Will Charging the Camper's Battery off my Spyder overload the Alternator

I am wanting to charge a RV battery in my Timeout Slipstream camper which I pull with my 2016 RTL. I have run positive & negative wires from the cranking battery to the rear of the bike with a fuse at the battery.

At the trailer connection I have a simple 4 pin plug for the trailer lights, with a separate 2 pin battery tender type plug for the battery charging connection. This way I can disconnect the trailer charging circuit when stopped for the night to keep from drawing power from the cranking battery in the bike.

In the trailer I have mounted a 100 AH deep cycle gel cell battery. The plan is to connect the charging wires to the battery to keep it charged when traveling. The purpose of the trailer battery is to charge small electronics, i.e. tablet, laptop, camera batteries, etc.

My question or concern is: will this overload the alternator on the Spyder? :yikes: And if so, is there a way to accomplish this? :dontknow: I have the same type of setup on my trucks with batteries on different trailers that power small winches and hose reels, and this works great for that. :yes:

Right now, I have a reading of 12.8 volts at the plug at the back of the bike when stopped. When the bike is running it jumps up to 14.5 volts, which is consistent with my truck readings. I also plan on plugging a battery charger to the trailer plug when stopped and shore power is available.

Have any of you attempted this, and if so what do I need to look out for?

T.I.A.

They make small solor pannels that you could put on the trailer they don't cost much, and they will charge the battery in the trailer when the suns out. Just a thought!:dontknow:

I'm not sure what the output amps of the alt. is on the spyders. Over working the alt. would be my main concern.
Time will tell, I guess.

I like the solar panel idea!

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Originally Posted by Mikey

They make small solor pannels that you could put on the trailer they don't cost much, and they will charge the battery in the trailer when the suns out. Just a thought!:dontknow:

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First off, I’m sure not an automotive electrician not would I attempt be one, hence, I would not attempt to try this. I’m almost positive that you’re headed for problems with your Spyder. Secondly, although the solar panel sounds good, I doubt if you would get enough power out of it to do much good. My recommendation is to seek out an automotive electrician for solid advice.

+1 on solar. Simple, ez, separate walmart & harbor freight. Some more weather resistant than others sorry not sure what 1. Fully charge trailer battery from grid power, then the solar can handle rest & whenever camping/using trailer battery. With as finicky as spyder power can be& faults there in -would leave wiring alone(add star washers to battery terminals) could maybe carry some jumper cables if needed faster charging from spyder while parked:dontknow::popcorn:

I doubt you will tax the alternator, but you might want to run your battery wire thru a relay so it is only active when the motor is running.

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Originally Posted by Mjhitman

I am wanting to charge a RV battery in my Timeout Slipstream camper which I pull with my 2016 RTL. I have run positive & negative wires from the cranking battery to the rear of the bike with a fuse at the battery.

At the trailer connection I have a simple 4 pin plug for the trailer lights, with a separate 2 pin battery tender type plug for the battery charging connection. This way I can disconnect the trailer charging circuit when stopped for the night to keep from drawing power from the cranking battery in the bike.

In the trailer I have mounted a 100 AH deep cycle gel cell battery. The plan is to connect the charging wires to the battery to keep it charged when traveling. The purpose of the trailer battery is to charge small electronics, i.e. tablet, laptop, camera batteries, etc.

My question or concern is: will this overload the alternator on the Spyder? :yikes: And if so, is there a way to accomplish this? :dontknow: I have the same type of setup on my trucks with batteries on different trailers that power small winches and hose reels, and this works great for that. :yes:

Right now, I have a reading of 12.8 volts at the plug at the back of the bike when stopped. When the bike is running it jumps up to 14.5 volts, which is consistent with my truck readings. I also plan on plugging a battery charger to the trailer plug when stopped and shore power is available.

Have any of you attempted this, and if so what do I need to look out for?

T.I.A.

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Easy but important question: What size fuse did you use? And what size wire? From memory, #14 wire is good up to 15 amps, #12 for 20 amps, and #10 for 30 amps. Beyond 30 amps I despair for the life of the alternator. Hopefully you used auto or marine wire rather than house wire. House wiring gets brittle easily.

To begin, the Spyder alternator is automotive sized and actually puts out more power at low RPM than high (I believe that's done for fuel mileage reasons). And you want to charge your trailer battery at 30amps? That's only 400watts. The alternator is good for over 1000watts.

What is important are two things: an isolator (so trailer doesn't feed back into Spyder) and a fuse box. I recommend two fuse boxes: one at the point you connect into the Spyder circuit and one at the entry point of the trailer (before the isolator). I also recommend an isolation relay in the Spyder circuit, coil driven off the headlight or similar circuit, so the trailer cannot draw power when the Spyder engine isn't running. You do not want a circuit that comes on when the ignition key is turned on -- you want a circuit that comes on only when the engine is running.

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Originally Posted by EdMat

I doubt you will tax the alternator, but you might want to run your battery wire thru a relay so it is only active when the motor is running.

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Excellent!

An automotive alternator works at maximum capacity anyway, when the unusable part to the AC goes to earth via the rectifier/regulator. That's why they run hot. Charging 2 batteries connected in parallel, as yours would be, can be troublesome due to current flowing (charging) going primarily to the one with the least resistance after all the electrical demands of running the trike are met.

https://www.redarcelectronics.com/au...llel-charging/

PS you are quite correct to not use house wiring, even if stranded. You want to use a high strand count wire. Welding wire is great although I don't know if goes down to 10AWG. Perhaps extension cord cable would work. Be careful buying Chinese cables -- many are copper-covered aluminum not copper-core.

I've done it to keep my cpap battery charged. No problems that I can detect. Voltmeter shows a constant 14.X volts when running with spare/second battery attached.

If you want to get serious-er, find a "voltage sensitive relay" (VSR), which only "releases" current when the source voltage is above, say, 13.5 volts.

I installed a VSR on my last motorcycle, wiring in a switch as well, so I could turn on or off the VSR altogether (thus stopping any charging.) It worked a treat.

I am too lazy to do the same on the Spyder. So far the only problem I've had is keeping wires connected to the second battery in the frunk. Frunk contents often knocks things loose.

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Originally Posted by Columbia

I've done it to keep my cpap battery charged. No problems that I can detect. Voltmeter shows a constant 14.X volts when running with spare/second battery attached.

If you want to get serious-er, find a "voltage sensitive relay" (VSR), which only "releases" current when the source voltage is above, say, 13.5 volts.

I installed a VSR on my last motorcycle, wiring in a switch as well, so I could turn on or off the VSR altogether (thus stopping any charging.) It worked a treat.

I am too lazy to do the same on the Spyder. So far the only problem I've had is keeping wires connected to the second battery in the frunk. Frunk contents often knocks things loose.

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Put a pigtail on it, like the one you would use for a battery tender!

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Originally Posted by EdMat

I doubt you will tax the alternator, but you might want to run your battery wire thru a relay so it is only active when the motor is running.

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:agree: I think the alternator will put out what it puts out, which may or may not be sufficient to provide full charging amps to both batteries and run lights at the same time. Intriguing idea, actually; I'm interested in how it turns out.

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Originally Posted by Mjhitman

I am wanting to charge a RV battery in my Timeout Slipstream camper which I pull with my 2016 RTL. I have run positive & negative wires from the cranking battery to the rear of the bike with a fuse at the battery.

At the trailer connection I have a simple 4 pin plug for the trailer lights, with a separate 2 pin battery tender type plug for the battery charging connection. This way I can disconnect the trailer charging circuit when stopped for the night to keep from drawing power from the cranking battery in the bike.

In the trailer I have mounted a 100 AH deep cycle gel cell battery. The plan is to connect the charging wires to the battery to keep it charged when traveling. The purpose of the trailer battery is to charge small electronics, i.e. tablet, laptop, camera batteries, etc.

My question or concern is: will this overload the alternator on the Spyder? :yikes: And if so, is there a way to accomplish this? :dontknow: I have the same type of setup on my trucks with batteries on different trailers that power small winches and hose reels, and this works great for that. :yes:

Right now, I have a reading of 12.8 volts at the plug at the back of the bike when stopped. When the bike is running it jumps up to 14.5 volts, which is consistent with my truck readings. I also plan on plugging a battery charger to the trailer plug when stopped and shore power is available.

Have any of you attempted this, and if so what do I need to look out for?

T.I.A.

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I have been doing this for years, have this hookup on the old Bunkhouse camper and the 2015 spyder, and have the setup on the Aspen camper and the 2022 spyder.
I ran a fused link from the battery to a 7way connecter, then the trailer plugs in and charges as I drive.
Here are a couple of pics. I have a seperate fuse block in the camper also. All current runs through that fuse box befor charging the two battries.

The Spyder alternator has an electronically-controlled field which is how the power output can be lower at higher engine speeds -- I believe this is done for fuel economy reasons as well as battery protection. As as EdMat said there's plenty of power available.

Spyder side wiring path:

Battery => 15amp fuse => Engine-Running relay => 2-pin Trailer connector

Trailer side wiring path:

2-pin Trailer connector => 15amp fuse => Isolator (basically a diode) => 100AH battery

If there's a concern about too high charging current, put an incandescent bulb (eg 1157) in series between the trailer fuse and isolator.

I don't like the voltage-sensitive isolators for this application because they continuously draw a small amount of current. Not enough to bother an automotive battery but Spyders have a fussy relationship with their batteries.

here is the thread on the Aspen project. It charges as you drive, and has a built in battery charger. We charge headsets, phones, watches, computer, run LED lights in the lower basment of the trailer when the lid is lifted, and LED lights inside the tent camper, along with a 12 volt fan to keep us cool. We can run about 10 days without any recharging.
https://www.spyderlovers.com/forums/...Classic-mods-1

If your system is in good condition, you should be fine. An isolator system with a 1 way current flow is indispensable. This avoids dead system issues so you can always start your Spyder regardless of the trailer battery's condition.

You might want to take the additional precautions suggested here as well. Solar panels are fine. But most people will park in the shade whenever possible. Realistically, it takes bright sun and a fairly large panel array to really make enough difference to bother.

What I would not recommend is using your Spyder as a stationary generator. Letting it run at idle for periods of time to charge the battery is not what it was designed to do.

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Originally Posted by Fatcycledaddy

I have been doing this for years, have this hookup on the old Bunkhouse camper and the 2015 spyder, and have the setup on the Aspen camper and the 2022 spyder.
I ran a fused link from the battery to a 7way connecter, then the trailer plugs in and charges as I drive.
Here are a couple of pics. I have a seperate fuse block in the camper also. All current runs through that fuse box befor charging the two battries.

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Wiring diagram please:2thumbs:

Thank you for your post on my question. Would you know of any type isolator with the 1 way current flow you would recommend?

Does this model have a VVA as referenced by BR in reply 15? Interesting info I have just learned of. :2thumbs:

A Variable Voltage Alternator (VVA) monitors vehicle loads and driving conditions. The vehicle ECU varies the output of the alternator based on these conditions. The voltage range can typically be 12-15V.

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Originally Posted by Bfromla

Wiring diagram please:2thumbs:

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I didn't make one, but I am sure I can draw one up. Do you want the entire thing from battery, bike, to the converter for the lights, to the 7way, then on into the trailer, or just the charging system for the batteries?

The charging system for the batteries should be enough. Bike starting battery through the trailer connection to the trailer battery.

Thank you!

Needless to say, the 7way is the middle connection in this.

Thank you Bert for your concise explanation of how to wire what I'm trying to accomplish. I like your idea of putting the isolator in the trailer before the Aux battery. What type of isolator are you talking about? Do you have a link to what you mean?

Looking at your diagram, was wondering what type of charger you are using. I see it is powered by 12v starting battery.