Finally pulled the trigger on my solar system!

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BigT

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After 7 months of agonizing, flip-flopping and second-guessing over what to get, I decided not to go with the 300 Watt panel I had originally planned on because the dimensions (39" wide) were too wide and would have resulted in shadowing from the kayak I plan to keep on the roof most of the time (all the time if/when I go full time).  

In the spirit of "Good enough is better than taking about it forever and not getting anything at all, or shooting for perfection" : I ended up getting a Grape 190 Watt Monocrytalline panel and a 15 Amp Morningstar MPPT charge controller (SS-MPPT-15L) and a temp sensor.  I also picked up 40' of 10-AWG MC4 cable.  The controller is good for up to 200 Watts, which of course means that if I ever want to increase the Wattage I'll have to replace the CC (no biggie).  

http://www.civicsolar.com/product/morningstar-sunsaver-ss-mppt-15l-15a-charge-controller-w-trakstar

For another $75 I can add a digital display to better monitor the battery and state of charge, but I'm not sure if I'm going to go that far just yet.  

Now I just need to get my AGM battery (92Ah is my plan), a fuse-block, and what else?  What else do I need??  
The guy at the solar shop suggested a 15 Amp fuse/breaker to go between the panel and charge controller.  Is that a good idea?  
We don't get a lot of thunderstorms around here (OK, any), but I supposed it's possible the panel could be hit by lightning when traveling cross-country.   

I was also told that I could use the 10 AWG MC4 wire to run between the charge controller and battery.  
What about the wires that will run from the battery to the fuse-block?  Can I use the MC4 there as well?  
I assume I'll need to ground the battery to the van?  I know the frame would be best, but could I get away with using the body of the van?

And one last question for SternWake: Is the 190W panel going to be sufficient to keep the AGM happy for a while?  I still plan to get a 120V charger, or use the one at work, when I need a little extra power to the battery.  

 

akrvbob

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With the MC4 I'm assuming it's an extension with male and female at both ends. You're going to cut it in half and plug it into the male and female coming off the panels. Get red electrical tape and mark the positive end of the wire at both ends!!! Run it from the panel to the controller, leave a little extra, and cut off the rest. Crimp on the connector that works best for your controller--probably a spade. You started with 40 feet, cut it in half so it's 20 feet and my guess is you will have plenty left to go from the controller to the batteries. 10 gauge should be fine if it's a short enough run. Double check with a gauge calculator.

Yes, put an in-line fuse between the panel and controller and controller and batteries. It's so cheap why wouldn't you? It'll allow you to disconnect them from each other and protect the devices in case the wire is damaged.
Bob
 

SternWake

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A negative buss bar like this:
http://www.amazon.com/s/ref=nb_sb_n...?url=search-alias=aps&field-keywords=buss+bar

ring terminals for buss bar

http://www.amazon.com/Gardner-Bende...7094786&sr=8-1&keywords=10+awg+ring+terminals

http://www.amazon.com/12-10-Yellow-...pebp=1437094850371&perid=1ZEZZ40KZ47S394PFZA9

Charge controller should be close to battery, but not in same compartment, and ideally, over as fat of wire as you can stuff into the charge controller terminals but 10 awg is not too thin if the distance is short

 Follow morning star instructions as to fusing the CC.

If that CC allows you to hold Absorption voltage of 14.4X for as long as you desire, then every 7 to 10 deep cycles, or after a few days without getting back to 100%  Apply 14.4x volts for an hour or 2 longer than normal.

It won't be ecstatic with that lesser regimen, but will be happy enough if you do that.

Both my Northstars required a 50% discharge and a 25+ amp initial recharge for it to hold over 13 volts resting open circuit voltage.  I could not get them to hold that until I discharged to 50% and hit them with 25+ amps.

That older NS Blue top will pretty much require this treatment before you begin cycling it with the Cpap, and the salesman will not say it is necessary, but don't believe him.

I've been cycling my NS 27 the last 3 nights, and 200 watt solar recharging only.  It is still behaving well holding 14.4v until amps taper to 0.4, but tomorrow morning, I am going to hit it with 40+ amps.
 

BigT

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I was thinking of running this fuse block between the battery and my accessories.  http://www.amazon.com/gp/product/B0...ue&ref_=ox_sc_act_title_1&smid=A1EQP448COWZL4  I was going to mount it to the battery box on the opposite side as the cc.  I'm trying to keep all my wires as short as possible to keep things simple and tidy.  

As for the distance between the cc and battery, I was planning to mount it to the outside of the wooden battery box I built, so less than a foot of wire should be needed.  

Bob.  Yes, the MC4 is 40' with a positive connector at one end and a negative connector at the other.  I figured 20' would be more than enough and would leave me some extra to use in other places, like from the cc to the battery.  At $0.50 a foot, I wasn't too worried about buying a little extra.  
I've got buckets of electrical connectors and fuse holders, so I'm sure I'm covered there.  I'm just not sure what Amp fuses to run between the panel - cc - battery.

SternWake.  I'm not happy about the reduction in Watts either, but I want to make sure the panel isn't sitting under the kayak on the roof.  I'm starting to have buyers remorse, though, and wish I had just gone with the 300W and figured out a way to make it work. :(  
I'm a little worried that 190 Watts won't be enough to carry me through on rainy days or cloudy weather.  

If you look closely at the photo of the panel on the van you can see how close the 190W 32" wide panel is to the left kayak saddle.  The 300W is 7 inches wider and would shove the right side of the panel completely under the boat.  I'd get wider crossbars, but I just bought those and they stick out a lot on the sides already.  I guess I'll just have to learn to live with less than perfect.  

I assume I need to ground the entire system to something?  Probably the battery to the van....

Is there any way I can disconnect the wires coming out of the black box on the panel and attach only the cables I bought without cutting anything?  I'm not thrilled about having exposed plugs on the roof of the van.  I was hoping the only plugs would be those that attach to the panel.  I didn't realize there was going to be a 3' pig-tail on the underside of the panel.  :s
 

SternWake

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I would personally choose a Bussman/cooper ATC fuse block as opposed to a no name brand.   I recently got a Bussman for my current project, and i can tell it is of significantly higher quality than the one in my Van, and makes me want to swap it out for a Bussman.  The fuses are grasped very tightly.  I've noticed my Van's Block can get warm when I'b being an electrical pig.


http://www.cooperindustries.com/con...ion/Resources/catalog_pages/BUS_Tns_15600.pdf

 The lights are just a gimmick, and the cover, seems like a nice feature. But,  If mine came with one, I bet I would have chucked it out the first time it fell off and got in my way.

I'd say ground the battery to the frame or a seat bolt.  That way when you are sitting in a rain storm, watching a peasly 1.5 amps flowing into a battery 50 AH shy of full questioning if it will get you through the night, you can dream about charging while driving, via the alternator, knowing it is just one simple wire between the two.
, said the cat herder. ;)
 

Optimistic Paranoid

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BigT said:
I've got buckets of electrical connectors and fuse holders, so I'm sure I'm covered there.  I'm just not sure what Amp fuses to run between the panel - cc - battery.


Is there any way I can disconnect the wires coming out of the black box on the panel and attach only the cables I bought without cutting anything?  I'm not thrilled about having exposed plugs on the roof of the van.  I was hoping the only plugs would be those that attach to the panel.  I didn't realize there was going to be a 3' pig-tail on the underside of the panel.  :s

Well, you've got a 190 watt panel.  At 18 volts, you should be seeing 10.5 amps.  10 gauge wire can safely handle 30 amps max.  Your controller is a 15 amp unit.  Was me, I'd be using 15 amp fuses.  If you blow them, it means you're overloading your controller anyway and need to replace it with a bigger one.

Don't see how you can replace the MC4 connectors without cutting it off, and that voids the panel's warranty.  After hooking the extension wire up, I'd wrap it good and tight with GOOD electrical tape like 3M brand (not no-name junk from China) and use a wire tie or two to suspend it in the air, so it couldn't lay in any puddles on the roof.  Remember, these MC4s were DESIGNED for this purpose and environment, so I wouldn't obsess about it too much . . .

Regards
John
 

BigT

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SternWake said:
That way when you are sitting in a rain storm, watching a peasly 1.5 amps flowing into a battery 50 AH shy of full questioning if it will get you through the night, you can dream about charging while driving, via the alternator, knowing it is just one simple wire between the two.
, said the cat herder. ;)
:p :p
You make a very good point and convincing argument for including the alternator in the charging of the battery, especially now that I'm running less Watts than originally planned.  
Having restored, repaired, installed and modified many electrical harnesses on cars over the years, I know I can handle running a single wire through the bulkhead (aka a firewall in the old days), with a grommet of course, to the battery.  
I just have to check with the Ford dealer to see how it will effect my warranty.  

Now that I can put the panel on the roof to check for space, I'm going to take a few more measurements to see if there's any way I can install the 300 Watt panel after all.  That is of course if the solar shop will let me exchange/upgrade to the larger panel.  Or would that even be necessary if I ran alternator charging?
 

BigT

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Before I try to upgrade to the 300 Watt panel, I have to ask.  Will the 190 Watt panel combined with alternator charging provide enough "juice" to keep a single, 92 Ah AGM happy?  

I just looked under my hood.  This is definitely not an old Chevy V8 with an easy-to-reach alternator.  It's crammed down next to the engine so tightly, I'll need a shoehorn just to get my hands in there to work on it!  

As for the panel...  With a 39" wide panel like the 300W, my kayak will shadow the right side of the panel, even at high noon!  So unless I only drive South in the morning and North in the evening, keeping the sun on my left at all times, having the alternator attachment won't do me much good.   :p

 

Optimistic Paranoid

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BigT said:
Before I try to upgrade to the 300 Watt panel, I have to ask.  Will the 190 Watt panel combined with alternator charging provide enough "juice" to keep a single, 92 Ah AGM happy?  

I just looked under my hood.  This is definitely not an old Chevy V8 with an easy-to-reach alternator.  It's crammed down next to the engine so tightly, I'll need a shoehorn just to get my hands in there to work on it!  

The answer to the first question depends entirely on how you answer a couple of counter-questions.  How many amp hours will you pull out of the battery every day?  How far/long will you drive every day?

As for your second point, you don't HAVE to hook up directly to the alternator.  You could also hook the house battery up to the OTHER end of the alternator power wire, which will either be on your engine battery, or often on some intermediate point between the alternator and battery.

As for the kayak shadowing the solar panel, that is most definitely Not A Good Thing.  Are you by any chance familiar with THIS:  http://www.yakima.com/shop/trailers/trailer/rack-and-roll-66

Regards
John
 

BigT

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Optimistic Paranoid said:
The answer to the first question depends entirely on how you answer a couple of counter-questions.  How many amp hours will you pull out of the battery every day?  How far/long will you drive every day?

As for your second point, you don't HAVE to hook up directly to the alternator.  You could also hook the house battery up to the OTHER end of the alternator power wire, which will either be on your engine battery, or often on some intermediate point between the alternator and battery.

As for the kayak shadowing the solar panel, that is most definitely Not A Good Thing.  Are you by any chance familiar with THIS:  http://www.yakima.com/shop/trailers/trailer/rack-and-roll-66

Regards
John

Ah yes, good point about not needing to connect directly to the alternator..  I don't know what I was thinking.  In my own defense, I haven't restored an old car since 1999 when I moved in with my, then, girlfriend and lost a place to restore old iron.   :p  Connecting to the positive battery terminal would simplify my life considerably, and if the fuse box is near the battery, I would likely have an easy way into the passenger compartment.  

As for my likely Amp draw (Approx #'s): 
CPAP = .35 - 1.0 Amps
12V electric fan, like the "Fan-Tastic" = Low/1.0 - High/3.0 Amps
12V LED reading lights (1 or 2 of them) = .175 - .26 Amps

If I add up those numbers using the higher numbers (= 4.26), then multiply by 8 hrs, I get 38.24 Ah.  
That would be about 35% of the 92Ah AGM I'm looking at.  But this would not be a daily occurrence.  At most it would be weekends and the occasional 3 or 4 day trip.  If I were full-timing it, I'd be in trouble because my commute to work would be 0 miles.

As for drive/charging times.  I'm not living in the van, I just use it for weekend getaways to go kayaking or camping, and I tend to drive 2 - 4 1/2 hrs one-way.

Edit: I forgot to mention the trailer option.  I don't want to be slowed down by pulling a trailer, and I don't have a place to keep it when not in use.  
Eventually I hope to get one of these.  http://www.amazon.com/Thule-897XT-H...TF8&qid=1437178832&sr=8-2&keywords=hullivator
It makes getting the kayak off the roof easier and would allow me to move it out of the way of the sunlight when stationary.
 

Optimistic Paranoid

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BigT said:
That would be about 35% of the 92Ah AGM I'm looking at.  But this would not be a daily occurrence.  At most it would be weekends and the occasional 3 or 4 day trip.  If I were full-timing it, I'd be in trouble because my commute to work would be 0 miles.

As for drive/charging times.  I'm not living in the van, I just use it for weekend getaways to go kayaking or camping, and I tend to drive 2 - 4 1/2 hrs one-way.

Well, it sounds to me like you're going to arrive at your campsite with a fully charged house battery.  Then, while you're parked, you will be totally dependent on the solar panels to replace the 40 ah you use every night.  If the panel is putting out 10 amps in bright sun, it should easily cover that.  You will not be able to park under trees for shade, of course, and ideally you will need to park so the kayak doesn't shade the panels if you don't take it down as soon as you get there.

The only real problem is if you use 40 ah at night and wake up to a miserable, rainy day with no sun.  Another night of pulling 40 ah out of a 92 ah battery is going to leave you with a SERIOUSLY unhappy battery.  Wouldn't surprise me if the cpap stopped working before dawn on that second night. You would really have to plan to go for a long drive on a day like that, rather than sitting there in the rain reading a good book and contemplating the whichness of why.  If you had a bigger battery bank, you wouldn't have to do that.

If you pay attention to the weather forecasts and only go when conditions will be favorable, should be no problem.

Either way, the alternator should bring the battery back to near full charge on the drive home, and if it sits out in the sun for a week, it will be fully topped up by the next weekend trip.

Regards
John
 

SternWake

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For the record, I usually recommend to hook right to the alternator (+) as it is, usually, a much shorter circuit path.

Also when one hooks to the engine battery, one is relying on the original alternator to battery circuit path to carry the current for the house battery.

The manufacturer does not use a healthy amount of copper here, and bypassing this original circuit not only eliminates the OEM charging circuit, but it might also allow the voltage regulator to allow higher voltages be held for longer, which speeds up battery charging.

Much more amps can flow at 14.5 as opposed to 13.7v on a battery in the 65%+ state of charge range.

So if one is relying on maximum alternator contributions to house battery, taking power right from the alt(+) can be significantly more effective than from the the Engine battery(+).


I just wired up a system for my friend's truck. On the (+) cable from alternator, to the engine battery (+), there was a fuse right on the battery terminal.  I believe this fuse might have blown had I hooked the Aux battery directly to the starter battery, as this OEM cable would then have to carry all the current.

The depleted Lifeline AGM initially took somewhere north of 100 amps, at Idle, over 2awg, and amps did taper to about 86, due to alternator heat.  The Lifeline AGM  battery voltage indicated it could not have been limiting the amps yet.

You can certainly take power from Engine battery.  Most sources will say to take power here.

If you look at a wiring diagram, hooking it right to the ALT(+) is basically the same thing, just a much shorter circuit path with the benefit of possibly allowing the voltage regulator to hold higher voltages for longer.

How much difference there will be is highly platform specific. 


This shorter circuit path makes the alternator work harder
It will wear out quicker.  My alternator, at this moment, is basically toast. I believe the Stator has a short.  It is either that or a bearing.  it is making a loud whirring sound, which I assumed was a bearing, but when I removed the belt and spun the  pulley, it seemed fine.  

I can replace mine in under 15 minutes, and Kragen Autoparts sold me a lifetime warranty for 5$  back in 2006.  Oreilly's is going to honor that warranty, surprisingly.

But it is going to be a few more days until it arrives.  I am going to disconnect the field wires. If the noise goes away, it is the Stator, if it continues it is a bearing.

I am researching options for a more durable alternator.  The remanufactured alternators are not confidence inspiring, at least for an '89.

Don't let this stop you from utilizing the alternator. 
 If the alternator is 1000$ to replace , then I'd have second thoughts on pushing an alternator so hard via a short thick copper path to a depleted AGM battery.  That is not my situation, so I will whip my alternator to an early demise, as replacement is a mere fraction of the price of my battery(s).

If this is a worry, run some 8awg from the engine battery, instead of 2awg or 4awg right from alternator to house battery.  Better for the alternator, worse for the battery, worse for appliances relying on battery  to run the next night, especially during bad weather.

Everything is a compromise.
 

BigT

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Having my alternator fail in the middle of nowhere is something I'd like to avoid, or at least mitigate the chances of,  if possible.  
Would running a 300 Watt panel to 2, 92Ah AGM batteries help?  Or how about a single, higher Ah AGM hooked to a 300W panel?  
There's very limited space in my tiny van, but I supposed I could cram a pair of batteries under the bed if I had to.  
I was also thinking maybe I could figure out a way to hinge the panel so the right side isn't under the boat during drive times.  

It looks like a 250 Amp high output alternator runs around $550 - $600.  A refurbished 150 Amp unit is about $200.  
It looks like stock/OEM is 150 Amps.
 

BigT

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Here's another idea:  What if I was able to reduce my nightly power consumption to around 3-5 Ah instead of 38?  That would be by running the CPAP alone (.35 - .50A) and getting a rechargeable 12V fan that I could charge up while driving and run in the evening on its own power.  As for lights, I'm happy to use my trusty old LED head-lamps that I've been using while camping for years.  

If I absolutely had to have the 12V "Fan-Tastic" running, I could always set it to Low (8 Ah per 8 hr. night) and increase my draw to 13 Ah/12% a night.  

Given the numbers you guys have quoted me, that should give me 2 or 3 nights of use without sufficient sunlight hitting my 190W panel and 92 Ah AGM, right? 
(I'm still willing to get the 300W panel and a 100 +/- Ah AGM if necessary) 

The yellow part of the tape measure (i.e.. not including the orange case) is 39" wide.  That's the width of the 300 Watt panel.  
The 190 Watt panel is 7" narrower and wouldn't have the same shadowing issues from the kayak.  
That said, however, I have come up with a pretty simple way to hinge and tilt the 30 Watt panel so the right side can be lifted above the kayak's shadow if necessary, so its still an option if the 190 isn't going to "cut it", even with the reduced comsumption.
 
(This photo was taken facing 180 degrees due-south at 1:39 PM).  

 

SternWake

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My alternator started making warning noises many months ago at very high loads, and the noise disappeared when the battery was quenched and not greedily asking for everything the alternator could make.  It still is charging, I just do not trust it.


Mine is a 50/120 chrysler alternator, 50 amps at Idle supposedly, 120amps maximum at higher rpm.

My engine Idles at only 525 rpm, and maximum current when hot at idle is about 32 amps.

Not being sure when the warranty replacement will arrive, I am going to disconnect the field wires and just not drive and charge.  Not today, which is actually raining in SanDiego( only getting 1.5 solar amps at 3:30 pm)  but driving in sun, I believe my solar could run the engine electrics.

I believe my Van requires about 8 to 11 amps to run the electrics( fuel pump and ignition), so I could in theory drive several hours just on battery power.  With a Dashbord voltmeter, any non charging incidents would be overwhelmingly obvious.  Stranding is unlikely.

I've been using between 30 and 45AH nightly from my NS AGM, and with 200 watts of solar, making it to 'full' charge daily via solar only, but this slower charge rate is not making my NS AGM happy.  I am 35Ah from full as I type due to thick clouds from Tropical Storm Deloris., at 12.2v under a 3.5 amp load.  I forgot to plug in yesterday morning and last night it was obvious to me that this AGM is craving a high amp recharge.



About the Kayak and the Roof rack, can you widen the cross bars?
Can you put the Kayak on its side for a narrower footprint?
How about raising the panel to be higher and have storage under it.

How about having a frame to hold the panel high enough that the kayak can go underneath?

Do you know how the roof rack feet are connected to the body/ substructure?

In the early 90's, I used to have a NissanPathfinder whose roof rack I did not trust to not rip out of the roof at highway speeds with 2 large surfboards up top.  I used to run a ratcheting canvas strap over the boards and through the back doors as a fail safe.

Really, with alternator recharging and 200 watts of Solar, you should get a respectable lifespan from the Northstar AGM.  You can spend a lot more Money for 'Ideal', money which could just be spent on a new battery instead when the first one fails.  if you keep an eye on the Voltmeter throughout many discharge and recharge cycles, you will not be surprised when the battery performance begins to fade.

It is unlikely to fail without notice, as long as you keep an eye on a voltmeter and it falls within your expectations from previous observations over many cycles.

Far too many people are surprised when their relatively new battery 'no longer takes a charge', but they neither knew they were chronically undercharging the battery, that chronic undercharging is bad for the battery, and that a hail mary once the battery is heavily sulfated is by far too little too late.  Usually they malign the battery manufacturer, when the reason for its failure is in the mirror.

Your posts indicate this will not be you.

I do recommend you get a simple Wattmeter like this:
 http://www.amazon.com/gp/product/B0...d_t=201&pf_rd_p=1944687582&pf_rd_i=B00C1BZSYO

And plumb it inline to your house fuse block, so you can see how much AH and WH you are using.

These are not perfectly accurate and can only count current flowing in one direction, but as far as learning tools go, it is very good and very affordable.

That specific link above, is, of the 3 watt meters I have bought of this design, the most accurate and will read very light currents that the other 2 miss.

I use 45 amp anderson Powerpole connectors, and can plug this inline on any single device to measure current consumption.
 

BigT

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Wow, that's a lot of things to reply to.

- I just bought wider crossbars a few weeks ago ($100).  They're 66" wide.  The ones before them were 48".  That's about all I can fit without having them stick out too far and possibly hit things.  

- Yes, I can mount the kayak on "J-Racks" that place the boat on its side, but that's not really necessary if I keep the 190 Amp panel, as it doesn't get shadowed like the wider, 300 Amp unit would.  http://www.amazon.com/SportRack-ABR...qid=1437269007&sr=1-7&keywords=yakima+j+racks

- As for raising the panel higher...  It would have to be adjustable like the hinge/tilting design I'm currently brainstorming due to a low beam in my carport.  
As it is, I have barely 2" of clearance above the crossbars.  
I'd be afraid to mount the panel high enough for the kayak to fit under it.  That would put the panel up so high it would surely catch the wind and act like a wing on top of the van.

- The towers, or "feet" as you call them, are attached via factory hard-points/bolts in the roof, so it's not going anywhere.  Still, I don't have vertical room for raising anything.  I have to back out of my carport before loading the kayak on the roof.  

What effect, if any, will plugging the AGM into the alternator have on the voltage regulator, and maybe even the charge controller?  
I should also ask the Ford dealer what it will do to my warranty.  

Here's a question I've been meaning to ask, and I'm sure has been asked a million times before:  Since the Northstar AGM boasts having a huge amount of CCA, suggesting that it could be used as a starting battery, what would happen if I replaced the stock battery under my hood with the Northstar (if it would even fit) and plugged my solar into it?  Keeping in mind that I'm not planning to run anything seriously energy-sucking in the van (CPAP, fan, LED reading light, and maybe charging a laptop).  Could the AGM pull double-duty as a starting battery and aux battery under my planned light conditions?  

One of the reasons I chose the tiny Transit Connect was for it's amazing fuel economy (27mpg/highway) that makes long distance driving for fun something I don't have to plan for or worry about the cost of.  That means I'd have no problem driving more to keep the battery charged via the alternator.  

I get the feeling it's not that simple, though, or more people would be doing it.  

Here's something fun to think about:  "I would avoid equalization. The 15+ volts may damage your electronics (such as car/engine computers even if key off). And, if you disconnect your battery for manual recharge/equalize--Your engine computer will usually lose its emissions parameters--In California, you cannot pass a smog test if some (or all) of the self tests are not "pass" state (which may take 50 to several hundred miles to "pass" in normal driving)."
 

SternWake

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The Northstars (and Odyssey) do have very high CCA figures.  CCA figures are more applicable to an older carb'd engine as the test was for 30 seconds of engine cranking.


Modern fuel injected engines start so easily and quickly, that Odyssey, Northstar and lifeline have a 'pulse' cranking amps which is of much shorter duration and a much higher number rating.  My 930CCA Northstar can crank my engine over violently fast.  Faster than 2 group 27 marine batteries( at 650CCA each) in parallel for 1300CCA could. It is rather impressive, but kind of meaningless as I use it.  Higher CCA figures can relate to ability to still crank the engine even when seriously depleted, say to the same level of discharge where an equal capacity flooded battery could not still crank the engine.

As I type, my Northstar AGm27 is both my engine starting battery and house battery.  My previous Flooded battery lived out its useful cycle life a month or so Ago, and finances, and my ability to plug in to the grid have had me delay replacement.  Also the Flooded battery I desire, a Trojan T-1275 is too tall to fit in my intended location and I have not completed modifications to accept it.

Many AGMs are dual purpose batteries, due to low internal resistance they have High CCA figures, and when recharged properly and fully, can also give good deep cycle service.  But recharging properly is the Key. Ideally, that is high amperage applied initially for long enough for voltage to rise to 14.4 to 14.7v, and hold that voltage for long enough for amps to taper to 0.5A per 100AH of capacity. Some AGMs like Optima red top are said to be for starting only, and Lifeline AGM are built primarily around deep cycle longevity, so there is some cross over.

You could get away with putting the NorthStar under the hood, assuming it will fit, and get by having no Auxiliary battery set up and run a wire from or two from charge controller to engine battery.  Then I would recommend carrying a fully charged jumper pack just in case you drain it too far, and do not have  to wait for the solar to replenish enough to start the engine.  The physically small Lithium jumper packs are quite capable at assisting a weak battery to start an engine and  are dropping in price.  Do not equate this engine starting ability with high capacity though.  One of them could charge a smart phone 3 to 4 times only.

http://www.amazon.com/s/ref=nb_sb_n...+jumper+packs&rh=i:aps,k:lithium+jumper+packs

Another option some prefer is an Automatic disconnect which disconnects all loads from the batteries once voltage drops too low.  These do consume some current to operate.  I've not really researched all of the offerings.  It is not an option that appeals to me.

Having multiple charging sources running at the same time is no problem.  Sometimes they will work together, and usually as battery nears full charge, one or the other charging source stops and allows the other to continue. It Depends on the absorption voltage setting on each of the charging sources.  If I set my solar charge controller absorption voltage higher than 14.9v, then in sufficient sunlight, my engine electrics are running  partially or mostly from the Solar.  I still need to test how much it actually requires electrically, just to run the engine.

There is no issue with an AGM in the engine compartment instead of a flooded battery.  The only possible issues with AGM, is when they are depleted, due to their lower internal resistance, they can overtask the alternator, but this is very platform specific with many other contributing factors. If your current engine battery is still newish, then this is a less appealing option unless you can get OK  money for it.  Batteries have shelf lives so having a battery sitting around doing nothing does not stop it from aging and losing capacity, even if hooked to a maintenance charger.  that only slows the aging.

Heat is a big killer of batteries, so an underhood battery will age faster than one located away from underhood engine heat. Also a hot battery needs lower charging voltages.  Ideal charging is hard to achieve and batteries are pretty durable considering the wide temperatures and wide charging voltages they are subjected to in all sorts of different operating climates.

Heck,  Northstar says 14.46 is ideal absorption voltage at 77F. My vehicles voltage regulator goes as high as 14.9v.  It will be 2 years old in November and still exceeds rated capacity in my 50% discharge tests, and I mostly use it as the engine starting battery, so every time I drive it gets brought up to and held at 14.9v for a good portion of all drive time.

You can certainly run just a single group27 Northstar battery as both House and Starting battery, but you have less safety buffer.  My chosen method, usually is to have one flooded deep cycle battery to cycle the piss out of, and keep the other battery 100% charged at all times.  When I get my Trojan T-1275, the Northstar will go back to primarily engine starting duties, its capacity and abilities, mostly unused, but there to be called upon if required.

I think if you can park facing Due west, the Kayak shadowing will only be an issue in early morning or late afternoon in summertime, when there is not much harvest anyway.

You've got a good grasp on this.  There is no one right way to accomplish it.  Monitor your overnight usage, know how much you have to use, how much you can use, and the expected weather and whether the Solar will have a chance to hold the Northstar battery at 14.46 for ~4 hours and if cycling it nightly for a week straight, hold 14.46v for 6 hours instead of 4.

When you get that older bluetopped Northstar battery, it will not be rip roaring ready to cycle.   A 50% discharge followed by a 25 amp minimum recharge and hold 14.46 until amps taper to 0.45a should allow the resting open circuit voltage to go above 13 volts and the battery to have its full remaining capacity available.  Do you have access to a 25 amp charger?

Mine holds 13.06v for weeks, but would not hold that voltage until 50% discharged and high amp recharged. And it requires this every so often too, which is why I keep pushing for you to allow the alternator to quench it when most depleted.

I am impressed with my Northstar battery, but only because i can feed it properly.  I would not get it as a Solar only recharge battery.  The T-1275 battery I desire will be mostly solar recharged, and my Solar cannot meet trojan's 10 to 13% recommendation either( 15 to 19.5 amps), but since I can blast it with alternator amps, or 40 amps from my power supply, and can equalize it whenever Specific gravity does not respond properly to a normal full recharge, I know I can get excellent service from it as it is also one of the Few true deep cycle 12v batteries that has plates as thick as a golf cart battery.

In theory I could just do the same with My AGM, but I often do not drive for several days in a row, and I take pride not having to plug into the grid.
 

jimindenver

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We haven't plugged in while camping in three years and that isn't going to change just because we got the AGM's. I'll be able to separate each battery out if needed for high amp charging or conditioning. Normally they will have such a shallow cycle that it wont make much difference. The system provides for most all loads in the daytime and we just don't use much at night.

If any of you are near Denver and need some crimping done, let me know. I finally got to test my 16 ton crimping tool on a 1/0 lug and the welding wire. It made short work of it and that lug is NOT coming off. It will do considerably larger wire as the die for 1/0 is the #50 and I have dies going up to #240. I'll make the inter connects between the 8-D's tomorrow but will have to restrain myself from hooking up the inverter and playing. My only means of recharging is the solar and it wont be sunny again till Tuesday.
 

Seraphim

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Were it me, I'd 1) run the alternator wire, 2) get a larger storage battery and 3) probably go for the 300 watt panel, as well. The extra battery capacity will hold you over in stormy weather. All of our vehicles have charged the house battery off the alternator with no problem. An isolator to protect the truck battery from draining would be nice. And with the alternator charging, you'd only have to worry about the panel being shaded when parked. Just park accordingly, or pull off the kayak. With those little extras, you won't have to worry about conservation, and may find you can do other little things like charge a phone or laptop during the afternoon, without interfering with the house battery being charged.
 

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