Charge controller

[Nikia]

I'm in the process of fitting a 100w solar panel & SE300 wind generator (rated at max 300w).
Batteries = 2 x 220amp domestic
1 x 85amp engine start

Which charge controller would you recommend?

Thanks in advance for helpful advice, (not counting telling me not to get a wind generator)

 

[William_H]

Charge controllers (regulators come in 3 basic types. The simple one switches charge off (disconnect) when the battery reaches voltage ie about 14v then switches on again when the battery voltage falls below that. this switching can be quite fast. It has the advantage that the transistor switching charge is either off or on so dissipates very little power. So they are cheap.
The second type has the sloar and wind gens connected to the battery direct. A transistor circuit senses the battery voltage and begins to conduct (bypass) current as voltage approaches 14v. The transistor itself might dissipate the power or more commonly it switches in a resistor to dissipate the power. Being linear varying between on and off a fair bit of power is wasted in the transistor (only when battery is fully charged) so requires larger more robust transistor and heat sink.

The last type is known as MPPT type. (Max Power Point Tracking) It takes whatever voltage the source might be from solar between 20 volts and perhaps 10v and possibly similar from wind gen and converts it by switch mode and transformer to exactly 14v. It in effect decides the optimum voltage to suck from the panel to give max power. It can give more current into the battery than panel actually produces by reducing (transforming the higher voltage). There are power losses however with perhaps 92% efficency.
Just to explain a solar panel apears electrically to have a 20v source in series with an internal resistor of in your case about 4 ohms. So if you draw a lot of current from the panel the internal resistance causes the panel voltage to fall. Hence try to draw 6 amps from your panel and voltage will fall to 10 volts so power is only 60w. If you draw only 3 amps then voltage will be 20v but again power will be only 60w. If however we draw 5 amps and voltage falls just a little to say 18volts we get 90w. So for any amount of sunlight there is an optimum current and voltage to give max power. Hence max power point tracking.
By contrast if you connect a panel straight to a battery then the voltage of the panel is dictated by the battery voltage. In other words the current flow pulls the panel voltage down to around 13v (battery voltage) and the current into the battery is max the panel can provide while maintaining that voltage. This simple arangement works Ok for small panels and big batteries but witha big panel it can charge the battery fully but having 20 volts available can continue to charge the battery at an only slightly reduced current until the battery is cooked. (Boiled dry).
With any controller then it needs to limit the voltage presented to the battery of around 14v so that as the battery inherent voltage approaches 14v the voltage difference means less current into the battery.
With many of the controllers available now the charge voltage is increased at first to get max volt difference hence max current into battery then is reduced to a float voltage to maintain a small charge current only when battery is judged fully charged. Often called smart charging the same principal is used for mains battery chargers or altenrator controllers. No I can,t tell you what to buy. I would imagine most controllers could handle the 2 inputs at once at the max total current but do check. good luck olewill

 

[VicS]

I'm in the process of fitting a 100w solar panel & SE300 wind generator (rated at max 300w).
Batteries = 2 x 220amp domestic
1 x 85amp engine start

Which charge controller would you recommend?

Thanks in advance for helpful advice, (not counting telling me not to get a wind generator)

Your choice of regulator will be influenced by what type is suitable for the SE 300. It is too large for the Marlec HRDi and HRSi regulators and AFAIK it will need a dump type of regulator anyway.

I may be that you will need to fit separate controllers for the wind turbine and solar panel. That at least will give you the opportunity of choosing between an MPPT or PWM regulator for the solar panel.

I'd start by looking at the regulators recommended/offered by LE for the SE 300. If they offer one which can combine it with a solar panel all well and good otherwise go the separate regulator route.

 

[noelex]

The regulation is a bit more complex than presented above.

Normally it is a multistage affair. Rather than maintaining exactly 14v. It will rise to absorption setting voltage (typically about 14.6v) hold this voltage for the absorption time (typically about 1.5 hours) then drop to the float voltage (typically about13.6v).
(They may also have a equalising step)

MPPT controllers and simpler PWM controllers do this in the same way (cheaper models tend to be less adjustable). So both types will get the batteries to 100% given enough power. MPPT is just extracts slightly more power from the panel.
Simple on/off regulators are available at the very cheap end of the scale, avoid these.

Now onto the question.
It is generally much better to have separate controllers for wind and solar. The requirements for the two types of regulation are different. Don't try and use a solar controller for wind. Some combined controllers are available but they are expensive for what you get and you loose redundancy.

For the solar panel I would go with one of the Genasun controllers, or the Rogue if you anticipate adding more solar later.
Wind generators are harder as they are more specific for the individual generator so I will leave those recommendation to others.

 

[Nikia]

I'd start by looking at the regulators recommended/offered by LE for the SE 300. If they offer one which can combine it with a solar panel all well and good otherwise go the separate regulator route.

Thanks for all the advice. The LE300 comes with a dump coil regulator, but I thought it may be more efficient to manage both through a smart controller. It seems that keeping them seperate is the way to go.
Thanks again,
Brian