Solar panel

[30boat]

Only the very crudest controllers are quite that simple. Once you exceed the heady heights of a tenner on eBay, the controller is sensing the battery voltage and using that to decide what current to stick into it. If you put a diode in the way the controller will always overestimate the battery voltage by 0.7V, resulting in a heck of an undercharge. Precisely the same problem, of course, affects machine-sensed alternators when split charge diodes are used.

Stupid question.What if I use two regulators.one for each battery?

 

[JumbleDuck]

Stupid question.What if I use two regulators.one for each battery?

I think that feeding two regulators from one panel would be a bit iffy. I installed a cheapish dual-baterry regulator this year, and it seems to be working very well. I've set it up to send 90% of available charge to the house battery and 10% to the engine battery ... When either is, or becomes, fully charged the other gets full whack until it's full too. For another thirty quid I got a nice remote monitor which tells me what's going on with each battery and what the panels and regulator are doing. 178Ah supplied this trip! All from Photonic Universe in London, of whom I am just a happy customer ... One of my panels is from them, too - a nice semi-flexible, back contact 50W one.

 

[ghostlymoron]

I've bought to controllers recently. On/off was five quid, pmw was seven. Haven't bought a mppt as I don't think they're worth it unless you have a large array.

Only the very crudest controllers are quite that simple. Once you exceed the heady heights of a tenner on eBay, the controller is sensing the battery voltage and using that to decide what current to stick into it. If you put a diode in the way the controller will always overestimate the battery voltage by 0.7V, resulting in a heck of an undercharge. Precisely the same problem, of course, affects machine-sensed alternators when split charge diodes are used.

 

[Jaguar 25]

Kemo regulator instructions - do not use with other current sources????

This one is designed for two batteries and I have one fitted - So far so good

http://www.ebay.co.uk/itm/141107861...X:IT&_trksid=p3984.m1497.l2649#ht_2037wt_1190[/QUOTE]

Just fitted this regulator last week and noticed that you should not use it in conjunction with any other current source
To quote the exact wording from the instruction leaflet "Only 12v solar panels may be connected as current source, no chargers, power supplies, other batteries , windmills, etc."

I read this as meaning that you cannot have the engine alternator connected to the batteries or carry out a rechage using a battery charger (which I have already done).

Doesn't this make this regulator unsuitable for most boats or am I misinterpreting it?

 

[JumbleDuck]

I expect it means "only feed this regulator with solar panels", i.e. on the input side.

 

[30boat]

I expect it means "only feed this regulator with solar panels", i.e. on the input side.

Ahh that makeds sense!

 

[JumbleDuck]

Ahh that makeds sense!

I've finally done it!

 

[Jaguar 25]

I expect it means "only feed this regulator with solar panels", i.e. on the input side.

Thanks JumbeDuck, that makes sense.

 

[VicS]

This one is designed for two batteries and I have one fitted - So far so good

http://www.ebay.co.uk/itm/141107861...X:IT&_trksid=p3984.m1497.l2649#ht_2037wt_1190

Just fitted this regulator last week and noticed that you should not use it in conjunction with any other current source
To quote the exact wording from the instruction leaflet "Only 12v solar panels may be connected as current source, no chargers, power supplies, other batteries , windmills, etc."

I read this as meaning that you cannot have the engine alternator connected to the batteries or carry out a rechage using a battery charger (which I have already done).

Doesn't this make this regulator unsuitable for most boats or am I misinterpreting it?

As JD has deduced.

Because it is a simple on off device it can be used to control the output from solar panel but it cannot be used to control the output from an alternator , a windmill or any other ( inductive) device where interrupting the current flow would cause a voltage surge which might damage the controller or the source itself.

Alternators are of course regulated by controlling the field current, while wind generators are commonly ( but not without exception ) controlled by diverting the current to a ballast resistor to be dumped as heat.

Pretty much the same objections would apply to PWM controllers although the Rutland wind generators can be controlled by the Rutland PWM controllers.