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Old 12-10-2012, 12:18   #1
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12v Solar 48v Batteries

I have 12v panels and I know I can hook them up in series to get 48v but if I leave them at 12v in parallel will it put anything into the 48v bank?

I have an Outback MX60 charge controller.

Thanks
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Old 12-10-2012, 12:34   #2
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Re: 12v Solar 48v Batteries

No.
Most MPPT regulators will not boost voltage and the Outback falls into this category.
The Voc of "12"volt panels is about 22v. Current will not go "uphill" so there will be no output into 48v batteries.
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Old 14-10-2012, 07:19   #3
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Genasun makes an mppt controller that will boost your 12 volts from the panel to 48 volts.
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Old 14-10-2012, 19:55   #4
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Re: 12v Solar 48v Batteries

12v batteries in parallel are still only "one" 12v battery. Which can only charge a 48v battery to something like 11.5 volts.

Now, if your Outback MPPT controller says that it can boost 12v up to 48 volts to do the charging, that's something else again. RTFM on the Outback.
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Old 14-10-2012, 20:02   #5
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Re: 12v Solar 48v Batteries

You have a 48V bank on a Catfisher 28?

Why?

B.
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Old 15-10-2012, 02:01   #6
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Re: 12v Solar 48v Batteries

Quote:
Originally Posted by btrayfors View Post
You have a 48V bank on a Catfisher 28?

Why?

B.
48v is used commonly for electric propulsion. Having a large bank at 48v to power the motors it's sensible to try and use this for house systems and to be able to charge the 48v bank from solar.
There does not seem a great consensus on how best to do this at the moment.

Having one large 48v bank and solar system etc and running the house systems with a 48v to 12v converter would seem the best way to me, but I am not involved in electric propulsion.
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Old 15-10-2012, 06:38   #7
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Re: 12v Solar 48v Batteries

Reminds me of the way that ten years ago we were all told our cars would have 48v power systems and electric power steering and other goodies which would run better on the 48v systems.

Then someone figured out that meant every piddling switch and bulb and socket in the car also had to run at 48V and that just jacked up the costs so high it wasn't worth doing.

The voltage conversions, a trivial engineering exercise. The practical decisions of which way to do it (main bank 12 or 48?) and how often and robustly to convert...Roll the dice? <G>
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Old 15-10-2012, 07:27   #8
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Re: 12v Solar 48v Batteries

Quote:
Originally Posted by noelex 77 View Post
48v is used commonly for electric propulsion. Having a large bank at 48v to power the motors it's sensible to try and use this for house systems and to be able to charge the 48v bank from solar.
There does not seem a great consensus on how best to do this at the moment.

Having one large 48v bank and solar system etc and running the house systems with a 48v to 12v converter would seem the best way to me, but I am not involved in electric propulsion.
Noelex:

I've been using electric propulsion for five years. I kept my exsisting 12 volt house and 48 volt propulsion battery banks separate. My decision was based on being able to monitor each independently and not have all my eggs in one basket. Though while at anchor I will tap into the 48 volt electric propulsion bank from time to time using a 48 volt to 12 volt converter for things like powering the laptop. Since at anchor the 48 volt bank is not being used and has both solar and a 48 volt Marine Air X wind turbine to recharge it after use. Though of course I will also be able to use it as an emergency backup for the 12 volt house bank if I should ever need it. I like backups!
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Old 18-10-2012, 07:38   #9
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Re: 12v Solar 48v Batteries

Yes the 48v bank is for electric propulsion, I have 7 solar panels at 12v with a total of 660watts.

I have ordered a 48v <-> 12v converter but its on 3-4 weeks before it will ship and I will be leaving for the Canaries in the next week.

Right now I have 2 - 12v banks that make up 2 - 230AH 48v banks (4 x 12v batts).

I also have 2 x 120AH 12v bank for the house and electronics.

I am just trying to figure the best way to be able to keep everything charged and running from the solar.

I know I can put a 12v line off the 48v bank if needed.

Can I not put 12v back into each battery on the 48v bank? Like running it in Parallel and Serial at the same time? (sorry if that is such a stupid questions.) The batteries have dual posts on them they are Trojan J185H.

Thanks
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Old 18-10-2012, 09:20   #10
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Re: 12v Solar 48v Batteries

Quote:
Originally Posted by deepthought View Post
Thanks
Slight detour here, your username and current post count (42) are just too ironic to not comment on.

Further reading for those not getting the reference: http://en.wikipedia.org/wiki/The_Hit..._to_the_Galaxy
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