Solar Power Controller set up

Searush

Searush

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I am sticking a couple of large (2x100w) solar panels on the roof of my motorhome & will be feeding them thro a fancy controller to manage the output & allow pulse charging of the battery (yes, only 1x110Ah at the moment). The manual for the controller shows the solar input (no problem there) and the output to the battery (again pretty straight forward) but it also shows the DC load feeding from the controller too.

I hadn't planned on doing that I was simply going to leave the DC load feeding from the battery, but I can see the advantage of running the load via the controller as it has overload protection & can be isolated from the controller too. I presume it also allows Solar power to go direct to the load to reduce the drain on the battery in daylight hours, altho I suspect that the drop in battery voltage of a heavy load would draw more cahrge from the panels anyway.

My question is - Has anyone fitted a hefty solar panel system to their boat (or a van) & kept the load fed direct from the battery rather than from the Regulator/ Control unit? And are there any disadvantages in doing so?

Ta muchly. This is the controller I got (I didn't pay that much for it) http://www.ebay.co.uk/itm/30A-Solar-Panel-Charge-Regulator-12V-24V-Auto-Solar-Controller-SOLAR30-720W-30A-/120987190377?pt=UK_Gadgets&hash=item1c2b660469
 
Did it about a month ago.

As I see it the disadvantages are that it could drain the battery at night as the current flows the other way without some sort of blocking diode.

Secondly if there is no fuse and no regulator the charging system is inefficient ( google " how mppt controllers work")

thirdly unregulated it could fry your batteries/ set fire to your boat.
 
Searush said:
I am sticking a couple of large (2x100w) solar panels on the roof of my motorhome & will be feeding them thro a fancy controller to manage the output & allow pulse charging of the battery (yes, only 1x110Ah at the moment). The manual for the controller shows the solar input (no problem there) and the output to the battery (again pretty straight forward) but it also shows the DC load feeding from the controller too.

I hadn't planned on doing that I was simply going to leave the DC load feeding from the battery, but I can see the advantage of running the load via the controller as it has overload protection & can be isolated from the controller too. I presume it also allows Solar power to go direct to the load to reduce the drain on the battery in daylight hours, altho I suspect that the drop in battery voltage of a heavy load would draw more cahrge from the panels anyway.

My question is - Has anyone fitted a hefty solar panel system to their boat (or a van) & kept the load fed direct from the battery rather than from the Regulator/ Control unit? And are there any disadvantages in doing so?

Ta muchly. This is the controller I got (I didn't pay that much for it) http://www.ebay.co.uk/itm/30A-Solar-Panel-Charge-Regulator-12V-24V-Auto-Solar-Controller-SOLAR30-720W-30A-/120987190377?pt=UK_Gadgets&hash=item1c2b660469
Click to expand...

I think you will find that there are two different things the load output may be for.

It might be designed to disconnect a load normally left running if the battery volts fall to some preset value ( and reconnecting again when the solar panel has recharged the battery a bit) Thus avoiding running the battery totally flat

OTOH if the controller is designed for street lights or signs, which I believe many of these inexpensive controllers are, it may disconnect the load (ie the light) when the solar panel is operating, ie in daylight.

You should be able to figure out which from the manual.
 
OTOH if the controller is designed for street lights or signs, which I believe many of these inexpensive controllers are, it may disconnect the load (ie the light) when the solar panel is operating, ie in daylight..
Click to expand...

That controller is designed primarily for street lights. Various functions such as low battery voltage cutout, overload protection and the time switch will operate through the "load" connections. However, the specification says that the maximum load is 12 amps so, if you are confident that you will not draw that much and that timer settings etc allow you to leave everything on during the day, you could connect through that circuit. Otherwise a direct connection to the battery would be necessary.

It may even be an idea to connect things like a bilge pump or anchor light through the "load" outlet and all the main circuits direct. That way a bilge pump couldn't flatten batteries when you are away or the anchor light could be set to switch on and off when you want......(though I use a light sensitive switch).
 
Rigger Mortice said:
That controller is designed primarily for street lights. Various functions such as low battery voltage cutout, overload protection and the time switch will operate through the "load" connections. However, the specification says that the maximum load is 12 amps so, if you are confident that you will not draw that much and that timer settings etc allow you to leave everything on during the day, you could connect through that circuit. Otherwise a direct connection to the battery would be necessary.

It may even be an idea to connect things like a bilge pump or anchor light through the "load" outlet and all the main circuits direct. That way a bilge pump couldn't flatten batteries when you are away or the anchor light could be set to switch on and off when you want......(though I use a light sensitive switch).
Click to expand...

Probably no bilge pump or anchor light in Searush's motorhome:D
 
I have 300W of solar panels going through our MPPT controller. I haven't bothered with the load terminals on the controller, however it has the uses as described by others above. One thing the manual for mine mentions is if you wish to run a load larger than the rated capacity of the load terminals, then run the load via a relay.

However, I'll stick with running things form the batteries.
 
VicS said:
(snip).

You should be able to figure out which from the manual.
Click to expand...

It is because the "manual" (actually a one page overview) is unclear that I am asking, Vic.

But interesting responses thanks everyone, it looks like my original idea of just connecting the panels thro it to the battery & leaving the load wiring "as was" is the normal way of doing it. It wouldn't be rocket science to disconnect the load wiring from the battery & run it up to the controller alongside the charge leads from the controller, but why bother if I don't need to manage the load? I was struggling to spot the benefits & it would seem I am not alone.

And no, I don't use an anchor light or bilge pump on the motorhome (yet).
 
It is because the "manual" (actually a one page overview) is unclear that I am asking, Vic
Click to expand...
I was wondering if there was any additional information or a more detailed spec that would give a clue.
If it was for disconnecting a load when the battery volts fell I'd expect it to give cut-out and cut-in voltages..... but RM has confirmed it for controlling a street light anyway so not now of any consequence.
 
The spec on the Ebay listing gives a cut out figure of 10.5 volts which I assume means that it cuts out at that reading when under load rather than as an open circuit voltage.
Thinking about it, there's not much point in cutting out when on open circuit! :D
 
Rigger Mortice said:
The spec on the Ebay listing gives a cut out figure of 10.5 volts which I assume means that it cuts out at that reading when under load rather than as an open circuit voltage.
Thinking about it, there's not much point in cutting out when on open circuit! :D
Click to expand...

Having bothered to look I have found the "manual" online http://www.yoosmart.com/30a-solar-controller-solar30.html I find that is does in fact say


[TD="class: STYLE1, bgcolor: #FFFFFF"]
rated working voltage​
 [/TD]
[TD="class: STYLE1"]
12V/24V​
 [/TD]
[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
installable maximum cable​
 [/TD]
[TD="class: STYLE1, width: 156, bgcolor: #FFFFFF"]
7# AWG (16mm2)​
 [/TD]

[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
rated working current​
 [/TD]
[TD="class: STYLE1, width: 84, bgcolor: #FFFFFF"]
30A​
 [/TD]
[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
working temperature​
 [/TD]
[TD="class: STYLE1, width: 156, bgcolor: #FFFFFF"]
-10℃~60℃​
 [/TD]

[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
voltage of solar panels​
 [/TD]
[TD="class: STYLE1, width: 84, bgcolor: #FFFFFF"]
≤50V​
 [/TD]
[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
storage temperature​
 [/TD]
[TD="class: STYLE1, width: 156, bgcolor: #FFFFFF"]
-30℃~70℃​
 [/TD]

[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
float charging voltage（settable）​
 [/TD]
[TD="class: STYLE1, width: 84, bgcolor: #FFFFFF"]
13.8V/27.6V​
 [/TD]
[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
temperature requirement​
 [/TD]
[TD="class: STYLE1, width: 156, bgcolor: #FFFFFF"]
≤90％,no condensation​
 [/TD]

[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
low voltage protection（settable）​
 [/TD]
[TD="class: STYLE1, width: 84, bgcolor: #FFFFFF"]
10.7V/21.4V​
 [/TD]
[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
dimension​
 [/TD]
[TD="class: STYLE1, width: 156, bgcolor: #FFFFFF"]
90 mm×188 mm×48 mm​
 [/TD]

[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
low voltage recovery（settable）​
 [/TD]
[TD="class: STYLE1, width: 84, bgcolor: #FFFFFF"]
12.5V/25.0V​
 [/TD]
[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
distance of installation holes​
 [/TD]
[TD="class: STYLE1, width: 156, bgcolor: #FFFFFF"]
60 mm×178 mm --Φ5​
 [/TD]

[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
no load loss​
 [/TD]
[TD="class: STYLE1, width: 84, bgcolor: #FFFFFF"] ≤30mA [/TD]
[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
weight​
 [/TD]
[TD="class: STYLE1, width: 156, bgcolor: #FFFFFF"]
360g​
 [/TD]

[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
loop voltage drop​
 [/TD]
[TD="class: STYLE1, width: 84, bgcolor: #FFFFFF"] ≤170mV [/TD]
[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"][/TD]
[TD="class: STYLE1, width: 156, bgcolor: #FFFFFF"][/TD]

[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
charging mode​
 [/TD]
[TD="class: STYLE1, width: 156, bgcolor: #FFFFFF"]
PWM mode​
 [/TD]
[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"][/TD]
[TD="class: STYLE1, width: 156, bgcolor: #FFFFFF"][/TD]

[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"]
temperature compensation​
 [/TD]
[TD="class: STYLE1, width: 156, bgcolor: #FFFFFF"]
-4mV/Cell/℃​
 [/TD]
[TD="class: STYLE1, width: 120, bgcolor: #FFFFFF"][/TD]
[TD="class: STYLE1, width: 156, bgcolor: #FFFFFF"][/TD]


The settable low voltage protection and recovery figures suggest to me that my first suggestion was in fact correct ie that will disconnect a load to prevent total battery drain.


I said RTM. ;)
 
Last edited:
VicMallows said:
Curious that so many of us seem to migrate towards motorhomes :o
Click to expand...

I had a caravan & then a caravanette (pop-top) then a motorhome long before I had a proper boat (just had dinghies back then) I'm rather reverting to land cruising again after a longish break.

Thanks for the link Vic, I shall have a poke around in that.

Edit; DOH, that's just the e-bay ad I posted. It doesn't actually tell me what I asked in the first place.

It tells me what it can do but not whether it has to be wired that way or not. But several people have already told me that they left the supply wiring unchanged. It seems it all depends if I want XS discharge level cut-off or not. So, as I already have a ZIG unit to cut off loads when teh battery voltage drops too far, I really don't need to have another controller to do that.
 
Last edited:
Just as a matter of interest to anyone thinking of solar panels on a motor home or similar. The panels used for domestic PV systems are crazy cheap compared to those for 12v boats etc. They produce 40v open circuit and are very large around 200 watts. A friend found a source here for equivalent 80 squid. Suppliers are overstocked with Chines panels due to government incentives running out. You do need an MPPT controller though to convert the 40v to 14volts for battery charging. olewill
 
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