Return to Hobie.com
Hobie Forums
It is currently Tue Dec 11, 2018 9:27 am

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 20 posts ]  Go to page Previous  1, 2
Author Message
PostPosted: Sat Sep 08, 2018 2:28 am 
Offline
Site Rank - Captain

Joined: Thu Mar 23, 2017 12:47 am
Posts: 38
Location: new smyrna beach
BobAgain wrote:
FWIW, I mounted a 50 w solar panel (Grape Solar sourced on sale at Home Depot) on the forward portion of my starboard Haka. MC4A connectors live in the forward net pocket and the line runs through the hull (using a Hobie thru-hull kit) to the forward hatch. Waterproof battery box holds an LED Solar Controller,.


what controller are you using? i am currently running a 15w nature power panel from west marine with no controller to a group 24 101AH battery and want to move up to a 50-100 watt panel, but in doing so i know i'll need to run a controller. my concern is waterproofing the controller and heat dissipation. only two ways i could think of to waterproof was either epoxy the unit or use a water box, but both ways i am not sure if heat buildup would be an issue for the controller.


Top
 Profile  
 
PostPosted: Sat Sep 08, 2018 7:23 am 
Offline
Site Rank - Old Salt

Joined: Thu Jun 01, 2006 1:16 pm
Posts: 567
Location: Colorado
15W solar and a group 24 battery should have a controller unless you are watching the voltage often - in which case you are the controller.

A little about solar controllers. There are two types MPPT and PWM.

The simpler and less expensive controllers are usually PWM and these basically just use an electronic switch to connect the panel to the battery. When the controller wants to cut back on the solar charging, it starts to modulate the switch so that the panel is not connected to the battery all the time. The PWM controller can still have all the normal charging phases of bulk, absorption and float so will do a good job of charging the battery.

The more complicated type of solar controllers are maximum power point tracking (MPPT). This type of controller will actually search for the best voltage to operate the panel at to get the maximum power from the panel. These pretty much also have smart battery charging of bulk, absorption and float so do a good job of battery charging. The solar panel output voltage is temperature dependent and on a cool day, you might get 20% even up to 30% (perfect conditions) more power out of the panel than a PWM controller would. But on a hot day, you might only get 5%. On average, you might get 10% more power out of the panel by using a MPPT controller.

The two controllers that I have used in the last few years have both been MPPT.. and neither is completely waterproof (used them on a sailboat). Both of these are for lead acid wet cell batteries. I thought both of these performed well. Ive also used PWM type controllers in the past and they also worked well.. you just get slightly less battery charging for a given solar panel size.

I used a Genasun GV-5 for panels between 10W and 40W Its 5 amps so will actually handle up to maybe even an 80 watt panel but has some nice specs for very low power panels https://www.amazon.com/Genasun-GV-5-Pb- ... 9161&psc=1


A couple years ago I put an electric fridge on the sailboat and these are big power hogs so I went to a 160 watt solar panel. I changed the solar controller to a Victron 75 15 (up to 75 volts solar voltage, up to 15 amps current). I bought one that does not have the bluetooth feature but a friend did get this feature and it shows a lot of cool information with an ap for a smart phone.

https://www.amazon.com/Victron-SmartSol ... dpSrc=srch

FYI, as mentioned, nothing at all wrong with a less expensive PWM type controller, you will just get slightly less output - like maybe 10% on average. If the panel is always cool, MPPT gain goes up. If you are in a hot place, MPPT gain goes down.

One final thing I have learned the hard way.. NEVER short the solar panel side of the controller when there is sun on the panel. Even with fusing, it almost always burns out the controller.


Top
 Profile  
 
PostPosted: Sat Sep 08, 2018 9:40 am 
Offline
Site Rank - Captain

Joined: Thu Mar 23, 2017 12:47 am
Posts: 38
Location: new smyrna beach
ok....my understanding was......
"Do you need a charge controller?
As a general rule panels that produce less than 1.5% of a battery’s rated capacity in amp hours don’t require regulation. This means that a 1.5A panel is the largest you should use without a regulator on a 100-amp-hour battery. Regulators should generally be used any time you have two or more large panels connected to your batteries.

If you’re concerned about damaging your new gel or AGM batteries due to overcharging, you can add a small, inexpensive charge controller. These controllers, also called regulators, are rated by the maximum number of amps in your solar array, and we offer versions handling between 7A and 50A. Regulators are ideal if you can’t be onboard to monitor your electrical system, and the top units now feature smart, multi-stage charging."

so since i am currently charging at .87-.9 amps max OC voltage of 15v to a 101ah battery i figured i was pretty much safe (w/o a controller) as in real world i am barely charging above anticipated natural battery loss just sitting of appx 1ah or less.????
ok so so here in fl. there really isnt such a thing as "winter" unless ones figures in wind chill/humidity.....my understanding is by what you say is the pwm is less temp sensitive but at the cost of being less effective?


Top
 Profile  
 
PostPosted: Sat Sep 08, 2018 11:02 am 
Offline
Site Rank - Old Salt

Joined: Thu Jun 01, 2006 1:16 pm
Posts: 567
Location: Colorado
This guy https://marinehowto.com/do-i-need-a-solar-controller/ did some tesing with a slightly smaller panel and slightly larger battery and demonstrated battery over charging.

If you leave the panel on the battery all the time.. I wouldn't chance it.. get a regulator. If you have a lot more solar capability than you are using and the battery tends to be full all the time.. I would get the regulator. But if you are using every bit of power from the panel as its being produced.. maybe you dont need one. Just about any solar controller you can buy now will do the smart charging algorithms and the battery would last longer. Your choice.. my choice was to use a solar controller on a smaller panel (10W) and an even larger battery bank but I also let this sit for long periods of time when not there.

Yes, the PWM is less sensitive to the solar panel maximum power voltage simply because the PWM just drops the panel output voltage to be the same as the battery. Its the same as what you are doing connecting the panel directly to the battery. PWM is less sensitive temperature and also to wire size.. etc.

Really nothing wrong with PWM and they tend to be less expensive. Especially true if you have more solar output than you really need. The possible 10% doesn't mean much if you are not using it anyhow.

You have been talking "amp hours" (which is just amps times time). Using this assumes 12 volts. Do you have an estimate of how many amp hours @12V that you expect to use each day?

One thing to add.. If you are connecting a panel directly to a battery, it needs to have a series diode so that the solar panel does not drain the battery at night (leakage can be like 5% of rated current).

Most panels of any larger size do not have that diode built in because the solar charge controller already disconnects and isolates the panel at night. If you have the series diode in place and are using an MPPT controller, that diode drops the voltage to the MPPT controller and reduces the efficiency somewhat. Since the PWM isnt using the full voltage anyhow, that series diode doesnt decrease the power from the panel at all.

Point being.. even a cheap PWM controller also does the function of a series diode so the panel doesnt trickle drain the battery at night. Another good reason to just use a controller.


Top
 Profile  
 
PostPosted: Sun Sep 09, 2018 5:18 am 
Offline
Site Rank - Captain

Joined: Thu Mar 23, 2017 12:47 am
Posts: 38
Location: new smyrna beach
Wow, good read on that link, thank you.i had no idea I was using false information all this time. Guess I'm off to get a controller now.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 20 posts ]  Go to page Previous  1, 2

All times are UTC - 8 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
cron
© Hobie Cat Company. All rights reserved.
Powered by phpBB® Forum Software © phpBB Group