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Post by markhez on Nov 29, 2017 8:33:49 GMT
Mixing solar panel sizes (in parallel) is fine, as long as VMP is about the same on them.
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Post by quaysider on Nov 29, 2017 14:02:54 GMT
I cant REALLY change them as otherwise the wire I used at to go from the front of the boat to the back will not be thick enough to take the higher current at the lower voltage if you follow. it's a long run so doing them as is kept the current low until the the charge increases it. Honestly, the amount of power you'll be losing is phenominal. What size cable is it wired in? I think they are twin 2.5mm (as in 2 of each for the + and - ) - its about a 48ft run though - litterally from the front to back doors... I've ordered a triple mc4 adaptor plug so will test it out to see if it makes any difference and report back. |
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Post by markhez on Nov 29, 2017 14:15:20 GMT
Honestly, the amount of power you'll be losing is phenominal. What size cable is it wired in? I think they are twin 2.5mm (as in 2 of each for the + and - ) - its about a 48ft run though - litterally from the front to back doors... I've ordered a triple mc4 adaptor plug so will test it out to see if it makes any difference and report back. Not an ideal situation I know, but remember peak current will be about 10a per pair of cables at 30v, so over 50ft a volt drop of 1v (3.5%). Ideally they'd be run in 10mm. [edit] Just re-checked your solar specs, 3 165w panels with VMP of 35v gives roughly 7a down each pair of cables, so a volt drop of 0.75v (2.1%) over 50ft. |
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Post by Clinton Cool on Dec 24, 2017 9:13:56 GMT
A tip for installation: Rather than drilling through the roof run the cables through the mushroom vents.
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Post by quaysider on Dec 25, 2017 8:16:05 GMT
an update on this - I bought a couple of extra cables and tripple mc4 adaptors to swap things over... to be honest, it didn't make any difference - all I got was freezing cold fingers and cut (trying to pull apart the mc4s) finger. Perhaps my mppt works ok as is.
Not to worry - I'll just put the "spare" cables/connecters in my box of "things that might come in useful one day"...
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Post by Andyberg on Dec 25, 2017 8:18:31 GMT
my box of "things that might come in useful one day"... Advice for the future......Buy a bigger box, you're gonna need it👍 |
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Post by Mr Stabby on Dec 25, 2017 19:24:15 GMT
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Post by Clinton Cool on Dec 25, 2017 23:30:46 GMT
Hi Vince I'm no expert but from what little I know that package seems like a pretty good deal. Remember though that you'll need to add a fair length of cable, which isn't cheap, and brackets of some kind to fit the panels to the roof.
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Post by Mr Stabby on Dec 26, 2017 6:28:46 GMT
Hi Vince I'm no expert but from what little I know that package seems like a pretty good deal. Remember though that you'll need to add a fair length of cable, which isn't cheap, and brackets of some kind to fit the panels to the roof. Ta, was talking about this yesterday with one of the other boaters on my mooring, he has spare brackets left over from his own installation which I can have, the website says they can supply cable and although I'll measure it I guess I'd need about 10m. How much per metre is it? |
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Post by Telemachus on Dec 26, 2017 8:48:09 GMT
Package looks fine to me but the comments on the controller are a bit confusing. The pictures show the extra MT50 display which is very useful and allows the charging parameters to be adjusted. Although it’s shown in the pictures it’s not mentioned in the text. The text talks about a “built in LCD” which that controller doesn’t seem to have. I’d just check with them that you get the MT50 display in the package.
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Post by Clinton Cool on Dec 26, 2017 9:02:34 GMT
Hi Vince I'm no expert but from what little I know that package seems like a pretty good deal. Remember though that you'll need to add a fair length of cable, which isn't cheap, and brackets of some kind to fit the panels to the roof. Ta, was talking about this yesterday with one of the other boaters on my mooring, he has spare brackets left over from his own installation which I can have, the website says they can supply cable and although I'll measure it I guess I'd need about 10m. How much per metre is it? Good news re. the brackets, they aint cheap! With your cable length calcs, remember that (I'm pretty sure) you'll need 2 cable lengths (positive and negative) from the panels to the controller. Assuming the controller will be at the back of your boat and I think you said the panels will be at the front, 10m seems a bit short? You'll also need 2 cables from the controller to the batteries. I bought my cable from Bimble along with the other stuff, think it was 1.50 a metre, from memory. That was 5mm stuff, good enough for my 375w of panels, so that thickness should be fine for you too. Pity you're not up this neck of the woods, I'd give you a hand. I'm no expert but managed to do mine on my own without blowing anything up. It was easy really. The trickiest bit was running the cables from the mushroom vent I put them through, to the controller. There's insulation in there, makes it awkward. Managed it using a combination of bits of coat hanger, a fishing pole and fishing line. Top tip: if you do run the cables through a vent don't be temped to choose the vent closest to the panels. While this might be neater in theory in practise, you'll just multiply your cable running problems. Best to choose the vent that's closest to where you'll fix the controller, just run the cables along the roof to there. |
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Post by Mr Stabby on Dec 26, 2017 9:29:11 GMT
I already have one small solar panel at the rear of the boat, I'm guessing it must be about 30w, I seem to remember we had a look at it in Nantwich? I was going to run the cable through the existing hole which must already be there beneath the panel. Come to think of it, possibly I could just add a couple of solar panels to the set-up which is already there, although I don't know if the controller is up to that?  |
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Post by quaysider on Dec 26, 2017 9:32:41 GMT
I've got 2 of the triangle tippy brackets spare if you need them... don't have the twiddly bits to tighten them up though so you'd need to use an m8 nut and bolt.
Re cable from controller to batteries, I cut up a spare set of jump leads.
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Post by Telemachus on Dec 26, 2017 10:24:58 GMT
I already have one small solar panel at the rear of the boat, I'm guessing it must be about 30w, I seem to remember we had a look at it in Nantwich? I was going to run the cable through the existing hole which must already be there beneath the panel. Come to think of it, possibly I could just add a couple of solar panels to the set-up which is already there, although I don't know if the controller is up to that? You can only mix panels into the same controller if they either have roughly the same Vmp (for parallel connections) or Imp (for series connections). Of course there’s nothing to stop you keeping the existing panel and controller, and adding the new panel and controller separately. Though to be honest it hardly seems worth keeping the 30w panel. |
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Post by Mr Stabby on Dec 26, 2017 16:02:35 GMT
I already have one small solar panel at the rear of the boat, I'm guessing it must be about 30w, I seem to remember we had a look at it in Nantwich? I was going to run the cable through the existing hole which must already be there beneath the panel. Come to think of it, possibly I could just add a couple of solar panels to the set-up which is already there, although I don't know if the controller is up to that? You can only mix panels into the same controller if they either have roughly the same Vmp (for parallel connections) or Imp (for series connections). Of course there’s nothing to stop you keeping the existing panel and controller, and adding the new panel and controller separately. Though to be honest it hardly seems worth keeping the 30w panel. Thanks, I don't really understand solar so this sort of advice is helpful. How about if I were to install 400w of solar for the domestic batteries and rewire the small solar panel shown to keep the starter battery topped up, does that sound like a plan? |
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