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Old 06-13-2019, 03:37 PM   #21
JRTJH
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The comparative information on the Interstate GC2 (6 VDC system with 2 batteries) and the GC12 (12 volt single battery system):

GC2: price 94 each/188 for the pair)
amp/hr rating: 20hr/210

GC12: price 229 (41 more expensive than two GC2's)
amp/hr rating: 20hr/150

So, "doubling up" to install 4 GC2's would cost 376 and provide an amp/hr rating of 20hr/420

"doubling up" to install 2 GC12's would cost 458 ($82 more than the 4 GC2's) and would provide an amp/hr rating of 20hr/300.

It looks to me like the 2 GC2's are about 50% more power capacity with a savings of $41 and the 4 GC2's remains about 50% more power capacity than the pair of GC12's with a savings of $82.

The "downside" for me, is the weight. The GC2's weigh 58 pounds each and the GC12's weigh in at 84.5. So the 4 GC2's would weigh 232 pounds while the 2 GC12's would weigh 169. That 50% added power capacity comes at a "cost" of about 65 pounds more weight. Of course, in batteries, thicker led plates weigh more and additional plates make the battery weigh more.

Given the information, for me, I think I'll accept the weight penalty to gain the power advantage. For someone with a "weight challenge" or a "space challenge" may benefit from the GC12's.

Bottom line, at least for me, is that no matter which you choose, GC2's or GC12's, there is a marked improvement over a pair of "dual duty GP27 marine deep cycle/cranking" batteries.
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Old 06-14-2019, 04:37 AM   #22
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A few more thoughts here: The solar panel will not charge until the output voltage climbs high enough. A 37 volt panel will begin producing a usable voltage sooner in the morning (due to angle of the sun) than one with a lower voltage output and that usable voltage will continue later into the day. The full output of the panel will be affected by the type solar controller i.e. MPPT vs PWM. A MPPT controller is superior to the PWM controller. I've found that a given wattage of panel ultimately only produces about 80% of it's stated capacity. A large capacity battery storage system needs an adequate charging system to renew it.
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Old 06-14-2019, 08:34 AM   #23
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Originally Posted by JRTJH View Post
If you think about how the emergency braking system actually functions, there's a "perfect storm of events" that must occur BEFORE the brakes will activate. First, when the trailer separates from the ball, IF the safety chains hold, a SECOND event must occur. The plunger on the break-away switch must be pulled. Far too many people don't cut/shorten the plunger cable, so effectively, if the "OEM cable is used as supplied at delivery" chances are very good that it will not function as expected.

In theory (yeah I know) the way it's supposed to work is this:

The trailer separates from the ball.
As the trailer moves back, the break-away cable tightens BEFORE the chains reach full extension and the plunger is pulled.
The break-away switch closes, applying braking action using onboard battery power. The reason for this is that there is no assurance that the 7 pin umbilical will remain connected to the tow vehicle AND, if the safety chains do not hold, that connection will definitely be severed.
The brakes slow the trailer and prevent it from "overrunning the tow vehicle" preventing increased damage and helping to maintain control by not "banging into the back of the tow vehicle" as you attempt to slow/stop the rig.

If the safety chains are shorter than the plunger cable, the trailer brakes won't function. If the 7 pin umbilical cable is shorter than the safety chains, it will sever BEFORE the chains reach full extension and remove any power from the tow vehicle that might reach the trailer brakes. If the plunger cable is too long, you have an increased risk of the trailer slamming into the back of the tow vehicle, causing loss of control and increasing the chances for injury.

In the event of a separation, you want the trailer brakes to hold the trailer back from the tow vehicle as you slow to a stop. If it "works as planned" the safety chains will keep the trailer in line with the tow vehicle, but don't count on the 7 pin umbilical to remain connected.

In the event the safety chains fail, then you definitely want the onboard battery to power the trailer brakes to slow the "runaway trailer" before it slams into an oncoming vehicle or sideswipes a vehicle going in the same direction.

So, it may be a good idea to think through the actual sequence of events that occur, inspect your plunger/cable assembly to be sure it is shorter than the safety chains and that the system actually works as expected.

ADDED: While I'm sure there are "some" I've not yet, in 50 years of towing and being around RV's, seen a dealership that cuts/shortens the break-away plunger cable so it "fits" the tow vehicle/safety chain/hitch for that application.... My guess is that probably 50% of the break-away cables in use by members on this forum are 'too long to pull the plunger' if the trailer separates from the ball or from the fifth wheel hitch.


Excellent and VERY important post!!!!!!

In all my years of towing TT's I never realized the importance concerning the length of the break-away cable's length..... I know for a fact the cable on my TT is way to long...... And it will be shortened to correct length before it's ever moved again!!!!!!!

Lee
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Old 06-14-2019, 02:27 PM   #24
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PICK up a small generator for tv
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Old 06-16-2019, 02:26 PM   #25
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I am late to the thread but thought I might share my experience. We have just returned form a 5 night trip to Michigan Reservoir located west of Camron Pass in the Colorado Rockies. Campground elevation is 9k feet with no hookups. We have two Interstate 12v batteries (SCM-24?) and a Renogy 100w monocrystalline panel with an entry level 30a PWM controller. Night time temperatures dropped into the low 20's to low 30's so the furnace was set to 55 degrees and ran frequently each night. The batteries were about 60% by morning but were fully charged by mid to late afternoon. Must days were full sun a a few were partly cloudy. I re-positioned the panels twice each day to orient with the sun. We never needed to use the generator. However we do conserve our power. Frig, water pump and a few lights are a must, but no TV or stereo. So it is possible to do a 6+ night stay with 2 12v batteries and a 100w solar panel if you monitor your power consumption and have the right sun conditions.
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Old 06-16-2019, 04:32 PM   #26
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Originally Posted by P&DZ View Post
I am late to the thread but thought I might share my experience. We have just returned form a 5 night trip to Michigan Reservoir located west of Camron Pass in the Colorado Rockies. Campground elevation is 9k feet with no hookups. We have two Interstate 12v batteries (SCM-24?) and a Renogy 100w monocrystalline panel with an entry level 30a PWM controller. Night time temperatures dropped into the low 20's to low 30's so the furnace was set to 55 degrees and ran frequently each night. The batteries were about 60% by morning but were fully charged by mid to late afternoon. Must days were full sun a a few were partly cloudy. I re-positioned the panels twice each day to orient with the sun. We never needed to use the generator. However we do conserve our power. Frig, water pump and a few lights are a must, but no TV or stereo. So it is possible to do a 6+ night stay with 2 12v batteries and a 100w solar panel if you monitor your power consumption and have the right sun conditions.
Good report. Thanks for sharing your positive experience.
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