cowcharge
1K Member
Posts: 1,003 
Likes: 328
Currently Offline
|
Post by cowcharge on Aug 13, 2015 7:29:41 GMT -8
If you're charging the camper from the tow vehicle, make sure you get a battery isolator switch. They switch the alternator over to charging the camper battery after the car battery is charged up. Just hooking into the system via the trailer plug means that your alternator will be charging two batteries at once, just as if they were both in the engine bay, hooked up in parallel. Depending on which battery the alternator listens to, either your car battery will end up overcharged as the alternator tries to charge the more-drained camper battery, or your camper battery will be undercharged because the car battery got to full first. Either way it'll shorten the life of one of them, if not both, and probably won't do the alternator any good either. Isolator switches are easy to install, in my old van I had it screwed into the inside of the wheel well near the alternator. They're sized to match the alternator amp rating, so find out what your alternator puts out before choosing one, and buy one with at least as high a rating as your alternator. And I would recommend running a better (bigger) charging cable than that little one in the trailer harness. There can be a lot of amps coming from the alternator, and the 20-30 feet from truck to camper is long enough to get some good voltage drop in a thin wire. No sense in using most of your charging power just to heat wire. I think I have this one, from NAPA: www.napaonline.com/Catalog/CatalogItemDetail.aspx/Battery-Isolator-Multiple-Vehicles-Equipped-w-CS-Series-Alternators-Nippondenso-Or-Sense-Terminals/_/R-BK_7821769_0006398311 |
|
RinTin
Full Member
Posts: 760
Likes: 292
Currently Offline
|
Post by RinTin on Aug 13, 2015 9:44:17 GMT -8
According to Wikipedia:
"A battery isolator is an electrical device that divides direct current (DC) into multiple branches and only allows current in one direction in each branch. The primary benefit of such an arrangement is the ability to simultaneously charge more than one battery from a single power source (e.g., an alternator) without connecting the battery terminals together in parallel."
When it comes to things electrical my knowledge is very limited, so please correct me if I'm mistaken, but I don't believe isolators also monitor the individual batteries state of charge and switch between them.
I may be beyond my depth here, but my understanding is that when charged this way, the auxiliary battery receives a surface charge, not a true deep charge that deep cycle batteries need. So you cannot depend solely on your vehicle's charging system to keep your deep cycle batteries fully charged.
Some alternators may not be up to the task of effectively charging two batteries simultaneously, especially in smaller, lighter weight vehicles. A higher output alternator may be needed.
Also, an appropriate circuit breaker is usually needed between the isolator and the auxiliary battery.
|
|
cowcharge
1K Member
Posts: 1,003
Likes: 328
Currently Offline
|
Post by cowcharge on Aug 16, 2015 19:05:13 GMT -8
I think how it charges depends on the type. This one (http://www.powerstream.com/battery-isolator.htm)says "In the normal state the main and auxiliary batteries are separated by the isolator. The control box will constantly monitor the main battery voltage until it is charged to 13.6 volts and stays there or above for 15 seconds. The isolator will then connect the two batteries in parallel through the solenoid contactor to allow both batteries to be charged. When there is a heavy or sudden drain on either battery (due to large loads such as starting the vehicle or shutting down of the alternator) the voltage across the main battery drops to below 12.6 volts and the batteries are separated by turning off the relay coil. The cycle will repeat to ensure full protection and priority charging of the main battery at all times and to allow safe charging of the auxiliary batteries."
I wouldn't use the vehicle as a primary charging source anyway, it's way too inefficient. But if you've got a long drive, why not take advantage and throw a few amps into the camper battery? It means less demand for a generator or solar panel. And if you're going to charge from your vehicle, use an isolator, if only to keep the starting battery safe from you falling asleep with the lights and fan on.
The fact that there's a voltage drop through it means even more that the harness hot lead is probably too small to use for charging.
|
|
bb
New Member
Posts: 6
Currently Offline
|
Post by bb on Dec 27, 2015 5:45:41 GMT -8
Hello I have the same convertor that I'm using in a fishhouse I build. Everything works good except I can't get a car stereo to power off of the three fuse lines. But lights. 12v ceiling fan, etc. work good. I don't have a battery hooked up to line 4 I'm gonna do that today. I'm thinking I don't have a ground. The only ground is 110 coming in. There's no ground to frame on the converter. I'm not even sure which wire I would use to ground it. I got 13.2 on fuse 1 and 2, 3 isn't hooked up.
|
|
|
|
Post by vikx on Dec 27, 2015 22:00:19 GMT -8
Welcome bb.
Please let us know a little more. We will try to help. I'm guessing you are correct on the grounds. However, keep in mind that the 12 volt system and the 110 system are separate, so each needs it's own ground.
Pictures will help. I will probably move your post to a different thread to keep everyone on track.
|
|
Ten
3K Member
Posts: 3,432
Likes: 1,467
70 Shasta 16SC + 1964 Airflyte
Currently Offline
|
Post by Ten on Dec 28, 2015 5:33:26 GMT -8
Hi bb.
If I am reading this correctly, your converter is grounded by way of the bare copper in the 110-V wiring feeding the converter. If that bare copper is screwed down to the housing, the unit is grounded back to the breaker, and ultimately back to the frame. If it were not grounded, you would not have anything working. It seems to me the problem you have with the stereo is that the body of the stereo is not grounded. Remember, any fixtures, lights, etc, have to be grounded in order for them to complete the circuit and work properly. The lack of the battery is only really going to effect the charger/maintainer circuit, and only shows up really as fluctuation in the output voltage at those lugs.
Adding the battery will add a buffer to the system. But I do not believe it will fix the problem at the output of the numbers one, two, and three circuits. Let me know if I am wrong, however, after you try the battery in the system. I love learning new stuff!
|
|
bb
New Member
Posts: 6
Currently Offline
|
Post by bb on Dec 30, 2015 5:42:34 GMT -8
Thanks for the reply
This converter has me concerned. I think your right. Nothing's grounded except the 110, I got the stereo to work with the battery running through the converter out its battery leg. But you would think the 110 being grounded would allow the radio to work. Only if it's the battery leg running it. Explain if I'm just chasing my tail here....
Thanks
|
|
Ten
3K Member
Posts: 3,432
Likes: 1,467
70 Shasta 16SC + 1964 Airflyte
Currently Offline
|
Post by Ten on Dec 30, 2015 19:15:49 GMT -8
Actually the system is two parts. First part of it is the 110-V side, which is essentially like plugging in any other appliance. In order for the toaster to work, both legs of the AC have to be connected and the circuit needs to be grounded. The ground allows the appliance, in this case the converter, to operate properly. This has no affect on the 12-volt side, except that the converter works to put out the 12-volt current.
The 12-volt current needs to flow all the way through any appliance hooked to it, be it a light, fan, radio, etc. The 12-V feed from any of the legs of the converter (or any battery) will only go as far as the completed circuit allows. The current stops at the filaments of a bulb, if there is no through-pass to a ground. Same happens with a fan or radio. The converter does not supply the ground to complete any circuit, and any fixtures will need their own secure ground to operate. Just as wiring to a battery requires a lead to both sides, so too does a feed from the converter, only the converter does not provide the ground side.
This is tough to describe and I can't be more specific without seeing what you are working with, so the principle will have to do.... I'll try to get a diagram to help with this wordy description.
|
|
bb
New Member
Posts: 6
Currently Offline
|
Post by bb on Dec 30, 2015 20:29:22 GMT -8
Ok thanks again, I'll get a picture of what I have. Where would you attach a ground from the converter? Is there a wire designated on it? or just ground the negative wire to the frame in the wiring going to the stereo, lights, etc.?
|
|
|
|
Post by vikx on Dec 30, 2015 22:18:54 GMT -8
Most converters have a ground lug on the 12 volt fuse board. It's a square block with a set screw. The ground wire is tightly set in the lug, thereby grounding the converter.
Each item or fixture in a 12 volt system must have a ground, so that means two wires to each. (ground and hot) So, each ground wire has to go to the trailer frame eventually. That doesn't mean 5 or 6 ground wires to the frame. Instead, they can be joined with only one ground to the frame.
As an example, say you have a ground wire close to the radio. A j box close by could join other grounds in that section of the trailer with only one wire to the frame; lighting, cigar plugs, etc.
|
|
mobiltec
5K Member
I make mistakes so you don't have to...
Posts: 9,822
Likes: 3,749
1954 Jewel In Progress...
Currently Offline
|
Post by mobiltec on Dec 31, 2015 19:34:20 GMT -8
Most converters just don't have enough constant supply to run everything. Most converters are really nothing more than a battery charger with a brain. With a battery, between the two they can keep up with your demand but the converter by itself will have to work too hard and too long and will burn up. Remember I'm saying MOST converters. Some will burn up slower than others. There is a big difference between a power supply and a converter.
|
|
bb
New Member
Posts: 6
Currently Offline
|
Post by bb on Jan 1, 2016 8:20:06 GMT -8
ok hooked up the ground to the frame, the lights work but not the stereo, the stereo only likes the battery line off the convertor. I got 110 coming in, the lug grounded, the battery hooked up the battery ( + )the negative ( -) to the battery. Im using line 1 to power the lights which isn't the battery line that's 4. the strereo doesn't like it says" miswiring"{ |
|
Ten
3K Member
Posts: 3,432
Likes: 1,467
70 Shasta 16SC + 1964 Airflyte
Currently Offline
|
Post by Ten on Jan 1, 2016 14:37:54 GMT -8
|
|
bb
New Member
Posts: 6
Currently Offline
|
Post by bb on Jan 1, 2016 17:58:22 GMT -8
<img style="max-width: 100%;" alt="" src="">My pic isn't as clean as the other guy but there it is. I got nothing across c&d for voltage. The leads all work 1 thru 3 for lights but line 4 doesn't work without a charged up battery. The stereo doesn't work on 1 thru 3. The converter is dirty cause it's inside a fishhouse I was building , I used it for the lights. Maybe its time to get a different converter.
|
|
|
|
Post by vikx on Jan 1, 2016 21:44:30 GMT -8
I think you may be right, bb. Electronics aren't fond of dust and dirt...
|
|
