Charging third battery in Camper trailer

Submitted: Wednesday, Jul 30, 2003 at 12:07
ThreadID: 6259 Views:3768 Replies:4 FollowUps:5
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I have a Piranah dual battery system in the car and wish to set up a system to charge a deep cell battery in the camper trailer. The camper I have is an Aussie Swag and it has a isolator in the trailer. I have received conflicting advice as to whether ot not I should connect a 6 B&S cable via an anderson plug to the main starter battery or my 2nd battery. My thoughts are to connect it to the starter so that when that it fully charged the isolators will then charge both the camper and the 2nd battery in the car together. Also what size fuse should I use - 30 amp?

Any thoughts?
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Reply By: Rod - Wednesday, Jul 30, 2003 at 14:06

Wednesday, Jul 30, 2003 at 14:06
In have a similar setup. I have a Rotronics setup which charges the starter for the first 10 minutes and then charges the aux for the rest of the time until the main goes below a preset voltage. As a result, the alternator is charging the aux battery 90% of the time, so in my setup, I have the trailer battery connected to the aux, not starter. Not sure how the Piranah operates.

Not sure what 6 B&S cable is but if this is only 6mm, you will get too much voltage drop in the run back to the trailer. I'm using 16mm which is probably slight overkill.

I have some rather large switches in the cab rated at 50A 12VDC to allow me to isolate whether the dual battery system charges the existing aux battery, the campertrailer battery or both. This is a nice to have.

From memory, I'm using a 30A fuse and definitely using Anderson plugs.

A good resource for further info is the campertrailers group on www.egroups.com You will find many messages in the archives on this topic, including advice on what size cable to run.

Remember that a standard automotive alternator will never charge the batteries above 70%. If you want to understand why, read the article in Jul 03's Silicon Chip magazine.

Best of luck
AnswerID: 26346

Follow Up By: outahere - Wednesday, Jul 30, 2003 at 17:49

Wednesday, Jul 30, 2003 at 17:49
Thanks - the 6B&S is apparently battery and starter cable and the 6 is not the mm size. It is thick so it should do the job. I like your idea of the switches
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FollowupID: 17971

Reply By: Member - Roger - Wednesday, Jul 30, 2003 at 20:11

Wednesday, Jul 30, 2003 at 20:11
Hi Outahere,
I to have a third battery in my C/van that charges from the Auxilary Battery via a 50amp Anderson plug to a Twin Charge battery controller situated in the van.
This unit charges at a max of 20amp and increases the voltage to 13.8v for charging purposes.
This unit is available from the 12 volt shop.
I have had this unit in 2 vans now and have had not one bit of trouble from them, indeed when I sold my last van the unit had been in for 5 years and was still happily keeping the same battery going.
The 12v shop has a web site.....
www.12volt.com.au
Also you could ring them on 08 94581212 or fax on 08 94581977.
6ml wire from the aux to the anderson plug and the same to the twin charge in the van. I also have a charge and maintain charger for when stored, it is permanently connected to the van batt and auto looks after this batt when the van is connected to 240v.
RegardsDodg
AnswerID: 26378

Follow Up By: Andy - Wednesday, Jul 30, 2003 at 20:49

Wednesday, Jul 30, 2003 at 20:49
Hi Roger,

I am interested to know what type of isolator you have between your cranking battery and your auxilary in the car.

I also have the Arrid twin charge like yours in my camper. I fitted an ARB isolator in the car and have cable from the new auxilary in the car to the arrid in the camper. I found the Arrid started to make a whistling sound on and off, and disconnected it in the fear that something was wrong. Does yours make any sound???

cheers

Andy
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FollowupID: 17993

Follow Up By: EvIlBoYsPaWnEd - Thursday, Jul 31, 2003 at 08:43

Thursday, Jul 31, 2003 at 08:43
I'm new to 4w driving and I'm thinking of buying a van. I'd like to know how long does a van's power source or battery last on average, until you have move no or recharge the batteries ?

EvIlBoYsPaWnEd
Every minute of every day could be the minute that turns it all around for you !
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FollowupID: 18029

Follow Up By: EvIlBoYsPaWnEd - Thursday, Jul 31, 2003 at 08:43

Thursday, Jul 31, 2003 at 08:43
I'm new to 4w driving and I'm thinking of buying a van. I'd like to know how long does a van's power source or battery last on average, until you have move no or recharge the batteries ?

EvIlBoYsPaWnEd
Every minute of every day could be the minute that turns it all around for you !
0
FollowupID: 18030

Follow Up By: Member - Roger - Thursday, Jul 31, 2003 at 22:57

Thursday, Jul 31, 2003 at 22:57
HI All,
Really opened a can or worms eh'.
I have a simple solenoid system that seperates the main from the aux battery that is connected each time one turns the ignition on, this then gives more power for cranking and as I have a 9000lb Warn winch connected to the Aux battery it also allows both batterys to power it when the engine is running. I have noted that others have made the remark that the Aux can drain the starting batt when it is very low and you want to start the vehicle, however in three yrs of use I have not had this problem. I may add that contrary to popular opinion the Aux batt is a deep cycle one. This has not effected the winching ability as I always have the engine running at least 1500 revs when winching and I do not operate the winch for more than a couple of minutes without giving it a break.
But I digress, I have a 40 amp relay mounted on the fire wall between the aux batt and the lead to the caravan connection (anderson plug) which is controlled from a switch mounted in the cab. This also is wired so that the relay will not work unless the ignition is on. Thus the van batt does not drain the aux when the engine is not running.
As for the twin charge making a noise, I have not noticed anything out of the ordinary except that the inbuilt fan in the unit makes a small noise when running.
As I have previously said this system has worked in my other vehicle and van for approx 5 yrs and the new unit in this vehicle and van for 3 yrs.
Regards,Dodg
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FollowupID: 18094

Reply By: Member - John - Thursday, Jul 31, 2003 at 10:07

Thursday, Jul 31, 2003 at 10:07
In reply to An dy, I have a Twin Charge, very good unit, and yes mine makes a noise, contactede the 12 volt shop and was assured that it should be making the noise. Re connect and keep using this very good unit.
AnswerID: 26416

Reply By: Member - John- Thursday, Jul 31, 2003 at 19:31

Thursday, Jul 31, 2003 at 19:31
For theses matters you will find excellent knowledge and advice from Collyn Rivers in his books on motorhome and caravan electrics. You can buy them online at www.caravanandmotorhomebooks.com

JohnS
AnswerID: 26451

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