Ctek Installation

Over our almost 5 years of owning our 550, including 195 nights and a bit more than 49k miles, we've done a lot of dry camping. We've frequently moved from dry camp to dry camp, 'cause, well, that's where the best camping is.

I killed the original AGM battery in about a year and a half by not getting it fully charged often enough. I just didn't know what I was doing. The problem was using a dometic fridge and thinking that 6+ hours of driving between campsites would charge up the battery fully. I sure was wrong. Car alternators just don't give AGM batteries what they need to get truly a full charge, I don't care how long you drive.

So when I replaced that battery I added a trimetric battery monitor and have worked hard to get the battery fully charged every five days or less. We use a solar panel so sometimes that does it if we're in a nice sunny spot. Other times we've opted to find a campground with shore power just to get a full charge.

This is not optimal camping for us. We like to get out there and stay out there. Most forest service campgrounds and pretty much all national parks are dry camping only.

When I read on this forum about the CTEK charger I was intrigued. A really full charge on the battery when I get to the campground? That's a game-changer for us.

I inquired of Cary about how Camp Inn feels about these chargers and he replied strongly in the affirmative. We talked about possible mounting locations (they mount them in the curbside galley storage bin) and I ordered one up and installed it.

I really didn't want this charger mounted in the galley storage so I decided to give mounting it over the battery a try.
Here's what it looked like before the CTEK was installed. Above the battery to the right is the battery isolator. That can be eliminated by using the CTEK. The small device to the left is the shunt for the trimetric.



I removed these devices and this is what it looked like. The shunt will have to be remounted.



I had to add a strip of wood to give me a place to mount the CTEK.



The CTEK was easy to install at this point but I had to install it "upside down" because the power wire from the seven way plug wasn't long enough and I didn't want to splice it (hope no electrons spill out). I also had to use a small round file to open up the ring terminals because the CTEK mounting studs are bigger than those on the now-removed battery isolator. I made a new wire to run from the CTEK output stud to the 50 amp breaker because the existing wire just wasn't quite long enough.
Here's what it looks like installed. It's pretty tight with the trimetric shunt but it all fits fine. You can see the CTEK temperature probe taped to the top of the battery near the positive post. That's how they say to do it.



I've only tested it briefly because my January southern Arizona camping trip got canceled by a DC hissy fit. The trimetric voltage came right up and the amps started high (around 10) but quickly settled back to 3-4 and came down steadily from there. The battery wasn't very discharged so I didn't expect the amps to be very high.

The only other details I can think of is that there's a wire from the CTEK you have to ground if you have an AGM battery. That was easy enough. There's also another wire to tell the unit that you have a "smart alternator" (we don't) and I'm not sure how that gets hooked up. We may be getting a new TV this spring so I guess I'll find out.

If I can get out on the road in March I'll get some more data and report further.

Robert Dickson
550 #645

 

Great writeup , thanks. My tow does have a "smart alternator" and I discovered it was not charging the AGM battery in the truck, not to mention the trailer or my fridge auxiliary battery. I "dumbed" the alternator down and charging is now much, much better. Every vehicle design is different so I won't try do describe what I did, mine is a rather uncommon Nissan Xterra; I can describe it if anyone is interested, its actually a very simple fix but other systems will likely be different.

The CTEK charger sounds like a good solution for you, and I can imagine other places where this technology could be applied. It's filed into my memory bank for future use.

 

Great writeup, thanks too!

Rotus, I'm towing with a 2015 Frontier; what year is your XTerra? I think they're the same platform... perhaps I also have a smart alternator? How does one dumb it down - is that a replacement alternator?

Robert, I'm not sure if I'm reading the last photo right; are you also using the CTEK charger to manage your solar panel?

 

nope, not yet, but it'll be easy to hook up. We've only got an 85 watt panel putting out less than 5 amps so the morningstar 10 amp that CampInn installed works just fine.
I'm seriously considering creating my own suitcase-style panel with maybe two 70+ watt panels. At that point I'll likely remove the morningstar and just use the CTEK. This is tied to swapping out our VW jetta TDI wagon for maybe a VW Tiguan which would have a bit more space. Man, I hate to give that diesel up, though.

rd

 

Ah, the 85-watt is a portable too?

The big advantage to having the CTEK manage solar is that with a permanent mount panel, it will choose the best source automatically between the tow vehicle alternator and the solar panel. So I’ve read! I’m thinking about the CTEK 12v/12v charger for next season...

 

Robert - sorry to hijack your thread, but I think this is relevant. Seth, you asked so here goes - Indeed your Frontier is closely related to the Xterra, though mine is a 2010. When my original battery died, I replaced it with an Optima AGM which in my experience has been a great choice in other vehicles. However, it didn't perform well in the Xterra, and after killing one I looked into what was going on. I found that after starting the engine, the charging voltage would start out at a healthy 14.5 volts or so, then drop down to about 13, not enough to make an AGM happy. Research discovered the "smart alternator".

Here is what I did to "dumb it down". Looking at the battery negative terminal, there is the expected cable going to the chassis. However, there is a magic box that the cable goes through. This is a current sensor that the car ECU uses to detect how the charging is going.

I disconnected the cable that goes to the ECU.


That's it. The charging voltage now stays at about 14.5 when the engine is running. I fully expected the ECU to throw a check engine code with this disconnected, but it has not in several months of running. The AGM is now happy, as well as the batteries in the trailer and my fridge auxiliary battery setup.

Nissan implements this feature as software (firmware?) in the ECU that monitors the current in the battery ground cable and combined with other stuff determines the charging state of the starting battery. If it feels the battery can stand a lower voltage, it sends a signal to the alternator to reduce the output voltage. The idea is that with a lower output voltage, the alternator will not work as hard, making a small but apparently noticeable improvement in fuel economy. This feature is based on the requirements of the factory standard lead acid battery and is not appropriate for AGM batteries. Disconnecting the current sensor fools the ECU into keeping the charging voltage at normal levels. I have no idea if this is the way other manufacturers have implemented the smart alternator, but it works for me.

 

I really wish I could see how your ground wires fit into your area. Ours are immediately above the battery. When I looked for a way to mount the CTEK inside the battery box area instead of in the storage compartment, there was absolutely no room for it.

 

I mounted a Ctek in the same location that the Morningstar solar controller was. It is kinda nice being able to check the indicator lights on it to see what is going on. My TV is a GMC Canyon and if I put it in Tow mode, then it is supposed to keep the alternator at hight output. The manual also says that turning on the headlights will also keep the alternator at high output - might be worth checking out on your TV.

 

the grounding posts in our 550 are aft of the battery, pretty much right in front of the tail light. Sorry for the repeat of this photo, but if you look in the lower right you can see the ground posts and their labels written on the wood. The battery sits just to the left of these ground posts.

 

I discussed this location with Cary but decided to give the above-the-battery spot a try, mainly because I didn't want to splice more wire to the power wire coming from the seven way. While this is a good spot, I discovered while wiring the trimetric that it's not all that easy to get to, and there are a couple of fat wires that need to be run to the CTEK. Also, I've the trimetric which tells me whats going on electrically all the time so I don't think I need to be able to look at. I don't think I've ever checked the morningstar while using the solar panel.


I need to add to this thread a possible issue with mounting the CTEK above the battery. Until today I hadn't replaced the cover over the battery compartment. When I did, I discovered a bit of interference from the wiring posts of the electrical system on/off switch touching the CTEK. and causing the cover to not sit quite flush. Those wiring posts are really long (at least 1/2 inch too long), and Camp Inn has recessed that switch so it doesn't hang out into the galley storage.
I'm either going to shorten the posts with a dremel or I'm going to remove some of the plywood used to recess the switch and I think I'll be all set. I'll report back if there are issues with this.

rd

 

Sorry for the total newby question here but how can we tell how well our TV is doing at charging? Should it be at a certain voltage when plugged in to the TV? I purposely don't use my battery hard (occasional light and charging phone) but don't want to discharge it too much and cause damage.

 

it is indeed relevant. The CTEK manual shows a connection to an "ignition signal, +15 clamp," whatever that is. Since Camp Inn is now installing these chargers maybe Cary will tell us what the mother ship does with this connection, or if they somehow disable or bypass it as you've done.

 

Interesting. It looks like your ground posts are set up differently than ours. I like Henry's set up, which would solve the space problem we found when I tried to find a spot for it in the battery compartment. I might take mine out of its box and reconsider using it.

 

Has anyone who has installed a Ctek in their trailer and knows they have a "smart alternator" checked out how it is working? If you have a smart alternator, they instruct you to connect the small red wire to an ignition signal, but Cary says they never bother with it and don't know what it's for. I'm not sure what I would attach it to in the trailer and I'm not going to run another line to the vehicle. I've read some accounts that said it didn't work right with their smart alternator. Any suggestions or experience with this?

 

I'm adding one last post to this thread regarding the Ctek D250SA. I got the following reply when I asked Ctek tech. support about it:

Since you have a smart alternator, it is necessary to connect the red wire to either the ignition or somewhere else that has voltage when the vehicle is running. That will enable the charger to function with a lower input voltage from your alternator. Smart alternators produce a voltage that is too low to power the charger on unless the red wire is connected.

I got a similar message from the Renogy people regarding their new charger in a trailer. What I did was connect the wire to the "lights" terminal stud in the trailer. I figure that when towing during the day, I'll just run with the parking lights on if I'm concerned about battery charging. I passed on the info. to Cary and he and Craig concurred that that was the best option and simplest solution and for now they'll be doing the same.

Also, I tow with a 2018 Outback (smart alternator) as well as a 15 year old Honda Pilot (dumb and happy alternator). Ctek said there is no drawback to having the wire connected with the dumb alternator also, it's just that you don't need to bother with it in that case. Thanks also to Rotus8 for the tip on the battery status monitor. I installed mine next to the fuse door and everything seems to be working well, 14.7 V when needed for charging and I can monitor the solar panel output and battery status.

 

I'm trying to figure out why the voltage at the lights terminal would be higher than that coming directly to the CTEK. Both are being powered by the car electrical system.

 

It's not that the voltage is higher there, it's just that there will only be voltage there when the car is running (unless I turn the lights on with the engine off), which is what we are after. The charge line going to the Ctek is connected directly to the car battery and will show 12V running or stopped.

 

First of all, I'm would imagine that the voltage seen by the CTEK while the vehicle is running is definitely higher than when it's not running, just not high enough to get the CTEK to start charging. And if the red wire senses any voltage at all it tells the CTEK to start charging. That sound right?
I'm likely to get a TV with a smart alternator in the next month or two so I'd like to know what's going on. I'll be interested to see how the CTEK does without the red wire sensing any voltage. It would be nice not to have to remember to turn on the running lights.
I looked through the very brief CTEK manual but I didn't find the voltage necessary for the CTEK to start charging.

 

Maybe it's not high enough though when the smart alternator shuts down the alternator to save gas if it senses the car battery is charged. I can only add that Ctek specifically said not to connect the red wire to the incoming charge line but to a line that's on only when running. I found that there was always some voltage (less than 1V though) on the electric brake line if the car is running, but that is not enough to trigger the Ctek.

The good news for you, Fernlane, is that you have the device mounted in the battery compartment, so it would be a trivial matter to connect the little wire to the lights. It probably reaches there without any extension.

 

wow, I had no idea that the alternator could be shut down. That actually doesn't sound so smart since it's probably being turned by a belt that keeps running anyway. I wonder if the CTEK is drawing steady amps from the TV if the alternator would never sense that the car battery is fully charged. I'll definitely do some testing with the lights on/off to see what happens at the CTEK.
You're right, it'll be easy to hook that wire to the lights in my situation. The only hard part will be getting my brain to remember to turn them on.
thanks for getting this info from CTEK, very helpful.