solar charge controller without the solar?
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changeip
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solar charge controller without the solar?

by changeip » Thu Nov 03, 2011 7:57 am

I have a site with 120v AC power but like to run on battery and use DC directly - both for power efficiency and to get longer run time when there is a power outage.

I have an ice cube relay working to transfer power from DC source 1 (12 or 24v power supply) to DC source 2 (battery). This transfers power without anything going down.

Can I replace this setup with a solar charge controller, but instead of using a PV i can use a 24v DC power supply? I would like the benefit of charging the batteries properly - as well as not running off the battery 24x7. I am wondering if there are charge controllers that will transfer from PV to battery without dropping the load.
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tgrand
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Re: solar charge controller without the solar?

by tgrand » Fri Nov 04, 2011 4:13 am

Use a smart charger to charge the battery banks.
On the load side use a Xantrex controller as a load controller to protect the batteries.
There are 2 point of views on the load controller and protection of batteries.

My view... Better to protect your investment in batteries, for the few minutes you'd get otherwise.

changeip
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Re: solar charge controller without the solar?

by changeip » Fri Nov 04, 2011 8:22 am

I have a smart charger now. I am running the load directly from the battery terminal (well, thru a dc-dc to 24v first). I would like to separate them.

I just bought a xantrex freedom sw 3000 today for my RV. I don't see what load controller they sell that you mention - can you point me in the right direction? Thanks!
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Re: solar charge controller without the solar?

by SurferTim » Sat Nov 05, 2011 1:54 pm

Take a look at this:
http://www.solar-electric.com/mosumpsochco.html
It will regulate any DC source from 16v to 75v.

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Re: solar charge controller without the solar?

by changeip » Sat Nov 05, 2011 11:26 pm

if i unplug the solar / dc power supply will it immediately serve up the load using the battery without it dropping?

also, i read on morningstars website to not use a DC power supply in place of a solar panel because of the capacitance that its expecting from the solar panel... otherwise i think this would work great. Anyone know how to make the DC power supply match what its expecting better?

Can I use a power source other than a PV panel to charge my batteries?

We do not recommend using a DC power supply with any of our controllers. While they appear to be similar to PV modules in function, DC power supplies have considerably more output capacitance. Connecting a DC power supply to our controllers may cause excessive heating and premature failure. AC powered battery chargers are a better alternative for systems requiring AC battery charging
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SurferTim
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Re: solar charge controller without the solar?

by SurferTim » Sun Nov 06, 2011 12:29 pm

@changeip: Thanks for that info. That is not what I was told. The Wind and Sun tech support said you can use that MPPT charger to charge a 12v battery from a 24v battery. What could have more "capacitance" than an 85AH lead acid battery?

This is from The Wind and Sun page on that charger:
This controller can also be used with almost any DC source, such as a power supply or higher voltage battery bank, where the max voltage is between 16 and 75 volts. It has built in current limiting*, so may be used to step down a 24 to 60 volt battery system to a 12 volt auxiliary battery for accessories. It is commonly used in tel-com sites to keep a smaller 12 volt battery system charged from a 24 or 36 volt system.

* According to Wind and Sun, this feature is what allows this particular model to perform this function. Without current limiting, I could see a problem with other than solar panels as a power supply.

They also gave me this warning: "Do not try this with any of the other solar chargers".

Edit: I use this feature to overload my charger/battery with solar panels. It is not the good days here that are the problem. If I were in Arizona or New Mexico, I would probably not have this problem. But here in Florida, just yards from the Gulf of Mexico, it can cloud up and rain for a week. Now my almost 20amps of solar panels produce about 5 amps in the overcast conditions, but the charge is still limited to 15 amps on the sunny days.

changeip
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Re: solar charge controller without the solar?

by changeip » Sun Nov 06, 2011 7:30 pm

cool, i might try one of those. Before i get one, can you tell me if you unplug the solar panels while everything is running transfer to the battery is seamless without drop?
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Re: solar charge controller without the solar?

by SurferTim » Sun Nov 06, 2011 8:30 pm

Of course! The sun "disconnects" the panels every evening, and "reconnects" them in the morning, and it is seamless. :D

The controller has three sets of connectors.
1) solar panel
2) battery
3) load

The battery and load terminals are connected by the Low Voltage Disconnect circuit. If the battery drops below about 10.5 volts, the load is disconnected until the battery reaches about 12v.

The solar panels are diode protected, so there is no reverse current flow through them. The only concern is the reverse voltage limit on those diodes. Insure the parallel power supply does not exceed that limit.

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Re: solar charge controller without the solar?

by jasong » Sun Nov 20, 2011 11:48 pm

I wouldnt mess around with the solar charger. Just buy a power supply / charger that is specifically built for what you want to do. The below link is for a 12/24 volt charger power supply that I use daily. it is rated at 4 amps and will auto change over to battery upon failure. There are also dry contacts for monitoring the status of the AC and battery if you want. Need more power, go to the larger supply.


http://www.altronix.com/index.php?pid=2 ... num=OLS120

SurferTim
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Re: solar charge controller without the solar?

by SurferTim » Sun Nov 27, 2011 1:03 pm

Thanks, normis. I didn't catch that. You can remove this also. :)
Last edited by SurferTim on Mon Nov 28, 2011 7:20 pm, edited 1 time in total.

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Re: solar charge controller without the solar?

by normis » Mon Nov 28, 2011 3:34 pm

SurferTim wrote:A little off topic, but...


It was spam, I deleted it
No answer to your question? How to write posts

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