Apologies the intro is a bit long but will hopefully answer a lot of questions people might have.
I have a car trailer that is fitted with movers and an on-board 110A 12V AGM battery.
The trailer is towed by a number of vehicles that now all have 13-pin electrical sockets ranging from a VW-T2 transporter to an 2021 Audi S6 diesel.
I also lend the trailer to friends so it could be towed by anything.
The company that manufactured the trailer have the battery connected to Pin-10 (12V Ignition On) on the 13-pin electrical coupling and until I acquired the Audi I’ve had no problems with the setup and I’ve never had a dead trailer battery, however I’ve now had three instances where the car isn’t charging the battery.
I initially thought I was probable an expiring battery so this is new.
What I have discovered is modern cars don’t like the direct connection and I need to charge the battery using a DC-DC charger.
The ISO 11446 spec states that pins 9 & 10 (12V permanent power and 12V Ignition On) should provide 20A so my thought was to install an 18A Orion-Tr Smart 12/12-18 DC-DC charger isolated on the trailer alongside the trailer battery and take the supply from Pin-9 of the 13-pin and use Pin-13 for the ground.
I was also considering connecting Pin-10 to the H-Pin on the Orion to keep the charger active the whole time the ignition is on.
Do the collective think this will work and does anyone have a better solution?
Oh, and finally the ability to check the status of the DC-DC without needing to physically look at it is a must; when the trailer is loaded the trailer battery compartment isn’t accessible and it’s the only dry place to put the charger.
Any constructive feedback would be greatly appreciated.
I’m personally not a fan of trying to run the Orion through any trailer plug. While the plug itself is bound to iso standards, the vehicle manufacturers are free to do as they wish on their end of it. In my experience they tend to undersize the wiring when it comes to using the circuit at or near its rated capacity for a prolonged period of time such as while running a charger.
keep in mind that the 12/12-18 will draw over 20a and is intended to be on a 40a fused circuit. It has a rated output of 18a and can output up to 25a peak, so tack another 13% onto those numbers for your efficiency loss which will net you 20a/28a(peak) draw from the tow vehicle when the charger is bulking.
The smaller orions are pretty limited for configurability, the xs 12/12-50 while more expensive offers much more flexibility (ie setting a low amp charge limit to both protect the tow vehicle wiring as well as not hammering the trailer battery which I’d assume is a deep cycle, with a unnecessary higher amp charge for no reason)
How often does this trailer get used and more importantly would you have any idea how much power(ah) you’re pulling out of that battery in a typical trip? Chances are you don’t need a lot of amperage for the charger, you just need to overcome the voltage drop to be able to bring the trailer battery up to ~100% soc
Because you intend to use this on multiple vehicles I would encourage you to stick to your plan of using the switched power at the plug to enable the charger. I have had good luck using the automatic run detection, but that likely will not work 100% across multiple vehicles without fiddling with the settings
The Orion xs and tr-smart lineup offer Bluetooth connectivity. whenever the charger is “on” you can connect to it with your phone and check the status of the battery
Dave, Just the type of feedback I was looking for, much appreciated.
On with the research into the XS 12/12-50. Slightly above my project budget but needs must.
Dave , apologies I didn’t answer your question.
110AH battery installed and maximum discharge notes was 15mins at 180A peek load (80A average) so very roughly 20-30Ah is my guess.
I did look at the 9A unit (can’t remember the part-number) but not a “Smart” unit so I couldn’t check is working easily due to where I can install the unit.
How long would you say you will have the vehicle running between the uses (charging time)?
Even with the 12/12-18, with your estimations you would need at least an hour of run time to recharge the battery. The 12/12-9 is likely closer to 3h
There’s a lot of variables at play here especially with multiple vehicles being used. I’ll go out on a limb here and assume a 3h charge time is probably not going to be satisfactory.
That basically leaves you with trial and error using the 12/12-18 which may work fine depending on how the vehicles are wired and of course ambient temp(and if it doesn’t work out, is a big paperweight) or step up to the XS 50 and fine tune the charge current to keep the plug/wiring from getting too hot
so a few hours works.