battery charge problems

Submitted: Sunday, Jan 18, 2009 at 20:00
ThreadID: 65239 Views:4011 Replies:9 FollowUps:8
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I have a new (2 months) Jayco off road CT, all has been working fine, battery has been fine for 16 days camping. whilst away last week, the battery in the camper (FullRiver) went flat. Drove 6 hrs the following day. Battery was still flat at 11v. Disconnected the battery terminals checked the voltage at the connectors, all ok at around 14v. As soon as I connect the battery up the reading drops to 11v (flat reading). Car is running when I do this.

Put the battery onto a separate charger and it is charging up fine.

Does this mean I have a short somewhere. If so where do I start?

Any advice appreciated.

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Reply By: Mrbrush - Sunday, Jan 18, 2009 at 20:35

Sunday, Jan 18, 2009 at 20:35
I`m no sparky, But just a thought . When you say you connect the battery up and car is running I assume that is via an anderson plug at rear or similar. If so now you have two batteries connected and checking voltage will average them out. Perhaps your vehicle battery is stuffed ?
AnswerID: 344975

Follow Up By: Maîneÿ (wa) - Monday, Jan 19, 2009 at 02:54

Monday, Jan 19, 2009 at 02:54
If vehicle battery is stuffed, how did he start the vehicle ?

Mainey . . .
FollowupID: 612999

Reply By: Member - Scrubcat (VIC) - Sunday, Jan 18, 2009 at 22:13

Sunday, Jan 18, 2009 at 22:13
G`day mintrax,
I am only a back yard Tinkerer with this 12 volt stuff but I reckon
more info is required.
What is the A/H capacity of the battery?
What was the combined load on the battery?
Did you charge it during the 16 days ?
If so for how long with what type and size of charger?
How long after charging did you take readings?
How is the battery connected and to what, i e from the starting battery direct, or through an isolator, or from the alternator, or joined to the 12v system somehow???
What is the size and length of the cable from vehicle to camper and how are the two connected?

The people on this forum who are good at these type of problems may even require additional info.

If you still have a problem perhaps an Auto Lecky might be a good place to start.

I don`t know where i`m going but i`m enjoying the journey.

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AnswerID: 344989

Follow Up By: Member - Scrubcat (VIC) - Sunday, Jan 18, 2009 at 22:19

Sunday, Jan 18, 2009 at 22:19
Sorry mate ,
I clicked Submit a bit quick.
I am sure you will sort it out.

Good luck

I don`t know where i`m going but i`m enjoying the journey.

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FollowupID: 612981

Reply By: Notso - Sunday, Jan 18, 2009 at 22:26

Sunday, Jan 18, 2009 at 22:26
If it's showing full voltage without the battery connected and 11 with iy connected you most likely have a high resistance in the charging circuit somewhere.

If so you'll feel it heating up, so check all your connections, fuses etc and see if any of them warm up whilst the battert is on charge.

If so then you'll need to remake the joints.

AnswerID: 344991

Follow Up By: Grungle - Monday, Jan 19, 2009 at 08:32

Monday, Jan 19, 2009 at 08:32
I agree with Notso - you have a large voltage drop occur when you place a load in the circuit (the flat battery).

I suspect that mintrax is using the 7 or 12 pin trailer plug to charge his battery and this may be the week link. Alternatively he could be using a chassis earth return and has a high resistance earth connection.

FollowupID: 613016

Reply By: oldtrack123 - Sunday, Jan 18, 2009 at 23:54

Sunday, Jan 18, 2009 at 23:54
Hi Michael
The sypthoms you have are typical of a high resistance joint. Burnt or Dirty ]
. You may detect it by leaving the battery connected with engine runningleave for about 5,10 minutesthen see if you can feel any local hot spotswhere ever thre is ajount or connection including any plugs.
If you cannot find any that way you will need a mutimeter or a 12v test lamp[ any 12v lamp will do just connect a couple leads to it some how]
Then, with engine running, starting @ the van battery start testing back towards the main bat @ at some point you will get 12v indicated by a brighter glow if you are using test lamp or ajump in voltage if using a multi. THE FAULT WILL BE BETWEEN THE POINTS LAST TESTED & @ THE ONE WHERE THE VOLTAGE INCREASED..
You should have a neg cable running between both bats if the installation has been done correctly.
Running your battery down to 11v is not good for ANY battery , IT WILL SERIOUSLY SHORTEN IT's .LIFE [ NO MATTER WHAT TYPE OF BATTERY
IF you have done this regularly the battery may already be kaput
AnswerID: 345001

Follow Up By: oldtrack123 - Sunday, Jan 18, 2009 at 23:57

Sunday, Jan 18, 2009 at 23:57
Sorry , boy was there some typing / spelling errors in that last post< & no edit function. Should have run spell check
FollowupID: 612990

Reply By: Maîneÿ (wa) - Monday, Jan 19, 2009 at 03:18

Monday, Jan 19, 2009 at 03:18
Can we review the situation.
You went away camping for 16 days (excess of 2 weeks) some time ago and the battery was working perfectly, then last week the Fullriver battery went flat, even after driving 6 hours it was still flat (11v)

However, when disconnected it shows 14v, (indicating it has VERY recently been receiving a very good charge) so we 'assume' the vehicle is fully charging the battery by the numbers you've indicated.

However, you also say "as soon as I connect the battery up the reading drops to 11v (flat reading) ... the car is RUNNING when I do this"
So (theoretically) it can't possibly be charging the battery as I thought ?

The battery does charge when on a 240v charger!

I think more detailed information is required :-)

Mainey . . .
AnswerID: 345004

Reply By: mintrax - Monday, Jan 19, 2009 at 10:00

Monday, Jan 19, 2009 at 10:00
Thanks to all who have replied, much appreciated.

I guess I should make it clear that my knowledge of this stuff is very limited. A man with little knowledge and a multimeter can be dangerous!

When I bouight the Jayco CT all the electrics were installed (12v and 240v, fuses, 12v plug...the works) and there was a place for a 12v battery if you wanted to put one in. The connecting wires were sitting there waiting to be connected to the battery.

So I installed the battery, checked that voltage was being supplied (around 14v) and left it at that. I only used the CT for 3 days with it in the original position.

After that I decided to re-locate the battery over the axle as the original position at the front of the CT was causing ball weight problems with my Forester.

I got some 50amp cable and joined it (twisted together and taped with the smaller cable that went to the original battery position) and ran the cable. I then tested that the correct voltage was present with it connected to the car and with the car running.

I then obviously incorrectly presumed that all was hunky dory, especially as I had been on the road from the 2nd Jan till 16th jan before it went flat.

Thinking about it now. I did spend 3 days in a row at a powered site in the middle of the trip. I would presume that it probably got charged correctly when connected to the 240.

The battery is a FR 100ah battery. It is connected to the car via pin 2 on the tralier plug, as is the fridge for running on dc while travelling.

Usage is fairly low, a light for an hour or two, charging mobile's and charging aa batteries through a 300w invertor once or twice and running a laptop say 2 hours a day.

Don't be too tough on me!



AnswerID: 345031

Follow Up By: mintrax - Monday, Jan 19, 2009 at 11:21

Monday, Jan 19, 2009 at 11:21
Also found this elsewhere on exploreoz

The problem is that the power supply (Setec) in Jayco vans is not an efficient battery charger. The maximum output voltage is a lot lower than that of a proper multi stage charger. If you want to charge your battery in a timely manner then purchase a proper battery charger. The Setec is only capable of maintaining a charged battery, not recovering a discharged battery.

With a good battery charger you can get rid of your Setec. The Cetek models are a favoured model with members of this forum.
FollowupID: 613039

Follow Up By: stephen looking - Monday, Jan 19, 2009 at 12:16

Monday, Jan 19, 2009 at 12:16
Hello mintrax, where are you located mate? if your in melbourne i could possible give you a hand.

It sounds like you have a few different issues there.

Also another good source world be derek from Sidewinder he has helped a lot of people on this forum.

Happy travels............Stephen.
FollowupID: 613046

Follow Up By: mintrax - Monday, Jan 19, 2009 at 13:00

Monday, Jan 19, 2009 at 13:00
Hi Stephen,

Actually in Yea, could you give me your email address by emailing me at


FollowupID: 613050

Follow Up By: Member - Graham H (QLD) - Monday, Jan 19, 2009 at 13:43

Monday, Jan 19, 2009 at 13:43
You say you just twisted the ends of the two cables together.

That in itself is not only bad but could be dangerous.

You should at the very least use crimped connectors or better still run a whole new cable.

Probably the first place to look for hotspots I would think.

It would read Ok until you put a load thru it and then would get very hot I would think.

FollowupID: 613052

Reply By: Nomadic Navara - Monday, Jan 19, 2009 at 13:05

Monday, Jan 19, 2009 at 13:05
The standard Jayco installation is extremely poor for recharging deeply discharged batteries. It is more for running the lights off the mains power or supplying the lights with from your tug on overnight stops. The Setec power supply is only designed to maintain charged batteries, it is not an efficient battery charger. The standard wiring from your tug through a 7 pin connector does not have enough copper to charge your battery in a reasonable time. The power supply, converter (or what ever you like to call it but please don't call it a transformer) in your camper is of the same type as described in this article Site Link

If you wish to use your battery for several nights before recharging you need to reconfigure your battery system. The first thing is to replace the Setec (or did they install the Centurion) with a quality battery charger - 3 stage type. If you want to charge your battery from your tug then you need to upgrade your 12 V wiring with much heavier cable. You will also need to change your 7 pin plug for a 12 pin one or an Anderson connector and also install a battery booster like the RanOx battery booster

Retired radio and electronics technician

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AnswerID: 345057

Reply By: Dennis Ellery - Monday, Jan 19, 2009 at 13:41

Monday, Jan 19, 2009 at 13:41
Recently had similar problems with a new Jayco.

2 circuits
1st - Battery charging circuit direct connection to the battery
2nd - Feed to the fridge.

One circuit from the battery – bridged out at the vehicles plug to supply the 2 circuits on the caravan.

PROBLEM (Towing vehicle incorrectly wired)
The fridge current was causing a large enough volt drop to stop the caravan battery charging from the towing vehicle.

Install 2 circuits on the vehicle to suit the 2 circuits on the caravan.
I installed separate heavy cable from the vehicle battery to the caravan battery.

Cheers Dennis Ellery
AnswerID: 345060

Reply By: Member - Dogbolter (VIC) - Wednesday, Jan 28, 2009 at 19:20

Wednesday, Jan 28, 2009 at 19:20
I to have been thru the Jayco Outback Penguin charging fiasco.

First thing I found was wiring thru the 7 pin plug was totally useless so modified wiring using 6 B&S wire and anderson plugs.

Basically I found 3 scenario's that exist.
1. Bush camping - no power, charge batteries with ctek xs2500 from generator or solar panels.

2. Caravan park - power available. Plug in to power and use Centurion or Setec inbuilt power unit (13.2v 30amp). This has worked for me for over 2 weeks continuous, no battery problem as fridge _Affordable_Storage_Drawers.aspx only 2.5 - 3 amps and the inbuilt power supply will float the batteries at 13.2v and supply up to 30 amps for lights etc....

3. Daily drive and overnight camp. This has been ok for me if I camp and run the next day. The problem is that the cv batteries can never be charged to 100%, if you get 85% charge you will be lucky. Not much good if you have 100ah and a 12v absoption fridge running continuously drawing 10-12 amps. Ok for compressor type fridges with Danfoss or engel motors etc.

The Centurion power supply works fine whilst it is working, I have had it fail twice, from offroad vibrations I suspect. A capacitor vibrated out and a filter inductor disconnected itself from fatigue. Both easily fixed with a bit of soldering and a heap of silicone sealant to stop it happening again.

I have wired from a Redarc isolator in the vehicle to caravan batteries using 6 B&S wire via Anderson connectors. I can still never get 100% full batteries. The only way would be to use a DC-DC booster with built in smart charger (RanOx or similar). I looked at using a sinewave inverter driving the ctek but there would probably be an issue with the charger dropping back from float to absorpton mode when the fridge switches on and hence overcharging the van batteries. I have replaced the standard 3 way fridge with a Vitfrogo compressor fridge. This happend because the Dometic has leaked gas twice and at $500 to repair each time it was time to use something else. Lost the 240v and gas but have a 12v fridge that uses 2.5 amps instead of 12 amps. Batteries now last 3 - 4 days between charges when in the bush.

Van setup
2 x 12v 100ah Fiamm AGM batteries flooded cell type, not Gel.
NASA marine battery monitor
6 B&S wiring to batteries
ctek xs2500 charger
replace 3 way absorption fridge with Vitfrigo compressor type.
Will be upgrading the charging circuit to a RanOx to look after the batteries a bit better.
AnswerID: 346408

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