cbrautigam
Colorado
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I'm a brand new TT rookie, and have bought a used 2003 prowler 25 ft. I'm going to need to replace the batteries on this trailer. I'm wondering how the charging system works from my truck to the batteries. I have a 7 way plug, and I know my truck has the towing package, so I know the charge signal will be present.
The only wires that I see that would connect to the batteries from the trailer wiring harness are the positive and negative wires. I understand how to wire two batteries in parallel or in series depending on whether I go 12 or 6 volt, but what I don't understand is how the batteries get charged. Do the batteries get charged from the positive and/or negative wires? I guess I was kind of expecting to see another wire or two from the wiring harness that would hook to the batteries in addition to the +/- wires that would provide the charging, or does the charging just use the same positive and negative wires?
Am I missing wires on this wiring harness? or are the positive and negative wires used to provide electricity to the trailer, and also used to charge the batteries?
If someone could shed some light on how the charging aspect works, that would be awesome!
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bldrbuck
one or the other
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The 7 Pole RV Electrical Plug The 12volt Side of Life Trojan Battery Company - Charging
93 Ford F350 Turbo Diesel, DRW, Crew Cab. PullRite Hitch. 35' King of the Road 5er, 192 Watts Solar, 2800 Watt Yamaha Generator, 1750 Watt Inverter, 2 Trogan T105 Batteries, Me, my wife and 2 maltize furkids.
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RJsfishin
Winston Or.
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Anytime 2 batteries are connected in parallel thru pos and neg wires, they will charge together, and discharge together. Some one here will be able to tell you which pin in the plug is the positive/charge wire, if you don't already know.
Rich
'98 Flair, 454, Onan Microlite 4k, Intel PD 9155 w/ wizard, Sta-power 1500 watt Inv, 2 6v batts, ammeters, KingDome/sat, Oly Catalytic Heat, hauling 2 Bent Bikes and sometimes towing a Tracker F&S boat.
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pianotuna
Regina, SK, Canada
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Hi cbrautigam,
The seven pin plug is more about maintenance charging than recharging. Not many amps will be returned to the trailer battery bank.
Regarding replacement of the batteries--put in the greatest number of amp-hours that will physically fit in the storage compartment without overloading the weight limit.
Wiring the new batteries in a balanced manner is important. Method #3 is best for odd numbers of twelve volt batteries, and Method #2 is perfect for a pair of twelve volt batteries. Method #1 is there to show you how to do it wrong.
correctly interconnecting multiple batteries
For my further thoughts on battery replacement surf here:
Technology
and click on "Battery Selection".
Regards, Don
Kustom Koach Class C 28'5" 256 watts solar, 875 amp hours in two battery banks 12 volt batteries 5000 watt inverter.
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garym114
Texas
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The TT batteries get a little charge while connected to the truck but don't expect them to charge up, even after 6 hours of towing. The wires are small and the distance is long so not very much charging voltage gets back to the batteries.
You are not missing any wires.
Get a Digital Multimeter and Learn How to Use It
2000 Sea Breeze F53 V10 - CR-V Toad
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cbrautigam
Colorado
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Thanks,
I will definitely use the wiring diagram provided pianotuna.
So another dumb question.
So if the charge wire from my truck is just a maintenance charge, are you are saying that I will have to plugin to AC power to fully recharge the batteries after a few days of use?
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pianotuna
Regina, SK, Canada
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Hi cbrautigam,
That would depend on the energy use. Do an electrical energy audit.
Example:
If you have two 100 amp-hour batteries and do not wish to go below 50% state of charge, then only 100 amp-hours are available.
1 1156 bulb uses 2 amps x 4 hours per day = 8 amp-hours
12 amp-hours may be used per day for "parasitic loads"
10 amp-hours for 15 minutes of pump time
That's 32 amp hours of the available 100 and would represent frugal use of the electrical systems. So if you are not traveling then the RV will need a good long (39 hours) charge from AC power after 3 days.
Driving for 6 to 8 hours might replace 6 to 8 amps back into the battery bank, so by the time six days go by you may be approaching the 50% "brick wall".
If, on the other hand, there are just 60 watts of solar (5 amps) the net loss over a day may be 5 amp-hours, which means it would take 20 days to reach the 50% mark.
With my own system I can boondock literally "forever" if I do not use my inverter. I'd run out of consumables such as water before I ran out of power. See my solar boondocking thread on the Technology page.
It is also possible to "beef up" the charging path from the alternator. Personally I prefer the solar route. The benefits of solar are long battery life (years) and charging to 100% state of charge that, after the initial cost, is free.
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CamperTech
Seacoast, NH
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Joined: 01/05/2005
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CBRAUTIGAM
The truck WILL recharge your batteries!
There is some voltage drop across the 20ish feet of 10 or 12 guage wire provided by most truck manufacturers, but it's not significant enough to mention. A 4 or 5 hour drive should recharge most 24 group deep cycle batteries. Obviously, if you add more batteries, the recharge time will increase. In fact, charging from your truck will be a better charge than most of the cr@p converters that rv manufacturers use. I have more faith in the automotive alternators voltage regulators, than those converters.
You should be aware that some truck manufacturers don't activate the charge line just because there is a towing package installed. Some Fords require a relay and fuse install (usually found in the glove box on new trucks) and some GM's have the charge line wire, complete with terminal ring, coiled up under the brake booster (against the truck firwall). To see if you're live, take a test light or voltmeter and hook the ground to the truck chassis. Then connect the probe or red wire to the blade located at the 5 O'clock position inside the plug. With the ignition on (for most newer trucks) that pin should have voltage.
Happy Campin'
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smkettner
Southern California
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Joined: 03/21/2005
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The charging comes through both the positive and negative wires. You may not see the negative wire much as it probably connects to the frame. The battery negative is also connected to the frame. Alternator supplies about 14 volts that charges the trailer battery with about five to twenty amps depanding on battery state of charge. With everything connected check the trailer battery voltage before and after you start the vehicle. You should see about one volt increase when the vehicle is started.
The 12 volt side of life
2001 F150 SuperCrew
2006 Keystone Springdale 249FWBHLS
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cbrautigam
Colorado
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Thanks for all the responses I think I understand how this works now, and now all I have to do is find the most Amp hours per dollar batteries.
Does anyone have any favorite places for purchasing batteries?
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