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Hi From Seattle
#1
Hi Everyone!

I have been lurking around here for a couple years and was collecting old laptop batteries for a while, but now I've decided to go with Leaf batteries for my powerwall. I have been driving a Leaf since 2011 and was hoping at some point the release of vehicle-to-home box for backup power, but this doesn't seem like it's going to happen anytime soon. Thus the reason to build my own battery. I have a 10KW solar array and want to start using stored energy for evening consumption and use the least amount of power from the grid as possible. I have learned a whole lot here but have several questions I'll pose in the correct threads.
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#2
Welcome.  Batrium has a nice youtube on leafmons to manage a battery bank https://youtu.be/794Q4oWjhP0
For a 10kw array, you could use at least a 40kwh battery bank or larger - maybe some thing like this Smile .

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#3
(08-29-2019, 09:14 PM)OffGridInTheCity Wrote: Welcome.  Batrium has a nice youtube on leafmons to manage a battery bank https://youtu.be/794Q4oWjhP0
For a 10kw array, you could use at least a 40kwh battery bank or larger - maybe some thing like this Smile .

Thanks @OffGridInTheCity. I figured I'd be using the Batrium w/ Leafmons. But 40kwh battery is way more than I figure I'll need. Probably don't even have the space for that and the first 20 Leaf modules I purchased which I still need to test probably only make up about 6.5-7.0kwh at best. I should have done more research before purchasing those. My original thinking was if I can get to 20kwh, that would be plenty to run household loads in the evening.
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#4
(08-30-2019, 07:07 PM)ZimInSeattle Wrote:
(08-29-2019, 09:14 PM)OffGridInTheCity Wrote: Welcome.  Batrium has a nice youtube on leafmons to manage a battery bank https://youtu.be/794Q4oWjhP0
For a 10kw array, you could use at least a 40kwh battery bank or larger - maybe some thing like this Smile .

Thanks @OffGridInTheCity. I figured I'd be using the Batrium w/ Leafmons. But 40kwh battery is way more than I figure I'll need. Probably don't even have the space for that and the first 20 Leaf modules I purchased which I still need to test probably only make up about 6.5-7.0kwh at best. I should have done more research before purchasing those. My original thinking was if I can get to 20kwh, that would be plenty to run household loads in the evening.

A 10kw array is a prettty good size.  My own is 7kwh PV array, a 40kwh battery bank, a consumption profile of 2,800watts/hr for 14hrs a day (in summer).   This leads to a average of 15kwh/day battery delivery to avoid loosing any PV array power.    The 15kwh/day battery delivery is 14/40 = 37.5% DOD - which is good for battery life.

By extension, if you have the same consumption model, a 10kw array will lead to an average of 21kwh/day battery delivery - which would be >100% DOD (on a 20kwh battery) assuming you don't want to lose any PV array power for the day.

Of course this depends on your specifics (consumption profile, space available, $$, and goals) and I don't mean it as discouraging in any way...   a 20kwh battery would certainly be a substantial battery.   

My goals are
1) To use all PV power that I get - e.g. do not leave any on the table due to reaching float on the battery bank
2) To extend the life of my battery as long as I can - I need 22yrs to get my money back which requires a low DOD Smile
3) To have a large enough system to live 'OK' in a Puerto Rico type event.

From that viewpoint, my suggestion is to leave room in your design for a larger battery in the future as I think you'll find in the long run that you'll need a larger one to efficiently use 100% of your PV power and to prolong the life of your battery.
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#5
Thanks @OffGridInTheCity. You make some good points. I'll have to find a way to expand battery pack. My solar array is grid tied and between production credits and net metering the PUD has been paying me for excess electricity. The production credit program ends next June so I'll be just on net metering. That's when battery bank will come in handy.
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Who read this thread?
14 User(s) read this thread:
Sean (08-31-2019, 02:40 PM), jawe (09-04-2019, 11:56 PM), hschlech (09-10-2019, 12:44 PM), ZimInSeattle (09-05-2019, 04:03 PM), Suncatcher1 (09-01-2019, 03:41 AM), OffGridInTheCity (09-05-2019, 04:40 PM), ajw22 (08-30-2019, 11:07 PM), chuckp (08-30-2019, 10:36 PM), Walde (09-01-2019, 09:00 AM), Oz18650 (09-11-2019, 01:30 AM), slimf (09-09-2019, 03:44 AM), Geek (09-06-2019, 01:18 AM), jdeadman (09-05-2019, 07:42 PM), Saaide (09-06-2019, 06:13 PM)

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