Advice on inverter/solar upgrade

[markrw]

I currently have a 12v Axpert with 600W PWM charger and 600W of panels connected

I just replaced my Lead Acid Batteries with a Hubble S120 Lithium battery and so far its running nicely.

I use it mainly for load shedding but also the extended outages we seem to have more frequently these days in jhb. I mainly run small loads....TV, router, laptop etc and sometimes a PC or 2.

I would like to upgrade to a second Hubble battery mainly for the extended outages. I would however also love to be able to upgrade my solar but am currently at the limit of the inverter

I have a few choices and would like some advice on the pros and cons of each:

1) I could simply get a second Hubble battery and connect in parallel but I wouldn't be able to upgrade my solar

2) I could get a 3Kva 24 inverter with a 1200-1500 MPPT solar charger. This would allow me to charge the batteries at a higher current from DC (Currently my 1000w only allows 20A) and would allow me to upgrade my solar array. I would have to replace my 12V panels though. I would then connect the 2 Hubble batteries in series. Here I wanted to know the pros and cons of going to a 24v system with batteries in series. I see on the specs for the Hubble batteries I would need a cell balancer if connecting in series. Is this recommended? Where do I get one? How much are they? I tried to find but could only find battery balancers, not cell balancers. How do I connect it to the batteries?

3) Is it possible to get a separate MPPT charge controller with a new set of panels and connect that in parallel with my inverter so both the PWM of the inverter and the MPPT charge controller can both charge the batteries together? So that way the PWM in the inverter can be used to run the load and excess charge batteries and the separate MPPT controller can charge the batteries. Does this work?


Also do you know if Axpert inverters are able to charge from petrol generators? I see the new ones say they they charge from AC or generator power. Not sure about my 1000W 12V.

 

[TheChamp]

12V panel? How does your panel configuration look like? Strings and panel specs?

 

[markrw]

I currently have 4x150W 12v (or 18V) panels for the PWM controller in the inverter

If I upgrade with MPPT then I know I can go for much bigger panels

 

[Kawak]

12v panels are either very small or very old, which configuration is yours?

1. For your use case of backing up small items, do you really need more than 5kw? You should have enough to last 12 hours already. You are correct, parallel means you don't need a new inverter but it doesn't mean not upgrading your solar, you can also do solar in parallel.

2. Going to 24v will save on wiring, you no longer need huge wires, but 24v is still not high, you mention mppt, you can usually go much higher when using mppt chargers. As with batteries, balancing shouldn't be needed at 2, I don't use hubble but their BMS should be able to handle at least 4 in series at 48v as that's the standard install. Cell balancers are basically BMS units that control how each Cell takes in voltage and ensure they are within a close range.

HA02 Battery Balancer

Battery Balancer: Can be connected to 24V, 36V or 48V battery banks (2, 3 or 4 in series) Monitors each battery voltage On deviation of more than 10 mV, the higher voltage battery will be discharged to the lower voltage batteries until all the battery voltages are equal Battery banks of...

shop.thesunpays.co.za

3. Not possible, mppt needs to sense voltage and adjust, any other input will interfere and you won't get any use out of that. You can definitely get separate charge controllers but makes no sense cost wise. I would setup your current 1kva as an inverter only, switch off chargers entirely and just use it that way.

Axpert inverters can definitely charge from AC, they are hybrid which means they can take power from solar or grid. Generator is "grid" or AC in this case.

So, I general, lithium batteries can be put in series with little trouble, parallel will depend, solar panels can be in series or parallel, in series the large panels will loose amps, volts get added, parallel is the opposite, so it all depends on what you have currently and what you want to eventually achieve as solar is a process.

 

[markrw]

12v panels are either very small or very old, which configuration is yours?

1. For your use case of backing up small items, do you really need more than 5kw? You should have enough to last 12 hours already. You are correct, parallel means you don't need a new inverter but it doesn't mean not upgrading your solar, you can also do solar in parallel.

2. Going to 24v will save on wiring, you no longer need huge wires, but 24v is still not high, you mention mppt, you can usually go much higher when using mppt chargers. As with batteries, balancing shouldn't be needed at 2, I don't use hubble but their BMS should be able to handle at least 4 in series at 48v as that's the standard install. Cell balancers are basically BMS units that control how each Cell takes in voltage and ensure they are within a close range.

HA02 Battery Balancer

Battery Balancer: Can be connected to 24V, 36V or 48V battery banks (2, 3 or 4 in series) Monitors each battery voltage On deviation of more than 10 mV, the higher voltage battery will be discharged to the lower voltage batteries until all the battery voltages are equal Battery banks of...

shop.thesunpays.co.za

3. Not possible, mppt needs to sense voltage and adjust, any other input will interfere and you won't get any use out of that. You can definitely get separate charge controllers but makes no sense cost wise. I would setup your current 1kva as an inverter only, switch off chargers entirely and just use it that way.

Axpert inverters can definitely charge from AC, they are hybrid which means they can take power from solar or grid. Generator is "grid" or AC in this case.

So, I general, lithium batteries can be put in series with little trouble, parallel will depend, solar panels can be in series or parallel, in series the large panels will loose amps, volts get added, parallel is the opposite, so it all depends on what you have currently and what you want to eventually achieve as solar is a process.

Not sure if I understood about 5kw? I currently have the single Hubble battery which is 1.2Kw and was looking at a second. So that would me 2.4Kwh?

My current panels are 8A each. I have 4 panels in strings of 2 each taking 16A each. So I already have the wiring for higher amps. If I ditched my 12V system and went for 24V and replaced my 150W panels with 330W panels (which are also 8A, 36V I think) I could use all the same wiring and fuses.

I did see battery balancers but apparently I would need a cell balancer, makes sure each cell charges to 4.2V? I'm very new to Lithium so I only know a little.

If I turned off charging on my current Axpert, how would I charge from grid? What would happen if I bought a MPPT charge controller and bought new panels and charged from AC on the inverter and solar on the MPPT. Only problem there is its almost as expensive to buy a 50A charge controller as it is to buy a whole new 3KVA inverter with 50A charger.

I have never actually tried to charge my inverter from my generator for fear of damaging it. I used to have one of those Smart Power inveter trolleys and it was not happy to charge from the generator. I don't think it likes the inconsistant frequency. Has anyone here tried to charge their Axpert from a generator?

Would there be an issue putting the Hubble batteries in parallel? I see you said parallel will depend.

 

[markrw]

12v panels are either very small or very old, which configuration is yours?

1. For your use case of backing up small items, do you really need more than 5kw? You should have enough to last 12 hours already. You are correct, parallel means you don't need a new inverter but it doesn't mean not upgrading your solar, you can also do solar in parallel.

2. Going to 24v will save on wiring, you no longer need huge wires, but 24v is still not high, you mention mppt, you can usually go much higher when using mppt chargers. As with batteries, balancing shouldn't be needed at 2, I don't use hubble but their BMS should be able to handle at least 4 in series at 48v as that's the standard install. Cell balancers are basically BMS units that control how each Cell takes in voltage and ensure they are within a close range.

HA02 Battery Balancer

Battery Balancer: Can be connected to 24V, 36V or 48V battery banks (2, 3 or 4 in series) Monitors each battery voltage On deviation of more than 10 mV, the higher voltage battery will be discharged to the lower voltage batteries until all the battery voltages are equal Battery banks of...

shop.thesunpays.co.za

3. Not possible, mppt needs to sense voltage and adjust, any other input will interfere and you won't get any use out of that. You can definitely get separate charge controllers but makes no sense cost wise. I would setup your current 1kva as an inverter only, switch off chargers entirely and just use it that way.

Axpert inverters can definitely charge from AC, they are hybrid which means they can take power from solar or grid. Generator is "grid" or AC in this case.

So, I general, lithium batteries can be put in series with little trouble, parallel will depend, solar panels can be in series or parallel, in series the large panels will loose amps, volts get added, parallel is the opposite, so it all depends on what you have currently and what you want to eventually achieve as solar is a process.

https://www.hubblelithium.co.za/uploads/1/3/5/0/135079623/hubble_lithium_s-120_brochure.pdf

"External cell balancer required when placing in series to ensure balancing"
I have been trying to see what these look like and how to connect them but am struggling

 

[Kawak]

Not sure if I understood about 5kw? I currently have the single Hubble battery which is 1.2Kw and was looking at a second. So that would me 2.4Kwh?

My current panels are 8A each. I have 4 panels in strings of 2 each taking 16A each. So I already have the wiring for higher amps. If I ditched my 12V system and went for 24V and replaced my 150W panels with 330W panels (which are also 8A, 36V I think) I could use all the same wiring and fuses.

I did see battery balancers but apparently I would need a cell balancer, makes sure each cell charges to 4.2V? I'm very new to Lithium so I only know a little.

If I turned off charging on my current Axpert, how would I charge from grid? What would happen if I bought a MPPT charge controller and bought new panels and charged from AC on the inverter and solar on the MPPT. Only problem there is its almost as expensive to buy a 50A charge controller as it is to buy a whole new 3KVA inverter with 50A charger.

I have never actually tried to charge my inverter from my generator for fear of damaging it. I used to have one of those Smart Power inveter trolleys and it was not happy to charge from the generator. I don't think it likes the inconsistant frequency. Has anyone here tried to charge their Axpert from a generator?

Would there be an issue putting the Hubble batteries in parallel? I see you said parallel will depend.

Sorry, i read Hubble 5120 and thought its a 5.5kw battery, my bad.

The same file you provided also mentions configuration where it allows a 4x4 for upto 16, and it includes BMS so the external balancer make no sense and will interfere with their internal BMS, best to actually enquire with them.

Lithium batteries relies on the BMS to ensure correct voltage across cells, so it really depends on the BMS thats included, once again, it makes no sense to require a balancer for anything less than 4 in a bank.

if you go into the settings menu of your Axpert inverter, you can select charge priority and set it to grid only or all off, you can then setup your new inverter as the sole charger. however, you need to have an end goal in mind when you go further into this setup, do you intend to be off grid? to have a much bigger system to cover for the entire home? piecing things together will only go so far before you will eventually end up with loads of pieces that can't fit.

I ran a 24V axpert as my primary backup power setup from 2009, until I started my solar journey in 2013, have used my generator on it with no issues, but every generator is different, when you say your power trolley didn't like the inconsistent frequency, what were the symptoms?

Parallel is an issue when internal BMS isn't designed for it, but your hubble is capable of a 4x4 config so that should be ok as well.

 

[markrw]

3. Not possible, mppt needs to sense voltage and adjust, any other input will interfere and you won't get any use out of that. You can definitely get separate charge controllers but makes no sense cost wise. I would setup your current 1kva as an inverter only, switch off chargers entirely and just use it that way.

What about if I another another PWM charger? Would that work better in parallel with the inverter?

 

[TheChamp]

What about if I another another PWM charger? Would that work better in parallel with the inverter?

What is the motivation for this, to find use for the smaller panels?

 

[Kawak]

What about if I another another PWM charger? Would that work better in parallel with the inverter?

PWM, in your case, literally means wasting at least 33% of energy as it modulates voltages to charge batteries, ie. from 18/36V to 12/24V at the same amps. that is a no go.

 

[markrw]

What is the motivation for this, to find use for the smaller panels?

That would have allowed me to keep my current inverter and my current panels but to increase my solar power using an additional controller. That would allow me to upgrade my current system at the lowest cost

 

[TheChamp]

That would have allowed me to keep my current inverter and my current panels but to increase my solar power using an additional controller. That would allow me to upgrade my current system at the lowest cost

I get you, unfortunately some setups are just not scalable, that's why it's so important to get the foundation of your system right.

If only there was a way to set you charger to zero Amps on the inverter but I doubt it can.

Yes a parralel pwm charger can work but you will need to make sure the current is properly controlled.

 

[markrw]

I get you, unfortunately some setups are just not scalable, that's why it's so important to get the foundation of your system right.

If only there was a way to set you charger to zero Amps on the inverter but I doubt it can.

Yes a parralel pwm charger can work but you will need to make sure the current is properly controlled.

I got the 1000W converter from a friend who had it lying around for an awesome price so it was a no brainer to get at the time. I could probably sell it now for the same as what I paid. So I don't really mind replacing the inverter with a large one. The throw away is just my current 12V panels which won't really make a lot of sense in a 24V system. I suppose I could connect the 4 panels into 2 series strings and then buy 2 new 300W panels to give me 1200W on a new inverter but then I also need additional roof mounts and rails.
I have been looking at some youtube videos about connecting multiple charge controllers (even mixing PWM and MPPT) and it sounds like it will work as long as they have the same voltage settings
(

)
I just obviously don't know if it might affect the longevity of the batteries.
I would have contemplated trying it out but the a Victron 50A MPPT controller is more than half the price of a whole new inverter. Not sure why.

On my inverter I can set total charge amps and AC charge amps. I don't think zero is a setting but I wouldn't want that anyway because I want to charge my batteries from AC when available.

 

[TheChamp]

I got the 1000W converter from a friend who had it lying around for an awesome price so it was a no brainer to get at the time. I could probably sell it now for the same as what I paid. So I don't really mind replacing the inverter with a large one. The throw away is just my current 12V panels which won't really make a lot of sense in a 24V system. I suppose I could connect the 4 panels into 2 series strings and then buy 2 new 300W panels to give me 1200W on a new inverter but then I also need additional roof mounts and rails.
I have been looking at some youtube videos about connecting multiple charge controllers (even mixing PWM and MPPT) and it sounds like it will work as long as they have the same voltage settings
(

)
I just obviously don't know if it might affect the longevity of the batteries.
I would have contemplated trying it out but the a Victron 50A MPPT controller is more than half the price of a whole new inverter. Not sure why.

On my inverter I can set total charge amps and AC charge amps. I don't think zero is a setting but I wouldn't want that anyway because I want to charge my batteries from AC when available.

I would just buy a cheap PWM, an MPPT will be a good waste in such a situation.

 

[Stokstert]

https://www.hubblelithium.co.za/uploads/1/3/5/0/135079623/hubble_lithium_s-120_brochure.pdf

"External cell balancer required when placing in series to ensure balancing"
I have been trying to see what these look like and how to connect them but am struggling

That is a typo in the Hubble S120 brochure, it should read battery balancer and not cell balancer. Cell balancing is done by the internal BMS.
Geewiz has this one with Bluetooth app.

 

[catman37]

Can you use this one as well?

Victron Battery Balancer - multiple battery SoC balancing

Victron Battery Balancer - multiple battery SoC balancing

www.geewiz.co.za

 

[TheChamp]

Can you use this one as well?

Victron Battery Balancer - multiple battery SoC balancing

Victron Battery Balancer - multiple battery SoC balancing

www.geewiz.co.za

Yes.

 

[catman37]

Yes.

Thanks.

 

[catman37]

Hi All.

I have a 24v inverter. 4 Hubble S120 batteries
2 x sets of 24v in parallel.

Will this balancer work with 2 sets of 24v in parallel?

Hubble Battery Balancer with Bluetooth

Hubble Battery Balancer with Bluetooth Available from Invest Solar. Buy Online or at one of our at of our many stores in South Africa

investsolar.co.za

Thanks

 

[wingnut771]

Hi All.

I have a 24v inverter. 4 Hubble S120 batteries
2 x sets of 24v in parallel.

Will this balancer work with 2 sets of 24v in parallel?

Hubble Battery Balancer with Bluetooth

Hubble Battery Balancer with Bluetooth Available from Invest Solar. Buy Online or at one of our at of our many stores in South Africa

investsolar.co.za

Thanks

The balancer only needs to see 2 batteries, the batteries in parallel will self balance.