solar panel trickle charging battery - will it blow up ....?

[noelex]

Similar design is the key part - Depends on the panel.

http://uk.farnell.com/raloss/sr5-36/solar-panel-5w/dp/1462491 - This one is 17.

The panel has a Vmp of 17v and a Voc of 21.6v. This is high enough to cause damage to a lead acid battery, even after applying some temperature compensation.

In this case it is only 5w, which in UK conditions is not likely to cause problems to a house bank, but it is the low wattage (and low insolation in the UK) rather than the slightly lower than typical voltages for a 36 cell panel, that allows for the relatively safe operation without a regulator.

Don't try this with a larger panel that has these voltages.

 

[ghostlymoron]

Look at this on eBay http://www.ebay.co.uk/itm/201656088156QUOTE=RichardS;6003040]So if I buy a simple 5W trickle charger panel for £15, you think it makes sense to buy a controller for another £20?

Richard[/QUOTE]

 

[RichardS]

Look at this on eBay http://www.ebay.co.uk/itm/201656088156QUOTE=RichardS;6003040]So if I buy a simple 5W trickle charger panel for £15, you think it makes sense to buy a controller for another £20?

Richard

That's strange. GM's post is the same as my post #12 and his link is to an eBay product in my name ....... and GM now signs off as "Richard".

Richard

 

[VicS]

That's strange. GM's post is the same as my post #12 and his link is to an eBay product in my name ....... and GM now signs off as "Richard".

Richard

He certainly made a cock-up of that post but its not too difficult to unravel the link which ITYWF should be to this £7 controller:

http://www.ebay.co.uk/sch/i.html?_o...X201656088156.TRS0&_nkw=201656088156&_sacat=0

 

[RichardS]

He certainly made a cock-up of that post but its not too difficult to unravel the link which ITYWF should be to this £7 controller:

http://www.ebay.co.uk/sch/i.html?_o...X201656088156.TRS0&_nkw=201656088156&_sacat=0

If that is the correct eBay product I'm not sure why GM is quoting me as it was Kelpie who introduced the £20 criterion.

Richard

 

[noelex]

If you are going to use a charge regulator, check it is not one of the very cheapest on/off or so called "bang bang" regulators. These not only extract much less power, but also don't help maintain the battery well.

The best cheap solar regulators are PWM.

 

[PaulRainbow]

Hmm, 26 posts so far, without knowing anything whatsoever about the OPs setup

Have "solar power" threads become the new "anchor thread"

 

[PaulRainbow]

Personally, i wouldn't have a cheap controller anywhere near my boat. Even forgetting the cost of my panels, i wouldn't want to chance £400 worth of batteries to a cheap Ebay controller.

 

[ghostlymoron]

I've never spent more than a tenner on a regulator. The first ,12 years ago, was a simple on/off type and worked quite satisfactorily for several years and was still going strong when I sold the boat as was the battery. Since then I've used PWM type as the price fell. These have also performed well with no detriment to the batteries. However, my batteries don't cost £400.
Apologise for cocking up last post - it's not so easy to cut/paste etc on my phone with its small keypad.

 

[Cloona]

https://www.amazon.co.uk/Solar-Brie...71?s=telephone&ie=UTF8&qid=1488578514&sr=1-71

this is the thing - apologies for ignorance of electricity - watts amps etc

 

[PaulRainbow]

https://www.amazon.co.uk/Solar-Brie...71?s=telephone&ie=UTF8&qid=1488578514&sr=1-71

this is the thing - apologies for ignorance of electricity - watts amps etc

No need for a controller, unless it's charging a couple of AA batteries

 

[William_H]

The open circuit voltage of a panel is not a great concern. It does however mean that the panel will push current into the battery up to that voltage. ie even if the battery got to 18 volts it would still have the same current pushed in hence the risk of battery boiling or being damaged. However that current will only be approx watts of panel divided by 20. So a 10w panel can only, but will continue to push in .5 amp in full sun.
Will .5 amp continuous when in sunshine damage a battery ? Well maybe if it is a small battery. olewill