Help! Charging the camper trailers 2x batteries from the 80 series. (1 Viewer)

[CLUMZ]

Hi all,

I've purchased an 80 series that has had a 2nd battery added with charge controller. Seems to work by getting the starter battery to 100% and then charging the house battery.

I have a camper trailer with the only charging mechanism being a 240 volt charger (New Zealand).

How might I setup a charging system to take excess charge from the cruiser (without depleting the starter battery) and add it to the trailer?

I have a redarc charger (like this) http://www.redarc.com.au/products/product/charge-equaliser_10a/

Should I tap from the house battery on the cruiser to an Andersen plug on the back of the truck... then make a lead to run to the trailer with the redarc equalizer attached?

I guess further down the track it would be nice to use the 12v Andersen from the truck to power a winch that is mounted via a hitch receiver to either the front or rear of the truck, that in my mind would make mounting the redarc in the trailer a more sensible idea.

Cheers!

 

[greentruck]

Don't know if there's a trailer plug available in NZ with enough circuits so one could be denoted for charging or not, but that's the way it's often wired here. I'm a big fan of the Anderson Power Poles, but unless they have something new, they would tend to pull out too easily to use between the truck and trailer. You would need to secure at each end somehow, I would think.

Sounds like you want to add a second charge controller and a different one than is on the vehicle. Since these work by sensing the charge status of the primary battery, things may get confused here. Hard to say if it will or won't work without knowing what installed on the 80 right now. I know many of the charge controllers will support charging a third battery, but this likely requires either a specific pair of charge controllers or special wiring AFAIK.

Maybe if we know more about the installed charge control and the plug? What does RedArc say about their unit and a third battery?

 

[titanpat57]

Calling @george_tlc ....is the Dr. in the house??

 

[LFD2037]

Only 2 options I've seen are a 7 way plug that'll charge the trailer battery, from the truck battery, while the truck is running or a solar power set-up on/for the trailer.

I'll be going this route due to price, ease of use, power output & positive reviews.

http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=0XV6QVF8AXY59MM284JV

 

[CLUMZ]

thanks for your replies, @greentruck I'll work out what model charge controller is in the truck and do some research as to what outputs/modes it has.

 

[greentruck]

I've been very happy with my Hellroaring isolator. Their BIC-95300B is recommended for apps just like the OP wants. Tech info here: http://www.hellroaring.com/rv.php
That should give a pretty good idea of how a 3-battery system is wired.

Install manual (pdf): http://www.hellroaring.com/BIC-95300B instructions rev -.PDF

HR does this, but others also IIRC.

 

[greentruck]

thanks for your replies, @greentruck I'll work out what model charge controller is in the truck and do some research as to what outputs/modes it has.

You're welcome. It very well might work. Check the very useful wiring diagrams at HR's site if the one you have doesn't have such great info.

 

[ntsqd]

In the European market that are trailer connectors with more than 7 contacts. It's a DIN std. for either 13 (?) or 21 (?) contacts.

There are also single and dual contact trailer connectors made specifically for charging battery banks on big truck trailers with hydraulic lift gates.

http://www.phillipsind.com/product/387.html
http://www.phillipsind.com/product/20.html

 

[CLUMZ]

She's a sure power model 1314
Don't imagine id have an issue running a feed from the aux battery to a charger on the trailer.

 

[e9999]

on the simpler side of things you could simply set up your trailer battery in parallel with your 2nd truck battery, it would then charge together with the second battery after the main truck battery is topped off. You would not need very heavy wires or a charger to do that. You could go through a trailer connector plug or separately. Putting a winch on those wires is a different story, though, you'd need to have wires that can handle possibly several hundred amps over a fairly long distance without too much voltage drop.

 

[CLUMZ]

Does anyone think it a completely stupid idea to buy a cheap solar MPPT charger, hook it up in the campers battery box and feed 12-15v from the tow vehicle into the 'solar input' on the charge controller?

eg: http://www.trademe.co.nz/motors/boats-marine/parts-accessories/other/auction-937250022.htm

 

[ntsqd]

Likely won't work. Solar panel output is normally in the range of 16-18 VDC.

A note on the charge wires from the vehicle. If you just look at ampacity then you might be persuaded into thinking that 10ga. may be large enough. It isn't. Figure out the full length of the circuit including the ground (strongly suggest a dedicated ground wire/cable too) then do a voltage drop calc or find such a chart for a max 3% drop. I'll guess that for that length you're looking at a minimum of 6 ga and possibly 4 ga.
Here's the deal, if you go too small on the cable the voltage will drop. Let's say that it's 10% At a charging voltage of 14.4 VDC that reduces your charging voltage at the trailer to 12.96 VDC. That will, over a long drive, sorta, kinda bring the battery up. The less voltage drop, the better. Do need to temper that with cost and weight considerations, so be realistic in what you expect the max charge current to be.

Do not forget to put a breaker or a fuse at both ends of the charge wire.

Over on the tiny trailers & tear-drops forum there is a small group who put an inverter on the tow rig, and run an extension cord back to the trailer mounted battery charger. I can't say that I'm all that fond of the idea, but it seems to work.

 

[george_tlc]

Greentruck's mention of a BIC is likely a good way to go so that your trailer battery is isolated (except for charging purposes when the vehicle is running) from the vehicle batteries.

MPPT stuff - forget about it. The solar stuff is designed to STEP DOWN from a higher solar array voltage. It's just NOT the right thing for your application.

Also, with a BIC you DO want decent thick gauge wires to carry the charging current when the trailer battery is quite discharged (presumably this will often be the case with it powering stuff in the trailer all night) and the BIC combines the trailer battery to the vehicle system while the alternator has charged the stuff in the vehicle. I presume you're talking of Anderson high current connectors, not the little powerpole stuff...

Wire gauge needs to be chosen based on the likely current that will flow when the trailer battery is quite discharged and factoring in voltage drops due to wire length which will be considerable since it is from the vehicle engine bay to where ever you have the trailer battery mounted. Search for "wire gauge amps" or a similar term to find tables that give resistance versus wire gauge. Of course these tables assume decent quality wire and not some of the cr@p that comes out of some sources (yeah, looking at you ebay/china - not all, but some).

cheers,
george.

 

[greentruck]

I'll second the mentions of having adequately gauged wire for the long run. But I'll throw in something that will make that easier to implement. Run the heavy gauge wire back to trailer socket on the rear of the truck and from where the connecting cable is connected to the trailer wiring to the battery. The wire in the connecting cable need not be so heavy, since it's a short run. Obviously, don't make it puny, but it need not be the heavier gauge for this.

Exactly what's ideal gauge for this is hard to say, as it depends what kind of load is thrown on it when the trailer has been unhooked and sitting in camp depleting the trailer battery. You can run the standard calculations and get a good approximation, then monitor it in use to make sure it doesn't get warm when you do have a high load interval.

It's a method you need to cautious about applying. I'm a model railroader and we do this all the time, with a 10 or 12 gauge main bus, then using 22 gauge for the short feeders from it to the rails. Just don't go too small or you'll be creating what is effectively a fusible link and you don't want that.

 

[greentruck]

On the Sure power Model 1314, you may want to check yours against this recall notice:
Battery Separator RECALL Information – North America
Says it's for North America, but who knows where yours came from?

More info on the SurePower is here.
All Sure Power Battery Separators
Says it will do multiple batteries, but refers to it as a battery separator, rather than isolator. I'll let folks consider what the difference is and details of how it might be used, as gotta go do some work...

 

[CLUMZ]

I've emailed Sure Power asking if I'm part of the recall, also saw that info when I tapped the model number into Dr Google.

re the seperator/isolator, I may just put a diode in the circuit to prevent the charge from the aux depleting the starter.

 

[ntsqd]

....

re the seperator/isolator, I may just put a diode in the circuit to prevent the charge from the aux depleting the starter.

Diodes have a "cracking voltage" that is one big voltage drop in a short distance. This is the reason that they've fallen out of favor. Can offset the alternator's voltage regulator to compensate, but then you have to do something to reduce the voltage to the batteries that don't have a diode in their charge wiring.