# Fitting a 2nd leisure battery



## Topic and Wanderer (Mar 20, 2010)

I have an Autosleeper (Marquis) Dorset, based on a Peugeot Boxer 2.2HDI (2006 model).

I want to increase my battery power from the 85ah currently fitted as standard. I have purchased a couple of elecsol 100ah batteries and have managed to locate these, 1 under the drivers seat and the other directly behind (sligt mod was req).

I am now at the stage where they need connecting and have spoken to a motorhome service engineer to see if he would do the wiring. He has thrown up a couple of questions over doing this.

1. Can the camper charging system cope with the extra battery capacity without causing any problems or being unsafe?
    The camper is fitted with a Inter-Power unit from Plug-In-Systems and the details are:-
Output voltage:- 13.8volts
Output current:- 12 amps
Overcurrent protection
Short circuit protection
Reverse polarity protection (battery)

2. Will the vehicle charging system be able to cope with the additional load when on the move without causing any problems?

I have read many articles where people have fitted additional batteries, but never come across these questions being asked or even them being a problem.

It seems that most none wildcampers assume we are all attached to the mains, so battery power isn't a problem.

I have also just ordered a couple of 50 watt solar panels to help when away.

Your comments on this matter would be much apriciated before I carry on.

Andy


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## derekfaeberwick (Mar 20, 2010)

You'll be fine, it will just take longer to charge, but then it will take longer to discharge the battery.

  No problems should arise at all.


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## Topic and Wanderer (Mar 20, 2010)

derekfaeberwick said:


> You'll be fine, it will just take longer to charge, but then it will take longer to discharge the battery.
> 
> No problems should arise at all.



Thanks for this, it is exactly what I thought and whilst I have no problems doing work on the electrics, there is a lot of power here so thought I would get a second opinion.

Andy


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## orian (Mar 21, 2010)

Hi Andy,

You said that " I have purchased a couple of elecsol 100ah batteries and have managed to locate these, 1 under the drivers seat and the other directly behind (sligt mod was req)."

Did you find a battery box under the drivers seat or did you modify?


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## biggirafe (Mar 21, 2010)

derekfaeberwick said:


> You'll be fine, it will just take longer to charge, but then it will take longer to discharge the battery.
> 
> No problems should arise at all.



I agree, sounds like your guy is being overly careful. Maybe find a more motorhome experienced electrition to have a look at wha your doing and give you a second opinion if you feel the need.


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## Hallii (Mar 21, 2010)

It will be fine, they will just be a bigger 12v battery when connected, the charger will work and cannot charge at a higher rate than the batteries will take and since it is over current protected it will even stand a short circuit.

Make sure to use heavy duty cable to connect the batteries together, starter motor cable should be available from your motor factors and will be fine.

Use soldered battery connectors, the clamp screw type have a habit of coming loose or going high(er) resistance due to corrosion.

Only connect two batteries of the same make and type together.

Use as short a cable run as is possible.

Connect +ve to +ve and -ive to -ive, do not use the body work as a ground for the second battery.

Use proper insulators on the battery terminals, a short circuit will result in hundreds of amps flowing, a fire is a very possible outcome.

Remember, hydrogen and oxygen are produced when charging, this makes a very explosive mixture, make sure that there is adequate ventilation and a tray to collect any acid spill ( during fault conditions).

If one battery fails you will need to change both, the older one will have a different capacity to the new one and could cause problems, anyway it will be due to fail since it will be the same age as the failed one.

Hallii


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## Mastodon (Mar 21, 2010)

What they said... and... put a fuse as close to the +ve terminal as poss on each battery. Most batteries have a vent tube which should be routed overboard. I use some aquarium type tube and a T piece to the original battery vent. Are they both in the same compartment? might not get best capacity if one of them is in a cold spot.


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## novice1968 (Mar 21, 2010)

Connect +ve to +ve and -ive to -ive, do not use the body work as a ground for the second battery.

what can be used as ground otherthanbogy work????

ans what is a soldered connector???


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## Mastodon (Mar 21, 2010)

Lots of vehicles use the vehicle body as the '-ve wire' to reduce costs. Much more efficient, reliable and safe to use 2 wires. Soldering is a method of joining electrical components using a low temperature melting metal alloy (solder), 'course if the components get too hot, the joint falls apart.


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## Topic and Wanderer (Mar 21, 2010)

orian said:


> Hi Andy,
> 
> You said that " I have purchased a couple of elecsol 100ah batteries and have managed to locate these, 1 under the drivers seat and the other directly behind (sligt mod was req)."
> 
> Did you find a battery box under the drivers seat or did you modify?



Hi Orian,

Yes the under seat box needed to be widened very slightly to accept the battery. 

As for the second battery, I added a false floor between the drivers seat and small bulkhead. I have also stood the batteries on a battery mat I found on ebay, any acid spill is absorbed and neutralised by the mat.

Andy


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## Topic and Wanderer (Mar 21, 2010)

Hallii said:


> It will be fine, they will just be a bigger 12v battery when connected, the charger will work and cannot charge at a higher rate than the batteries will take and since it is over current protected it will even stand a short circuit.
> 
> Make sure to use heavy duty cable to connect the batteries together, starter motor cable should be available from your motor factors and will be fine.
> 
> ...


Thanks Hallii for the advice. I have some 4guage battery wire from Maplin max length will be about 300 - 400 mm and I have stood the batteries on a battery mat for added protection. Have been given the phone number of a good auto electrician, so will see if he will make the connections and test the system for me.


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## Topic and Wanderer (Mar 21, 2010)

Mastodon said:


> What they said... and... put a fuse as close to the +ve terminal as poss on each battery. Most batteries have a vent tube which should be routed overboard. I use some aquarium type tube and a T piece to the original battery vent. Are they both in the same compartment? might not get best capacity if one of them is in a cold spot.



Many thanks, have fitted vent tubes got them free from local caravan dealer. Both batteries next to each other, so are in the ideal place.

Andy


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## phantom flyer (Mar 21, 2010)

Have just had second battery connected by an auto electrician.  He told me he used the same size of cable that was connected to the first battery to connect the two together plus a fuse between the two batteries on the positive link.  Does this sound ok?  Sounded ok to me but I am of the mechanical persuasion dont like things that I cannot see and counld bite me!!!


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## sponge dad (Mar 22, 2010)

Sounds OK to me, I have 2  extra 100amp hr elecsol batteries wired in the same way Also 80watt solar panel so i  don't use electric hook up when on a  campsite. Great for when wild camping can easily go for a few days without having to run the engine to charge batteries.


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## Mastodon (Mar 22, 2010)

phantom flyer said:


> Have just had second battery connected by an auto electrician.  He told me he used the same size of cable that was connected to the first battery to connect the two together plus a fuse between the two batteries on the positive link.  Does this sound ok?  Sounded ok to me but I am of the mechanical persuasion dont like things that I cannot see and counld bite me!!!



That's the way I did it. Make sure it's a nice big fuse and check it now and then.


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## Topic and Wanderer (Mar 24, 2010)

sponge dad said:


> Sounds OK to me, I have 2  extra 100amp hr elecsol batteries wired in the same way Also 80watt solar panel so i  don't use electric hook up when on a  campsite. Great for when wild camping can easily go for a few days without having to run the engine to charge batteries.



This will be the same set up as mine, I have two flexible 50watt solar panels on the way from china, so I am looking to be self sufficient for as long as possible while camping.


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