Need advice for electrical set-up - 12 month trip through the Americas

kerfro

New member
Hi everyone,

I am going on a year-long trip from Alaska to Ushuaia in May in a 2000 Jeep TJ. So far it is purely stock and I am planning the electrical mods right now. To be frank: I have read lots and now i am completely lost due to over-information.

What I want to power:

- small fridge/freezer (thinking: Dometic CF-025DC) behind the passenger seat
- Macbook Air 11" / Ipad /Iphone
- Camera battery
- various USB accessories (head lights, kindle etc.)

How I will travel:
I will be camping for 2-3 days without moving at maximum and would like to not worry about getting the car started.
Laptop will be used 1-2 hrs a day.

I want to keep mods to the minimum (cost and complexity) and without the freezer I would have just gotten a goal zero or volatic battery and a decent solar panel, with the freezer I don't know if I need a dual battery for the car or if there is another option to keep the freezer running. I read some threads that suggest that I don't need a dual battery at all, but a decent primary battery and I am starting to get confused. Maybe I should get a bigger independent battery and a solar panel?

Any help would be much appreciated!

Thanks,
Kerstin
 

DiploStrat

Expedition Leader
Great Trip

Kerstin,

Great trip, you are going to have a wonderful time. (As an aged dinosaur, I would prefer a vehicle with a bit more living space. Do remember that the altiplano is cooler than a penguins dreams; pack yer woolies.)

If you have the time, consider a visit to Overland Expo in May; you will meet several people who have made exactly your trip in recent years.

Now, to your question. This isn't really hard. Try this decision path:

-- Get a handle on your total load, rounding up. If you use LED lights for camping, the only big load you have will be the freezer. Many of the other loads can be handled while you are driving.

-- Once you have a SWAG of your load, multiply it by the number of days that you will not drive or start the engine. In your case, three.

-- Now, assuming that you are using a deep cycle, AGM battery (which you may want to for ease of mounting, ease of charge, lower maintenance), size it to twice the load you calculated. So, if you worked out 50Ah per day, times 3 days, times two, you would want 300Ah. You get the idea.

-- Now comes the hardest part, finding a place to store the batteries. (Unless your load is so low that you can simply stash a second battery under the hood.) Wherever you put it/them, be sure to use a true deep cycle battery.

-- There are several ways to wire everything up, but I strongly recommend a intelligent relay. Also know as an voltage sensitive relay or an automatic charge relay or any number of other trade names, basically this is a controller and a relay. Size the relay to be equal to or greater than the output of your vehicle's alternator.

-- Size matters, so be sure that the cabling between your starter battery and your camper battery is large enough. If your camper battery is in the back, you are starting at 1/0 AWG. There are many calculators out there, this one is easy to use. You want to shoot for 0.5v drop, or less.

Try to use 12v chargers for everything you can, but you may need an inverter as well. Get the smallest one you can get away with as they all have about 10-25% loss.

Finally, try to add as much solar as you can. Bogart, well known for their TriMetric meter, have just started selling a low cost solar controller. Given their bullet proof reputation, I would consider this for any solar set up under 30A. (And, on a Jeep, you won't have room for a 30A array.) http://www.bogartengineering.com/content/solar-charger

I really recommend any solar you can mount as:

-- Solar is really good for assuring that your batteries achieve a full absorb/acceptance charge.
-- With an automatic relay, it will keep your vehicle batteries fully charged.

Do read over this forum as most of this has been argued into the ground. Others will have comments to add and catch any oopsies that I have made. Hope this is helpful.

 
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Hi Kerstin, and welcome to ExPo! It sounds like you have quite an adventure planned!

As far as your electrical requirements, it does sound like you will need additional reserve for your fridge and gadgets. Ideally, you would need a large high quality deep-cycle batter and a solar solution to keep it topped off. Assuming you have adequate sunlight everyday this would serve you well. However, adding a second battery and a solar panel to a rig that already has limited space may be avoidable with some small precautions.

Make sure your current charging system is in good working order. Unless you have already done so, replace the battery wiring and terminals with new factory style replacements. This includes the battery ground, and the wire from the battery to the starter and the starter to the alternator. If the alternator is the original it would also make sense to replace it with a new factory unit. Try to avoid the aftermarket here, ie. high amperage alternators, fancy car audio battery terminals, or advice telling you to just make your own with welding cable -keep everything KISS simple and don't over think it. The factory parts have served you well up to now, why create a problem where there is none?

For your battery, you will need something that will withstand not only the cold, but the burden of constant charge and discharge. I recommend the Sears Diehard Platinum deep-cycle battery. They are nothing more than a rebadged Odyssey battery at a substantial discount. Since one battery will not offer enough reserve capacity to start your engine after charging your gear, you will need to idle the engine for 15-20 minutes a day. This should sufficiently recharge the battery to keep you at a safe voltage. You may want to bring a cheap volt/ohm meter to check the battery voltage when you wake up in the morning. While the engine is running it will also tell you when the alternator is in maintenance mode so that you know the battery is fully charged and it's safe to shut off the engine -this will help you save fuel.

As a bit of reassurance and for personal safety reasons, I would also recommend the Antigravity Batteries Micro-Start. This will not only jumpstart the Jeep if you do happen to run it down too low one night, but it will charge your smartphone, laptop, and other gear to help alleviate some of the burden on the battery in your vehicle. The best part is that it can be charged by the vehicle while you drive from point A to point B. You can usually find it on Amazon for ~$100 USD.

I hope this helps.

Brandon
 

CSG

Explorer
Do not rely on the Antigravity jump starters. I had the bigger one and it was a total failure at starting my truck. I've written of my experiences on Amazon. Pay attention to the negative reviews.

No first hand experience with the ArkPak but many seem to like it and I'm looking into getting one for my LandCruiser along with the Sears 31M Platinum battery. It might be something for you to look into. http://www.arkportablepower.com/pages/about-the-arkpak
 

DiploStrat

Expedition Leader
...you will need to idle the engine for 15-20 minutes a day. This should sufficiently recharge the battery to keep you at a safe voltage.

I don't like to quibble, but this is a bit misleading. A starter battery can recover from starting a car with a few minutes of charge, but this is not the case with a deeply discharged, deep cycle battery.

The bad news about charging lead acid batteries is that it is a matter of time. Lots of time. Typically, you must replace about 110% of the energy used. Battery charging is a chemical reaction and it takes a very long time for the charge to spread through the battery. The Lifeline tech manual, linked here: http://www.lifelinebatteries.com/manual.pdf has the formula on page 19. Notice that all of their recharge regimes call for at least two hours of absorb charge after the battery hits the 80-90% charged point.

Let me share a quote from an e-mail exchange that I had with Lifeline:

Most damage is caused simply from not charging enough. For example I have a lot of customers that tell me the batteries were low and the let their engine idle for 15 minutes and they're still not charged. It is not how the voltage that damages them, it's the lack of charging. What most people don't know is undercharging (amperage) is often just as harmful as overcharging with voltage.

This is one reason that I am such a fan of solar, it is always there. (It is pouring rain right now and my solar array is still producing 4A; almost enough to cover my background loads. Granted, I have a bigger array and bigger battery bank than you can fit, but the concept is there.) With a larger battery bank it is hard to drive long enough to achieve a full charge. That is where it is great to have a solar array to finish the job.

There is one case where starting the engine can be really useful and that is when you have a large, short term load, for example a microwave or an induction cooktop. Start the engine and the alternator will take most or all of the load, sparing your battery bank. Of course, this won't do you much good with a freezer, but again, you get the idea.

 
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jonyjoe101

Adventurer
a 12 volt danfoss compressor fridge when set to 40 degrees comsumes 27 amps in a 24 hour period. When i try to run my fp430 edgestar 12 volt fridge as a freezer set to 0 degrees, I couldnt even run it 1 day off of my 75 ah agm battery and 120 watt solar panel. But at 40 degrees it ran 24/7 nonstop for months at a time. To run it as a freezer you need a large battery at least over 100ah and a big enough panel or generator to charge back up quickly the next day.

solar panels lying flat on the roof
60 watts will give you about 3 amps (pwm)
120 watts will give you 7 amps (pwm)
240 watts will give you 12 amps (with mppt)

solar charge controllers has 2 types, pwm (cheap) and mppt (expensive) . While mppt will work on any panel, it only increase the amp output on high voltage panels (over 30 volts) on the smaller 20 volt panels it will just perform like a cheaper pwm controller.
 

dwh

Tail-End Charlie
You *can* get by with a single battery. For a year long trip, I'd carry two with either a split-charge relay (as DiploStrat described) or a DC-DC charger to charge it off the engine.

And if you can squeeze in some solar, I'd do that as well.



solar charge controllers has 2 types, pwm (cheap) and mppt (expensive) . While mppt will work on any panel, it only increase the amp output on high voltage panels (over 30 volts) on the smaller 20 volt panels it will just perform like a cheaper pwm controller.

This is not correct. MPPT works by down-converting the voltage from the input side to the output side. As long as the Vmp of the solar is higher than the voltage of the battery, MPPT will do its work. (And if the Vmp is not higher than the battery voltage, it won't charge the battery anyway. :) )

Let's say 100w panel with a Vmp of 18v charging a battery at 12v:

100w / 18v = 5.5 amps IN
100w / 12v = 8.3a OUT

Now let's double the input voltage:

100w / 36v = 2.7a IN
100w / 12v = 8.3a OUT

While the higher PV voltage appears to result in a greater "boost" - 2.7a to 8.3a, rather than 5.5a to 8.3a - that's deceptive. It's actually still 100w IN / 100w OUT. Either way gets 8.3a to the battery.

Of course, if the Vmp of the panel is 15v, and the battery is at 14v...the torque multiplication from electrically shifting gears won't help much...

100w / 15v = 6.6a IN
100w / 14v = 7.1a OUT

But there is still *some* measurable increase.


EDIT: Also note - the lower Vmp *starts out* with a higher amp rate on the input side.
 
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I don't like to quibble, but this is a bit misleading. A starter battery can recover from starting a car with a few minutes of charge, but this is not the case with a deeply discharged, deep cycle battery.

The bad news about charging lead acid batteries is that it is a matter of time. Lots of time. Typically, you must replace about 110% of the energy used. Battery charging is a chemical reaction and it takes a very long time for the charge to spread through the battery. The Lifeline tech manual, linked here: http://www.lifelinebatteries.com/manual.pdf has the formula on page 19. Notice that all of their recharge regimes call for at least two hours of absorb charge after the battery hits the 80-90% charged point.

Touché. You are correct regarding deep cycle slow recovery. I had paired the deep cycle with solar panels in my mind and in doing so transferred that battery to the engine bay of his TJ. My mistake, thank you for clearing that up!
 
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DiploStrat

Expedition Leader
The Case for Lithium

Lithium batteries are appallingly expensive and there is some anecdotal evidence that they need low voltages to charge, annoying now that vehicle manufacturers have finally gotten their charging voltages up into the 14-15v range needed for lead acid batteries.

That said, their smaller size and lighter weight may be just the ticket for folks traveling in smaller Jeeps/Land Cruisers. Lithium also has the advantage of having a flat charge curve, that it, the charge rate doesn't need to taper off as the battery charges. This means that they recharge much faster. Again, just what you want on a smaller vehicle with no space for a solar array. There was a Dutch (I believe) gentleman who was using a Lithium camper battery on his Land Cruiser. It was a relatively small set up, but seemed to be working well.

The challenge, at this point, may be to find a proper secondary regulator. This may bring battery to battery chargers, like Sterling's units, back into vogue, especially as they are now claiming high voltage tolerance on the input and actual voltage drop on the output, specifically a Lithium profile: http://sterling-power.com/collectio...chargers/products/battery-to-battery-chargers (Kudos to user dwh for finding the new units.)
 

4x4junkie

Explorer
I think a simple portable solar setup might be the way to go here.
Mine is a 170W "suitcase" style setup I put together with a SunSaver MPPT controller. It keeps up with my loads with more than plenty to spare (43qt fridge/freezer, 10-20 watts of LED lights, playing of the stereo all day, which you could sub your laptop, etc. in place of that). When you expect to be parked a couple days or more, just unfold the panel and set it out in the sun, clip the controller's leads to your battery, and plug the cord from the panel into the controller.
I normally stow the panels on the roof while under way, though they could be stored inside as well (they are not very thick, about 3" folded, but do need some room length & width-wise). I know a TJ puts space at an extreme premium, but I still think room could be found for a 120-140W setup (two modern 60-70W panels) that would keep up with your loads fine (especially if you're able to reposition the panel toward the sun once or twice during the day).

I also run two 95Ah deep-cycle group-27 batteries in a simple straight-parallel setup (no isolator). I have found if the fridge drains the batteries enough that it cuts off due to low voltage, there's still enough juice between the two batteries to turn the engine over, so I don't worry too much about not being able to start it (so an isolator would add unneeded complexity in my case). Plus I have a manual trans so worst-case I could always bump-start it. I get about 4-10 days before the fridge cuts off (dependent on ambient temperature of course) if I don't have the solar connected (but will go indefinitely with solar).


And FWIW, you can put quite a bit of juice back into a deeply-discharged battery with 30 minutes to an hour of running the engine. No it will not be a full charge (more around 60-70% maybe) but if you plan to be back under way within a day or two, then I don't see a problem. Once back on the road for a few hours or longer, the battery should then receive a full (or at least near-full) charge from the alternator. It's when a battery sits at something less than 100% charged for weeks or months at a time that damages them (so if your drive time during the day never exceeds a few hours straight, then solar or some type of shore charger will be a requirement to keep your batteries healthy).
 

kerfro

New member
Hi all,
thanks for your info. A lot to take in.

As I see it at the moment I have three options:

(1) One large battery
- This requires to buy a new battery, battery monitor and an emergency jump-start solution.
- Everybody seems to recommend the Sears DieHard Platinum 31.
- Questions: How could I connect the solar panel to this? What would I need?

(2) An external battery (i.e. ArkPak) and a deep cycle battery (potentially add solar power)
- Seems like the easiest solution to me right now. I could charge it as a second battery and run the fridge from it (as well as the other gadgets) without having to worry about the starter battery.
- I could even add a portable/foldable solar panel to charge it (I believe).
- Downside: I would need to find space in the Jeep (behind the driver's seat?) and space is limited.
- Question: What type of battery would I use? The same deep cycle one as in the set-up 1?

(3) Build-in dual battery set-up (with Solar panel)
- I would need to find a way to put a second battery plus everything else that is needed under the hood as well get some outlets into the the dash.
- Question: How would I connect a portable solar system to this?
- Question: What type of battery would I use? The same deep cycle one as in the set-up 1?

My current assessment:
Set-up 1 (one battery) would be a little risky but doable, Set-up 3 would be the cleanest solution but also the most expensive and the scariest (as I would need to tamper with the Jeep's electrical system), Set-up 2 (external battery) seems easy but I do not like the space it takes up inside the vehicle (space is very scarce and precious).

Am I missing anything? I will investigate the costs for the dual battery set-up. Any gear recommendations are appreciated.

Again, thanks so much for all the help.
K
 

DiploStrat

Expedition Leader
Some More Comments

Option 1 would be a very bad idea. The Sears Die Hard Platinum 31 is a 100Ah marine battery. That would give you 50Ah per day, assuming that you achieved a full recharge every day. Not much if you are talking about a refrigerator.

Options 2 and 3 are really the same thing. I am not a great believer in magic booster batteries, if only because, if you do it properly, your camper battery is your booster/jump start battery.

You really have to determine your daily amp draw. (If worst comes to worst, call it 5A per hour. That is about what I have with the heat on and a refrigerator running. I would suspect that you would probably only have about half that with a cooler.)

Then you have to determine how manes days you want to go without engine start/sun on solar panels.

Then, unless you have a Lithium battery, you have to size your camper battery to twice that.

So if your cooler takes 2.5A per hour, that equals about 60Ah per day x three days that equals 180Ah, call it 150 and you need about a battery bank of about 300Ah. You aren't going to get that from a marine battery; you want a real, deep cycle battery.
 

dwh

Tail-End Charlie
(1) One large battery
- This requires to buy a new battery, battery monitor and an emergency jump-start solution.
- Everybody seems to recommend the Sears DieHard Platinum 31.
- Questions: How could I connect the solar panel to this? What would I need?

Soon, the Diehard platinum might fall to the wayside as the most commonly recommended - been a few threads lately on the subject.

A) Might not actually BE identical to an Odysssey. Same basic construction from the same manufacturer, but might be a sort of "budget" model.
B) Scuttlebutt says Sears is going to discontinue it.
C) Several people have reported problems, which seem to be related to the battery occasionally needing some special charging which it isn't getting under normal vehicle use.


(2) An external battery (i.e. ArkPak) and a deep cycle battery (potentially add solar power)
- Seems like the easiest solution to me right now. I could charge it as a second battery and run the fridge from it (as well as the other gadgets) without having to worry about the starter battery.
- I could even add a portable/foldable solar panel to charge it (I believe).
- Downside: I would need to find space in the Jeep (behind the driver's seat?) and space is limited.
- Question: What type of battery would I use? The same deep cycle one as in the set-up 1?

The Odyssey, and Diehard platinum are dual use batteries - cranking and deep cycle. Most batteries are *either* cranking or deep cycle. You could put a dual use in the ArkPak or you could use a dedicated deep cycle type. Looks like it uses its on-board 12v charger to handle solar, so it would be limited to 6a of solar. To use more solar, you'd need your own solar charge controller to go with your panel, and connect directly to the battery.


(3) Build-in dual battery set-up (with Solar panel)
- I would need to find a way to put a second battery plus everything else that is needed under the hood as well get some outlets into the the dash.
- Question: How would I connect a portable solar system to this?
- Question: What type of battery would I use? The same deep cycle one as in the set-up 1?

Aux battery could either be dual use, or dedicated deep cycle. To connect solar you'd need a solar charge controller (usually included with a folding portable solar kit), unless you went with something like a CTEK 250s which is a temperature compensated DC-DC charger (to charge the aux battery from the engine) - and also has an MPPT solar controller built in.


My current assessment:
Set-up 1 (one battery) would be a little risky but doable, Set-up 3 would be the cleanest solution but also the most expensive and the scariest (as I would need to tamper with the Jeep's electrical system), Set-up 2 (external battery) seems easy but I do not like the space it takes up inside the vehicle (space is very scarce and precious).

Setup 1 isn't particularly risky if you have a portable solar along. Worst case, you turn everything off, hook up the solar and wait a while till the battery comes up enough to start the truck. People who do the single battery setup seem to regularly recommend bringing along a jump start pack.

Setup 3 isn't that big a deal. It's been done a million times and there are a bunch of different smart isolators on the market. I'm liking the looks of the new one from Samlex:

http://samlexsolar.com/rv-power-products/ProductDetail.aspx?pid=478

I'd say it's worth the investment for a year long trip. And it'll probably end up costing around the same as the ArkPak anyway. There isn't any tampering really - just adding some fat wire from the main battery to the aux, with something in between (solenoid (smart or dumb) or DC-DC charger) to see to the charging of the aux battery.


Am I missing anything? I will investigate the costs for the dual battery set-up. Any gear recommendations are appreciated.

My recommendation: Setup 3. Dual battery, under hood. Either CTEK 250s Dual and *at least* 100w worth of portable solar, OR, Samlex ACR with *at least* 100w of portable solar. I give preference to the first option, but the second is probably cheaper.
 

dwh

Tail-End Charlie
Then, unless you have a Lithium battery, you have to size your camper battery to twice that.

Diplo...bro...

JEEP. It's a Jeep. Where the hell would you put 300ah of lead-acid in a Jeep and still have room to carry what you need for a couple to live for a year out of the thing?

In this case, I think he's just going to have to just fit what he can and live with whatever the resulting daily energy budget is.
 
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DiploStrat

Expedition Leader
Oh I get it, and agree. Methinks that the answer will have to be a smaller/higher tech cooler and less autonomy. (See also my first comment on her choice of vehicle. :) But then I'm old and ugly. And I have frozen my ankles off on the altiplano.)

Never having looked under the hood of a modern Jeep, I suspect that the practical limit is a 100Ah AGM deep cycle battery, somewhere in the back of the vehicle. Bonus points if there is a way to mount it outside of the body. Most of the loads in question, computer, phone, cameras, can actually be charged while driving. LED camping lights can almost be ignored. The refrigerator/cooler is the only real issue but it may be a real one.

FWIW, were it me, I would be looking at things like roof top tents - and monster sleeping bags for the altiplano. :Wow1: I still remember the time Beloved Spouse wanted hot soup at 10PM, at 15,000 feet.
 

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