Charging while towing using a Sunsaver-10

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Charging while towing using a Sunsaver-10

Postby wgwhitacre » Tue Apr 19, 2016 11:29 am

Hello, Everyone

A while back I found a post on this website about using a Sunsaver-10 to protect your battery from overheating while towing. Now I can’t find that post and I want get your thoughts on something.

I bought a 125ah AMG battery for my tear. I plan to charge it most of the time with shore power through a PD4045. I also plan an added a “charge-while-towing” setup. This will be a 10ga wire that connects from my car battery to the tear battery to trickle power to it while I drive.

Now, people say that you shouldn’t charge a AGM battery when the ambient temperature is above 120 degrees fahrenheit, as this can damage the battery. To solve this, someone on this site suggested routing the “charge-while-towing” line through a Sunsaver-10. Apparently this device has temperature sunsure that will protect the battery and stop charging if it gets too hot.

Has anyone done this? Is this a good idea?

Also, what should I do about the negative wire supplying power to the Sunsaver? I will have a positive wire coming in from the tow vehicle, but I am not sure where I should connect the negative. Should it be a grounding wire to the trailer frame? Should I connect it to the negative buss terminal? I have tried to add a picture to clarify my question.

Thanks for you help with this.

Sunsaver question.jpg
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Re: Charging while towing using a Sunsaver-10

Postby H.A. » Tue Apr 19, 2016 3:43 pm

F.
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Re: Charging while towing using a Sunsaver-10

Postby wgwhitacre » Tue Apr 19, 2016 4:19 pm

Thanks, H.A.

So, if the Sunsaver doesn't work, is there a battery charger that y'all use? Is there anything wrong with just connecting the wire from the alternator straight to the battery?
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Re: Charging while towing using a Sunsaver-10

Postby H.A. » Tue Apr 19, 2016 5:35 pm

[qu n.
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Re: Charging while towing using a Sunsaver-10

Postby Shadow Catcher » Tue Apr 19, 2016 5:47 pm

I have a SunSaver MPPT controller sitting on top of our 150 AH AGM with a 10 ga line coming from the TV to the trailer. I have not yet seen any real degradation of the battery.
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Re: Charging while towing using a Sunsaver-10

Postby H.A. » Tue Apr 19, 2016 6:00 pm

[quot?
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Re: Charging while towing using a Sunsaver-10

Postby MtnDon » Tue Apr 19, 2016 7:08 pm

Isn't the charge controller is going to limit the power going into the trailer battery the same as if the incoming power was coming from PV panels?
Our 6x12 deep vee nose cargo trailer camper conversion... viewtopic.php?f=42&t=58336

We have a small off grid cabin we built ourselves in the NM mountains; small PV solar system; 624 watts PV, Outback CC & inverter/charger ... http://countryplans.com/smf/index.php?topic=2335.0
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Re: Charging while towing using a Sunsaver-10

Postby H.A. » Tue Apr 19, 2016 7:50 pm

MtnDon wrote:Isn't the charge controller is going to limit the power going into the trailer battery the same as if the incoming power was coming from PV panels?


They dont think they will limit**
The current drawn relates to state of charge of the depleated battery.
(Size & type of battery play into current drawn also, but beside the point of this message)
If controller is installed as intended, its PV modules are a current limited source.
If trailer battery is low, and high current available. example, powered direct from the car, trailer may draw more current than a small charge controller is designed to carry.

A couple points.
Current may "automatically" limit by voltage drop in a low capacity supply circuit.
**Some charge controllers will shut down if current is exceeded & need to be powercycled to reset.
Aside from hassle to powercycle, I dont think its good to repeatedly cause an overcurrent device to activate.

If it works for somebody, thats great. But there are legitimate reasons it may not.
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Re: Charging while towing using a Sunsaver-10

Postby MtnDon » Tue Apr 19, 2016 9:13 pm

OK, I'm forgetting we're talking about a cheap charge controller. With the higher end equipment I use and am familiar with the CC can be programmed to limit the current. It is not uncommon now with the cheap price of PV panels, to "overpanel" to permit higher outputs when the sun is at sub optimal angles or it is cloudy. To consider the use of that Morningstar as described it would be best to make an inquiry with the mfg. You are exactly correct about the environmental temperature sensor / controller. A higher end piece of equipment may have a remote sensor available.
Our 6x12 deep vee nose cargo trailer camper conversion... viewtopic.php?f=42&t=58336

We have a small off grid cabin we built ourselves in the NM mountains; small PV solar system; 624 watts PV, Outback CC & inverter/charger ... http://countryplans.com/smf/index.php?topic=2335.0
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