Running trailer electrics off 12V umbilical

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Re: Running trailer electrics off 12V umbilical

Postby fishboat » Fri Sep 28, 2018 6:18 pm

KTM_Guy wrote:
What is your tongue weight now?
We've had the trailer about three weeks now. I haven't had time yet to get a curb weight and tongue weight determined. I'm guessing it's in the 150-200# range..but we'll see when I measure it..next week hopefully.


What’s the TV?
Toyota Sequoia, 5,7L, 4wd, 9600 lbs towing capacity w/ tow package

Do you need battery power for weeks on end or just to last a weekend trip?
Up to a week(for the next year or so, then longer after that), with more 3-4 day trips

Do you need the back of the trailer to be clear to hall stuff?
Yep..it's a toy hauler..we're avid cyclists(bicycle) and will be carrying 2-4 bikes, kayaks..etc.. There won't be any permanent cabinets or installs to get in the way of swinging the bed platforms up(they can be stored swung down flush to the walls). We plan to keep the interior functional, but very simple. We're long term (several decades+) tent campers that also have some experience with popups, truck campers, and fifth wheels over the years. Our camping gear(plus bikes..etc..) will be loaded in the rear when we're traveling, but it all comes out when we arrive. We travel with minimal "stuff". We don't take with us everything we're trying to leave behind.


Water is another high weight gain. Do you need to carry it and how much? Where will you carry that?
I usually carry two 5 gallon carboys of home water when we leave home. Typically they go in the truck, now they'll be in the rear of the trailer, 85ish pounds. There won't be any water systems installed in the trailer(no sink, pumps, white/grey/black water tanks, toilet, shower..nothing).

For us we are going the trailer route over the tent because we want to be able to say let’s go and grab some clothes, some food and head out. The last thing I want to do is have to load a bunch of stuff in the TV.
Yep..also with us. Everything is pretty organized, I'm retired. Getting out of town is a fairly short putt.


If no option in the trailer I would look into welding brackets off the frame behind the fenders and mount a battery box there.

Todd
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Re: Running trailer electrics off 12V umbilical

Postby fishboat » Fri Sep 28, 2018 6:29 pm

Ottsville wrote:
Good questions especially the first one. Don't assume that your trailer weight distribution is accurate to that 10 to 15% range from the manufacturer. Weigh it.
Yah..getting it weighed is on the list..haven't got there yet. Next week hopefully.

And if your tow vehicle is sufficient, I wouldn't be concerned about going up to 20%.
The truck could handle 20%. The Sequoia is basically a 1/2 ton Tundra pickup frame/drivetrain with a full box built on top. I'm just trying to avoid issues with planning up front.

Remember that weight added forward of the axle doesn't necessarily equal the same weight weight change in tongue weight. We're talking levers here. Play around with this calculator:

https://www.engineersedge.com/calculato ... vers_3.htm

Newtonian Mechanics in action. Thanks for the calculator..I'll do some ciphering with it...should be helpful.

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Re: Running trailer electrics off 12V umbilical

Postby fishboat » Fri Sep 28, 2018 6:51 pm

troubleScottie wrote:I would be concerned about having to rearrange anything once you arrive. Especially electrical stuff. Much of the reason for the trailer/5th wheel/motor home is that you can park and your done. Having to move things around immediately just so it is usable is not a great plan. Think 2AM arrival in a driving rain after a 8 hour drive. How much do you want to have to do to go to sleep. Same goes for leaving from home or the camp - how much stuff do you have to put away before you leave - again think in the dark in the rain?
I hear you. As tent campers, we're accustomed to setting up camp (tent, cooking area, rip-stop nylon tarp..), but would have no issues with a faster setup. We're trying to keep it simple. It's all in planning stages at this point with looking at different options. Eventually a final (initial) approach will surface. We'll be using the trailer in the mean time to sort out what works and what doesn't. As for arriving at 2am or packing up in the rain..well..20-30 years ago on occasion, but we're older and smarter now..and have lots more time available.

There are many designs here with similar trailers that have all of your issues. Look up the builds for them and see how they addressed the problems. You are definitely not the first one seeing this problem.
Yes, I agree. Since discovering this forum a few weeks ago I have a good 40-50 hours in searching and reading on various topics here. This is a wonderful resource with lots of very talented people. I've seen and taken extensive notes on many builds...most..nearly all I've seen (CTC builds) are quite elaborate. While I'm a woodworker and will be building nice cabinets in the nose, that'll be about it for internal construction. The largest other build-in is electrical options...which is being discussed here. With more elaborate builds comes more options of balancing weights front and back...I won't have that option..much, by choice, so I'm measuring twice and cutting once, as well as I can.

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Re: Running trailer electrics off 12V umbilical

Postby fishboat » Fri Sep 28, 2018 6:54 pm

John61CT wrote:The best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH pair from BatteriesPlus or Sam's Club

It is much harder to find 12V batteries that are true deep cycling.

Certainly not usually sold in auto or big box consumer channels.

And definitely more expensive per AH @12V.

Avoid sealed batts unless you really need them.


Thank You! I'll look into that battery. 200ah is a lot of juice..wow. (our needs are small)
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Re: Running trailer electrics off 12V umbilical

Postby MtnDon » Fri Sep 28, 2018 8:08 pm

Two 12V (smaller) batts in parallel is a good idea.


What john said just previously... For this type of use a true deep cycle battery will give longer life. True deep cycles are rare and expensive whereas 6 volt golf cart batteries are readily available, are true deep cycle designs and are relatively cheap when bought at a Sam's Club or Costco. Those 12 volt Marine/RV batteries we see are not true deep cycle. They are a little better than an automotive cranking battery, but not a great deal better. I kept ruining 12 volt batteries like those 40 years ago until a battery expert set me straight.

Also, two 6 volt in series is better than two 12 volt in parallel, even if the batteries are the same design. When in parallel, a small difference in internal resistance will cause more current to flow through one of the parallel batteries. That can result in one battery being overcharged or the other one being undercharged. The best lead acid based battery off grid systems, for example, avoid parallel batteries as much as possible.

Of course, if weight is a very important factor, and if the budget can stand the outlay, buy lithium-ion batteries. LiFePo4 are high density energy and quite light.
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: Running trailer electrics off 12V umbilical

Postby John61CT » Fri Sep 28, 2018 9:00 pm

fishboat wrote:
John61CT wrote:The best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH pair from BatteriesPlus or Sam's Club

It is much harder to find 12V batteries that are true deep cycling.

Certainly not usually sold in auto or big box consumer channels.

And definitely more expensive per AH @12V.

Avoid sealed batts unless you really need them.


Thank You! I'll look into that battery. 200ah is a lot of juice..wow. (our needs are small)
It is very difficult to find quality true deep cycling in smaller sizes, and they will cost a **lot** more per AH.

Shallow cycling improves longevity, properly cared for you could get 8+ years easy.

And divided into 2x 6v easier to move for weight balance purposes than say L16.

If money is not such an issue and you think your needs really will stay small (no fridge) consider Kodiak or Yeti's larger lithium units.

But not what I call good value.
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Re: Running trailer electrics off 12V umbilical

Postby John61CT » Fri Sep 28, 2018 9:09 pm

MtnDon wrote: two 6 volt in series is better than two 12 volt in parallel, even if the batteries are the same design. When in parallel, a small difference in internal resistance will cause more current to flow through one of the parallel batteries. That can result in one battery being overcharged or the other one being undercharged. The best lead acid based battery off grid systems, for example, avoid parallel batteries as much as possible.

Mostly right in your above post, but this part is a bit overstated.

Going past 3 parallel yes, but just a pair, balance issues not that significant.

If AGM is required, and especially high-current use like winching added to normal house use, a **true dual use** 12V TPPL unit like Odyssey PC2150 will give best of both worlds, and 2-3 paralleled is OK to increase the AH.

Just need to call them to locate a local source, don't ever want to pay to ship lead if you can help it.

And never imagine an AGM "marine deep cycle" from auto or big box sources should even be discussed in the same breath, really the FTC should prosecute those for false labelling.

https://marinehowto.com/what-is-a-deep-cycle-battery/
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Re: Running trailer electrics off 12V umbilical

Postby fishboat » Sat Sep 29, 2018 5:12 am

John61CT wrote:
fishboat wrote:I just looked up the suggested wire gauge for a 1% voltage drop over a 20 foot, 12V umbilical..cough..I didn't realize 12V voltage drop was so bad..yikes. The calculator suggested 0 GA wiring(8 amps, 20 feet, 12Vdc, 1% drop), 4 GA for a 3% drop..that's not going to happen.
Why? I very commonly use 00 or even thicker when needed.

Compared to managing a separate (consumable) bank, having to buy an expensive (more fragile) DC-DC charger, $500+. . .

The wiring will likely pay for itself in 5-7 years


John..maybe this option isn't dead. I wasn't looking forward to a wrestling with a loose wrap of heavy gauge stiff cable, but a memory popped into my head of welding cable...It comes in sizes in the awg 0-6 range, it's fairly cheap, and with fine wire strands, very flexible. So..would there be any down side to using welding cable as the umbilical? I see a 25 foot pair of black & red awg 4 cable on ebay, new, for $50, free shipping, USA copper.

https://www.ebay.com/itm/WELDING-CABLE-4-AWG-50-25-BLACK-25-RED-FT-BATTERY-LEADS-USA-NEW-Gauge-Copper/261080572842?epid=2256584620&hash=item3cc99d63aa:g:fWoAAOSwy0JZ~LRp
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Re: Running trailer electrics off 12V umbilical

Postby fishboat » Sat Sep 29, 2018 5:29 am

MtnDon wrote:

Of course, if weight is a very important factor, and if the budget can stand the outlay, buy lithium-ion batteries. LiFePo4 are high density energy and quite light.


100ah batt at 29 pounds (nice!)..$1000 (cough..maybe not today..)

The smaller 12V batts in parallel is mainly attractive (to me) due to less weight/battery. Whether it floats to the top in this application depends on how important those pounds turn out to be..
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