solar panels and charge controllers

[Andrew]

Solar panels and their charge controllers/regulators.

I'm thinking of upgrading my solarPv system a bit. The power draw on the battery has increased since the tiller pilot was installed, so trying to increase the recharging efficiency.

My battery charging system is the Tohatsu sailpro (puts out a few amps) and 1989 BP 37W solar panel (2 Amps?) with small 20A controller (ME super-solar, 2014, about 50x50x20mm).

[Andrew]

Starting the upgrade with a 40W monocrystalline solar panel, it's 690x440mm, seems about right sized to fit on the aft rail area . It's 69cm maximum width should allow plenty of space to use the boarding ladder as well. It's allot smaller than my old panel. Higher power per cm2/ more efficient. It's also allot lighter weight.

I'm trying to keep everything as simple as possible, yet still do the job.

https://www.bunnings.com.au/kt-solar-40 ... 7_p0510965

[Ozzie]

Good price Andrew. I hadn’t realised the green shed sold such stuff. I must have been too busy buying nuts, bolts, silicone and such to look. Technology is getting lighter, cheaper and better. Post a pic of your final installation.

[Andrew]

This is my progress so far. (I'm trying to use the most economical, and pre-made, componentry. Not sure if it will all work yet)

My KT Panel has a 90cm twin wire power cable with "MC4" connectors. Extending this with a 3m cable from supercheap auto ($29) which has pre-fitted MC4 connectors and an Anderson Plug at far end. (also have standing by, the other alternative Jaycar 3m heaby twin cable with 2 x MC4 connectors that need to be crimped on, the controller end just yellow horseshoe end terminals crimped on)

Bought a "Kings" MPPT 20Amp solar controller ($40, yearly runout sale, rrp$60) at 4WD supercenter. It has optional input lead with an anderson plug.

(These MPPT controllers should output 10-50% more power overall than the old style PWM types. The MPPT has a continuous but varied output to the battery. (PWM works with a switch on/off system, the output current is zero much of the time while it thinks about the battery voltage before switching on again, still ok if your power requirements can be met and it's usually the cheaper way to go)

Now the problem is my electrical box needs a major re-arrange (re-build?) to fit all these large devices inside it..
Next is the get a heavy twin cable from controller to battery..

MPPT - Maximum Power Point Tracking controller

PWM - Pulse Width Modulation controller

Hardkorr 3m 12vsolar cable Supercheap auto

[Peter T]

Hi Andrew, very interesting. Might I suggest, because that controller has brass terminals, and it is not marine grade, that you completely seal them from the air. I would seal the whole thing with silasttic or put it in a plastic bag and then completely seal the opening where the wiring enters with either silastic or sikaflex. I dont reckon you want corrosion forming in the controller or on the terminals. Also, all the wiring needs to be marine grade. i.e. tinned copper wire.
Just a thought. Cheers

[Andrew]

Yes, corrosion could be a problem down the track, so i've mounted the controller deep inside the louvred electrical cabinet. No salt spray ever gets in there. The instructions said the MPPT controller should have air ventilation for cooling but with only 40W/2.2A should be cool enough for a 20A unit. (will cover the wiring area once setup.) (It also has cooling fins on its back)

Yesterday expanded electrics into the top shelf of my cabinet, by fitting a 10mm plywood sheet to the bulkhead there (for wood screws/fittings etc)

Rainy day today, (highly unusual in dry season here, the vegetation appreciates it) so figuring out how to make a mast roller frame (same concept as Greg's "Law and Disorder"). Might try a simple wooden prototype initially, to determine best dimensions, also want to hang other stuff off it, like the solar panel (perhaps an anchor light mount too.) Ultimately it should be DIY staines steel (once design testing is done, NQ time..) .

Wondering what other Investigators (or similar TS) have set up.?

[Peter T]

Yes Andrew, I was wondering if the controller required air circulation or not. Perhaps just a light coating of Vaseline on the terminals might help make it last longer.
Also, I was wondering what amount of charging output you get out of your "Sail Pro ". I only get a few milliamps out of mine, which of course is only a small trickle charge and I was wondering if mine is normal or in need of attention. Thanks

[Andrew]

Will try that, watching some beginners 12v solar setup videos (English country life) today.(should've been done before starting!) Hugh explains it well, from simple to more advanced in a series.

He pointed out that mono-crystaline panels are more efficient than polycrystalline, and "PERC" panels get the most output (get a bounceback dose of energy).

Hugh said try to point panel at the sun when possible. (He used a TV bracket. marine ones?? or DIY?) (My "plan A" is to simply tie panel to aft rail and tilt up down with a braided line and cleat on the mast roller frame.)

There is not that much "clear sky" area on an Investigator, and down aft the quarters need to be kept clear for boarding ladder and outboard operation.

The Sail-pro regulator should generate a couple of amps in theory (saw a video, bloke took his multimeter out on a tinnie for it) Haven't done it to my motor yet. (only just learnt multimeter operation, utube In a test tank at idle it will be not much to zilch, at half throttle cruising speed around an Amp or two..?

[Peter T]

Thanks Andrew, I reckon mine needs a new charging coil

[Andrew]

Maybe take it into a marine mech to check it?

One main point from Hugh's videos (English country life). Always connect the charge controller to the battery first. (then connect the panel input later, protects the controller). Here is Hugh's part1 (of 5 in series) explaining small scale solar, it really helped me understand the subject better. https://www.youtube.com/watch?v=H7isiNC ... gk8aCpRzR2

I've got my system up and running just now. It's charging away in the late afternoon sun..