Solar panel charge controller recommendation?

Trundlebug

Trundlebug

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I've just ordered a 150w semi flexible solar panel.

Can anyone recommend a good value charge controller from personal experience?

I've read numerous previous threads querying the huge variation in the cost of controllers available, from under a tenner to around £100, but there doesn't seem to be any clear consensus on the best option, from the answers given.

Summarising previous threads on this subject, I have gleaned:-
  • Some controllers claiming to be MPPT are probably just PWM 3 stage chargers
  • There isn't necessarily much to be gained by using a MPPT controller on a single panel. They're better used on multiple panels
  • Despite various opinions and many people having solar panels, few seem to hold their hand up and say what charge controller they have
  • The only controllers people seem to own up to having are the Victron / Master Volt / Maplin / well known brand types that are the top end (or beyond) of the £10-100 price range for these items

So, my questions are:-
1. Are the cheapo eBay controllers worth buying?
2. Is there much difference between them? Despite different external covers their connections all look identical. Makes me wonder..

Your input and clarity appreciated.

TB
 
I've gone down the cheapo route, although as I only installed the system last week I can't really comment yet on long term efficacy.
I have a single 50w panel but at some point in the future would like to add two 100w panels as well. I also have two batteries so this drove me towards a 20A dual battery system. Ended up getting one with a neat little remote monitor as well, which displays current voltage for each battery bank and the panel, plus temperature (it uses this, apparently, to feed into the charging program), plus current from the panel, and the total accumulated current. The controller/monitor was £63 off eBay, but much cheaper ones are available, I was just wooed by the gadgetry of it all.
 
Trundlebug said:
Thanks, but it's a 3 yr old blog about a domestic installation with multiple panels in the US. And sheeesh can he ramble!
Not really relevant to the questions asked above, but thanks anyway.
Click to expand...

I dont think the points he makes about MPPT vs PWM, cable size and voltage have dated and its still a 12v system. I know your looking at a single panel now but you may find you want to expand, it also helps to understand the compromises you make with your choices. I found reading this and other material helped put a system together. A couple of months ago I chose a 4x50w rigid panel solar installation on the boat which is so far giving good results, I used a programmable controller which is not the cheaper end of the market.
 
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Kelpie said:
That looks the same as the one I've got, except mine is the 20A version. The monitor is an extra add on.
Click to expand...

I have the 10A dual battery version with remote monitor. The pair cost me about £60 on Amazon. As far as I can tell, from one season, it works just fine. Recommended.
 
I have a Victron Blue energy MPPT controller 15 amp and from memory will handle up to 200 watts. I have a fixed 80 watt panel and it works well it was £80 from Barden batteries the whole lot controller and panel cost £170.

J
 
JumbleDuck said:
I have the 10A dual battery version with remote monitor. The pair cost me about £60 on Amazon. As far as I can tell, from one season, it works just fine. Recommended.
Click to expand...

I also have the 10A dual battery version but without the monitor. I have two starter batteries which I have wired in parallel to battery 2 output and three house batteries wired in parallel to the battery 1 output. I send 80% to battery 1 and 20% to battery 2 and the 40W panel keeps everything fully charged. This is in the Med though.

Richard
 
I will admit to having one of the £10 cheapos from ebay. Fitted it and a 40w panel 2 seasons ago, both domestic batteries are always fully charged when I go down to the boat. If I was replacing it I would put in one of the dual regulators to charge the starter battery as well.$_57.JPG
 
smithy said:
I will admit to having one of the £10 cheapos from ebay. Fitted it and a 40w panel 2 seasons ago, both domestic batteries are always fully charged when I go down to the boat. If I was replacing it I would put in one of the dual regulators to charge the starter battery as well.View attachment 45286
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l also have one of these and I dont think it is even PWM. At 14.4V it simply switches off charging - there is no pulse charging phase although the flashing led suggests otherwise.
 
I've got a 20w panel costing £79 and a pmw controller which was £7. These seem to be working well and keep my house battery well charged. I concluded that the extra charge from an mppt type controller at about £50 was not justified (for me) but I'm not a power hungry sailor with a fridge for example. That's a whole new ball game. You just have to weigh up the cost of a more sophisticated controller against more panel area (and space for the latter).
 
Trundlebug said:
Thanks for your replies so far.

It seems paying about the £50 mark is about what most have done to get a controller of reasonable quality.

Has anyone tried one of the cheapy eBay specials like these?
http://www.ebay.co.uk/itm/New-30-20...195574?pt=UK_Gadgets&var=&hash=item19f053a376
or
http://www.ebay.co.uk/itm/MPPT-15A-...91066556309?pt=UK_Gadgets&hash=item43c4eb2f95
Click to expand...

I have the first one of your links. It is designed for battery powered street lights and will charge for 8 hours before ramping down. I do not think it is MPPT.
I have it mounted on the garage roof and I feel it goes into reset mode if the boom shades it. In any case the batteries are get fully charged when I am not there.
 
My controller is the Sunworks DB1C shown here http://www.sunworks.co.uk/MotorhomesandBoats.html#SB1C_SB2C although mine was bought many (10?) years ago and is rated at 9 amps. It charges my domestic and starter batteries according to needs and has been excellent. I find it useful to be able to see exactly which battery is being charged and how much. I had one problem with it when it stopped charging the starter battery but it was repaired quickly and at reasonable cost.

I have two panels, 45 and 80 watts, on a stern arch, in Greece. The fridge runs 24/7 in high ambient temperatures and the panels cope well in high summer, still doing well half way through September.
 
Many thanks for your replies, that's really useful feedback and information.

As my (albeit single) panel of 150w seems to be on the larger side of the installations fitted by most I guess it falls into the "huge solar panel area and/or expect lots of not so bright sunlight conditions" category, especially as I'm in the UK. Therefore I'm thinking that to get the best out of it, I definitely need MPPT and PWM.

From the responses above it would seem my suspicions are correct that the cheapo eBay units aren't quite what they claim (yes it is too good to be true) despite performing adequately for basic installations.

I also take on board the key point about voltage drop, and will be using wires as thick as the controller can take, usually about 6mm sq. As my panel will be mounted on the wheelhouse sunroof, and the batteries are in the lazarette the wire distance may be up to around 4m so I'll also bear in mind the comment on volt drop and controller adjustability.

I had just about decided on the Victron 75/15 blue controller for around £85 http://www.shop.solar-wind.co.uk/acatalog/mppt_solar_charge_controllers.html
and especially as Barden and Kuranda will be at the boat show I might be able to pick up a deal.

But that unit isn't adjustable, so I may opt for http://www.ebay.co.uk/itm/20A-MPPT-...81155546342?pt=UK_Gadgets&hash=item41762d2ce6
which is a similar price but seems to have more flexibility from what I saw on the youtube video assessment of it.

However, as that controller is a 20A unit will I lose out on some efficiency? I understood the controller capacity needs to match the panel output quite closely for maximum efficiency, hence the ideal for me being a 15A unit.
 
Trundlebug said:
I also take on board the key point about voltage drop, and will be using wires as thick as the controller can take, usually about 6mm sq. As my panel will be mounted on the wheelhouse sunroof, and the batteries are in the lazarette the wire distance may be up to around 4m so I'll also bear in mind the comment on volt drop and controller adjustability.
Click to expand...

Voltage drop between the controller and batteries matters more than voltage drop between the panel and controller. Both are losses, of course, but all the controllers looked at sensed battery voltage at the controller, so any drop between there and the batteries doesn't get noticed. Moral: put the controller as near the batteries as possible.

However, as that controller is a 20A unit will I lose out on some efficiency? I understood the controller capacity needs to match the panel output quite closely for maximum efficiency, hence the ideal for me being a 15A unit.
Click to expand...

It's just a switch, which has to be able to take the maximum current. Beyond that, no matching involved, so a 10A controller will be fine for your 150W panel, which will be flat out at about 8A (power is given at panel voltage of 19 - 20V). A 20A one won't cost much more, though, and will cope with more panels if you ever fit them.
 
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