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so much beauty in dirt
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im looking to have a 48v battery bank for an electric propultion system, besides having a generator for charging i want solar panels also. can solar panels be wired in series to multiply there voltage?
 

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im looking to have a 48v battery bank for an electric propultion system, besides having a generator for charging i want solar panels also. can solar panels be wired in series to multiply there voltage?
Well, yes, but that is not how you do it. You buy a charge controller and set the voltage output that you want.

On the Outback, 48V is an option.
 

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Johnny-

One panel will generally be 16-18 Volts... but the charge controller will step the amperage down and voltage up... To get any kind of real usable output for a 48 VDC panel, you'd probably need at least four 130 Watt panels at a bare minimum.
 

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sound pretty simple, will one panel still make 48v or would you need more?
My opinion on the matter for electric propulsion is that in order for it to be effective you will need a very large array. Even then, it will only be a small supplement to your generator.

- CD
 

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so much beauty in dirt
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Discussion Starter #6
i know the solar wont provide much charging power, it will be like a trickle charger to keep the bank toped off. i could fit 4 decent size panels on my hard top when its built, so this sounds doable, thanks for the replies!
 

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i know the solar wont provide much charging power, it will be like a trickle charger to keep the bank toped off. i could fit 4 decent size panels on my hard top when its built, so this sounds doable, thanks for the replies!
I currently have 4-Kyocera 130's wired in series to an Outback MX60. I get, on average, about 205-210 ah/day in N Texas. Some days it is more, some less. I would estimate it would be more in many latitudes, less in others.

Here is a pic:





 

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For trickle charging and topping up lets say you want a 5amp possible charge current at 48 volts this is about 250 watts total of panels. 2.5 amps would be 125watts of panels. What size will your battery bank be in amphours at 48volts? Note a 100amphour 12V battery gives you 25amphrs at 48vlts. That is the place to start.
 

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favorite solar panel recommendations

I have 2 solar panels for a trickle charge but will be adding more instruments and now need to increase the size of my array. Can anyone make some brand recommendations based on personal experience?

Thanks
 

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Kyocera and Siemens are pretty good brands. I've used both, but neither in a marine situation...
 

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I have 2 solar panels for a trickle charge but will be adding more instruments and now need to increase the size of my array. Can anyone make some brand recommendations based on personal experience?

Thanks
I have Kyoceras and other cruisers I know use them too without issues. They are well made and dependable. They come (at least mine did) with blocking diodes too.

Hope that helps.

- CD
 

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Blocking diodes prevent the panels from draining the batteries at night. If there isn't enough light hitting the panels, they can actually drain electricity...
what do those thingies do?
 

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so much beauty in dirt
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Discussion Starter #14
i dont know how to calculate the exact amperage of a 48v system, i know its would be beter to use 6v bateries, trojan makes a nice 300+ amp 6v, how much would that drop at 48v, and how much would it add up with 8 bateries in series? as for panels i figure i have room for 4 100+ watters, if there aprox. 50" long i could probably squeeze them onto my hardtop
 

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Eight 6 volt 300a/h batteries is the equivilent of ONE 48V battery with 300a/h's. So...you would have 150a/h's at 48V to work with to get to 50% discharge and need re-charging.
Most 100W panels provide 17V output and approximately 5.9 amps so you would be providing about 24amps at 17V with 4 panels BEFORE regulation to 48V...and this works out to 2.2amps or so at 48 volts with a good regulator. Figuring 5 hours of peak equivilent sunlight a day and some conversion losses this would allow you to replace about 10amphours at 48V back into your batteries.
 

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so much beauty in dirt
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Discussion Starter #16
thanks for the reply, sounds like it will definitly be a trickle charge, that should be nice for keeping them topped up at anchor, and will still help over the years on generator time and cycling.
 

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10 ah a day would be 15 days to fully recharge from a 50% drain with no other source of charge (mooring or no generator).

Powering a (48v) 30amp motor with 150ah of usable battery gives you 5 hours of run time, and if you are day sailing you'd need roughly a hour or less to just get out and sail (location dependent of course).

That 30ah for a day sail would be replaced in 3 days. Doing it twice on a weekend cruise plus minus overnight drain for house circuits (I run 40ah on average, but that's at 12v, you can call it an additional 10ah equivalent) and you'll be pretty much good to go week after week, if everyday is sunny enough to get you 10ah, 100% efficiency etc.

If the motor takes more than 30ah, adjust your throttle, run time etc.. and you'll be fine. Make sure you don't go short on system monitoring (meters).
Note normally I'm as anti-electric motor as it gets, for me this is a very positive post :)
 

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Also worth mentioning... 30 amps at 48 volts is 1440 watts - a little less than 2 hp. Works OK on a 16 foot boat but may not get you out of trouble on something even slightly larger.
 

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Max current on the 48v Solidnav is 150 amp, at that rate there would be on one hour total run time at full throttle before cycling (damaging) the proposed battery bank.

As I said in my post, I was trying to be positive :)

SolidNav :: The first alternative for everyone

of course the controller is rated at 4kw, so the max you can get out of it is somewhere around 5.3hp, disregard the link's stated 24hp equivalent - that would be at 150amp x 48v, 7200 amp controller needed.

Gosh, reckon they are fudging the numbers a tad?
 

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Chuckles-

Everyone knows that you can always trust a manufacturer's claims on their product completely. They'd never exaggerate or lie... would they???
 
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