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12V Charge controller help  RSS feed

 
Bernie Granier
Posts: 7
Location: Duval County, Texas
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I have a 12V setup that I'm having issues with charge controllers.  The setup is a 10W solar panel (oversized for the system as many of these end up in areas with very limited sunlight) and a pair of 9ah 6v batteries connected in series to become 12v.  I'm using the 6v batteries because of space requirements in the box that I'm using.  My constant load on the system is very low, less than 100ma, to power a cellular relay.  When the relay is activated, the load will go to 5A for 750ms as the relay activates a motor and then back to the low usage again.  These boxes are used to close the doors on wild hog traps.

The issue I'm having is finding a decent charge controller for this setup that has realistic power cut out and resume levels.  The setup will work reliably down to 9v and I've tried a couple of different controllers that are supposed to cut out at 10.5v but seem to be cutting out closer to 11.7v.  Some of these won't resume power to the load until they reach 12.6v, which may not happen for a few days in some locations and not at all for others.  Does anyone have a suggestion for a good charge controller that will actually cut out at 10 - 10.5 volts (or better yet is adjustable) and will resume power again at 10 - 10.5 volts as well?

I appreciate any help or input anyone can provide!
 
Steve Farmer
Posts: 401
Location: South Tenerife, Canary Islands (Spain)
3
forest garden greening the desert trees
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seems like you are not needing to deep discharge or fast charge these batteries. So instead of a charge cutting in and out, consider a trickle charger that provides a constant voltage.
If these are lead acid batteries then an appropriate trickle charge for the batteries in series might be 13V. If they are Li Ion / Li Poly then maybe 13.6V.

Be careful with charging lithium batteries, they should be charged inside a fireproof enclosure and the charging circuitry should have a temperature sensor. In the absence of this be sure they are somewhere that if they do ignite, there won't be any serious consequences.
 
Bernie Granier
Posts: 7
Location: Duval County, Texas
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Steve, the issue with a trickle charger is that some of these end up in mountainous areas with heavy canopy where they only get filtered sunlight at best, and then maybe only a few hours of that.   In those situations, I know the battery will eventually die but, I want to be able to make the most of the little bit of sunlight that does occur.

My biggest issue is that what I've been using cuts the power to the load too soon and wants too much voltage before it'll power it again.  As a stop gap, I've been connecting the load directly to the battery but there are drawbacks there.  Once power gets below 9v, the motor won't turn and below 6v, the relay starts to have problems.  I don't really care if it damages the battery with a deep discharge but, I don't want the relay damaged by long term undervoltage.  If the battery is too low, the power on the board will flicker when the panel starts charging and it often causes the relay to chatter, this is what I wpuld like to avoid.   The relay boards aren't super expensive but, they're not cheap enough to be considered disposable either.

I'm using sealed lead acid batteries, btw.
 
Steve Farmer
Posts: 401
Location: South Tenerife, Canary Islands (Spain)
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forest garden greening the desert trees
 
Matt Walker
Posts: 261
Location: North Olympic Peninsula
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Bernie, my opinion is that you would be far better served tackling it from the angle of trying to keep the voltage up rather than trying to make everything in the system work with voltage that it is designed to treat as a threat.

I would recommend more battery capacity as the simplest solution.  Can you find bigger batteries, or just double the size of the bank with two more 9aH and a Series/Parallel scheme?  Good luck.
 
Bernie Granier
Posts: 7
Location: Duval County, Texas
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Matt,

Some of them have had larger batteries connected and that is a solution that works in some cases but isn't always an option.  When additional or larger batteries are used, they have to be mounted somewhere external to the system, there isn't room for anything larger in the box that it all goes in or on many of the doors that the box is used with.  With no sun at all, these batteries will power the system for 2 to 3 weeks, depending on the quality of the cell signal.  In most cases, that's more than long enough to trap the pigs you're targeting, after which you'd be moving it somewhere else and could either replace or recharge the batteries.

With the charge controllers I've tried though, that time is reduced to a week or less sometimes if the signal isn't strong and/or there isn't much sun, even though the batteries could go longer.  
 
frank li
Posts: 209
Location: Michigan
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I would use the controller that suits the build. A lot of cheap to mid priced controllers do not even have load control and if the ones you are looking at do, then you can wire the trap mechanicals and such directly to the battery. If they do not have lvd, you could add one from automation direct or some other. Ill look for an adjustable lvd.
 
Bernie Granier
Posts: 7
Location: Duval County, Texas
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I hadn't thought about a separate low voltage disconnect, that would solve my problem.  Thank you!
 
Bernie Granier
Posts: 7
Location: Duval County, Texas
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I got a couple of these - http://www.ebay.com/itm/171557580106?_trksid=p2057872.m2749.l2649&var=470567204991&ssPageName=STRK%3AMEBIDX%3AIT and am trying them out.  They'll let you set the disconnect and reconnect voltage but, I'm not sure what the power consumption of the charge controller is yet.  They showed up earlier this week and I set one up on a test system to see how it'll perform.

I've also ordered a couple of LVD's to compare with.

Thanks for the help!
 
frank li
Posts: 209
Location: Michigan
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Yeah Bernie!
Thats the control that i referred to as having amazing features for the money. I have seen it or clones under Sunyoba, Tracer and several other names and it is near impossible to differentiate unless somebody has a them side by side in hand to compare.

I have not ordered any of those but i would like to get a few to have on hand. Maybe you could post a review? I know i always like to see people do the breakdown on what a product is made of and an explaination of the project and how it worked or didnt work.

The spec i am finding way down the page is less than .15mA (edit: also i assumed they meant .15a) I assume the spec at the highest battery voltage just in case. 1.8-3w max while operating load control is not too bad for inexpensive components, but it could be high for some micro systems, for sure. If you could measure its actual daily consumption, that would be interesting.

Here is a decent review that i found. I wouldnt worry about his claims of being ripped off for it not being mppt. I dont know how to tell other than observing it operate. A good indicator is if it will operate in low light.

Even if this control is not mppt, it would make no difference to actual value. It is an amazing bundle of features for twenty dollars.

It would be cool to see pics of your machine.

 

 
Bernie Granier
Posts: 7
Location: Duval County, Texas
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I haven't taken one apart but, I doubt it's an MPPT controller, it seems a little to cheap to be one to me.

This is the setup I'm building - 
    Keeping it powered reliably with batteries that will fit in the box has been the biggest challenge.
 
frank li
Posts: 209
Location: Michigan
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I tried the link and got 404 from google and a strange mix when cut and pasted to youtube.
 
Bernie Granier
Posts: 7
Location: Duval County, Texas
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I guess the forum was doing something weird with the URL.  I fixed the link.
 
frank li
Posts: 209
Location: Michigan
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Sometimes you can oversive the panel and limit the control to the max charging current that the battery is designed for and even though you will refuse some peak power, charging in low light and short duration sun will have a better effect. So you are only limited by budget and diminishing returns for an application and not module or battery current spec... to a point. Plus alot of 10w modules are as costly as some 100w panels.

If diminishing returns is an issue, i.e. battery is just too small for reliable operation as designed to be used, then a battery up-fit should go along with. Either lifepo4 for more power density than lead acid, but only in non freezing outdoor temps. If you have freezing temps, i would add another battery box and some leak tite cord grip/strain relief connectors, 1/2" watertite flex conduit or out door chase nipples for the wire to pass back and forth pass between the cases. Pvc electrical enclosures are tough enough and cheap. Project boxes for electronics are pricer but nice. This woul leave room inside the original case for half of the total battery or other additional electronics.

A logging meter(s) between the electronics and battery would tell alot.
 
frank li
Posts: 209
Location: Michigan
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It does sound like if your tact is to allow the battery to be a high wear item, then the most cost effective solution is the cheapest little shrink-wrapped, coin size charge controller for signage and such with the original 10w module and the lvd not used at all, with the trap and communications load tied seperately to the battery instead of through the controller terminals would be effective and cheap, while meeting your goal of extending un-attended operation to the maximum and battery replacement to minimum without downtime or losing a catch.

I did a trick... i re-read the thread!
 
Glen Apollo
Posts: 3
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Hi, I'm new to this forum. I'm trying to sort out a inexpensive pwm 30A controller issue, my first time using solar. My setup will be 2 150w 18v panels in parallel charging 2 batteries in parallel to start. The batteries are AcDelco DC31's.
This setup will be used at a remote RC field to recharge lipo batteries via 12V smart chargers. The duty cycle of discharge vs charge time will be weekends used, not used weekdays pretty much.

It will also power a 12V link trasmitter that reports wx conditions and battery voltage. 2 A on transmitt and .5A idle when the suns up, .1 amp when the suns down at night.

As demand gets more, more solar panels will be added as well as an upgraded controller and added batteries. For now this is a prof of consent project to generate interest and donations.

So my issue, my bench setup. I'm ising a 12v@18A sealed battery. Not having the solar panels to use for a bench test I've tried usung a 20A 20v power supply or 2 3cell lipo packs in series. The condition I get is both the battery charge output and the 12v user port, both climb to 15-6v and then pulse up to 20v.
This in turn make a very dirty and too high of a 12v DC source across the sealed battery.
The controller led's showing panel, charge, and output ate all lit up.

In doing a search I'm reading that one should never use a substitute for the panel input. I also read where one should never connect power to the panel input without first having the 12v battery connected. Sadly, I've done both now. Accepting that I may have damaged the controller, I've ordered another one and brand under $20 to try again. This time by the book!
What would help is info on these pwm controllers as to what the 12v buss output should be like. I would expect it to not pulse to 20v or test at 15-16? Especially the managed output 12v port?
14.2v range yes, but not 15-16v and dirty pulsing 20v spikes?

If I've presented my setup and outcome ok, I'm hoping someone can tell me this isn't normal and I've simply trashed the controller with my bench testing? That or I'll have to spend above $100 for a better option.
Low voltage load cutoff is going to be a separate device and it will kill via a 120A 12v relay, any external container  RC battery charging by users. I will also have the option of controlling this relay from anywhere via my smart phone once a clean 12-14v battery buss is solved. The link transmitter can also receive commands. More on that once this is solved.
Thanks
 
frank li
Posts: 209
Location: Michigan
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Glen Apollo wrote:Hi, I'm new to this forum. I'm trying to sort out a inexpensive pwm 30A controller issue, my first time using solar. My setup will be 2 150w 18v panels in parallel charging 2 batteries in parallel to start. The batteries are AcDelco DC31's.
This setup will be used at a remote RC field to recharge lipo batteries via 12V smart chargers. The duty cycle of discharge vs charge time will be weekends used, not used weekdays pretty much.

It will also power a 12V link trasmitter that reports wx conditions and battery voltage. 2 A on transmitt and .5A idle when the suns up, .1 amp when the suns down at night.

As demand gets more, more solar panels will be added as well as an upgraded controller and added batteries. For now this is a prof of consent project to generate interest and donations.

So my issue, my bench setup. I'm ising a 12v@18A sealed battery. Not having the solar panels to use for a bench test I've tried usung a 20A 20v power supply or 2 3cell lipo packs in series. The condition I get is both the battery charge output and the 12v user port, both climb to 15-6v and then pulse up to 20v.
This in turn make a very dirty and too high of a 12v DC source across the sealed battery.
The controller led's showing panel, charge, and output ate all lit up.

In doing a search I'm reading that one should never use a substitute for the panel input. I also read where one should never connect power to the panel input without first having the 12v battery connected. Sadly, I've done both now. Accepting that I may have damaged the controller, I've ordered another one and brand under $20 to try again. This time by the book!
What would help is info on these pwm controllers as to what the 12v buss output should be like. I would expect it to not pulse to 20v or test at 15-16? Especially the managed output 12v port?
14.2v range yes, but not 15-16v and dirty pulsing 20v spikes?

If I've presented my setup and outcome ok, I'm hoping someone can tell me this isn't normal and I've simply trashed the controller with my bench testing? That or I'll have to spend above $100 for a better option.
Low voltage load cutoff is going to be a separate device and it will kill via a 120A 12v relay, any external container  RC battery charging by users. I will also have the option of controlling this relay from anywhere via my smart phone once a clean 12-14v battery buss is solved. The link transmitter can also receive commands. More on that once this is solved.
Thanks


Usually, as long as the voltage is within range limits, a controller will just handle it. The controller (most) pulses power to manipulate conditions and provide regulation. Also i have heard rejection noise when batteries are full and there is no load.

I wouldnt expect spikes unless the control is damaged, input is incompatible or a battery is damaged, ? Dunno on that one.

I have run solar charge controllers on automotive type battery chargers for years as a cheap backup for small projects, to smarten the charger and care for batteries, i just switch the input.

Controllers are pretty tolerant and hearty. A good power supply should do well as long as it is set within range limits.

 
Glen Apollo
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Thanks for the reply. What I've found out with testing. Using a pwm controller setup for 12v, the solar panels want to be in the 18-20v unloaded range. Yes, this type of controller dios pulse the charging buss with pulses up to the 18-20v level when charging a battery that's low voltage.
These pulses are ok for many lighting and motor/pump requirements, but not for sensitive electronics.
I am going to try another $20 brand pwm controller just to verify mine isn't defective.
My work around I'm trying with the controller I have is to use a buck/boost regulator set to 12v out. It can make 12v at 5A from voltages ranging from 5v to over 24v. It's output buss seems to be clean and stable and not bothered by the pulsing 12-20v battery buss.
There are higher current rated buck boost on eBay.
For my use 5A is good for $5 as I'm only drawing .5A full time and every 3 min, 2.5A total for 10 seconds.
There is a waste of stored power with all this  m but that'll be reduced in a future design once it proves the concept. Probably more solar panels. I have a free source of damaged but fully functional panels that a swap outs, and a 40ft container roof to install them on.
I'll post as it progresses, my success and final solutions. Got to think positive ha ha.
Thanks again.

 
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