Basic questions ;electrical from a new owner

[Kent I]

I bought a new to me 1972 compact junior. The seller had the battery charged so the interior lights worked but they didn't by the day I got home, a day long trip. The battery is on the tongue exposed, in a holder but no box. When I made mention of 3 stage chargers to a local RV dealer he seemed to suggest all I needed was a trickle charger. I have no experience with batteries and trailers. the trailer has some 110 lights that would work with the shore power, plugged in, and some 12 volt lights. I believe a small water pump is 12 volt. I expect that I'll need a new battery. the trailer wiring is 4 pin flat. When I get another vehicle wired with the hitch should I go with 7 pin to include a charge line or should I have an independent charge line separate from the wiring harness and keep the four pin system. No converter. I believe there are adapters that will allow a four pin trailer to be plugged into a 7 pin but I would imagine not the other way. What steps would you take at this time?

[Kyle]

First - disconnect the negative on the battery. I don't know a lot about them either, but if there is a problem this might save the battery. Sooner the better.

Beyond that - wait for the good answers.

[Frederick L. Simson]

I bought a new to me 1972 compact junior.

[b]My first trailer was a 1971 Compact Jr.
Unfortunately, it was a gutted shell. I had few clues on how the manufacturer equipped the interior.
Fortunately, it was a gutted shell. I could learn by inventing my own interior.

The seller had the battery charged so the interior lights worked but they didn't by the day I got home, a day long trip.

The battery may not have been charged up fully; it should have lasted longer than that. The very [b]first thing I would do is get at least a DC voltage meter of some kind. One of the first things I learned is that a 12 volt battery should read almost [b]13.6 volts DC when fully charged, and when it reads 11.8 volts or less you should consider it in need of recharging.

[Frederick L. Simson]

The battery is on the tongue exposed, in a holder but no box.

Are the terminals clean and shiny? The [b]second thing I would do is get a battery terminal wire brush tool and make sure you have good metal-to-metal contact between the battery and the terminal connectors.

When I made mention of 3 stage chargers to a local RV dealer he seemed to suggest all I needed was a trickle charger.

Stick to your guns. A trickle charger will help keep a charged battery topped off, but it won't be much help for a deeply discharged one. A 3 stage charger will quickly bring it back without overcharging it.

I have no experience with batteries and trailers. the trailer has some 110 lights that would work with the shore power, plugged in, and some 12 volt lights. I believe a small water pump is 12 volt. I expect that I'll need a new battery.

I think it may be a good investment to get a fresh one. Not a Starting battery for a car, but look for the words Deep Cycle, meaning being able to be deeply discharged, and then recharged again and again.

Once again, no less than 11.8 volts; anything much less could mean it is only good as a turn-in for the "core" fee.

[Frederick L. Simson]

the trailer wiring is 4 pin flat. When I get another vehicle wired with the hitch should I go with 7 pin to include a charge line or should I have an independent charge line separate from the wiring harness and keep the four pin system. No converter. I believe there are adapters that will allow a four pin trailer to be plugged into a 7 pin but I would imagine not the other way. What steps would you take at this time?

I think the 7-pin connection including the charge line would be a cleaner, simpler-to-operate system than having a second umbilical between the tow vehicle and the trailer.

My first tow vehicle was a station wagon that the previous owners used to tow a boat trailer. They had a 4-pin flat connector for the trailer's lights, and a second umbilical cord that connected to the car's battery to power the boat trailer's winch. I was going to adapt that for a charge line, but the boat winch connectors at West Marine were more expensive than switching to 7-pin.

[Brian B-P]

I agree with what Frederick has said.

Also,

I believe there are adapters that will allow a four pin trailer to be plugged into a 7 pin...

Yes, so if a tow vehicle is wired with a 7-pin, it can still be used with 4-pin trailers.

...but I would imagine not the other way.

Sort of...
There are 7-pin sockets which have a 4-pin "pigtail" plus the extra wires. I use one of these to tow my Boler, with the 4-pin connector supplying the lights (brake, turn, tail), and the other wires connected to the wiring which I added to the van for battery charging and trailer brake control. These adapter sockets need mounting, since they can't just hang off the little 4-pin socket.

What steps would you take at this time?

I would likely get a new battery if required, and mount it in a box big enough to hold the biggest battery I might later want to use (likely a Group 27 for such a small trailer with minimal equipment).

I would likely also convert the trailer to 7-pin, and adapt or convert the tow vehicle to 7-pin.

If trailer brakes are not required, I would consider leaving the trailer and tug wiring alone, and depend on charging the battery before each trip and at each stop where there is shore power, using that 3-stage charger which is needed anyway.

[Steve Hilby]

Nice to see another Compact Jr. owner here. There are more of us than you might think.


On my sister's Compact Jr, we moved the battery indoors, to the forward end of the passenger-side under-bench compartment. That gave us space to put the spare tire on the tongue, and got the battery in out of the weather.

Sis does not have a charger permanently installed in the trailer; she charges the battery before she leaves on each trip. We've replaced the interior light bulbs with LEDs to cut power consumption, and the 12V water pump got removed, since it was nonfunctional anyway (Besides, using the hand pump is good exercise...) Right now, the big 12V power consumer seems to be the propane alarm.

She does carry along a conventional battery charger, so if she needed to she could recharge the battery; but I'm not sure she's ever used it while out on a trip.

She got a nice little voltmeter which plugs into a cigarette lighter socket so she can check her battery health (I installed a cig lighter socket as part of a rework I did a while ago).

[Byron Kinnaman]

Nice to see another Compact Jr. owner here. There are more of us than you might think.


On my sister's Compact Jr, we moved the battery indoors, to the forward end of the passenger-side under-bench compartment. That gave us space to put the spare tire on the tongue, and got the battery in out of the weather.

Sis does not have a charger permanently installed in the trailer; she charges the battery before she leaves on each trip. We've replaced the interior light bulbs with LEDs to cut power consumption, and the 12V water pump got removed, since it was nonfunctional anyway (Besides, using the hand pump is good exercise...) Right now, the big 12V power consumer seems to be the propane alarm.

She does carry along a conventional battery charger, so if she needed to she could recharge the battery; but I'm not sure she's ever used it while out on a trip.

She got a nice little voltmeter which plugs into a cigarette lighter socket so she can check her battery health (I installed a cig lighter socket as part of a rework I did a while ago).

I've heard some propane detectors draw a bit of current. The one I have only draws .046 Amps (46 miliamps). Not much more drain than sitting disconnected.

[Tom Trostel]

Kent,
My Compact Jr. had no battery or evidence of one when I bought it. All the lights were 110V AC as was the dorm frig and air conditioner. Water pump was manual and there were no brakes. The only 12V DC was the tail lights and side marker lights. I have left it that way except for adding several AAA battery powered LED lights. If we camp with no shore power I will use a generator. So far, we have never camped without shore power. Texas has very little federal land so there isn't a lot of opportunity to boondock. Depending on your camping style, you may not need a battery.
Tom Trostel

[Gerry]

my 7 pin connector has a 4 pin slot, right on the side of it all internally wired. Gerry the canoebuilder

[Borden]

We have a plug from local rv dealer plugs into our 7 pin and has 4 pin on other end for our small trailer was about $14

[John Jesse]

Lots of good advice here! Despite the fact that they are very common I find 4 pin connectors to be worthless, they are cheap and the never work properly as they wear out so fast. Get a 7 pin installed, they look cleaner, work better, and provide the option for a charge line and brakes if you need them. You can buy a 7 pin to 4 pin adapter for about $2 if you need to tow a trailer with 4 pin wiring.

If you get a charge line installed, which I would recommend, make sure that it is wired with a battery isolator, they are only about $20 and they prevent the trailer from discharging your vehicle starting battery.

If you are unsure about the battery you can always take it to a local battery shop or auto parts place and they will load test it for you so you know for sure if its dead.