Rectifier diode question

[The Danes Are Coming]

I am trying to make sure that my solar panel will charge my batteries when in storage and and main battery switches are in OFF position.

An RVer with knowledge about how I should connect things, kindly drew me a very simple diagram of what I need.

The only component I needed to go and get was a 10 amp diode so I went to Radioshack for this. Well - Radioshack don't sell a 10 amp diode. What they do sell is a 6 amp rectifier diode.

Question 1:
A rectifier diode (as I understand it) gets 12V AC in at the anode side and delivers 12V DC out at the katode side (not taking any voltage drop into consideration). What happens in a rectifier diode if I feed 12V DC in on the anode side? Do I still get 12V DC out on the other side?

Question 2:
I read on the Internet that if I parallel connect 2 diodes (2 no 6 amp in order to get the minimum 10 amp that I need) I am at risk that one of the diodes remains inactive, but that it is possible to do if the 2 diodes are EXACTLY the same.

I don't know if this is of any relevance but my solar panel is supposedly putting out only about 3 amps.

[rcoleman]

A diode also known as a rectifier only allows voltage to flow from the negative (cathode) to the positive side (anode). It can serve multiple functions. In AC circuits we most commonly use rectifiers to convert AC to DC . In DC circuits we use them to control voltage flow.

Your solar panel supplies DC voltage already, so there is no need to rectify. The purpose of the diode is keep voltage from flowing backwards from the battery to the panel.

You could use two diodes in parallel but if it were mine I'd wait (OH NO) for the special order 10 amp diode to arrive.

[bigskymt]

Solar panel output is DC Voltage, no need to rectify it. DC voltage into a rectifier remains DC voltage. I simply connected the + side from the solar controller to the battery side of the isolator (battery disconnect).
My solar controller has a diode built in that protects against draw from the panels when they are not producing current.

[The Danes Are Coming]

Thank you for your reply.

Quote:

Originally Posted by bigskymt My solar controller has a diode built in that protects against draw from the panels when they are not producing current.

My controller has also got a built in diode but here is why I need to add 2 more:

My solar system at present feeds only the house batteries and in this situation the build-in diode is all I need. Since we shortly is going into storage for may be an extended period of time I also want my chassis batteries trickle charged.

I now take the positive outlet from the controller panel and split it into 2. One side of the split goes to house batteries and the other to the chassis batteries. Each of the splits now gets a 10 amp diode in order to prevent hose- and chassis batteries feeding off each other.

Does this sound like a good plan?

[bigskymt]

Sounds like it would work with one diode on each leg. You may consider an in-line fuse for each leg also. In the case of a problem on one load you will only lose that leg and still keep output to the other.
So you have one 45 watt panel?

[wa8yxm]

I have heard it said that electricity and water are a lot alike.. A rectifier diode is a one way or "Check Valve" for electricity.

I do not know what Radio Shack carries these days but if they have a 15 amp or such,, It will work in place of a 10 amp.

When I need parts I try to find where "Joe's Television Repair" shops.. They still have a wide assortment of parts at that place

(NOTE: Joe's is generic for any TV repair shop)

THey still make diodes with ratings high enough to blow your mind (Hundred amps for example)

YOu just got to know where to find them, and pay for them.

[The Danes Are Coming]

Quote:

Originally Posted by bigskymt So you have one 45 watt panel?

Yes - I believe I do.

Would the in-line fuse be same size as the diode or would it be smaller?

Quote:

Originally Posted by wa8yxm I do not know what Radio Shack carries these days but if they have a 15 amp or such,, It will work in place of a 10 amp.

Biggest straight forward diode they had was a 3 amp which was definitely less than I was looking for.

[bigskymt]

You would want a fuse smaller then the output fuse on your controller so that leg will open before the main does, thus preserving the other leg.
Digi-key or Newark online are excellent sources for components.
A T10-60L (10amp) axial diode for example is probably less then $1 but you'd have to pay shipping and probably a minimum charge.

[Wetboy5776]

No offense...all these are workable ideas, but you are REALLY complicating things here. Do keep in mind, that the controller charging a battery still needs a voltage reference. So, which battery will tell the controller that it is "full?" When it does, the other battery will be done charging too. That will result in one undercharging, or the other overcharging. This is unless your controller has dual outputs for two different batteries, in which case you will not need any of this, as the diodes will be built into the controller.

To be honest, save some time & money and go get a $15 10 watt trickle charging panel you can leave on your dash. Then park facing south. Separate the two systems. As they have vastly different capacities and charging profiles, you will need to separate them to keep the larger pack charged.

If you are intent on going your route, then know that diodes can be hooked together to add up to the amps needed. I once needed an 8 amp diode, and found it was cheaper just twisting 10 1 amp diodes together for a total of 10 amps capacity. They were like 50 cents each. Just make sure they are all twisted together on the same side...Anode to Anode, for example.

Also, keep in mind that diodes suffer from voltage drop...so whatever the output from the controller, it will be less at the battery. If the output is low enough, the diodes may very well "eat up" any trickle charge coming thru.

To be honest, if all you have is a 45 watt panel, your batteries will not drain back into your panel at night. Esp if it is going thru a controller. Forget the diode idea, and just get a small trickle charger at Harbor Freight or Wal-Mart and point it as directly toward the winter sun as you can. That should keep your Chassis battery charged thru the winter. Any excess charge will just be dissipated as heat. Also, unplug the battery leads unless you REALLY need to keep those radio station presets. No need to have that additional drain.

Much easier.

[The Danes Are Coming]

WOW - I am now confused at a much higher level than I was previously.

I thought that I had found a simple, cheap and workable idea and now I am not sure any longer.

BTW - I have checked Harbor Freight's and Walmart's web page and I can't find a 10 Watt solar panel/trickle charger for little money. Harbor Freight has a 15W panel for $80 and this will require a control panel to be bought separately.

For about $80 I could replace my existing charge controller and get one that will charge both battery banks in a "professional way" - no "Do It Yourself" methods.

I tell you - it's hard to be an "electronic dummy". Maybe I should just bite the bullet and do things right the first time.

[TXiceman]

Try Alltex Electronics in Houston. They are NW of downtown out Hwy 290, close to the Beltway 8, Sam Houston toll road.

Ken

[hardy1000]

Quote:

Originally Posted by The Danes Are Coming WOW - I am now confused at a much higher level than I was previously. I thought that I had found a simple, cheap and workable idea and now I am not sure any longer. BTW - I have checked Harbor Freight's and Walmart's web page and I can't find a 10 Watt solar panel/trickle charger for little money. Harbor Freight has a 15W panel for $80 and this will require a control panel to be bought separately. For about $80 I could replace my existing charge controller and get one that will charge both battery banks in a "professional way" - no "Do It Yourself" methods. I tell you - it's hard to be an "electronic dummy". Maybe I should just bite the bullet and do things right the first time.

Most large chain auto part stores sell small solar systems for about $75. I just saw a small system at Sears in the auto part section. Depending on the type solar controller you use some allow you to add a module that would allow you to also charge the chassis batterys. Do you use a Blue Sky controller? just a shot, but if you do you can run a 2 amp charge to your chassis battery's.

Blue Sky Energy Inc. | Solar Boost 2512i & 2512iX

The SB2512iX module allows you to add a 2 amp charge to your chassis batterys.

Take a look at your existing controller and see if it has an aux for additional battery charging.

[The Danes Are Coming]

Quote:

Originally Posted by hardy1000 Take a look at your existing controller and see if it has an aux for additional battery charging.

I currently have Morningstar's Sunsaver 20 and there are unfortunately just 1 outlet for 1 battery(bank).

The Sunsaver duo have got 2 outlets for 2 battery(bank)s. If I am to spend $80 I will most likely go this route.

[Wetboy5776]

Quote:

Originally Posted by The Danes Are Coming WOW - I am now confused at a much higher level than I was previously. I thought that I had found a simple, cheap and workable idea and now I am not sure any longer. BTW - I have checked Harbor Freight's and Walmart's web page and I can't find a 10 Watt solar panel/trickle charger for little money. Harbor Freight has a 15W panel for $80 and this will require a control panel to be bought separately. For about $80 I could replace my existing charge controller and get one that will charge both battery banks in a "professional way" - no "Do It Yourself" methods. I tell you - it's hard to be an "electronic dummy". Maybe I should just bite the bullet and do things right the first time.

If you are going to be storing your vehicle every year, then it may be worth it to get a dual output charge controller, but I really don;t think you need to. My 15 watt panel suggestion was actually overkill, dunno what I was thinking. A 5-7 watt panel is plenty as long as its well positioned into the sun.

I found plenty of cheap panels online. Check wal-mart and Harbor Freight again for a smaller panel that puts out from 2-7 watts or so. Here is one for about $20. Grip on Tools Solar Powered Battery Trickle Charger 12V 5 Watt

Just google solar trickle charger and sort by price. A panel that puts 1-3 amp hours a day into your battery will be plenty, esp. if you disconnect the terminals so the computer and radio don't draw on it over the winter. Also, at that rate you will not require any kind of controller. Just clip it to your battery, run the wire into cab, place the panel in a south facing position (possibly propped up so it's straight into Winter sun). Close the hood and you are done!

As a plus, these are handy for charging your cell or netbook battery when your picnicking or away from your coach.