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Testing fast draining batteries and Replacement for Axpert


R3plic8

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Good Day, 

I Have a RCT Axpert 5k 5000VA\4000w connected to 4 x 100ah Vision 6fm100z-x AGM batteries @ 48V which we have been using for Back up during load shedding.
The batteries seem to drain quite fast recently. at a 100-150w load it only seems to be lasting roughly 1h45m. The batteries are roughly 2.5 years Old

Firstly, Is there a way to test the batteries to confirm if all or 1 of them are giving a problem? Im guessing just a voltmeter across the charged battery doesn't give much info to the hold of charge. Are there any places that will test the batteries?

Secondly, If its maybe one of the batteries? would it make sense to replace it with another one to fill the string until the rest dies, or to just change over to LifePo4 now?

Thirdly, Can anyone recommend which LiFePo4 banks people are using with the Axpert 5k? I do not currently have a BMS and guess its going to be wise to install one along with the bank.

Going forward i would Also like to add Some panels to the Inverter. Been looking at the JA Solar 500w + panels. Would they be compatiable or Any recommendations?

Thanks







 

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21 hours ago, R3plic8 said:

4 x 100ah Vision 6fm100z-x AGM batteries

I've heard bad things about the Vision brand. Maybe it's just certain LFP batteries from them.

21 hours ago, R3plic8 said:

at a 100-150w load it only seems to be lasting roughly 1h45m. The batteries are roughly 2.5 years Old

Axperts with factory firmware don't charge batteries properly. My guess is that all 4 of the modules will be high internal resistance and low capacity. 2-3 years is sadly all many users get from lead acid. In your case, 100 Ah is a bit light for a 5 kVA inverter, meaning that they work harder and don't last as long as say 200 Ah would have (i mean in longevity, though obviously 200 Ah would have twice the runtime as well).

21 hours ago, R3plic8 said:

Thirdly, Can anyone recommend which LiFePo4 banks people are using with the Axpert 5k? I do not currently have a BMS and guess its going to be wise to install one along with the bank.

I'll leave it to locals to make recommendations. But most of the LFP options have BMS built in (e.g. Pylontech). It's only if you build a DIY battery yourself from bare cells that you need to add your own BMS.

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27 minutes ago, Coulomb said:

I've heard bad things about the Vision brand. Maybe it's just certain LFP batteries from them.

Axperts with factory firmware don't charge batteries properly. My guess is that all 4 of the modules will be high internal resistance and low capacity. 2-3 years is sadly all many users get from lead acid. In your case, 100 Ah is a bit light for a 5 kVA inverter, meaning that they work harder and don't last as long as say 200 Ah would have (i mean in longevity, though obviously 200 Ah would have twice the runtime as well).

I'll leave it to locals to make recommendations. But most of the LFP options have BMS built in (e.g. Pylontech). It's only if you build a DIY battery yourself from bare cells that you need to add your own BMS.

Thank you very much for the reply. Yes i do realize the batteries were under sized. but we would probably only run at 2000w max peak for a minute or too. but normal loads was probably the 500-600w range. and lower during off peak. 

We have deleyed putting panels on, which has not helped.. So looking to ut a few on. and maybe get a 2.4-4.8kw/h LiFePo4 to start off with, and can hopefully add more storage in a year or so.

I understand load shedding would have taken its toll as well.

I'm guessing im going to have the bullet and look at a LiFePo4.
I have been looking at the DIY kits as well, I see the benefit of that still being able to change out cells quite easily, and feel i'm capable of putting it together in a boxed unit with temp sensors, fans, communicating with the bms ect.. But also doesnt seem to be that much cheaper here.

With shortages as well there seems to be a big problem with stock at the moment. Any others able to recommend any brands and Suppliers that wont take you for a ride?

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Can anyone advise, About Using Hubble, Blue nova or PylonTech on the Axpert 5k 5kva/4kw?

Looking at prices between the pylontech, Hubble, Blue Nova BP there is not much a price difference between them. 
Obviously the pylontech's have a proven name but must say i am bit concerned with the 0.5C discharge and the images i saw of the workmanship on another thread.

The Hubble looks decent specs as well, Especially with the 1C Discharge, But bit worried as there does not seem to be as much infortmation in reagrds to cycles and curves
.
The Blue nova is appealing as well , seems to have a wider voltage range. and also has the 1C discharge, but think with 40V cutoff, I would lose some of the storage capacity.  However, Can the BP unit be used as daily cycle with solar? or would you need the DU unit, As that drastically increases the price?

In Regards to Communication with the Inverter. It does seem they mostly using CAN bus for the batteries, Does the Axpert 5k 5ka/4kw
support CAN bus?

Thanks

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1 hour ago, R3plic8 said:

The Hubble looks decent specs as well, Especially with the 1C Discharge, But bit worried as there does not seem to be as much infortmation in reagrds to cycles and curves
 

Here is the curves for the Hubble:

am-2-1.thumb.PNG.9c5343e0e669b88796669ce66fdefb3f.PNG

 

am-2-2.PNG.48cc2051f45c9725f4bdc84c6b1304b5.PNG

 

Link to the original document: https://www.hubblelithium.co.za/uploads/1/3/5/0/135079623/am-2_discharge_graph_and_dod.pdf

 

Edited by PowerUser
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1 hour ago, PowerUser said:

Here is the curves for the Hubble:

am-2-1.thumb.PNG.9c5343e0e669b88796669ce66fdefb3f.PNG

 

am-2-2.PNG.48cc2051f45c9725f4bdc84c6b1304b5.PNG

 

Link to the original document: https://www.hubblelithium.co.za/uploads/1/3/5/0/135079623/am-2_discharge_graph_and_dod.pdf

 

Thank you for that. Is anyone able to explain the difference in cycle usage? between the Hubble and Blue Nova. I see the DU Unit says 7000 cycles @80%DOD compared to the hubble showing 3000 cycles to 80% retention. How would that stack up against each other? Have got a decent price for the DU one, So its come into the picture now.

Only thing that is still worrying me, Is the capability of communication with CAN Bus from the AXPERT 5k 5kva/4kw to these LiFePo4. It has the RJ45(RS232) port and gather i would need to upgrade the firmware to 73.00e

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55 minutes ago, R3plic8 said:

Thank you for that. Is anyone able to explain the difference in cycle usage? between the Hubble and Blue Nova. I see the DU Unit says 7000 cycles @80%DOD compared to the hubble showing 3000 cycles to 80% retention. How would that stack up against each other? Have got a decent price for the DU one, So its come into the picture now.

Only thing that is still worrying me, Is the capability of communication with CAN Bus from the AXPERT 5k 5kva/4kw to these LiFePo4. It has the RJ45(RS232) port and gather i would need to upgrade the firmware to 73.00e

The difference in cycles is due to the type of chemistry used ,the Hubble AM2 is not a LiFePo4 battery .It has NMC  cells typically used in the electrical vehicle market.They have higher energy density and discharge/charge rates than  LiFePo4 at the cost of a reduced lifespan.

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6 minutes ago, Nexuss said:

The difference in cycles is due to the type of chemistry used ,the Hubble AM2 is not a LiFePo4 battery .It has NMC  cells typically used in the electrical vehicle market.They have higher energy density and discharge/charge rates than  LiFePo4 at the cost of a reduced lifespan.

Thank you. I'm leading more and more towards that Bluenova DU... Just now to try find out if it is compatible with the inverter communication wise.
I did read some people had issues with Bluenova and the axperts, With What seemed to be inverter kicking off at 97-98%% charge. Is anyone more familiar with this and if there is a fix or what their experiences are with the bluenova rac power DU on the rct axpert 5k?

Thanks again 
 

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