Solar panel regulators

[malcy]

I've been reading with interest A &N,s comments on the positioning of solar panel regulators when installing a panel. I'm not technically gifted with regards to electricity so I will gratefully accept any advice from a professional such as A&N but I am a bit confused. He states that the regulator should be situated as close to the battery as is practicable, but on all the stand alone ones I've seen it is fixed to the panel itself. Don't know if I've misunderstood what I've read but still confused all the same. Anyone with the knowledge or experience on this matter or indeed A&N himself, could you please enlighten me further. As I said at the beginning I am a bit thick as regards electricity so don't be hesitant if you feel you need to start from the basics.

 

 

 

[Ocsid]

In simple terms I hope:

Controllers are I expect plonked on the back of solar panels offered as a stand alone unit, because the maker can offer it as a working, wired up unit, all tested and complete.

It is technically a dreadful location as any decent controller features battery temperature compensation and the controller located there has not a clue what the temperature is at the battery. Plus, a side effect of a solar panel making electricity is it gets hot, thus a back mounted controller gets hot and backs off the charge voltage too readily.

Add to this the controller is not seeing the battery voltages as the interconnecting wire to the battery loses some voltage in transmitting the current to charge the battery. Thus it does not know what it should really be doing, and as said has no idea of the temperature compensation it needs at apply.

 

Located physically close to the battery the controller hopefully "feels" the temperatures the battery sits at. Also close the controller "sees" the true battery voltages, plus it can adjust for the voltage losses in the long wires from the panel.

 

By far best to locate the controller close to the battery, not to the panel.

[keninpalamos]

This is about voltage drop between the regulator and the battery in simple terms. So the closer the regulator to the battery the better. Also be aware that if the stand alone solar panel is to be used in conjunction with say a fitted solar system on your 'van it would make sense to by- pass the stand alone regulator on the panel and connect your panel to the input side of the regulator on your 'van. Hope that helps.

[malcy]

Apologies, I thought I had replied to you both yesterday but it seems on checking just now that it's out there in the ether somewhere or more likely my my legendary fat thumb syndrome has hit the wrong button. AGAIN.

So thanks for your replies which have made it a lot clearer for me to understand. It seems ,to me at least,that like a lot of things in life there is a 100% nailed on, best practice way,or the the often used more simple way without overly worrying about every aspect of the end product. I'm not advocating the simple way myself but it seems that's why these regulators are fitted as they are. So as I'm considering buying one myself, it's got to be up to me to decide. Hmmm??

Thanks again.

[747]

Your domestic 230 volts house supply is delivered from the Power Station at 33,000 volts and reduced locally to you. That is to overcome a large voltage drop over long distances

 

The solar panel output voltage is normally in the very high teens or low 20's. After the regulator, it is reduced to a max of around 14 volts (+ or -). The voltage drop is less at the higher voltage and that is why it is best practice to have the regulator closer to the battery.

[aandncaravan]

I would agree with all the above.

The point made about temperature compensation is a good one and often misunderstood by many.

 

It isn't just about lowering the charge rate when the temperature rises to protect the battery, but you can actually raise the charge rate, to higher than normal, when the battery is cold.

 

Ford used this to good effect in the Ford Ka which used a really antiquated engine that had it's roots in the 1970's. By the early 2000's the Kak was lagging way behind it's 16v rivals, so Ford adopted a number of 'Clever', low cost measures to allow them to claim greater fuel efficiency figures.

One of which was to use an 'undersized' Alternator (so drew less power from the engine and was cheaper to make). However, that strategy risked the battery sometimes not being fully charged on repeat short town runs which was the Ka's 'market'.

 

So to counteract this, they increased the Alternator charge rate to up near 16v when the battery was cold. Fast charging it, at the time it most needed it. Note this only applied to the latest 'new at the time' Silver Batteries Ford also fitted. Conventional batteries would, and did, have a very short life.

 

As soon as the 'battery warmed up', the Alternator dropped to 14.4v. On later versions, the Alternator charge dropped as low as 13.2v to save even more Fuel if the battery was fully charged.

 

It was probably more successful in markets like Norway but not quite so useful in Saudi Arabia?

 

 

So if a battery charger, Alternator/Solar/Mains/etc, has temperature compensation, then significantly faster charger can be achieved, especially so if you holiday in Norway.

 

The benefit to a Motorhome in Spain might be almost solely as battery protection.

 

 

Note : This little feature is used by some aftermarkets B2B manufacturers to inflate the charging rates of their products because they tend not to quote the 'average' improved charging figures but the absolute maximums.

So where a B2B might "charge an Icelandic Motorhome owners battery twice as fast", check out exactly the figures behind the claims.

 

Few are anything like the marketing claims in the real World unless the original manufacturers Installation is very poor.