Kilo
Well-Known Member
I've always assumed that Uma haven't gone electric outboard because they want redundancy - for whatever reason they have insufficient battery reserves they still have 22ltr+ of petrol outboard.
In support of solar
- Thread starter geem
- Start date
Stemar
Well-Known Member
Maybe no one will give them a Torqeedo?
I'm not sure if two panels each side will give much advantage, but definitely split them each side of the mast. IIRC, wiring the panels in parallel works best if one is likely to be shaded
Are they flexible or semi-flexible ones? Rigid do seem to last better. The installation is more difficult, but rigid panels have the added advantage that they can be mounted with an air gap under them to give a bit of cooling, which helps efficiency
A typo for delamination
lustyd
Well-Known Member
ETFE panels are the ones to go for and solve many of the issues of older designs. Unfortunately flexible panels have a bad name because too many people had the old style and had delamination or poor performance. Looking at my Renogy ones I’d be very surprised if they ever delaminate and the output is 104W on each 100W panel!
coopec
N/A
Thanks for your thoughts.
The boat is not in the water yet (cue PVB) so I don't know how the mizzen boom will affect the panels (it's a worry). I've thought of mounting a couple on the push-pit as well- at least they wouldn't be shaded. Maybe I will have to install diodes to overcome the problem of shading (apparently it can be DIY)
I always remember the survey they did of cruising yachts and they found that the average yacht spends 90% of its' time at anchor or penned
I thought a lot about 12V vs 24V and decided on 24V as I need an inverter to power the microwave, induction hob, bread-maker, HWS and water-maker. I was also swayed by what Rainbow Power Company had to say about 12V vs 24V.
12 Volt, 24 Volt or 48 Volt | Limitations & Solutions
24 Volt Electrical Systems | West Marine
I think you'll find most production yachts over 40ft are 24V these days
Kelpie
Well-Known Member
I don't think diodes will solve the problem. By wiring in series you are effectively creating one big panel, so any shade on either one will drastically reduce output. Guardwire mounting is a much better idea and not hard to arrange. You can also angle the panels to catch early and late sun.
I have my main panels under the boom but with a 4ft gap between them, so as far away from the boom as possible. Even when not under sail the shadow from the stackpack often falls on one of them, cutting the output in half.
I have my main panels under the boom but with a 4ft gap between them, so as far away from the boom as possible. Even when not under sail the shadow from the stackpack often falls on one of them, cutting the output in half.
coopec
N/A
My two 90W Renogy solar panels are working fine. I was surprised I was getting a good charge even when the panels were shaded by cloud AND
I got the 3000W/6000W inverter going just 30 minutes ago
Everything I tested worked fine - microwave, kettle, angle grinder. I had real problems though as I used a secondhand 9in. long cable from the battery to the inverter and guess what? It had a break in it! (The rest of the 3ft cable was fine when tested with the multi-meter)
I got the 3000W/6000W inverter going just 30 minutes ago
Everything I tested worked fine - microwave, kettle, angle grinder. I had real problems though as I used a secondhand 9in. long cable from the battery to the inverter and guess what? It had a break in it! (The rest of the 3ft cable was fine when tested with the multi-meter)
Kelpie
Well-Known Member
Get rigid panels and then they can't delaminate. Much cheaper too.
I saw a video where somebody described how their delaminated flexi panel suffered from corroded wiring, which then led to a short, and then a fire. The sunbrella bimini burst in to flames above him and it was only because he was on the boat, at a pontoon with a hose to hand, that he was able to save the boat.
My first rigid panel had a hard life. Bought the cheapest unbranded one I could off eBay, and in the five years I had it, never missed a beat. It even fell off one night whilst the boat was beached, about seven feet down on to the stones, where it stayed whilst the tide came in and covered it. I was amazed that it had no cracks and still worked. And it was still working when I sold the boat a year later.
PaulRainbow
Well-Known Member
What do you mean by 24V system ?
Are the batteries wired as 24V ?
Do you have 24V equipment onboard ?
coopec
N/A
Maybe I will spend a bit more to get solar panels with diodes already installed.
Blocking and By-Pass Diodes Used in Solar Panels
Kelpie
Well-Known Member
But surely bypassing one of your 12v panels just means you are trying to feed a 24v system from a 12v source? Which won't put one milliamp in to the batteries.
(Can MPPT controllers boost the voltage enough to compensate for that?? Even if they can, I'm sure you're better off wiring in parallel and then converting to 24v).
lustyd
Well-Known Member
Each panel will have two strings with bypass diodes. If one part is shaded you’d end up with 1.5 panels not 1. The panels aren’t 12V more like 18V so would still work
ctva
Well-Known Member
As far as I know, and with info from Photonic Universe, very helpful people, panels tend to have bypass diodes built in. I’ve two 100w panels in parallel, with blocking diodes fitted on the junction box below deck, very simple and cheap DIY job.
coopec
N/A
Those diodes aren't meant to overcome shades panels.
These are the diodes you are referring to;
Attachments
cherod
N/A
I wonder how much that little lot cost
noelex
Well-Known Member
Virtually all solar panels that you would consider on a boat come as standard with at least two bypass diodes. They are necessary to prevent localised overheating and damage to the panel. If you are connecting the panels in series, it is worth installing additional bypass diodes to conduct past the whole panel in the event of shade, although there will only be a minor improvement in shade tolerance. This is especially true for low voltage panels fitted with a high number of internal bypass diodes.
Panels do not come with blocking diodes as standard. These can be easily added, but except in unusual cases such as when no solar regulator is used, these additional diodes will be counter productive and result in a slightly lower overall output.
Panels do not come with blocking diodes as standard. These can be easily added, but except in unusual cases such as when no solar regulator is used, these additional diodes will be counter productive and result in a slightly lower overall output.
lustyd
Well-Known Member
No the blocking diodes are to stop power loss at night and are not required with MPPT which will prevent that anyway. Bypass diodes allow individual strings to be bypassed without affecting the rest so two panels with a tiny amount of shade will output 27V instead of 36V
lustyd
Well-Known Member
Unnecessary as the included bypass diodes already perform this function.
coopec
N/A
I agree with what you say but I am not using a MPPT controller but a cheap Chinese PWM so I don't know what it does.(Just as well the panels have blocking diodes!)
lustyd
Well-Known Member
If you don't know whether it does then yes I'd fit one for sure
noelex
Well-Known Member
Each of the bypass diodes will have some voltage drop. When a single panel is deeply shaded, the current from all the other panels needs to pass through multiple internal diodes installed within the solar panel. Installing a bypass diode around the whole panel provides a shorter path through just a single diode and so in some circumstances will increase the power out of a solar array connected in series when subject to shade.
The improvement is only minor. The additional diodes are cheap, but they do add another failure point and can be difficult to install in a neat fashion. In most cases owners would be better to connect their panels in parallel or even better with one controller per panel rather than in series, but this is not always the case.