# Thoughts on solar charging for trolling motor battery.



## Smackdaddy53

I asked the same question a while back and supposedly trickle charging to maintain a deep cycle battery is possible but not fully charge one from a deeply discharged state in the same time as a 120 volt system. I think Captain Bob Lemay has a solar setup on his boat, maybe he will chime in.


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## richg99

Always wondered if a wind charger, similar to what is used on sailboats, wouldn't be a better approach. Price doesn't seem to be too much higher than a solar set up. I guess it all depends on whether you get more wind or sun.
https://www.amazon.com/Happybuy-Tur...la-569732240791&ref=&adgrpid=60522766686&th=1


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## jhreels

richg99 said:


> Always wondered if a wind charger, similar to what is used on sailboats, wouldn't be a better approach. Price doesn't seem to be too much higher than a solar set up. I guess it all depends on whether you get more wind or sun.
> https://www.amazon.com/Happybuy-Tur...la-569732240791&ref=&adgrpid=60522766686&th=1


Wind or solar, assuming your able to generate around 100-200 watts and 12v, will the charge controller be capable of recharging a deep cycle?


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## Zika

Have been using a Coleman 30 watt panel and controller for 2+ years to charge my single trolling motor battery (Odyssey gel). No issues whatsoever. The panel (mounted on the roof of my boat shed) has survived hurricane force winds. Never discharged the battery so low it hasn't fully recovered. In fact, the power indicator on my MG Xi5 has never gone below a full charge even after running it most of the day.

Have about $240 invested in my set-up, including panel, controller, wiring, clips and hardware. Used scrap lumber to build a frame to attach to shed studs.


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## Zika

Got my panel and controller through tractorsupply.com, by the way.


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## lemaymiami

No solar panel for me (at least not yet) since my rig is garaged when it's not on the water... but sounds like a great idea... If anyone has gone that route successfully with a 24 volt setup I'd love to hear about it....

The only drawback that I can think of (provided the setup will actually charge up a discharged battery and maintain it over time... is the same problem you face in any storage facility - theft... (and a solar setup would have to be right out in the open - a temptation to thieves..).


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## Smackdaddy53

lemaymiami said:


> No solar panel for me (at least not yet) since my rig is garaged when it's not on the water... but sounds like a great idea... If anyone has gone that route successfully with a 24 volt setup I'd love to hear about it....
> 
> The only drawback that I can think of (provided the setup will actually charge up a discharged battery and maintain it over time... is the same problem you face in any storage facility - theft... (and a solar setup would have to be right out in the open - a temptation to thieves..).


I thought I read where you had one on your boat for long days of trolling in the glades. Must have been someone else. I read a lot!


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## Marsh Pirate

I have one of the Battery Tender solar chargers hooked up to my small skiff. It keeps it fully charged for me. I rarely use it, so it has plenty of time to charge it.


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## jhreels

Marsh Pirate said:


> I have one of the Battery Tender solar chargers hooked up to my small skiff. It keeps it fully charged for me. I rarely use it, so it has plenty of time to charge it.


Can it charge the battery from a deeply discharged state? Like after a day of trolling motor use?


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## Zika

My solar panel keeps the battery topped off so I've never approached a deeply discharged state, even after a full day's use.

By the way, my panel is mounted flat on the roof of my shed, which is about 15 feet high. You can't even see it from the road and you'd need an extension ladder to try and steal it. But then again, I thankfully don't live in South Florida anymore.


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## jhreels

Zika said:


> My solar panel keeps the battery topped off so I've never approached a deeply discharged state, even after a full day's use.
> 
> By the way, my panel is mounted flat on the roof of my shed, which is about 15 feet high. You can't even see it from the road and you'd need an extension ladder to try and steal it. But then again, I thankfully don't live in South Florida anymore.


Im gunna give it a shot, the decision I have to make is between the smaller 5w setups like this:

https://www.amazon.com/Battery-Tend...5923996&sr=8-6&keywords=solar+battery+charger

Or a larger setup to deliver more current for deep discharge like this:

https://www.amazon.com/Tishi-Hery-M...ons&keywords=100w+solar+battery+charger&psc=1


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## Zika

Mine is 30 watt and it does fine for a single 12-volt battery. 

Will you be charging a 12 or 24-volt system?


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## jhreels

Single 12v battery, 55 lb motor


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## Vertigo

Sure, solar panels can charge trolling motor batteries, but if you fish two days in a row, not much chance that solar can charge the batteries over night.


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## Zika

Agreed, that is the drawback. But so far I haven't had a problem even when fishing back to back days with my particular components. And it sure beats lugging a battery home after every trip.


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## Marsh Pirate

jhreels said:


> Can it charge the battery from a deeply discharged state? Like after a day of trolling motor use?


Yes, it can.


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## RaspberryPatch

I have to be brief. The reference systems in Amazon have some flaws or concerns from my side. Liability for insurance in the case of fire or false claims.

Yes, a solar panel can charge a battery. Look to a Morningstar or Phocus Charger. PWM algorithm is fine. Quick look > https://www.morningstarcorp.com/products/sunguard/

I have no commercial interest, but I have much experience in designing-deploying hybrid solar systems - on-grid and off-grid globally - for commercial applications. I am a tier above this, where compliance and safety is critical, but as well as performance. For consumer, I have respect for Morningstar, Phocus and a few more.

I often get ask (as a side from my profession) to point to residential-consumer solutions. For simple DC Chargers, in NA:
1. Morningstar https://www.morningstarcorp.com/products/sunsaver-mppt/
2. Phocus https://www.phocos.com/na/blog/portfolio/eco-2/
3. Midnight Solar http://www.midnitesolar.com/productPhoto.php?product_ID=615&productCatName=Charge Controllers -
Brat&productCat_ID=49&sortOrder=1&act=p

I know the people - technical people and in the couple of cases the power designers. They have manuals that make sense and technical support people you can call.

So when of my commercial customers who asks for a recommendation, I will point them to the above.

I like SMA Inverters (bigger than what you need), but they are being harmed and downsizing from China competition (Huawei). Good product - good! - but I am not sure how well their technical support has survived. (Longer story, on other German suppliers - Schletter, SolarWorld, et cetera).


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## RaspberryPatch

Good things to look for

1. PWM is fine, MPPT is an un-needed cost.

2. Units that just say CE, with no reference to UL-CSA mean the converter will not meet "code" for US. So as it is not compliant to NFPA (National Fire Protection Association), and may be used by Insurance companies to disqualify claims in the event of a fire. So consider the liability risk you incur is doing a non UL-CSA product in the US. Yes, I have seen this.

In places such as Africa, India, et cetera, I do provide products that are just CE, but here I am not increasing the liability in the event of a fault.

Sidebar: CE is self-declared. I have tested many Asia-Pacific products that have CE, but have failed when we have tested them. While in Africa, I could still sell a CE label product (that has failed proof testing), I cannot do so in Europe. The importer owns the liability.

3. Bulk Charging or CC-CV. It is the Bulk, aka CC (Constant Current) that properly restores the battery from a deep discharge, reducing sulfation of the plates and thus NOT accelerating the death of the battery. Trickle Charge is acceptable for float applications, like an UPS, as other factors will contribute to the death of the battery.

This is specific to Lead Batteries. There are other issues and control mechanisms for Sodium, Reflow, NiMH, NiCd and Lithium.

Chargers that just do Trickle Charge, so as they do not have address Point 4.

4. Temperature Compensation to prevent you dehydrating your battery and turning your enclosed space into a hydrogen bomb. A hydrogen outgas explosion not pretty. Yes, I seen this, and usually do to gross setup and maintenance years.

If you (battery that is) are in open air, then an explosion is unlikely, and the cost is just accelerate battery death, either because ...

1. Your just doing trickle charge after a deep discharge
2. Dehydrating your battery. An OpenCell battery, where you refill versus a Value Regulated battery, with a quarterly maintenance programme will not suffer this.

5. Solar Panel.
a. Flexible Panels are fine. You will not get the reported 21% efficiency from a cell with a two wire thin silicon cell, as reported by one of the link Amazon sites. I distrust suppliers whose claims are exaggerated. Where else have they exaggerated.

Right now at the top end, I am shipping 5 wire PERC panels (top end for standard silicon without copper plate) and I am below <19%. I am using, for commercial operations thin-film, poly-crystalline and mono-crystalline.

b. Thinflim is fine and better is you are dealing with a shady placement.

c. Silicon is fine and provides best value.

Point the panel south!

Avoid Shadows.

Panel Voltage is a function of Temperature, and Current a function of Sunlight, if you are monitoring.​
6. How much current? You want a panel that can produce a minimum of 0.15C10 of the batteries capacity for life.

So if you have a 50 AHr Battery, you want a minimum of 7.5A output from the converter. 0.15*50 = 7.5.

The threshold is closer to 0.10 for most chemistries, but I have rounded up to account -"just in case" - including losses in the solar panel.

I am not sure if they have something small enough > https://www.civicsolar.com/products/solar-panels

But I have pointed those I support - for personal projects - homes, et cetera to Civicsolar. Again, they have real people there to support you.

edited, as I had more time this morning


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## RaspberryPatch

To the above, I have no financial or personal interests to the companies I have listed, though
* I have bought items from them at full price - solar panels from Civicsolar. I typically buy direct though. 
* As a designer I have a collection of charge controllers, all of which I have paid full price for. This includes those above, and others who I do not recommend and do not list.
* I have on occasion provided technical or business - over the phone or at technical conference. But this is secondary, as my customer space is Industrial-Commercial.
* Communication and support is a two way street, as well, hence, why I can comment positively on their NA support.


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## Marsh Pirate

RaspberryPatch,

Thanks for the info. Is there a complete solar set up that you would/could recommend? In lew of that, a solar panel and controller that you like? One that would keep an Odyssey 34M-PC1500 ready to go, with weekly use.


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## RaspberryPatch

I apologize, but, I am going to do this in sizable chunks of information.

* Odyssey made by EnerSys is a VRLA (AGM) is a TPPL (Thin Pure Plate Lead) Technology. It is not easy to construct, so it is more expensive, but a very good technology. I have sites in the mountains of California still running 7+ years on this, as well in Africa. A few years ago, a customer had sites "shitting out" batteries frequently in Ghana due to really bad grid - micro-cycling. We transition them to EnerSys TPPL - but SBS line (same we use at AT&T) - and they have been happy since.

For Bad-Grid, I try to steer customers to EnerSys SBS (TPPL) or NorthStar Blue+ (Carbon) (not all carbon is equal!). If I have to go Chinese, I will use either a Narada ICS. Yuasa has some very noce batteries, but I do not have a global contract with them.

I have also moved some to Lithium now.

No experience with this battery, but I have been in the EnerSys plants in the US and Wales were TPPL are made. I have TPPLs in my private lab.

* TPPL accepts high current, more than most AGMs.

* More often, the EnerSys EMEA (European site) has better information than the US. I often noted this to EnerSys direct, but the Odyssey site is ok.

* https://www.enersys.com/EMEA/ODYSSEY_Batteries.aspx?langType=1033

Open the Technical Manual - sorry .... then goto Table 3 and Table at top of Page 9.

To key data points from this .... 25A is your charge current.

Your C10 Capacity is 62.3 AHr, so requested recharge is .40C, which is fine, but a little high, which means investing more in solar to maintain the life.

If the battery was also on an alternator and getting once a month several hours (6 minimum) running off the engine (this is known as cyclic equalize), then you would not need this high current. We could do life repair on a well regulated alternator (if design so).

Please note these steps are all, just to ensure your battery last as month as it can. So it is about extending your purchase investment, transitioning from cheapest part to best TCO (Total Cost of Ownership), for thr life.

Also note that Owners Manual at Odyssey states minimum of 40% too for life. Refer to http://www.odysseybattery.com/documents/US-ODY-OM.pdf


What is the significance of this? This sizes your controller and solar panels .....


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## RaspberryPatch

Size of the Array ... we know for your battery you want 25A, lets say a nominal of 12V, so you need a minimum of 300W solar panels, but the 300W assumes you meet STC conditions.

The 300W STC rating is a perfect BRIGHT DAY CLEAR SKIES, VERY COLD (0C) et cetera. I am get this in Morocco in the mountains, but not in Florida. So once we apply atmospheric conditions, you are looking at 400W solar array.

Sidebar, the STC Ratings given to solar panels is based on how you measure the panels as they are flashed-graded out of production. It is optimistic for real life use, but it is honest measurement and there is virtually no exaggeration from the original panel manufacturers..


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## RaspberryPatch

I have never used altE, but I have been aware of them for YEARs. The pitch is reasonable, they have good product and the on BS counter, they are low.

I believe they put packages together ....

https://www.altestore.com/store/charge-controllers-c432/

So I would call them, ask for a quote for a 400W minimum solar array, plus 12V PWM charge controller, plus cables, fuses and if necessary a combiner box.


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## RaspberryPatch

You may want to find panels locally to avoid shipping cost.

The most common panels made globally are 60 cell (1.7mx1m) panels, they typically have a power rating of 270-310 Wstc. 

Panel prices are high in the US, relative to the world right now.


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## Steve_Mevers

A lot of good information. I can tell you that I run a 200 watt system with a Blue Star controller on my truck camper. I can run my batteries down to 50% -60% (50% is considered fully discharged for a 12v system) and if it is a sunny day they are charged back to 100% by early afternoon. On a sunny day you can expect about 6amps charge rate per 100 watt panel. I have been running this setup on two different truck campers for the past 5 years. If the boat is going to sit attached to a 200 watt solar system for a couple of days it will charge your batteries from a deep discharge to 100%, maybe even in one day. A good controller will also safely charge your batteries and reduce the charge to a float charge when fully charged. Renology 200 wat kits on Amazon are cheap and a lot of campers use them. I bought all my panels and controller from Amsolar.com, probably overkill for what your are trying to do. There are also systems out there that will charge your batteries from your truck and outboard engine, but that is a totally different setup. https://www.amazon.com/Renogy-Monoc...ocphy=9012215&hvtargid=pla-318232541946&psc=1


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## RaspberryPatch

For Code .... the parts I see at AltE should be acceptable to any inspector. There some panels that I am not aware of. 

Globaly, I use Trina as a major source. I ship direct (containers) from China to destination (I am currently shipping 275 poly and 305 mono). Panasonic HIT high temp separation issue I believe has been solved, but I still avoid Panasonic.. Sharp is the Cat's ass, Hanwha great, as is LG, Canadian Solar soldering I am not the most fond off, but I have installations in jungle on cell sites in Papua New Guinea that have worked for years.

Code says, you need a breaker on the battery - I think this is good, given the high Interrupt Current.

Most inspectors and fire officials in the US will want a disconnect or breaker near the array. I disagree with the logic, but you cannot always win an argument with an AHJ (inspector - Authority Having Juriscation). One breaker but the controller and battery is good.

A lighting and surge protector will be asked - the following logic applies to unoccupied building - I maintain if the building is hit by lighting, you have greater issues than protecting the battery and 100$ charge controller.

If I have an array on a residential building in Germany, with people,computers, et cetera, yes to Surge SPD.​
And there is some validity to a Ground Fault, but a good ground fault device on a 12VDC circuit may not be available. I think you can ague an exemption at 12VDC anyway.


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## RaspberryPatch

Steve_Mevers said:


> A lot of good information. I can tell you that I run a 200 watt system with a Blue Star controller on my truck camper. I can run my batteries down to 50% -60% (50% is considered fully discharged for a 12v system) and if it is a sunny day they are charged back to 100% by early afternoon. On a sunny day you can expect about 6amps charge rate per 100 watt panel. I have been running this setup on two different truck campers for the past 5 years. If the boat is going to sit attached to a 200 watt solar system for a couple of days it will charge your batteries from a deep discharge to 100%, maybe even in one day. A good controller will also safely charge your batteries and reduce the charge to a float charge when fully charged. Renology 200 wat kits on Amazon are cheap and a lot of campers use them. I bought all my panels and controller from Amsolar.com, probably overkill for what your are trying to do. There are also systems out there that will charge your batteries from your truck and outboard engine, but that is a totally different setup. https://www.amazon.com/Renogy-Monoc...ocphy=9012215&hvtargid=pla-318232541946&psc=1


1. Never tested BlueStar, but I am aware of them and no issues.
2. I see no BS in the Amazon link you provided.
3. 100W giving 6A, that is about right.
4. As with Point 1, a good controller will correctly charge your battery when matched.

The MorningstarStar site I reference includes marine, campers and good. Also like Phocus and Midnite, there are good people there you can call to.

No commercial interest.​5. What is properly charge? if a function of the specific battery - if the interest is life. There is high quality 2V US Made AGM but usually for standby, but you must not exceed may be limited to 0.15C, but the TPPL as listed above is 0.4C and needs nearly 3x the current. This is why I pulled the EnerSys manuals.

Theft rate in South Africa, batteries do not last 2 years, so they do not care about life. But in Egypt, they want 5 year warranties - 2000 cycles.

So in South Africa, we run them hard. In Egypt, we focus on life, and the decision lies with the people who have to maintain the sites.​
Not all construction and electro-chemistry is the same, thus charge currents must reflect size, application, et cetera.

Hey, do what you believe is right. I just being doing this for some time, and thought I would pass on best practices. Nothing more.

Sidebar, this site in in the Jungle, Papua New Guinea - EnerSys SBS Batteries, Canadian Solar Panels. Operational for 5+ years.










and this is Joshua Tree NP in the background (a before picture, it was destroying batteries, before the change-out). Change to an EnerSys OPzV 6+ years ago, still on the same battery.










near LA - Trina panels and still going. Now on 7+ years.










Dallas, newer, only in 2 second year - using thinfilm.










New Zealand, but a seriously different storage technology - ZnBr reflow. I have similar solutions in Saudi and Thailand.










Do what you believe is right. No judgment being applied, just highlighting best practices for life.

Pictures are sort of a resume, yes, I have some experience, and there is not intent to slam anyone.


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## Steve_Mevers

RaspberryPatch said:


> 1. Never tested BlueStar, but I am aware of them and no issues.
> 2. I see no BS in the Amazon link you provided.
> 3. 100W giving 6A, that is about right.
> 4. As with Point 1, a good controller will correctly charge your battery when matched.
> 
> The MorningstarStar site I reference includes marine, campers and good. Also like Phocus and Midnite, there are good people there you can call to.
> 
> No commercial interest.​5. What is properly charge? if a function of the specific battery - if the interest is life. There is high quality 2V US Made AGM but usually for standby, but you must not exceed may be limited to 0.15C, but the TPPL as listed above is 0.4C and needs nearly 3x the current. This is why I pulled the EnerSys manuals.
> 
> Theft rate in South Africa, batteries do not last 2 years, so they do not care about life. But in Egypt, they want 5 year warranties - 2000 cycles.
> 
> So in South Africa, we run them hard. In Egypt, we focus on life, and the decision lies with the people who have to maintain the sites.​
> Not all construction and electro-chemistry is the same, thus charge currents must reflect size, application, et cetera.
> 
> Hey, do what you believe is right. I just being doing this for some time, and thought I would pass on best practices. Nothing more.
> 
> Sidebar, this site in in the Jungle, Papua New Guinea - EnerSys SBS Batteries, Canadian Solar Panels. Operational for 5+ years.
> 
> View attachment 55030
> 
> 
> and this is Joshua Tree NP in the background (a before picture, it was destroying batteries, before the change-out). Change to an EnerSys OPzV 6+ years ago, still on the same battery.
> 
> View attachment 55028
> 
> 
> near LA - Trina panels and still going. Now on 7+ years.
> 
> View attachment 55032
> 
> 
> Dallas, newer, only in 2 second year - using thinfilm.
> 
> View attachment 55034
> 
> 
> New Zealand, but a seriously different storage technology - ZnBr reflow. I have similar solutions in Saudi and Thailand.
> 
> View attachment 55036
> 
> 
> Do what you believe is right. No judgment being applied, just highlighting best practices for life.
> 
> Pictures are sort of a resume, yes, I have some experience, and there is not intent to slam anyone.


Correction, I have a Blue Sky not Blue Star controller. I did not provide a link for the controller because it is overkill for the poster use ($234). The kit I posted is a cheaper alternative that has been used by a lot of people in the RV industry. I was just trying to provide some “solar for dummies” type info.


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## RaspberryPatch

Sorry, my typo Blue Sky


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