Please help me ?

pauldb38

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Oct 9, 2016
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Hi all I have started to collect 18650's out of old laptops etc. I intend to build 48volt pack etc. The think that has got me a stumped is i have 4Kw solar system but the INvertor doesn't support battery charging. I know the simple solution would be buy a box that supports charging of battery's etc. But i have been told its possible to connected to a existing solar system with a piece of hardware to charge the battery's and i suppose kick in when theirs no solar ?

paul
 
Are you using Grid-tie inverter? Grid-tie inverter will use grid as backup, no battery needed.
If you want to use battery, then you have to change to Solar>MPPT>Battery>Inverter=AC. This is off-grid.
 
DanLim said:
Are you using Grid-tie inverter? Grid-tie inverter will use grid as backup, no battery needed.
If you want to use battery, then you have to change to Solar>MPPT>Battery>Inverter=AC. This is off-grid.

Hi yes sorry my current system is On grid , what i'm wanting to achieve is is have my system charge battery's so when the sun goes down the battery pack will kick in.

paul
 
There is commercial products out there that todes this. But there arent many DIY systems out there as of now. But you could potentially for instance use this device as a part:
https://goo.gl/36y8uu
(Ebay link)

It could use battery power and send to grid and do 0meter. Not sure if its ideal though since i have not looked into it myself.
 
Same product with no customs from europe.

https://goo.gl/DcQ0gW

It is one of my options but 2000w max and it is a mppt inverter so don't know if it can be used with batteries. It is designed to connect to solar panels and grid not for batteries and use it as Dan Lim says as inverter in his equation but grid-tied.

Regards
 
The above linked grid-tie inverter work fine on Battery since you can limit the output. I have seen people do it and also talked to the guys working on the unit in their facebook group.

I though never asked if it was the recommended way of doing it :)

Generally on grid tie: AS long as you can set the output current/limit it you can run it on any incoming source. (Kind of...)
 
pauldb38 said:
DanLim said:
Are you using Grid-tie inverter? Grid-tie inverter will use grid as backup, no battery needed.
If you want to use battery, then you have to change to Solar>MPPT>Battery>Inverter=AC. This is off-grid.

Hi yes sorry my current system is On grid , what i'm wanting to achieve is is have my system charge battery's so when the sun goes down the battery pack will kick in.

paul

I am looking into this myself, apparently you have to configure AC coupling for grid-tie.
 
I have a very similar situation. Grid tied, 16 Kw system, 9.86 Kw tied to SolarEdge 7800 StorEdge inverter, capable of working with Tesla Powerwall and LG batteries. The remaining 6 Kw is tied to a regular SolarEdge 5Kw inverter.

I previously ordered two Tesla Powerwall 2's, but cancelled the order when I found out it would be $18k to have both installed.

Have been harvesting 18650's for the last month, and have enough ready to start building my packs. Was thinking that 14 80p packs would be about 10 Kwh storage. But would like to eventually add another 20 Kwh storage, and would need very little if any from the grid during the evening hours.

Questions:

What other devices do I need to make this work?
Is a 48 volt system the right choice?
Should additional devices needed for this system be enclosed inside the fire resistant cabinet planned for the exterior brick wall of my garage? Or can they be about 20 feet away inside the garage on the wall next to my inverters?
Thinking that 4 x 8 x 1 foot Hardieboard cabinet would be large enough to house 3 rows of 14 packs, but advice welcome...

Thanks for any assistance...

Charles
 
CharlesFrancisSpeakman said:
I have a very similar situation. Grid tied, 16 Kw system, 9.86 Kw tied to SolarEdge 7800 StorEdge inverter, capable of working with Tesla Powerwall and LG batteries. The remaining 6 Kw is tied to a regular SolarEdge 5Kw inverter.

I previously ordered two Tesla Powerwall 2's, but cancelled the order when I found out it would be $18k to have both installed.

Have been harvesting 18650's for the last month, and have enough ready to start building my packs. Was thinking that 14 80p packs would be about 10 Kwh storage. But would like to eventually add another 20 Kwh storage, and would need very little if any from the grid during the evening hours.

Questions:

What other devices do I need to make this work?
Is a 48 volt system the right choice?
Should additional devices needed for this system be enclosed inside the fire resistant cabinet planned for the exterior brick wall of my garage? Or can they be about 20 feet away inside the garage on the wall next to my inverters?
Thinking that 4 x 8 x 1 foot Hardieboard cabinet would be large enough to house 3 rows of 14 packs, but advice welcome...

Thanks for any assistance...

Charles

Charles, I was quoted 6,000.00 including install for a 14kW battery and that includes a 10 year warranty. I have been researching using AC Coupling, I have been looking at a MagnaSine inverter. You would create a micro-grid.
 
as said before, 6k incl. install is unrealistic

"One 14 kWh Powerwall battery $5,500

Supporting hardware $700

Price for Powerwall equipment $6,200

Requires $500 deposit for each Powerwall

Typical installation cost ranges from $800 to $2,000. This does not include solar installation, electrical upgrades (if necessary), taxes, permit fees or any retailer/connection charges that may apply. Installation cost will vary based on your electrical panel, and where you would like your Powerwall installed. Installation will be scheduled after you place your order."

straight from tesla themselfs, everything below the marketprice should make you suspicious
 
MajStealth said:
as said before, 6k incl. install is unrealistic

"One 14 kWh Powerwall battery $5,500

Supporting hardware $700

Price for Powerwall equipment $6,200

Requires $500 deposit for each Powerwall

Typical installation cost ranges from $800 to $2,000. This does not include solar installation, electrical upgrades (if necessary), taxes, permit fees or any retailer/connection charges that may apply. Installation cost will vary based on your electrical panel, and where you would like your Powerwall installed. Installation will be scheduled after you place your order."

straight from tesla themselfs, everything below the marketprice should make you suspicious

Actually the price is with Tesla Energy and it is good only at the time that I have my PV system installed. I suspect since they are going to be here already, they are going to wave the installation fee. None the less, I still will not go with the deal because I will be locked into the Tesla battery. I am more interested in going with a second inverter and using AC Coupling.
 
yeah i guess so, since they are doing everything they just cut it short because they touch the cables anyway

i wouldnt be against the tesla wall, but only if it is a straight battery, not this mischmasch battery inverter ups 1phase-thingy
 
Since my StorEdge 7800 inverter is supposed to be battery friendly, will it "just work" with my DIY Powerwall? I will need to get a SolarEdge electricity meter that I do not currently have, but that is about all that shows up extra if you look at the diagram that can be found on the SolarEdge site. Could also configure a backup panel to supply specific things like AC/frig/water heater. Would rather just have it for backup of everything and just have it tied into my main AC panel.

But it may be that there is software for battery management in the real Tesla Powerwall 2 that it will be looking for...and it will not work...would be nice if someone else here has done this already. Next place to go would be other solar energy forums that are using other types of batteries. I mean, batteries are NOT new here.


Regarding the Tesla Powerwall 2 pricing...

Tesla advertises $5500 per wall, plus installation fees.

Spoke to a Tesla certified installer. He told me that if I really wanted a powerwall soon, that I would need to cancel my order with Tesla, and order through him.

First Powerwall would be $11-12k, second one would be $7K. Said Tesla doesn't tell you about all the costs that go into installation, and he also said he would mark up the Tesla price from $5500 to $7500.

So, I decided to cancel with Tesla, although unable to get anyone from Tesla to call me back to get my $2k deposit money back. No contact whatsoever from Tesla, except for the order confirmation email after I sent the deposit money.

So DIY Powerwall full speed ahead for me. Almost ready to build the packs.
 
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