Battery Bank sizing- 17ft

[freejuice]

Hi Everyone,
Since the 17ft bug has a hold of me, I was wondering what is the average size  battery banks people are using for the 17ft alternators?
 
 I know everything is dependenat on the available winds and alternator voltage..so heres what I've got:
 Wind up and down the scale....the last two days we have had 25-30 mph gusts with a steady blow of about 15mph, but a daily average would be 8-10 miles an hours ( some days more.... some days less)
Since most of you folks steered me towards a 48 volt system, I will eventually wire everything for 48v.

 So the bare mimimum is 8, 6v batteries, however since I dont have any hands on experience with the power generating abliity of the 17 footer, I'm wondering if 8, 6volt batteries would be considered a minimum for my wind conditions....or should I think of larger capacity?
 Thanks everyone!
 Gavin

 

[bj]

I don't have good knowledge,  maybe not even bad knowledge, anyway for two 10 footers my plan is
double that.  Kind of loosly based on my draw, (shop is large) my wallet (small).  I figured that as long as I
don't wait too long, I can add more strings of eight.
You, however will have more from the 17 footer, so maybe 8 makes sense.
I'll be watching your replies as well

bj  Lamont AB Can.

[TomW]

freejuice;

I would suggest that you not use # of batteries as a unit of battery size.

Much better to think in terms like AH (Amp Hours) or KWH (Kilo Watt Hours).

The reason is batteries come in an astounding variety of voltages and capacities.

By using units of energy you can eliminate much confusion.

A 17 footer is a large power source and just off the top of my head I think you will need several hundred AH of capacity.

One 10 footer here with 850 watt solar assist can quickly drive my 450 AH 24 volt bank into dangerous territory on voltage.

A 17 footer is much more powerful than both my mill and solar cranking full out combined. Wild Arse Guess is you will want something like 1000 AH to be able to soak up the power that will make. No math just guesses but the basics apply.

That is a LOT of power.

Just early off the top of my head response.

Good Luck with it.

Tom

[Volvo farmer]

This is the way I read your question.

I have 1200 sq ft of roof.  It rains here every week 1/2" or so but sometimes it rains 2" overnight.

How big of a rain barrel should I buy?

Do you see any missing information in my question? 

[Boss]

I do, I do, forgot to mention duration! kilowatt - hours

[ghurd]

By 8 6V batteries, I figure you are thinking like Sam's Club golf cart batteries?
That would be ~210AH.

A 48V 17' can make bursts past 100A, and sustained past 80A.
I like C/20 charging.  80A x 20H = 1600AH.  That's 8 sets of 8 golf cart batteries.  That's a lot of batteries to deal with, especially when they start showing some age.

Need to consider some Huge batteries.  Probably something that comes in 2V packages?
G-

[DanG]

And... you need to have work for the batteries to accomplish --- when the bank finishes charging in 15 minutes what other work do you have for the incoming energy to perform?

[ChrisOlson]

Much better to think in terms like AH (Amp Hours) or KWH (Kilo Watt Hours

kilowatt-hours is probably better.  Amp-hours doesn't mean a lot because if you take four 12 volt 250 ah batteries and connect them in series for 48 volt you have a 48 volt 250 ah battery bank and every battery in the bank has to deliver the full total amp load of the inverter.  If you take those same four batteries and connect them in parallel you have a 12 volt 1,000 ah battery bank and every battery has to deliver 1/4 of the total amp load of the inverter.

Both banks have the same kWh capacity.
--
Chris

[freejuice]

Hi Folks thanks for the helpful replies,
 Volvo, I guess I will need a bigger rain barrel, sorry for sounding so elusive but i was thinking about the voltage string setup more than amp hours, i realize it amp hours and kilowatt hours are important here but I didn't add them in, sorry about that.    I have done what I should have done, that is, get a good aeronometer and take a yearly average, as usual I'm "guesstimating"

Ghurd, Tom,
 Yes they are the Sam's club variety 6v I was basing my question on....but it looks like those 2volt forklift batteries are the way to go...I was wondering just how many 6 v's something like a 17 footer could load up...it appears the alternator can generate some significant power....by far it overshadows a 10 footer! Ghurd, you're saying the 17 footer could keep a battery bank of 64 6v batteries charged....gasp....gulp!

Dan G,
 Wow....15 mins later a bank of 8 would be full again?
 The water heater would be my next dump load on the 17 footer, and I would like to ad more storage capacity...I hope to run a majority of the 110 voltage in the house from this beast....I have to add as I go...I'm not poor but not rich..I'm in the meaty part of that bell curve, I guess I will add capacity as I go.

Chris, As I buy batteries, I will have to do it in blocks of 48 volts....buy some now and add some later and so on...it will be a situation of series/parallel
 
Bj, Stay tuned, I will  have to add batteries adhoc and dump the load like a mad man until I add capacity

Boss, Thanks I ned to start speaking in amp-hours or kilowatt hours