looking for charge controller recommendations

[tater1337]

I have a 25W small panel and plan on using it for keeping a 7ah 12v battery (or two) charged to run a remote weather station (raspberry pi once I get the weather station part figured out)

I am also looking at getting one of those small 12v wind plants. the ones everyone tends to bash as being completely useless, then finally upgrade to something larger

this is for a house out in the country that I only visit once a month or so, so no POCO and no internet or other utilities

what kind of charge controller should i get? shopping around for spring.

are most charge controllers plug and play?

[SunEagle]

I am sorry to say. There really isn't any "plug and play" solar equipment. You have to know something about the technology or it will not work very long for you.

Just about anyone can recommend a charge controller but the question is, will you really be getting quality information from an open forum?

I encourage you to do some reading and research on off grid solar/battery systems and then check out what is available with the understanding that if it is cheap to buy it will not last long or is not what they advertise. Spend your money wisely only after you have learned what this technology can do for you.

[littleharbor]

For your low power needs The Morningstar SunSaver 6 is about the only small, quality controller that comes to mind.

[Sunking]

I have a 25W small panel and plan on using it for keeping a 7ah 12v battery (or two) charged to run a remote weather station (raspberry pi once I get the weather station part figured out)

Sounds like you are shooting yourself in the foot before you even get started. A raspberry pie pulls 10 watts @ 5 volts. That means you are going to have to use some DC power supply to drop 12 volt battery to 5 volts which uses power on top of the raspberry pie. Say the total is 12 watts draw. Even that conservative of an estimate means your project has a teeny weeny little bitty problem.

Assuming this weather station is ON all the time like most weather stations would mean you would consume 12 watts x 24 hours = 288 watt hours. Now here teeny weeny little bitty problem. At best the 25 watt solar panel you plan on using can only generate at very best in late June and July is 100 watt hours, and a 12 volt 7 AH battery only has 84 watt hours of capacity. What that means is your weather station will be dark and counted out with a dead battery on the second day of operation. Good luck with your plan. Here is roughly what it takes

Panel Wattage = 150 watts if you use a 15 amp MPPT Controller, or 225 watts using a 15 amp PWM controller. You plan on 25 watts.
12 volt Battery Capacity = 12 volts @ 125 AH. You plan on 7 AH.

All I can say is good job, goferit.

[tater1337]

Sounds like you are shooting yourself in the foot before you even get started. A raspberry pie pulls 10 watts @ 5 volts. That means you are going to have to use some DC power supply to drop 12 volt battery to 5 volts which uses power on top of the raspberry pie. Say the total is 12 watts draw. Even that conservative of an estimate means your project has a teeny weeny little bitty problem.

Assuming this weather station is ON all the time like most weather stations would mean you would consume 12 watts x 24 hours = 288 watt hours. Now here teeny weeny little bitty problem. At best the 25 watt solar panel you plan on using can only generate at very best in late June and July is 100 watt hours, and a 12 volt 7 AH battery only has 84 watt hours of capacity. What that means is your weather station will be dark and counted out with a dead battery on the second day of operation. Good luck with your plan. Here is roughly what it takes

Panel Wattage = 150 watts if you use a 15 amp MPPT Controller, or 225 watts using a 15 amp PWM controller. You plan on 25 watts.
12 volt Battery Capacity = 12 volts @ 125 AH. You plan on 7 AH.

All I can say is good job, goferit.

Woah, you need to look at specs again, your wattage is for recommended power supplies, not consump[tion rates.

https://raspi.tv/2018/how-much-power-does-raspberry-pi-3b-use-power-measurements

if I can get away with it, I'll be using a Pi zero https://raspi.tv/wp-content/uploads/...Pi-3B-plus.png

we'll go with the max power usage they list for it. 250ma(round up), 0.250a@5v is 1.25W* this means a 25 panel that gets 2h hours of sunlight a day (50Wh) should be plenty for the Pi running 24 hours (30Wh), and the battery should last for 67.2 hours

did I get my math wrong? buck converter for 12-5v conversion.

heck, using the B3 is only double that, which means a second panel and maybe a second battery, which might happen anyway. 25w panels are cheap

[tater1337]

I am sorry to say. There really isn't any "plug and play" solar equipment. You have to know something about the technology or it will not work very long for you.

Just about anyone can recommend a charge controller but the question is, will you really be getting quality information from an open forum?

I encourage you to do some reading and research on off grid solar/battery systems and then check out what is available with the understanding that if it is cheap to buy it will not last long or is not what they advertise. Spend your money wisely only after you have learned what this technology can do for you.

been reading for 20 years.

are you honestly telling me you cannot recommend a charge controller for a 25W panel and 7ah 12V battery with a load of 5V at .250ma?

and if an open forum is questionable, what makes you think anything else i read will be less questionable?

[tater1337]

Sounds like you are shooting yourself in the foot before you even get started. A raspberry pie pulls 10 watts @ 5 volts. That means you are going to have to use some DC power supply to drop 12 volt battery to 5 volts which uses power on top of the raspberry pie. Say the total is 12 watts draw. Even that conservative of an estimate means your project has a teeny weeny little bitty problem.

Assuming this weather station is ON all the time like most weather stations would mean you would consume 12 watts x 24 hours = 288 watt hours. Now here teeny weeny little bitty problem. At best the 25 watt solar panel you plan on using can only generate at very best in late June and July is 100 watt hours, and a 12 volt 7 AH battery only has 84 watt hours of capacity. What that means is your weather station will be dark and counted out with a dead battery on the second day of operation. Good luck with your plan. Here is roughly what it takes

Panel Wattage = 150 watts if you use a 15 amp MPPT Controller, or 225 watts using a 15 amp PWM controller. You plan on 25 watts.
12 volt Battery Capacity = 12 volts @ 125 AH. You plan on 7 AH.

All I can say is good job, goferit.

mods ate my other post, but it might show up

long story short, your load numbers are off, Pi uses 0.100A to 0.250A at 5V(0.5 to 1.25W), not 10 watts, that is power supply recommendation (I am betting surge current, which a battery would negate)

[Mike90250]

mods ate my other post, but it might show up......

Nope, posting too many links triggers the spam filter and the forum sw automatically mutes the post for a mod to approve. Your Welcome.

[littleharbor]

These are some pretty inexpensive charge controllers, granted, but they have dual USB outputs. Might not be what you'd want being your remote unattended site. Just another option which would also solve your 5 volt needs without adding more components. I'd buy two at their low price incase you need a quick replacement.

30 amp charge controller.jpg

[SunEagle]

been reading for 20 years.

are you honestly telling me you cannot recommend a charge controller for a 25W panel and 7ah 12V battery with a load of 5V at .250ma?

and if an open forum is questionable, what makes you think anything else i read will be less questionable?

Most people that ask for "plug and play" usually have no clue to what is needed to build a solar / battery system. If you have been reading for 20 years then you should have some clue as to which hardware will work for you and what is worth the money you spend on it.

As for recommendations, you can always go with something cheap and easy like what littleharbor shows or pay a little more and get a quality CC.

I hate to provide specific manufacturer make and model recommendations because I really do not know what a person wants to spend and how important it means to have quality hardware.

So what you get will really depends on how important and critical it is to you to keep your loads running and happy without destroying your battery and what you can afford to spend.

[J.P.M.]

and if an open forum is questionable, what makes you think anything else i read will be less questionable?

What makes you think it makes any sense to start with the premise that an open forum or other unvetted source has any credibility to begin with ?

Like everything else you're always read or been exposed to - of course it's questionable. The question is not whether the source is questionable - all are to some degree for reasons that may or may not be applicable depending on the situation. The question might be put rather as how (un)reliable does your common sense tell you the source is, or how much trust can you put in the source of the information ?

Try being a bit selective about the sources of your information, starting with traceability to who wrote what you're reading or hearing, and then not believing everything your see, read or hear.

Unvetted or non peer reviewed stuff that's becoming ubiquitous at what seems to be an increasing rate cannot necessarily be trusted.

[tater1337]

What makes you think it makes any sense to start with the premise that an open forum or other unvetted source has any credibility to begin with ?

Like everything else you're always read or been exposed to - of course it's questionable. The question is not whether the source is questionable - all are to some degree for reasons that may or may not be applicable depending on the situation. The question might be put rather as how (un)reliable does your common sense tell you the source is, or how much trust can you put in the source of the information ?

Try being a bit selective about the sources of your information, starting with traceability to who wrote what you're reading or hearing, and then not believing everything your see, read or hear.

Unvetted or non peer reviewed stuff that's becoming ubiquitous at what seems to be an increasing rate cannot necessarily be trusted.

I tend to do this anyway, but I am kind of amazed at the lack of providing information, or even opinions on this forum

which is sort of why I trust it.

also, I would assume some of the people here have the products I am looking for, and could give some opinions about the gear they have. just collecting information, and not expecting to have someone justify their opinions if I follow their recommendations and it doesn't work for me

[tater1337]

Most people that ask for "plug and play" usually have no clue to what is needed to build a solar / battery system. If you have been reading for 20 years then you should have some clue as to which hardware will work for you and what is worth the money you spend on it.

a bit, but things i ready 10 or even 5 years ago can have changed, and asking someone about practical experience they have with an item they owned would be useful

As for recommendations, you can always go with something cheap and easy like what littleharbor shows or pay a little more and get a quality CC.

ok, what the heck is "a quality CC"?

that is what I am asking. what is the current list of quality CC's available? gimme a start there and i'll do more research

[littleharbor]

For your small system There aren't many choices for a quality CC. I would refer you back to post #3.

[SunEagle]

a bit, but things i ready 10 or even 5 years ago can have changed, and asking someone about practical experience they have with an item they owned would be useful



ok, what the heck is "a quality CC"?

that is what I am asking. what is the current list of quality CC's available? gimme a start there and i'll do more research

A quality CC would be one made by Morningstar, Midnite, Outback, Xantrex, Schneider and some Tracer MPPT type to name a few. Any CC's that claims to be an MPPT and are cheap are also fake.

Most other low cost PWM type CC can be found just about anywhere but as they say you get what you pay for.