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Topic: solar charger controller (Read 1091 times) previous topic - next topic

solar charger controller

     Has anyone had to replace a solar charger controller?  I am replacing my house batteries and found the 12v wire to the controller burned next to the unit.  Could anyone reccomend a replacement brand and source?  Any help would be appreciated.  BTW I purchased 8D Lifelines from Centex in Bastrop, TX for $535. each, FOB. 
    The owner delivered the batteries to the State park in Bastrop.
Laurel Hill, FL
 To do is to be---- Nietzsche
  To be is to do-----Kant
  Do be do be do----Sinatra

Re: solar charger controller

Reply #1 –
This answer might open up a fluid discussion, but, I have to ask, why do you need a controller?
What size are your panels? How many watts, total?
If you only have one panel and you boon dock, you will use what the panel will give and not have the reduced voltage that the regulator eats up.  The battery bank is big enough to absorb anything the panels give without overheating or overcharging.
I believe all panels (reputable) today have diodes to keep them from discharging or affecting the other cells, therefore, my question. ::)
Michael Baldacchino
'97 40' U320

Re: solar charger controller

Reply #2 –
     Does anyone else have an opinion on not using a controller on  solar panels?
Laurel Hill, FL
 To do is to be---- Nietzsche
  To be is to do-----Kant
  Do be do be do----Sinatra

Re: solar charger controller

Reply #3 –
Can a solar panel work without a controller (another name for voltage regulator)-- sure.  Can it overcharge and ruin the batteries if run without a controller-- sure.

Same can be said for your alternator and converter or inverter/charger. 

As long as the voltage supplied to the batteries is not excessive, you don't need any control on them.

In the real world, we try to spec alternators, converters AND solar panels to take care of our anticipated 12 VDC needs.

If the solar panel is small enough that it won't overcharge the batteries, no controller is needed.

The risk is yours.  Personally, I would size the solar panel(s) such that they would supply my needs under less than ideal conditions.  Which means that under ideal conditions they would overcharge the batteries.  Therefore, I would fit a controller.

Brett Wolfe
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: solar charger controller

Reply #4 –
I run about 180W combined on the roof of mine (4 old panels), and use a Blue Sky 25IX MPPT controller.
The Blue Sky is a nice 'medium size' controller (up to 25 amps - perfect for most RVs) and includes a second bank trickle charge option if desired. 25 amps gives you about a 350 watt limit on panels It replaced an old original RV-30 that went south on me and was actually overcharging the my new MKs at the time to 16 plus volts.
 
If you are running any significant wattage, multiple panel, or the newer higher voltage 'grid tie' style panels then you should have a controller - and it should be an MPPT controller.
 
Northern Arizona Wind and Sun is a great website with tons of information.
http://store.solar-electric.com/chco.html
 
Panel prices have dropped about 30% - they used to run 5 bucks a watt, on average. They are now down to about 3 bucks a watt - and if you are claiming your RV or boat as a home/second home there are federal (and some state) writeoffs and rebates (including install costs!) you should look into.
 
Kyocera still makes some nice 12V panels. I'm partial to them, Suntech and Mitsubishi. You can easily put together a 15-20 amp system with 2 panels and a decent controller for $1000-1200.00.
 
Quote
On 8/22/2010 9:11 AM, Jerry Steele wrote: 
Does anyone else have an opinion on not using a controller on solar panels?
 1998 U-320, 36 WTFE #5261 1999 Toyota Tacoma
Laurel Hill, FL
 
The selected media item is not currently available. Dave Head & Megan Westbrook
Titusville, FL - The Great Outdoors
'98 270 buying this month
Toad is a 2018 F150 XLT

Re: solar charger controller

Reply #5 –
     Thanks!  You guys are a great source for information.  You make owning a Foretravel fun.
Laurel Hill, FL
 To do is to be---- Nietzsche
  To be is to do-----Kant
  Do be do be do----Sinatra

Re: solar charger controller

Reply #6 –
Solar panels can be manufactured with a lower volt output of about 15 volts under load, that do not require a solar controller.  These are called Self-regulating and do not work as well in less than ideal conditions.
 
Many solar panels have an open voltage rating of 21 volts, and a load voltage rating of 17 volts.  I think that a solar regulator is a good value to keep fully charged batteries in control.  Keep in mind that solar panels come in many amp-hour sizes and often multiple panels are connected together in parallel, so their amps output in high sun can easily exceed 25 amps.
 
I one has a small amp size or few panels, they may be able to connect panels directly to battery bank.  Usually the large battery bank cannot be easily damaged in this case.
 
Solar panels electricity flow is into batteries when sun is shining on them, and from batteries when sun is not shinning, like at night.  Diodes may be prevent this reverse flow, but diodes lower voltage output, so often relays are used in a controller to prevent back flow from battery.  This is another benefit of a solar controller.
 
A popular type of solar controller called MPPT, maximum point power tracking, can actually increase the amps from solar panels in certain conditions.  This basically comes about when solar output is 17 volts and battery only needs 14 volts for charging, so the MPPT controller converts the extra 3 volts into increased amps.
 
Controllers may be optional, but not for our situation.  We have 4 panels with a MPPT controller.  Also controller may have a digital display for volts and amps to better manage the resource.

Re: solar charger controller

Reply #7 –
I know they aren't very high quality, but Harbor Freight has a three panel, 45 watt panel package with 25 amp controller for just $149.00 with the coupon from HiWays magazine. They aren't very powerful but that's a very low price. I have had mine for over a year with no problems so far.
The selected media item is not currently available.Kent Speers
Locust Grove, OK
1993 U300 SSE 40' (Restored at FOT 2009) Build 4323
720 watts Solar
6V92TA DDEC Silver Engine
2014 Subaru Outback

Re: solar charger controller

Reply #8 –
You didn't give us much info to work with on this.
How many watts of panels are YOU running?
I take it that YOU are only charging two 8D batteries, correct?
Are you boondocking on a regular basis and depending on solar for ALL of your power or do you supplement?
Wire sizes for the panels to the regulator?
Distance from panels to regulator?
Distance from regulator to batteries?
Alternative charging sources, i.e. Windpower, portable genny, etc...
Are you familiar with the RV2025 from Bogart Engineering?
Regards,
JON TWORK KB8RSA
Full Time RVer (10+ Years) & Dedicated Boondocker
Retired, Unemployed, Homeless Transients
1996 Foretravel U270-36 w/24' Timberwolf Trailer
I firmly believe that tomorrow holds the possibility for new technologies, astounding discoveries, and a reprieve from my remaining obligations.
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