Auxillary power set up for touring-both XJ and camper trailer

[JEEPCHIK]

In the last couple of weeks I have taken the plunge and bought my first hard floor camper trailer. Did my research and it paid off, built last year, used once up the Cape and never used again and I got it for under 6k! :D

So, as you can imagine I have been busily getting things set up the way I want it and this brings me to the small dilemma of how do I set up my auxillary power? I've purchased a 38 Litre Engel which will reside in the back of the XJ most of the time, it would be too impractical for me to take it out of the XJ when I'm camping so I need to look at my powering options for that. I also have to set up power for the trailer as it has a 70 litre stainless water tank which is fed through a 12 volt electric pump as well as lighting for the camper. One idea is to fit a maintenance free battery in a battery box inside the large tool box on the front of the camper and recharge the battery via an anderson plug on the XJ rear bumper as I'm driving along.

With the fridge I was planning on having a second battery in the back of the XJ for that job but this is where things start getting a bit tricky in my thought processes. How can it all work?? How can I recharge the 2nd battery in the car as well as the camper battery?? Won't this be way too much overload for the alternator? I will be getting solar panels eventually for charging while stationary. Lighting will be L.E.D strip lighting so the power draw from those will be fairly low however I'm not sure how much power the water pump will need.

So, my question is: what does everyone else do with their Jeep and camper trailer set ups? I'm pleased to say ( touching wood) that the XJ towes like a dream with no overheating issues, handles the extra wait well and makes reversing fairly straight forward. I did have an extra leaf fitted to my rear springs as the XJ really sagged with the trailer hooked up. Now everything is nice a level again and eats up the corrugated dirt roads like they aren't even there :D:D

[Raisins78]

Easy.....Get a dual battery relay/isolator/kit.
Set it up as per normal (Read instructions or see my pics) with the battery in the rear of the XJ.
Get a dc - dc charge controller for between the dual battery (rear of xj) to the trailer, via said anderson plug.

This setup will require no monitoring, no unplugging etc when camped so set and forget!
For extra security, run a solar panel and controller to your engine battery.
This will charge the start battery, then the dual battery once the engine one is full, and inturn the trailer too........everybody wins.

http://www.ausjeepoffroad.com/forum/attachment.php?attachmentid=56260&d=1345252598
http://www.ausjeepoffroad.com/forum/attachment.php?attachmentid=57153&d=1348579338

[Raisins78]

the DC to DC charge controller is vital, unless you run battery sized cable to the trailer.
It will limit the current between the dual battery and trailer battery to whatever its charge rating is (Some are 10amp, some 20amp, some 40amp etc)
Make sure the cable from, and to the Anderson plug is rated to the charge controller.

[Steve F]

I just have solar on the camper, normally does the job just fine with no charging from the Jeep. If the camper battery gets low I move the fridge to the Jeep and run it off the second battery in there, the LEDS in the camper draw next to nothing so without the fridge the 100ah battery will run the LEDS for ages.

Cheers
Steve

[andyperth]

[QUOTE=JEEPCHIK;1326829]In the last couple of weeks I have taken the plunge and bought my first hard floor camper trailer. Did my research and it paid off, built last year, used once up the Cape and never used again and I got it for under 6k! :D

Wow i did the same mine was 7k :( i was think about the very same problem . So I was thinking of a power pack like a thumper or engels one and run my fridge, lights and water pump from that.
I was going to recharge it with solar panels and run the fridge in the jeep when driving.What do you think?

[Gildo]

I'd keep the starting battery well out of loop, using a dual battery controller only for the supply from the alternator.
As Steve said, the LED lighting load is negligible, why does the fridge need to stay in the XJ?.
If you use a large enough battery in the trailer, fully charged before you leave, add a solar panel or two to the trailer and you should be good to go.
There is plenty of reading on the www to calculate your load/time/charge rate. It's basic high school maths.
Jaycar had a unit a while back that was a solar charger, inverter and 240v charger all in one. Great for plugging into the mains for topping up at home or on powered sites and solar regulated when you are unplugged, with the bonus of 240v if you need it.

[BatteryBusiness]

A lot of good information already in this thread.
I think Raisins78 way is a simple and good setup for a triple battery system.

For the second battery in the back of the XJ you can use a simple dual battery isolator like the Redarc SBI12 (http://www.batterybusiness.com.au/cart/product_detail/7521) or anything similar.

For the third battery in your camper trailer I would suggest the Redarc BCDC1225 (http://www.batterybusiness.com.au/cart/product_detail/7810) which is a DC-DC charger with solar regulator built in. Mount it in the camper trailer and connect it with an Anderson plug to the car using the same feed that goes to your second battery.

This set up gives priority to your starter battery for charging (only if your starter battery is full will the other two batteries get charged) and protects it from discharge (your fridge or trailer cannot discharge the starting battery).

Second and third battery have equal priority for charging but are isolated against each other.


The BCDC1225 is a good choice for your camper trailer because if you get some solar panels in the future you can just connect them to the BCDC1225 with no additional wiring. Also the DC-DC charger means you can get away with a more modest cable size (25A max) and it will charge your battery to 100% which will not happen with a direct alternator feed.

There are alternative versions for example instead of the BCDC1225 you can use a CTEK Dual which does the same or you can use a DC-DC charger instead of the simple SBI12.

And lastly remember that batteries carried inside vehicles must be dry batteries eg AGM or GEL. This applies certainly for the one in the back of your XJ. The battery in the camper trailer can be a standard wet battery if it is in the tool box also I would prefer an AGM there as well.

[JEEPCHIK]

I'd keep the starting battery well out of loop, using a dual battery controller only for the supply from the alternator.
As Steve said, the LED lighting load is negligible, why does the fridge need to stay in the XJ?.

The fridge will stay in the XJ as it's way too heavy for me to move empty let alone full. Everything in my camping set up needs to functional for me by myself.

[JEEPCHIK]

A lot of good information already in this thread.
I think Raisins78 way is a simple and good setup for a triple battery system.

For the second battery in the back of the XJ you can use a simple dual battery isolator like the Redarc SBI12 (http://www.batterybusiness.com.au/cart/product_detail/7521) or anything similar.

For the third battery in your camper trailer I would suggest the Redarc BCDC1225 (http://www.batterybusiness.com.au/cart/product_detail/7810) which is a DC-DC charger with solar regulator built in. Mount it in the camper trailer and connect it with an Anderson plug to the car using the same feed that goes to your second battery.

This set up gives priority to your starter battery for charging (only if your starter battery is full will the other two batteries get charged) and protects it from discharge (your fridge or trailer cannot discharge the starting battery).

Second and third battery have equal priority for charging but are isolated against each other.


The BCDC1225 is a good choice for your camper trailer because if you get some solar panels in the future you can just connect them to the BCDC1225 with no additional wiring. Also the DC-DC charger means you can get away with a more modest cable size (25A max) and it will charge your battery to 100% which will not happen with a direct alternator feed.

There are alternative versions for example instead of the BCDC1225 you can use a CTEK Dual which does the same or you can use a DC-DC charger instead of the simple SBI12.

And lastly remember that batteries carried inside vehicles must be dry batteries eg AGM or GEL. This applies certainly for the one in the back of your XJ. The battery in the camper trailer can be a standard wet battery if it is in the tool box also I would prefer an AGM there as well.

Thanks Raisins78, that's pretty much the simple system my dad and I had been discussing. Batterybusiness, all that information has been read and absorbed and I'll be using Redarc all the way. I want to keep the battery set up as simple as possible but also functional. I only used MF batteries now as I am good at killing wet batteries. I've started doing research on the battery I will need for the camper but have a lot more reading to do. I know I will only need a relatively small battery but what size I don't know.

Thanks again for all the info everyone, I will keep this thread updated on what I do:D

[BLU-125]

BB, why should only AGM or Gel batteries be used inside the vehicle? Surely the hydrogen emissions from a flooded wet cell battery are so slight that any vehicles ventilation system would take care of it.

I have used "wet" batteries in the back of XJs & TJs for many years, after finding AGMs tend to not like vibration & heat.

[BatteryBusiness]

BB, why should only AGM or Gel batteries be used inside the vehicle? Surely the hydrogen emissions from a flooded wet cell battery are so slight that any vehicles ventilation system would take care of it.

I have used "wet" batteries in the back of XJs & TJs for many years, after finding AGMs tend to not like vibration & heat.

Yes, primarily for venting reasons but also because a leaking battery creates a real mess.
Obviously many people have "wet" batteries inside the car and I would not think this would be a big issue but personally I would not want them in my sleeping room eg in a camper/caravan and because I sometimes sleep in the back of my GC not there either.

AGM's usually do not have problems with heat but sometimes vibrations. As a general rule, a good marine grade AGM should handle vibrations well
.

[Raisins78]

And lastly remember that batteries carried inside vehicles must be dry batteries eg AGM or GEL. This applies certainly for the one in the back of your XJ. The battery in the camper trailer can be a standard wet battery if it is in the tool box also I would prefer an AGM there as well.

Absolutely. I have a 100AH dry cell in the back (ebay. approx $300, much heavier than a wet cell.....) and an Odyssey AGM in the engine bay for maximum cranking (PC1240 from memory, fits like a stock battery, with more capacity and CCA)

[Raisins78]

Thanks Raisins78, that's pretty much the simple system my dad and I had been discussing. Batterybusiness, all that information has been read and absorbed and I'll be using Redarc all the way. I want to keep the battery set up as simple as possible but also functional. I only used MF batteries now as I am good at killing wet batteries. I've started doing research on the battery I will need for the camper but have a lot more reading to do. I know I will only need a relatively small battery but what size I don't know.

Thanks again for all the info everyone, I will keep this thread updated on what I do:D

Just make sure the cable from front to back is thick, as you can get some high currents traveling from front to back.
I have a 140amp redarc smart relay, and a 200amp fuse inline.
The cable is 2Ga high quality, High temp Audio cable and is good for 300amp plus (Copper section is around 12-14mm across not inc insulation)
Be aware of eBay for cable. I have ordered 4Ga wiring kits for car audio that have less copper than brand name 8Ga kits....

P.s. also read up on solar panels before you buy them. Try and disregard the "Watt" rating, as some are far different.
e.g. I have seen 100w 12v panels with 4.6amp rating, and some with 8amp plus ratings...
If they take there rating from peak voltage and short circuit current, instead of working voltage and full load current it can inflate the "Wattage" rating alot.

[BatteryBusiness]

Thanks Raisins78, that's pretty much the simple system my dad and I had been discussing. Batterybusiness, all that information has been read and absorbed and I'll be using Redarc all the way. I want to keep the battery set up as simple as possible but also functional. I only used MF batteries now as I am good at killing wet batteries. I've started doing research on the battery I will need for the camper but have a lot more reading to do. I know I will only need a relatively small battery but what size I don't know.

Thanks again for all the info everyone, I will keep this thread updated on what I do:D

Almost missed this post ;-)

If you let me know what size batteries you are looking at, I can probably help with a few suggestions and we stock all the Redarc gear as well...

[BatteryBusiness]

Absolutely. I have a 100AH dry cell in the back (ebay. approx $300, much heavier than a wet cell.....) and an Odyssey AGM in the engine bay for maximum cranking (PC1240 from memory, fits like a stock battery, with more capacity and CCA)

We have some very heavy wet cell batteries ;-)
AGM and flooded wet cells are same in weight, however battery weight depends on designated purpose. If you want a lot of cranking amps you want a battery with more surface and therefore more but thinner plates and if you want a deep cycle battery you want thicker plates. So in theory a deep cycle battery will have more lead and should be heavier than a starting battery and my experience from lugging around batteries confirms the theory :D

If you turn that around you can also say that the heavier the battery the better the quality (same size and technology obviously) and again, there is a noticeable difference in weight between "budget" batteries and high quality batteries.

[Raisins78]

We have some very heavy wet cell batteries ;-)
AGM and flooded wet cells are same in weight, however battery weight depends on designated purpose. If you want a lot of cranking amps you want a battery with more surface and therefore more but thinner plates and if you want a deep cycle battery you want thicker plates. So in theory a deep cycle battery will have more lead and should be heavier than a starting battery and my experience from lugging around batteries confirms the theory :D

If you turn that around you can also say that the heavier the battery the better the quality (same size and technology obviously) and again, there is a noticeable difference in weight between "budget" batteries and high quality batteries.
The 100AH said 36kg's on the box...and id believe it!, was way WAY heavier than a full 20L jerry..... Its a deep cycle dry cell battery.

[BatteryBusiness]

The 100AH said 36kg's on the box...and id believe it!, was way WAY heavier than a full 20L jerry..... Its a deep cycle dry cell battery.

As I said, good batteries are heavy :p

[anthonygubbin]

I have two aux's in my XJ one 75ah Exide marine under the bonnet and now one 100ah Century marine in the boot. When I was away for Jambo I found my existing set up was not enough reserve capacity. My biggest problem was running the laptop. I know you did not mention it JC but since most of us now have mobile broadband I thought I would throw that one in.
Now in terms of charging the trailer battery I disagree that you need a DC-DC charger or 2bs cables. Both of which will be very expensive.....;) I also have a caravan with a battery and it gets ample charge by using 8bs cable. I am confident your cable length will not be as as long as mine. I also use 8bs cable to the battery in the boot. When I was looking at my options I was told DC-DC is what I needed and there was no other way. Now considering the DC-DC chargers are like $400 plus I did not get one. I instead spoke with two seperate auto electricians for their expert opinion. They explained the a DC-DC is usually only needed on large dual axle caravans where there is significant voltage drop, due the the cable length. Now while the battery will not reach full charge from the alt it is enough to keep it charged. The biggest issue with battery charging and killing a battery is deep discharge and not charging them up fully once deep discharged. For example if a marine battery gets to 11.8v then it will need full deep charge within a day or two or damage can occur. However if you keep it at around 12.2v you can go weeks without needing a full deep charge.
I know I might get flamed for giving MHO :( but seriously you can go overkill. If you have any doubt I would speak to an auto electrician. If you doubt what he says then you could go 6bs cable which will not be needed but could add piece of mind.

Regards A

[kjparker]

With the cable, whilst you might be able to get away with 8bs, if you can get bigger stuff cheap enough why not?

35mm welding cable (approx 2bs) is under $10 a meter. Double insulated, flexible, and easy to come by.

[junglejuice]

I must admit I run 35mm2 cable from the alt to the dual battery controller mounted in the rear and I wouldn't run anything less, being connected directly to the alt it is being fed with 14.7V at the front and from what I have read regarding AGM batteries is they like a reasonably high charge voltage and considering if you are at all interested in safety you need to have a rear mounted battery's supply wiring fused at both ends, as close as practical to both batteries, which justs adds to the voltage drop so starting with a higher voltage helps.....

[Raisins78]

I have two aux's in my XJ one 75ah Exide marine under the bonnet and now one 100ah Century marine in the boot. When I was away for Jambo I found my existing set up was not enough reserve capacity. My biggest problem was running the laptop. I know you did not mention it JC but since most of us now have mobile broadband I thought I would throw that one in.
Now in terms of charging the trailer battery I disagree that you need a DC-DC charger or 2bs cables. Both of which will be very expensive.....;) I also have a caravan with a battery and it gets ample charge by using 8bs cable. I am confident your cable length will not be as as long as mine. I also use 8bs cable to the battery in the boot. When I was looking at my options I was told DC-DC is what I needed and there was no other way. Now considering the DC-DC chargers are like $400 plus I did not get one. I instead spoke with two seperate auto electricians for their expert opinion. They explained the a DC-DC is usually only needed on large dual axle caravans where there is significant voltage drop, due the the cable length. Now while the battery will not reach full charge from the alt it is enough to keep it charged. The biggest issue with battery charging and killing a battery is deep discharge and not charging them up fully once deep discharged. For example if a marine battery gets to 11.8v then it will need full deep charge within a day or two or damage can occur. However if you keep it at around 12.2v you can go weeks without needing a full deep charge.
I know I might get flamed for giving MHO :( but seriously you can go overkill. If you have any doubt I would speak to an auto electrician. If you doubt what he says then you could go 6bs cable which will not be needed but could add piece of mind.

Regards A

The reason for a dc - dc charger is more to limit current, not to raise voltage for long cable runs.

here is a scenario....
Camping with friends, you have the fridge, lights etc on in the camper, possibly a stereo or laptop too....a big night is had by all, late, few beers etc
Morning breaks, you pack up...and unknown to you, your trailer battery (and possibly your aux battery) is now pretty flat due to the extended use last night.
You start your vehicle, and now the difference in voltage between the engine batt and alternator is high enough to cause massive current (E.g. my engine battery was full, my aux was down to 11.3, I then blew the 120amp fuse between them when i started the car...so we are talking 100-300amps potentially)

If you try to pump that sort of current through 8gauge....it has the chance to melt and catch fire.

If you have a 20amp dc - dc charger...it limits it to 20amps...max. so 8ga or even 16ga is fine.

So unless you monitor voltages all the time etc, you could find yourself in this situation.
I prefer overkill so I can just enjoy my trip, and not worry about overloading etc.

Alot of people underestimate the current capacity of a car battery...especially when pushed like that

[Raisins78]

http://www.ebay.com.au/itm/PROJECTA-12V-12-VOLT-DC-DC-20A-BATTERY-CHARGER-AGM-DEEP-CYCLE-CARAVAN-DC20-/400331301821?pt=AU_Car_Parts_Accessories&hash=item5d359ae3bd

[JEEPCHIK]

The reason for a dc - dc charger is more to limit current, not to raise voltage for long cable runs.

here is a scenario....
Camping with friends, you have the fridge, lights etc on in the camper, possibly a stereo or laptop too....a big night is had by all, late, few beers etc
Morning breaks, you pack up...and unknown to you, your trailer battery (and possibly your aux battery) is now pretty flat due to the extended use last night.
You start your vehicle, and now the difference in voltage between the engine batt and alternator is high enough to cause massive current (E.g. my engine battery was full, my aux was down to 11.3, I then blew the 120amp fuse between them when i started the car...so we are talking 100-300amps potentially)

If you try to pump that sort of current through 8gauge....it has the chance to melt and catch fire.

If you have a 20amp dc - dc charger...it limits it to 20amps...max. so 8ga or even 16ga is fine.

So unless you monitor voltages all the time etc, you could find yourself in this situation.
I prefer overkill so I can just enjoy my trip, and not worry about overloading etc.

Alot of people underestimate the current capacity of a car battery...especially when pushed like that

A car fire is the last thing I want to happen. I won't be cutting any corners by trying to scrape by with the bare minimum when it comes to the wiring/batteries/dc-dc isolators. My dad is a sparky by trade and when it comes the wiring up gadgets in our previous 4wd's, he's always made sure safety comes first. I will be using minimum 8 gauge for the wiring and if I've gotta save for the Redarc stuff then that's what I will do.

Overkill on electrical and mechanical is fine by me however some stuff you don't need overkill on.

[BatteryBusiness]

Overkill on electrical and mechanical is fine by me however some stuff you don't need overkill on.

You don't need overkill on electrical as long as you are aware what you are doing.

But a good point has been made. If you have a dual battery system with two batteries sitting next to each other then it is easy to use a proper very heavy gauge cable. If the second battery is sitting in the back then it becomes a pain to run the cables and if you have a battery in the trailer then can be almost impossible to do it. A DC-DC charger is a very sensible investment and one of the many advantages is that you can go with modest cable sizes which makes it much easier for the installation.

Also if you look at the spec sheet for the Optimas (just as an example) you will see that the recommended max charge is 10A for normal (= slow and gentle) charging. There is no current limit for fast charge as long as battery temperature remains below 51.7°C. I'm sure everyone of you has a temperature sensor on the second battery and a cut-off if temp gets too high ;)

There are some other good pieces of information in the spec sheet:
"Always use a voltage regulated battery charger with limits set to the above ratings. Overcharging can cause the safety valves to open and battery gases to escape, causing premature end of life."

and

"Not fully charging a battery can result in poor performance and a reduction in capacity."

A good DC-DC charger will take care of all this and the better ones even come with a temperture sensor to monitor battery temp.

[kjparker]

A car fire is the last thing I want to happen. I won't be cutting any corners by trying to scrape by with the bare minimum when it comes to the wiring/batteries/dc-dc isolators. My dad is a sparky by trade and when it comes the wiring up gadgets in our previous 4wd's, he's always made sure safety comes first. I will be using minimum 8 gauge for the wiring and if I've gotta save for the Redarc stuff then that's what I will do.

Overkill on electrical and mechanical is fine by me however some stuff you don't need overkill on.

Have a chat with your local welding supplies shop. I think you'll find you can get 16mm (approx 6 gauge) for the same price as the 8 gauge elsewhere. I was pleasantly surprised when I bought the cable I need to upgrade my battery wiring for under $25 (35mm)

[junglejuice]

You don't need overkill on electrical as long as you are aware what you are doing.

But a good point has been made. If you have a dual battery system with two batteries sitting next to each other then it is easy to use a proper very heavy gauge cable. If the second battery is sitting in the back then it becomes a pain to run the cables and if you have a battery in the trailer then can be almost impossible to do it. A DC-DC charger is a very sensible investment and one of the many advantages is that you can go with modest cable sizes which makes it much easier for the installation.

Also if you look at the spec sheet for the Optimas (just as an example) you will see that the recommended max charge is 10A for normal (= slow and gentle) charging. There is no current limit for fast charge as long as battery temperature remains below 51.7°C. I'm sure everyone of you has a temperature sensor on the second battery and a cut-off if temp gets too high ;)

There are some other good pieces of information in the spec sheet:
"Always use a voltage regulated battery charger with limits set to the above ratings. Overcharging can cause the safety valves to open and battery gases to escape, causing premature end of life."

and

"Not fully charging a battery can result in poor performance and a reduction in capacity."

A good DC-DC charger will take care of all this and the better ones even come with a temperture sensor to monitor battery temp.

Ok here is a question for you, what is the best charge voltage for a deep cycle 120A/H AGM (Ritar RA12-120), as mentioned above I have one mounted in the rear with 35mm2 cable fused both ends with the voltage at the alt terminal sitting at 14.7V with a Pirhana DBE150-s MkII controlling it which disconnects the second battery as soon as the ign is turned off (which I like).

Any thoughts?

[BatteryBusiness]

Ok here is a question for you, what is the best charge voltage for a deep cycle 120A/H AGM (Ritar RA12-120), as mentioned above I have one mounted in the rear with 35mm2 cable fused both ends with the voltage at the alt terminal sitting at 14.7V with a Pirhana DBE150-s MkII controlling it which disconnects the second battery as soon as the ign is turned off (which I like).

Any thoughts?

You are spot on, 14.6V - 14.8V, dropping to 13.6V - 13.8V for float charge.
From memory the DBE150 is a simple isolator and in this case you could easily go over the max charging current (36A) Ritar recommends. For these batteries we usually recommend a DC-DC charger for a gentler charge and increased life.

Spec sheet here http://www.ritarpower.com/upload/pdf/2011092316311124566077.pdf

[junglejuice]

Interesting, those DC- Dc chargers are around the $400 mark aren't they?

[BatteryBusiness]

Interesting, those DC- Dc chargers are around the $400 mark aren't they?

Starting at around $300. Plenty to choose from http://www.batterybusiness.com.au/cart/C59

[Raisins78]

I installed my solar controller today, it monitors battery condition, charge levels in both batteries, both battery temps (Have to run the engine temp sensor yet....tomorrow it will be done)
All for $90......$250 for the 110w solar panel.
Do it right the first time I say.
http://www.ausjeepoffroad.com/forum/attachment.php?attachmentid=57699&d=1351333945