DIY solar battery storage

[Wpk]

Hi all,

2 months ago I had a 7.8kw goodwe 6kw 6000-ms system installed which I was told I could retrofit with a battery, due to limited funds I wanted to go down the sealed lead battery route (48v 15kw) however I then realised this was going to be a hard task.

I looked into ac coupling using a goodwe retrofit charger 5000s-bp to add the functionality which promotes the use of lithium and lead acid batteries however after checking with goodwe they advised they cannot assist and the battery bank I wanted was incompatible, I queried the use of user defined settings in the configuration but they said it was disabled in Australia, I looked into dc coupling solutions(Morningstar) but ended up overwhelmed with information and it’s hard to find what I need to build a home diy solar bank at a cost effective price. I saw renogy offered some components but they don’t seem to be scalable to a house more to a camper an.

Any guidance and help would be greatly appreciated as I’m at my wits end, trying to keep the setup under 5k

 

[DThames]

Before you commit to lead acid, please do study what you get for your money. For a 100ah battery, manufacturers suggest you only discharge to 50% for max battery cycle life. LiFePo4 can cycle 400% or more the number of cycles that lead acid can and also cycle a lot lower than the 50% of lead acid and just keep smiling. Lead acid works and has a good reputation. They have simply been outclassed for many applications.

 

[Supervstech]

How much are those 4 batteries going to cost?

Hi all,

2 months ago I had a 7.8kw goodwe 6kw 6000-ms system installed which I was told I could retrofit with a battery, due to limited funds I wanted to go down the sealed lead battery route (48v 15kw) however I then realised this was going to be a hard task.

I looked into ac coupling using a goodwe retrofit charger 5000s-bp to add the functionality which promotes the use of lithium and lead acid batteries however after checking with goodwe they advised they cannot assist and the battery bank I wanted was incompatible, I queried the use of user defined settings in the configuration but they said it was disabled in Australia, I looked into dc coupling solutions(Morningstar) but ended up overwhelmed with information and it’s hard to find what I need to build a home diy solar bank at a cost effective price. I saw renogy offered some components but they don’t seem to be scalable to a house more to a camper an.

Any guidance and help would be greatly appreciated as I’m at my wits end, trying to keep the setup under 5k

The 300ish Ah cells are very affordable right now, and a set of 16 with a BMS and a cabinet may be a far better value than lead acid.

They said you can’t use lead, but did they say what you CAN use?

 

[Wpk]

The four batteries at $2500 AUD, have attached the approved list for the SBP model but most would end up being $5000 per 4-5kw.

If I was to buy this kit https://lifepo4oz.com/collections/l...attery-pack-kit-with-200a-deligreen-smart-bms would I need the following to charge the bank? https://lifepo4oz.com/products/60a-...96863&pr_ref_pid=7219332481183&pr_seq=uniform

But if I can’t retrofit it using the goodwe 5000s-bp what else could I use? Or have I missed a lot of what I need?

 

[dimsum2]

The four batteries at $2500 AUD, have attached the approved list for the SBP model but most would end up being $5000 per 4-5kw.

If I was to buy this kit https://lifepo4oz.com/collections/l...attery-pack-kit-with-200a-deligreen-smart-bms would I need the following to charge the bank? https://lifepo4oz.com/products/60a-...96863&pr_ref_pid=7219332481183&pr_seq=uniform

But if I can’t retrofit it using the goodwe 5000s-bp what else could I use? Or have I missed a lot of what I need?

Hey mate, did you end up finding an answer to this? Also based in Australia with a GoodWe Inverter looking to add storage via AC coupling...

 

[Wpk]

Hey I did finally get set on a path after weeks of research but then my wife googled lithium batteries exploding so I’ve had to think about an alternative.

Basically you can use the goodwe5000SBP however I would go for a lithium battery box modular system instead of the batteries I found above as they have built in monitoring and bms, if you go for something around current rates you would want to get between 14-15kw and the retrofit for around $11000-13000 [excluding install] without install cost you are looking at a payback between 7-8 years based on .25 cents per kw. Going by an average for 15kw purchase from grid a day. Provided the battery lasts 10 years you would start to see a benefit.

Also DYOR as I’m just an IT technician that builds websites there are other retrofit inverters out there but to keep it simple I would probably stick with goodwe however I did hear they update every so often so specific batteries may be rendered incompatible but I also found their support don’t want to help with non supported batteries. Hope this helps, brace for inflation!

 

[dimsum2]

Hey I did finally get set on a path after weeks of research but then my wife googled lithium batteries exploding so I’ve had to think about an alternative.

Basically you can use the goodwe5000SBP however I would go for a lithium battery box modular system instead of the batteries I found above as they have built in monitoring and bms, if you go for something around current rates you would want to get between 14-15kw and the retrofit for around $11000-13000 [excluding install] without install cost you are looking at a payback between 7-8 years based on .25 cents per kw. Going by an average for 15kw purchase from grid a day. Provided the battery lasts 10 years you would start to see a benefit.

Also DYOR as I’m just an IT technician that builds websites there are other retrofit inverters out there but to keep it simple I would probably stick with goodwe however I did hear they update every so often so specific batteries may be rendered incompatible but I also found their support don’t want to help with non supported batteries. Hope this helps, brace for inflation!

Thanks, Wpk. Data analyst myself so appreciate the info, there's a lot to take in here! Will share what I do if I manage to pull something off.

 

[grunthos]

lithium batteries exploding so I’ve had to think about an alternative.

I know this thread is a little old, but in case you're still looking into this: regular lithium-ion batteries have that concern, but lithium iron phosphate (LiFePo4) do not. They are the one safe chemistry that won't go into thermal runaway like the others. See if perhaps that clarification/distinction helps.

 

[DThames]

I know this thread is a little old, but in case you're still looking into this: regular lithium-ion batteries have that concern, but lithium iron phosphate (LiFePo4) do not. They are the one safe chemistry that won't go into thermal runaway like the others. See if perhaps that clarification/distinction helps.

Indeed.

 

[Tim Tim]

Hey I did finally get set on a path after weeks of research but then my wife googled lithium batteries exploding so I’ve had to think about an alternative.

Basically you can use the goodwe5000SBP however I would go for a lithium battery box modular system instead of the batteries I found above as they have built in monitoring and bms, if you go for something around current rates you would want to get between 14-15kw and the retrofit for around $11000-13000 [excluding install] without install cost you are looking at a payback between 7-8 years based on .25 cents per kw. Going by an average for 15kw purchase from grid a day. Provided the battery lasts 10 years you would start to see a benefit.

Also DYOR as I’m just an IT technician that builds websites there are other retrofit inverters out there but to keep it simple I would probably stick with goodwe however I did hear they update every so often so specific batteries may be rendered incompatible but I also found their support don’t want to help with non supported batteries. Hope this helps, brace for inflation!

Hi I’m in Australia too, well in Mykonos at the moment .

To be honest unless you are building your own batteries the cost is not worth the time it takes to recoup your investment. You should of installed the largest system possible and then switched do doing things like pool pump, laundry and dishwasher during the day.

My last two electricity bills were $58 and $62 per quarter so there is no way I can justify putting batteries at this stage even if I built my own.

I have a 9.9kW system with an 8.2kW inverter and knowing what i know now I should of gone larger as we do not get the solar rebate for a system size increase.

By the way, as previously posted LifePO4 do not explode they are a different chemistry to the battery banks and scooters etc that you have seen catching on fire.

 

[wattmatters]

To be honest unless you are building your own batteries the cost is not worth the time it takes to recoup your investment.

Yeah, grid tied battery economics sucks here. And it’s just not the terrain for DIY.

I have an off-grid DIY system for backup but do plan to move more regular loads to it. I’m going to use server rack batteries to supplement the lead bank I have but it’s as much a hobby as something useful. Very hard to justify on financial grounds alone. It will however reduce my consumption of fossil power.

 

[Tim Tim]

Yeah, grid tied battery economics sucks here. And it’s just not the terrain for DIY.

I have an off-grid DIY system for backup but do plan to move more regular loads to it. I’m going to use server rack batteries to supplement the lead bank I have but it’s as much a hobby as something useful. Very hard to justify on financial grounds alone. It will however reduce my consumption of fossil power.

Hi Wattmatters, yeah i been reading lots of your posts and you have built a beautiful system . Have you looked at connecting into the grid or aren’t you allowed?

I purchased cells from China for my caravan so have 560Ah@12v, but have an itch to buy some more . That of course means more panels, which leads to more batteries then more panels . It is an addictive hobby.

 

[wattmatters]

Have you looked at connecting into the grid or aren’t you allowed?

Grid tied storage requires a level of tech and regulatory requirements to be met which makes it uneconomic. Plus our home is 3-phase which just adds another layer of cost and complexity.

Current grid tied storage is > A$1,000/kWh once installed. It needs to be ~A$250/kWh to make sense here. Big gap.

So the plan is to move some loads off-grid as a way to further reduce fossil consumption. Pretty much the base loads of regular power outlets and lights plus a few extras. It means the grid will mostly support just higher power night time loads such as aircon and cooking as well as be a backup for poor solar periods.

During daytime the grid tied solar will mostly cover these, plus power the hot water and be able to supplement off-grid storage as needed. The off-grid storage is ~A$400/kWh. So barely financially rational. Like I said, I’m ok with that premium for a hobby and to reduce our fossil use by another 5-7 kWh/day.

The other aspect is that by changing grid consumption pattern I can then focus on selecting a retail tariff plan to further minimize our remaining grid consumption cost.