tetrasection

I am sorry, I do not completely agree with you here. Anyone that goes solar, knows they need to manage their power consumption constantly and will probably already have a lot of other energy saving tricks installed all over their home.

So let's say we have the parents over for a whole week. That is one (maybe two) extra LED lights constantly burning from (at worst) 6 to 10 at night, given they don't switch off the light in the room, which I will switch off for them. Maybe an extra fan running at night if it is in the summer months.

The rest of the electricity usage will be consumed in common areas that we are in any case occupying. Geysers are solar, gas cooking etc. So I do not see how this will seriously affect a properly sized system. You should size your system not for your best days but your worst or at least your average days.

Then also, what Google says regarding gel batteries does not imply guarantee from the supplier. Which is much lower than 6 years.

Yes gel is much cheaper, but I do still think that Lithium has a lot more advantages over them, especially as part of a daily managed system where they are cycled every single day.

So to each his own, I know I Victron is much better than my Axpert, but that is what I could afford, rather opting for optimal PV and battery backup and rather at this stage seeing the inverter as 'n much lower priced "consumable" for I few years, then moving on to something else, hopefully budget allowing something better.

59 minutes ago, PhilFM said:

tetrasection

I am sorry, I do not completely agree with you here. Anyone that goes solar, knows they need to manage their power consumption constantly and will probably already have a lot of other energy saving tricks installed all over their home.

So let's say we have the parents over for a whole week. That is one (maybe two) extra LED lights constantly burning from (at worst) 6 to 10 at night, given they don't switch off the light in the room, which I will switch off for them. Maybe an extra fan running at night if it is in the summer months.

The rest of the electricity usage will be consumed in common areas that we are in any case occupying. Geysers are solar, gas cooking etc. So I do not see how this will seriously affect a properly sized system. You should size your system not for your best days but your worst or at least your average days.

Then also, what Google says regarding gel batteries does not imply guarantee from the supplier. Which is much lower than 6 years.

Yes gel is much cheaper, but I do still think that Lithium has a lot more advantages over them, especially as part of a daily managed system where they are cycled every single day.

So to each his own, I know I Victron is much better than my Axpert, but that is what I could afford, rather opting for optimal PV and battery backup and rather at this stage seeing the inverter as 'n much lower priced "consumable" for I few years, then moving on to something else, hopefully budget allowing something better.

Totally agree, it's very dependent on your appliance setup and guests.

In my case there is no municipal water so a pump is required that pulls about 1.2kw which is the main concern. With added guests come showers, hand basin and toilet use, washing machine use, extra dishes etc so the pump is running a lot. They also bring laptops and on occasion an x-box.

So my situation is a lot different to yours where you only need a bit of extra power for lighting. In your case lithium is the obvious choice.

In my case I normally only use about 20% of my capacity daily so I have 80% spare capacity for use on these occasions. Using lithium in that same way would be very expensive and would not make much sense.

Edited October 8, 20205 yr by tetrasection

So I disconnected each battery one by one last weekend and did a quick 15minute 30W load test after a full day of sun. Found that 2 of my lead acid batteries went down below 11V after only 5 minutes  Two others went just below 12V after 15 minutes (not great) and the other 4 were all 12.2-12.4V. 

So I've removed the worst two and now the battery array is back to getting almost fully charged every day

Looks like I might no longer need to charge off mains for a bit every evening like I have been for the past few months and hopefully I won't have to upgrade to Lithium's quite yet, although I appreciate all the info shared here for when I do!

I noticed that if I put these two worst batteries on a charger they act like they are charged almost immediately and the voltage rises quickly, is this a sign of completely dead lead-acid batteries?

 

On 2020/10/02 at 6:28 PM, Boerseun said:

You Should have a Look at the ZTE 4.8 KW lithium battery not badly priced.

Hi, does anyone have experience with this battery? How does it perform compared to other brands?

On 2020/08/25 at 9:40 AM, gooseberry said:

For interest's sake, can you put two Pylontech US2500 batteries in series if you upgrade your inverter later?

Actually was going to ask the same question, meaning that 24v + 24v = 48v though running Pylontech UP2500 2.4kWh pack... is this feasible... anyone on the forum?

Pylontech say not to in their instructions.

I would not risk it.

On 2020/08/24 at 6:44 PM, Lindsay said:

I don't think I've ever used much more than 50A from my current setup and that was only for a brief moment. I never run the inverter to it's full capacity, usually peak at less than 1000W.

 

Pity they don't offer the sizes for 24v that they have for 48v, 3.5kWh would have been better, although I gather I could put two 24V units in parallel if I really wanted to?

Not sure what you mean, do I need special software to control the charging cycles on Lithium? I thought the voltages being setup correctly on the Axpert and the BMS on the battery would be enough?

Thanks, are these second hand / refurbished batteries and can one trust them to still have capacity and plenty of discharge cycles?

Any other concerns with running Lithium off a 3kVA Mever/Axpert, anyone had any problems, or suggestions?

 

Thanks everyone for all the comments so far!

 

I see that there are places selling Blue Nova Lithium Ion Phosphate batteries that are just drop in replacements for lead acid batteries. Does anyone have any experience with these?

If cost is a problem also look at the HUBBLE AM-4 Battery 25.5v 2.6KWh or the Hubble S-series.

On 2020/08/27 at 3:47 PM, Krokkedil said:

Hi there.

 

I have also research this a lot. I just bought a 48v Battery pack from Lithium Batteries SA. It has brand new cells and it comes with a 5 year guarantee. 

Please check out their website, they have  24v and 48v configurations. 

 

They shipped it for me to cape town for less than R500 or you can send your own Courier 

 

Seems to be out of stock on the website. Did you ever try to compare with the HUBBLE AM-4 Battery 25.5v 2.6KWh or Hubble's S-series as an option?

my suggestion for new batteries is something directly and confirmed to be compatible (just plugs in) with your inverter, keeping in mind current stock levels and pricing which has shot up lately.

perhaps while you make up your mind about which future battery to go for....

when my Lead Acids give up the ghost, I take them into a local battery crowd (had to find a good one that does this though), get the scrap value paid (around 56kgs per battery) and leave with "good used tested ones" paying in the difference which typically isn't much.

This in effect makes them disposable and well they just get used and abused now, knowing a replacement is 15 mins and a few hundred bucks away. basically all decent battery monitoring and maintenance is out the window, no battery balancing or any of the other stuff, just costs more than replacement.

admittedly its been awhile since I had to go back (6 - 8 months now), and some you need to cycle a few times to get their capacity back, as they get lazy being on float charge all the time.

This has sadly pushed my need to move to li ion onto the back burner along with a better inverter to match, but my guess is when ev's come around I'll finally have a need to move to a battery in the 10-15 kWh (unit) range.

 

Edited January 2, 20224 yr by Nitrious

We seem to be in the very same boat in terms of size of battery bank and it having reached End of Life (EoL). I would say you and I need to look at a Lithium capacity of no less than 200ah, 24v battery bank. Now given your inverter type I would recommend you trying to get one battery at that size. If you are not particular about brands then the attached would be recommended. Alternatively I would recommend you go for Lead Acid/Gel batteries, limp along for the next 4-5years and then upgrade the Inverter to a 48v system and then go Lithium properly.

On 2020/08/26 at 8:56 AM, jykenmynie said:

Obviously the battery's BMS is still only guessing, but it has MUCH more information available to it. All the internal cells' voltages etc.

Most of the more expensive Lithium batteries have an internal shunt on the BMS that measures the amount of energy that has flowed through it for more accurate SOC measurement.