I know little to nothing about solar systems. I have a boat with a 36-volt trolling motor setup. The motor is supplied by 3 Deka flooded DC 24 12-volt deep cycle batteries connected in series. I’m looking for a system that I can connect that will re-charge my batteries during downtime (when boat is in storage). My boat is stored in a dry storage lot with direct sunlight when not in use. On average I use my boat about 2x a month, so there are multiple days (10 to 14) between uses. I’m wanting a system that will give me some charging while utilizing the trolling motor, but the primary need is for the system to get fully charged (while in storage) for my next boating activity. Looking around on the internet has giving me some ideas, but because I have limited knowledge in this field (and there is so much to consider), I want to make sure that what I’m considering will be adequate for my application. I’ve compared some types of 36-volt system, however that can get very pricey (utilizing MPPT controller) as well as needed significant amount of real estate for mounting solar panels. One video and set-up that did catch my eye was the one of yours that was posted March of last year with the Renogy Rover Boost with the CIGS Flexible 80-watt solar panel that you connected to your golf cart. Of systems that I’ve considered, this really seems to be the simplest, cleanest and most cost effective (with MPPT controller). My boat has a hard top T-top, so I have a great area for attaching the CIGS solar panel. I understand that this system only supplies 10 amps, but was thinking it should be sufficient for what I’m trying to accomplish. Outside of that, it seems that I would need to jump to a 60-amp controller system (because of the 36-volt), which (I think) would also require me to supply 36-volt solar input. This type of system really starts to get pricy and I believe would be an overkill for what I’m trying to do. Any comments or suggesting would be greatly apricated.
36 Volt Trolling Motor System
- Thread starter Ward9922
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Bob B
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I would try to design something to utilize that existing charger .... maybe a small AGM battery connected to a small inverter which would power that charger.
Use the solar panels and SCC to charge that small AGM battery .... You would probably want a low voltage cutoff to between the AGM and SCC keep from over discharging the AGM.
That's just what comes to mind off the top of my head .... others may have better ideas.
Use the solar panels and SCC to charge that small AGM battery .... You would probably want a low voltage cutoff to between the AGM and SCC keep from over discharging the AGM.
That's just what comes to mind off the top of my head .... others may have better ideas.
Bob B, want to make sure that I understand how I would design an inverter system to utilize my existing charger. First I would need an inverter that my charging unit would plug directly into. Next I would need an AGM battery (if I went with that option, also have two additional boat cranking batteries that could possibly be used instead of adding in the AGM battery) to supply power to the inverter. Then I would need a solar panel connected to a SCC that charges the batteries suppling the power to the inverter. Is that correct or am I thinking wrong about this? If this design is correct, would I only need a 12-volt solar panel and controller for charging the inverter battery(s)? What would be the advantage of this design vs my original thoughts of using SCC to directly charge my trolling motor batteries?
Bob B
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I think you are correctly understanding what I'm saying.
The advantage would be that you would have a more conventional system ... and probably less cost.
36V isn't typical. A typical solar charging system would be either 12, 24, or 48V. You already have the charger and could use your existing 12V system to power the inverter that charges your trolling motor batteries.
You could also use the system to maintain your cranking batteries and your trolling motor batteries for an extended storage period if need.
The one drawback would be that the inverter would add an additional device and therefore maybe somewhat reduced efficiency .... but you would have pretty inexpensive off the shelf items.
Bob B, thanks for your feedback and helping me to understand different options I may want to consider. If I do decide to go by way of inverter, it would seem that I would need about a 2000 watt inverter to support my 15 amp charger. Looking around on amazon and other web sites, it looks like there are some brands in the $160 range while other bigger name brands are around the $300 price range. Not sure if the price difference is justifiable or not, but was wondering if there were any brands that you had used that I might want to consider. Additionally, what wattage solar panel should I be considering for this type of application? In my original thread I had mentioned a 80 watt CIGS flexible panel, just because it would be a cleaner and easier installation. However, if would be better for me to have a higher wattage and a more conventional panel, I can make it work (those panels are normally cheaper as well).
Bob B
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That 15A is on the 12V side .... so, if you figure 13V nominal voltage times 15 .... that's 195 Watts and if you add 15% for inverter losses that is only 225 W.
Or, if you figured 5A at 36V = 180W Nominal 39V at 5A = 195
If you double that to be way in the safe range ... 4-500 watt inverter would be more than enough.
The solar panel end is not my strong suite .... maybe get other opinions there. I'd try to size the solar for slightly more power than the 225 W draw if I were doing it.
Or, if you figured 5A at 36V = 180W Nominal 39V at 5A = 195
If you double that to be way in the safe range ... 4-500 watt inverter would be more than enough.
The solar panel end is not my strong suite .... maybe get other opinions there. I'd try to size the solar for slightly more power than the 225 W draw if I were doing it.
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Sorry for bumping an old thread, but what did you decide to do? Trying to figure this exact situation out myself.
Also don't get how one AGM battery powering an inverter could resupply 3 batteries.
