48 vdc system with 100% usage of PV and Wind energy

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48 vdc system with 100% usage of PV and Wind energy

Postby jweaver72 on Wed Jan 09, 2019 7:04 am

Application: Off grid Wireless Internet Service Provider
Equipment: Flex Power 4048
Electronics: Primarily all 48 vdc (One or two items are 110 vac)
Power generation: 10 - 327 watt panels, 1 2000 watt wind generator and a backup Generac
Batteries: Nissan leaf Li-I battery bank 28 kw

SCENARIO:
I want to be able to run the system with both 48 vdc and 110/220 vac. But I want the solar and wind to always be used before the batteries are tapped into.

My understanding is this. If I pull my 48 vdc from direct from the batteries the following will happen. The charge controller will charge to batteries to the set SOC and then stop charging the batteries even though the sun or wind is still generating and the energy will be dumped. I do not want any energy dumped.

I feel like the solution would be to run straight 110/220 service in the facility and use converters to get my 48vdc but then I get the loss of efficiency on two conversions.

Any suggestions?
jweaver72
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Re: 48 vdc system with 100% usage of PV and Wind energy

Postby jweaver72 on Wed Jan 09, 2019 9:09 am

I don't know if this can be achieved buy using the system contacts and a relay or if there is an optional device to add to the system.
jweaver72
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Re: 48 vdc system with 100% usage of PV and Wind energy

Postby Mike Curran on Wed Jan 09, 2019 10:11 am

I haven't experience with off grid systems and newer inverters like yours with multiple AC input modes to choose from, but I'll take a shot and hopefully smarter folks will chime in:

You might set up your inverter to operate in mini grid mode, described in the FXR manual like this:
Screenshot_20190109-120030.jpg
(link to manual: http://outbackpower.com/downloads/docum ... erator.pdf)

Then you could use the aux contact of your inverter to auto start your generator at a battery voltage slightly above the "connect to grid" setpoint so your genny is up and running when mini grid switches to grid (your generator) power.

- Mike
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
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Re: 48 vdc system with 100% usage of PV and Wind energy

Postby jweaver72 on Wed Jan 09, 2019 10:29 am

Mike Curran wrote:I haven't experience with off grid systems and newer inverters like yours with multiple AC input modes to choose from, but I'll take a shot and hopefully smarter folks will chime in:

You might set up your inverter to operate in mini grid mode, described in the FXR manual like this:
Screenshot_20190109-120030.jpg
(link to manual: http://outbackpower.com/downloads/docum ... erator.pdf)

Then you could use the aux contact of your inverter to auto start your generator at a battery voltage slightly above the "connect to grid" setpoint so your genny is up and running when mini grid switches to grid (your generator) power.

- Mike


That is interesting and I will read into that further. One of the things Im wondering about is how does it work when the bank has been built for 3 days of autonomy? We designed it this way so that the site only ever goes to the Genset as the last resort.
jweaver72
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Re: 48 vdc system with 100% usage of PV and Wind energy

Postby blackswan555 on Wed Jan 09, 2019 10:35 am

I am not sure of your battery charging requirements, Following is for "normal" FLA, gel etc,

My understanding is this. If I pull my 48 vdc from direct from the batteries the following will happen. The charge controller will charge to batteries to the set SOC and then stop charging the batteries even though the sun or wind is still generating and the energy will be dumped. I do not want any energy dumped.


Nearly right, The controller will charge the batteries at absorb voltage untill parameters are met then drop down to float voltage, While you have enough power coming in, Nothing will be taken out of batteries as the controller will try to hold float voltage,
Outback controllers do not "dump" your wind probably does,

Tim
My comments are based on my experience and research, They are not endorsed or checked by Outback.I am an independent British electrician living in Spain, So please take this into account when reading /acting on my post`s.
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Re: 48 vdc system with 100% usage of PV and Wind energy

Postby jweaver72 on Wed Jan 09, 2019 12:08 pm

blackswan555 wrote:I am not sure of your battery charging requirements, Following is for "normal" FLA, gel etc,

Nearly right, The controller will charge the batteries at absorb voltage untill parameters are met then drop down to float voltage, While you have enough power coming in, Nothing will be taken out of batteries as the controller will try to hold float voltage,
Outback controllers do not "dump" your wind probably does,

Tim


So as long as my DC equipment can handle the absorb voltage then it will continue to use the energy being created from the solar? That being said do I hook my DC load up to the batteries or should the shunt?
jweaver72
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Posts: 4
Joined: Wed Jan 09, 2019 6:03 am
My RE system: Radian 4048, Generac and LI-I Battery bank


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