what solar panel to use

[dwh]

Regulator is just another word for charge controller - like Americans say 'Motor Home' and English say 'Caravan'.

That charge controller in the link looks decent.

It's got temperature compensation, which is a feature found on better charge controllers.

And it's smart enough to NOT do equalization on AGM batteries.

Of course, a 30a charge controller is much larger than is needed for an 8a solar panel. If you don't plan to expand the system by adding more solar panels, you probably don't need an oversized charge controller.


I would imagine you could put together a comparable system for less if you buy components instead of a kit. Or find such a kit already available.

Here's one that uses top of the line components - Kyocera solar panel, Morningstar MPPT charge controller, Midnite Solar breaker box, etc.:

http://www.solar-electric.com/rvkitwi140wa1.html

 

[jkam]

what do you think of this kit? is the regulator that comes with it same as a solar charger? if it is a solar charger do you think it is efficient enough? been trying to call carmanah but very hard to get a hold of them, i will keep trying. the whole kit sell for about $700. http://www.gpelectric.com/products/new-145-watt-solar-charging-kit

i think the panel by itself sells about $600.

thanks

That controller is PWM, not MPPT and it makes a big enough difference that I would get an MPPT one. The Morningstar one is about the best one for small systems using under 15 amps.

As mentioned above, the kit uses better components and seems reasonably priced for what they give you.
#10 AGW isn't big enough in my opinion. I used #4 AGW on my system.
i think you could put a nicer system together on your own, you might spend a little more but you get exactly what you want.
Kyocera panels are good and Solar-Electric has a good reputation so you could find all you need there and they are very helpful if you need assistance.

 

[rideglobally]

http://www.morningstarcorp.com/en/support/library/SSMPPT_ENG10_111.pdf please help me understand this chart. The way I am reading it is that, it is most efficient at 75 watts 96.5%. Then it's efficiency begin to drops. Is this correct?

Then there is this write up on their website. I am considering the PMW charge controller.

http://www.morningstarcorp.com/en/support/library/MS.WP.MPPTvPWM.01.EN.pdf

PWM Over MPPT?
The preceding discussion of PWM vs. MPPT may cause some to wonder why a PWM controller
would ever be chosen in favor of an MPPT controller. There are indeed instances where a PWM
regulator is a better choice than MPPT and factors which will negate advantages the MPPT may provide.
The most obvious consideration is cost. MPPT controllers will cost more than their PWM counterparts.
When deciding on a controller, the extra cost of MPPT should be analyzed with respect to the following
factors.
Low power (specifically low current) charging applications may have equal or better energy
harvest with a PWM controller. PWM controllers will operate at a relatively constant harvesting
efficiency regardless of the size of the system (all things being equal, efficiency will be the same whether
using a 30W array or a 300W array). MPPT regulators commonly have noticeably reduced harvesting
efficiencies (relative to their peak efficiency) when used in low power applications. Efficiency curves for
every Morningstar MPPT controller are printed in their corresponding manuals and should be reviewed
when making a regulator decision

 

[dwh]

Among the solar engineering crowd (math freaks), it's been hashed over to death. The general consensus is that MPPT is nice, but the extra expense isn't usually worth it for a sub-200w solar setup.

MPPT controllers don't add anything - a 100w PV puts out 100w max no matter what (well...when they get really cold, sometimes they do put out a bit more than the rating, but they are usually hot, and when they are hot, they put out less than the rating). What they do is reduce the waste by loading the panel up to get the max watts that the panel can put out at the this particular moment. A nice hot 100w PV might only be putting out 80w, and with MPPT you might get that up to 85w or 90w.

The other thing they do is down-convert the voltage, to get the most efficient push into the battery. Sort of like the electrical version of down-shifting your tranny to get more torque.

Don't get too hung up on efficiency. A few watts one way or the other isn't going to mean squat.

Now, if you were going to run a couple of hundred (or couple of thousand) watts of PV, then yea, a 10% increase in watts to the battery would certainly be worth the extra money for an MPPT controller.

 

[rideglobally]

thanks dwh, i am thinking of running this kit plus another 95 watt panel for a total of 190 watt the two panels together. http://www.gpelectric.com/products/95-watt-solar-charging-kit using the charge controller that came with it, or the carmanah 145 watt kit. what do you think?.... thanks

 

[dwh]

Either one is fine. You can't have too much solar - you'll almost always end up using all you can get.

With mobile setups, the usual thing is to fit all you can. That determines your daily 'power budget'. Once you know that, you can then tailor your loads to fit within the budget.

With fixed setups, like an off-grid cabin, it goes the other way - you usually figure your loads first, then size the system to create a power budget to fit the loads.

 

[rideglobally]

decided - thanks

here is what i decided to go with. i will most likely be placing the order tomm.
Carmanah 145 watt most panel of this size i found are 140 watt, seem to be reputable and already use for RV application
http://www.gpelectric.com/products/145-watt-solar-module
Blue Sky Charge controller 2525IX i am told that this goes well with an enclosed battery AGM or GEL i also like the feature of charging the starting battery when the house battery is fully charge. it will also accept a second 145 watt solar panel if i find it necessary in the future
http://www.blueskyenergyinc.com/products/details/solar_boost_2512i/
Blue Sky IPN Remote probably not necessary but decided to go with it
http://www.blueskyenergyinc.com/products/details/ipn_remote/
Blue Sky battery temperature sensor i will be going in very hot location for sure
http://www.blueskyenergyinc.com/products/details/battery_temperature_sensor/

30 foot 10/2 UV rated wire. i wonder if this is the correct gage wire for this system.

let me know what you think, i will post the pictures when i begin the install. thanks for you help the ****** at the beginning of this forum was also very helpful.

next i will be needing your help on the inverter and battery charger.
thanks again:sombrero:

 

[dwh]

VERY nice setup!

The temp sensor is not just for hot locations - it will adjust the charging voltage to whatever the battery temp is. So it will crank up the voltage when the battery is cold, as well as crank it down when the battery is hot. Temp sensing is one of THE best things to have for long battery life.

#10 is fine as for the wire size from the PV module to the charge controller. It might be a little small from the charge controller to the battery though - unless you keep it short, like 3' or less between the charge controller and battery would be fine.


When you say battery charger - I'm assuming you mean a shore powered charger? One of these days, I plan to replace the old Shauer charger in my camper (but it works, so I don't fix it). If and when I finally get around to it, I'll be using a Samlex SEC-1215a which can do 1, 2 or 3 batteries (or banks).

If you do more than one though, you have to flip the dip switch to set it in 2-stage mode, but that's fine with me - I've usually got loads running while charging anyway, so 2-stage is better. After bulk stage, it drops to float and at float voltage on shore power, the batteries will still eventually absorb all they can - it'll just take a while longer.

http://samlexamerica.com/products/ProductDetail.aspx?pid=6



But it's perfect for bulking up my aux battery from my little generator - which I do all the time. I am a horrible battery abuser. I run my aux battery dead and then recharge off the generator a couple times a month. That's why I buy cheap batteries.

I had a no-name deep cycle that I bought for $45 from the Mexican battery shop (Battery Power) here in Los Angeles. I killed it in two years. I went to get another one, and I think the new guys working there saw me and decided to charge the "gringo" price - $85. I asked how the hell the price doubled in two years, and they played the ol' "no comprende" game. So I muttered a few choice curses in Spanish so they'd know that I knew the game they were playing, and left. No sale.

Just got a new (made 5/12) RV/marine from Auto Zone for $110 out the door. 115ah rating. It's got a one year free replacement, so maybe my abusive ways will kill it within the first year. After that, it's a pro-rate for 3 years so even if it lasts two years, I'll get another for 1/3 off.



As for inverters - if you've got less than 300w (600w surge) of loads, then I think it's probably impossible to beat the Morningstar SureSine.

For bigger loads...the Xantrex Prosine inverter/charger is good stuff.

 

[lostworldexpedition]

As usual Señor dwh proves to know his stuff. I wish i had contacted him when I was setting up my Landcruiser's electrical system.


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[lostworldexpedition]

Btw (and hopefully this isn't thread jacking as it is pertinent).
Dwh, what do you think of the c-Tek chargers? In specific the D250-S Dual, it seems like an interesting option... Sorry no link I am on the iPhone.


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[rideglobally]

Btw (and hopefully this isn't thread jacking as it is pertinent).
Dwh, what do you think of the c-Tek chargers? In specific the D250-S Dual, it seems like an interesting option... Sorry no link I am on the iPhone.


Sent from my iPhone using Tapatalk

definitely not hi jacking, it is the next thing that i am trying to figure out. stuff above is ordered i should be getting it next week.

i am now trying to figure out battery charger and an inverter. my battery is odyssey group 31 here is the link http://www.odysseybatteries.com/battery/pc2150sae.htm my understanding is that it will handle a 1000 watt inverter.

one of my question is should i get an inverter/battery charger combine or a separate?

dwh, i looked at your link on the inverter and i will be checking the combine inverter/charger that you are suggesting..... thanks

 

[dwh]

Btw (and hopefully this isn't thread jacking as it is pertinent).
Dwh, what do you think of the c-Tek chargers? In specific the D250-S Dual, it seems like an interesting option... Sorry no link I am on the iPhone.

I took a quick look at the manual months ago, and wrote quite a bit about that charger on another thread...um...the optima battery problems thread.

The docs are somewhat confusing...and it's been a while. But from what I remember...

Essentially, you hook it up so that whichever battery (or bank) is smaller, is charged from the alternator. That becomes the "primary" battery and gets charge priority over the "secondary" battery. Not so important on a truck where the cranking battery is almost always smaller than the aux battery, but could be important on a boat.


It's a 20a MPPT solar charge controller with temperature compensation that can do two batteries or banks. That REALLY rocks. Especially for under 300 bucks.

I had though that it was a DC-DC charger to do a proper mutli-stage charge on the secondary battery from the alternator side. Now...after sleeping on it. I'm not so sure.
(I know it can do a multi-stage from the solar to the secondary battery, I had thought it could also do a multi-stage from the primary battery to the secondary. Not sure though...could be wrong about that. It might just work like an isolator from the primary (alternator) side to the secondary side.)

It's got a desulphator. Of course, no one actually knows if desulphation does anything. (Except the manufacturers - they all claim their's works).



The Smartpass add-on...not so rockin...unless you needs its features, then it rocks. It adds two features:

1) It can take power from the secondary side to do (what looks to me like) a PWM float charge on the primary battery. Handy if you have an RV or boat with a shore powered charger on the aux side and you tend to spend lots of time hooked up to shore power.
2) It has a low-voltage disconnect from which non-critical loads can be fed (like a fridge). It can shut down the non-critical loads when the aux battery is low, to preserve some power available for critical loads like a two-way radio, or whatever.


There is a mention on their web site that the Smartpass kicks up the voltage from the primary to the secondary. That's not in the manual.

So here's my thinking now. The 250s does a multi-stage charge from the solar, but from battery to battery, it works like an isolator. The Smartpass, besides the other features, also adds the DC-DC charging feature, to do a proper multi-stage charge on the secondary from the primary side.

But again...the documentation sucks.


EDIT: Forgot the punchline...

The 250s/Smartpass looks to me like well-thought-out, good quality marine grade stuff. I think that rig was really designed with boats in mind, but it's good for trucks too.

If you are doing solar and just need a battery isolator to go with it, then you want the 250s. If not doing solar, and just want a DC-DC charger/isolator, then you want the Smartpass. If you want both a multi-stage solar charger, and a proper DC-DC charger, then you want both.

But they really should hire me to rewrite the bloody awful docs so people can understand what the gadget actually does.

 

[dwh]

i am now trying to figure out battery charger and an inverter. my battery is odyssey group 31 here is the link http://www.odysseybatteries.com/battery/pc2150sae.htm my understanding is that it will handle a 1000 watt inverter.

It can handle any size inverter. The problem is that the bigger the load, the less time the battery will supply it.

The main issue with hooking up inverters, is the wire size. Figure a 1000w inverter. Divide by 12 volts and you get an 83 amp load. That's a hefty load. If the inverter is rated for say 1000w continuous, and 1500w surge, then you have to size the wire (and fuse) to handle: 1500w / 12v = 125a.

If you've got a battery with say, 115ah capacity (like the one I just bought) it would run a 1000w load for around an hour before it would be totally dead. (Actually, according to Herr Peukert - it would be significantly less than an hour.)

So, for a big inverter, figure you'll need to run the engine to use it, unless you've got a big battery bank to feed it.

With the Morningstar SureSine - it's only rated for 300w continuous. It's also fully solid-state and has no fan to make noise or fail. But it ain't cheap and a 300w load is still 25a per hour being pulled from your battery.

The other issue with inverters, is PSW (Pure Sine Wave) or MSW (Modified Square Wave - though some marketroids will BS and say it means Modified Sine Wave. They lie.)

Anything will run fine from PSW - that's what the grid supplies.
Some things - not many, but a few - will have problems on MSW. Digital clocks might be off. Fan motors might hum a bit. A few - very VERY few - electronic circuit boards can be damaged by MSW.

I personally have a 200w MSW inverter and a 1000w MSW inverter. I used to use the little one for stuff like my laptop, but I got a 12v-19v lighter plug power supply for that, and haven't used the 200w in a couple of years. That and the 1000w stay in my spare parts box, just in case I need them. Not likely - I have a 1200w generator anyway. I much prefer to fire up the little 80cc generator to get 1200w than deal with a big inverter and have to run the 460 big block in the truck to power it.

My camper doesn't have a microwave or a/c, and I've now got pretty much everything running off of 12v except the battery charger - for that I have to use shore power or fire up the generator. I even have the 12v-18v "car charger" for the 18v Ryobi drill and flashlight that I carry in the truck (LOVE that flashlight).

one of my question is should i get an inverter/battery charger combine or a separate?

dwh, i looked at your link on the inverter and i will be checking the combine inverter/charger that you are suggesting..... thanks

Well, that link was to a charger - not an inverter or inverter/charger. I don't need an inverter, so that's the charger I'll be buying if I ever do decide to replace this antique that's in my truck now. I know I *should* do it...but I'm a project freak workaholic and I know it. Once I get started, I'll no doubt end up rewiring the whole damned truck. And I don't wanna.


If you don't need a bigassed inverter, then don't get one. If you do need one, and price is no object - then the Xantrex ProSine inverter/charger is the shiznitz.

If price is an issue, then a decent charger like the Samlex I linked to (goes for around 100 bucks) and any ol' inverter would be fine.

 

[GlennA]

I think you are using the wrong formula to determine current draw. The inverter is only supplying about 12.5A at 1500W. 1500w/120vac=about 12.5A. Or maybe I am mistaken!!


It can handle any size inverter. The problem is that the bigger the load, the less time the battery will supply it.

The main issue with hooking up inverters, is the wire size. Figure a 1000w inverter. Divide by 12 volts and you get an 83 amp load. That's a hefty load. If the inverter is rated for say 1000w continuous, and 1500w surge, then you have to size the wire (and fuse) to handle: 1500w / 12v = 125a.

 

[LandCruiserPhil]

1000w/1500w inverter

~8.3A/12.5A on the secondary output side of 120vac
~83A/125A on the primary input side of 12vdc