Help With Solar Install

[quo vadis]

Needing some advice from our electrically minded members

i am in the process of installing a 200w solar kit to my boat, the wiring diagram shows I connect a battery in my case my starter battery to the central 2 terminals on the controller and connect my domestic battery (which is the one I need topping up while moored during the day) to the right hand 2 terminals indicated by a lamp.

so am I correct in assuming the 2 right hand terminals can be connected to a battery (not a lamp) and secondly will the controller charge the starter battery.

any help would be appreciated, user manual attached.

thanks in advance.

 

[grendel]

certainly with solar, the controller should be connected to the battery before plugging in the panel, surely if you want to charge your domestic battery, just use that as the battery to start with, the load (lamp) is just that a 12v output to run some lights and use power direct from the solar, it probably wont charge a battery if connected to it. to charge 2 battery banks you would need a charge controller with 2 charge outputs and a load

[quo vadis]

1 hour ago, grendel said:

certainly with solar, the controller should be connected to the battery before plugging in the panel, surely if you want to charge your domestic battery, just use that as the battery to start with, the load (lamp) is just that a 12v output to run some lights and use power direct from the solar, it probably wont charge a battery if connected to it. to charge 2 battery banks you would need a charge controller with 2 charge outputs and a load

Thanks Grendel but here’s where I don’t understand what would I want to charge during the day but not at night.

the fridge is the big item and it is connected to the domestic battery hence my call for help.

[grendel]

If you wanted to charge from the start battery at night, you would need a dc to dc charger, but that would flatten your start battery. It is the nature of solar panels to only charge during the day, they don't usually work at night.

[dom]

The diagram is for a PWM controller. These are generally inferior to MPPT controllers. It's worth considering upgrading, as MPPT units aren't expensive these days.

[quo vadis]

33 minutes ago, dom said:

The diagram is for a PWM controller. These are generally inferior to MPPT controllers. It's worth considering upgrading, as MPPT units aren't expensive these days.

Gone right over my head please explain

[gancanny]

what he is saying is they both do the same job only one does it better than the other, 

[gancanny]

on the setup you have at the present i would connect my domestic battery to the 2 central terminals and that will take care of your fridge

[Smoggy]

Domestic battery should not really need charging so just use the solar for your domstic battery.

I don't think pwm vs mppt makes a lot of odds on small solar setups, mppt makes a much bigger difference on higher voltage input panels so with just one panel stick with the controller you have.

[gancanny]

could you make your first sentence a little clearer smoggy, lol

[quo vadis]

Ok so I connect my domestic battery to the middle 2 terminals. What do I connect to the lamp output? 

[gancanny]

11 minutes ago, quo vadis said:

What do I connect to the lamp output?

nothing

[grendel]

You don't need to connect anything to the lamp circuit.

This is the charge controller for my  shed solar system,  basically its a 235W solar panel charging 4 110Ah batteries, then I have connected a 1kw inverter to power the tools, but you can just feed your fridge from the batteries.

[grendel]

I could have connected my inverter to the load,  but that would have limited what the inverter was supplied, basically, you can connect anything to the load, and it will just get battery voltage, but in practice  you are then limited by the size of your charging cables, so I run my heavy load (inverter, or in your case fridge) straight from the batteries.

[Smoggy]

45 minutes ago, gancanny said:

could you make your first sentence a little clearer smoggy, lol

Doh!

Starter battery should not need charging is what I meant but brain was still asleep.

[annv]

Hi Qui Connect the two contra terminals to the domestic battery this will provide currant during the day to offset fridge plus any other items you may switch on. This won't necessarily provide enough currant BUT! the fridge doesn't run all the time but the panel will provide currant all day. However if you want to maintain your starter battery all the year round you will need a battery maintainer wired to your domestic battery. A much better way is to get a MPPT controller that has two outlets. one for domestic and one for starter this will then charge/maintain all your battery's while moored up or not using the boat, this will increase the life of your batteries providing you moor outside. John

[quo vadis]

So domestic battery is supplying controller fridge is connected to lamp outlet. 

[quo vadis]

No fridge at night unless I moor under a light 

[dom]

3 hours ago, Smoggy said:

I don't think pwm vs mppt makes a lot of odds on small solar setups, mppt makes a much bigger difference on higher voltage input panels so with just one panel stick with the controller you have.

PWM connects the battery directly to the solar panel, which pulls the voltage down, resulting in much less efficient charging. A 100w panel connected to a moderately discharged battery will, in reality, reduce to something like 65w because of voltage drop. Even as the battery approaches fully charged, you'll still only get up to around 75w.

MPPT isolates the panel from the battery and uses microprocessor control to keep voltage tracking at an optimum level, giving more like 95% of the panel's potential.

In effect, if you fit PWM you're wasting 25-35% of the panel's potential. If anything, it's probably more of an issue on smaller systems, where there's less total charge capacity to exploit.

A Victron MPPT unit can be had for less than £50 these days and you can rely upon the fact it's unlikely to set your boat on fire. I personally wouldn't trust a cheap Chinese PWM unit on the latter point. I've seen more than one heavily charred unit before now.

[grendel]

in theory the load will stay live even after the solar stops generating, but it will be draining the battery. that charge controller looks very similar to the one i have installed on water rail with a 50W panel, that charges the start battery (basically just stops the bilge pump draining the battery while not connected to shore power and guarantees enough power to start the engine) the wires to the fridge may need to be a bit beefier (depending upon the fridge consumption)

these charge controllers are adequate for a cheap system, but as Dom mentions the MPPT controllers are a bit better (but still a lot of them are made cheaply in china anyway- (almost everything is made cheaply in china nowadays)).

I got mine from low energy supermarket- they do do kits that have the victron MPPT controllers, generally the price difference is about £60 or 1/3 more expensive- other than that their products seem pretty well thought through and work as they are supposed to.

you also have to be aware that victron also sell the PWM chargers in their lineup

[quo vadis]

Victron MPPT ordered 

[annv]

Hi Don't forget to connect a inline fuze for each pos wire that is connected to an outlet from the MPPT controller to the battery side of the battery isolation switch. John