naff they are only plated steel can't beat the cheap old fashioned solid brass ones.

In that case there may be lots of Frankia, Pilote, Globecar and Autosleepers out there with this type of gear fitted.

Shocking eh

 

[funflair]

I guess most users don't pull more than a few amps at a time and these two examples seem to be pretty short run to the Elektrobloc so I would have thought the voltage drop would be pretty minimal, OK an inverter would change the scenario.

Martin

 

[daveandsan]

All the wires in the pictures are too thin if you're using an inverter. Ours are as thick as a finger and fused at 300A which is in line with the maximum draw from, the inverter (3Kw)

When I fitted twin batteries to the Hobby I used really beefy made up cable.

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[daveandsan]

In the photos from @daveandsan & @Blue Knight the cabling to the batteries looks way undersize, main battery cable to avoid volt drop should be 16 mm sq, if either of those vans were mine I would be rewiring the batteries.

The cabling in my photo is factory fitted.

 

[Lenny HB]

The cabling in my photo is factory fitted.

Doesn't surprise me a lot of manufacturers fit undersized cabling to save cost.
There a thread not so long ago with the Terms heater cuting out on an AT due to volt drop on undersized cables.
Battery cables on my Hymer are 16 mm sq.

 

[daveandsan]

I had to restrain myself from you giving a Funny.

While I'm at it those QR battery terminals are naff they are only plated steel can't beat the cheap old fashioned solid brass ones.

Can’t disagree about those terminals, I will replace those when I fit new batteries.

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[Lenny HB]

In that case there may be lots of Frankia, Pilote, Globecar and Autosleepers out there with this type of gear fitted.

Shocking eh

Doesn't mean it's good practice.

Q. Why would you need QR battery terminals on a Motorhome.

A. When you have AGM batteries

 

[PhilandMena]

Those QR terminals are crap ! I had them on my batteries and they became loose through vibration. Get the old bolt jobby on them.

 

[daveandsan]

Doesn't mean it's good practice.

Q. Why would you need QR battery terminals on a Motorhome.

A. When you have AGM batteries

Q. When don’t you need QR battery terminals on a Motorhome

A. When you have GEL batteries.

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