Hi all

I have a 5kW Sunsynk inverter, 10 × 535W JA panels and 2 Hubble AM2 batteries.

On the SS I can select under the Battery Setup setting, the maximum charging current. What would the max charging A I can safely go to? The batteries are 1C's so I understand I can go max 105A per battery so on the inverter it means 210A? But my inverter will limit it to about 100A

Currently mine is set on 50A charging. Can I safely take it to 75A or more?

Thanks in advance.

Please advise

Any reason you need to charge quicker? 50A on 2 batteries will already get them full in 4 hours assuming 5kWh each.

You dont have the array to charge any higher really unless you dont run any load during the day. Your array will max out at peak generation at 100A into the batteries with ZERO load. Only the grid will get you anywhere near the 100A limit of the inverter.

More current means more heat, you inverter will work a little harder, your fans also, and your batteries work a little harder also even though its mostly safe for most LFP to be charged at 0.5C which is about 50A per battery.

My only concern going higher is that you have 2 batteries, lets say each is rated for 0.5C max charging. If one gets full before the other and you set the inverter to charge at 75A for example then when one battery gets full, its own BMS will kill the charge to it, the remaining charge will go to the remaining battery and you will charge it higher than its spec.

But a quick check shows your batteries can do 100A charging. So you can set it to whatever you want. I would leave it at 50A personally.

55 minutes ago, Denns said:

My only concern going higher is that you have 2 batteries, lets say each is rated for 0.5C max charging. If one gets full before the other and you set the inverter to charge at 75A for example then when one battery gets full, its own BMS will kill the charge to it, the remaining charge will go to the remaining battery and you will charge it higher than its spec.

But a quick check shows your batteries can do 100A charging. So you can set it to whatever you want. I would leave it at 50A personally.

I fully agree with @Denns

Although many manufacturers rate their batteries as "1.0C" (or even higher) as an advertising gimmick, they don't refer to their own small print that normally state something like "... if operated at 25ºC". The service life of Lithium ion batteries depends on charge and discharge temperatures, depth of discharge, and rate of charge or discharge, and any deviation from any one (or worse, two or all three) or these parameters from the optimum values will have an effect on the total number of cycles that your batteries can provide. Now, given that our batteries are our single most expensive hardware, to my mind it just makes sense to look after the batteries by keeping them close to their optimum parameters.

I have a 12kW Sunsynk inverter and two 10kWh Sunsynk batteries, and my charge rate set in the inverter is 0.15C and the discharge rate is set at 0.25C. This not only nurse the batteries (and I do realise that I'm over-doing this...) but also allow me to be "virtually off-grid" by spreading the charging over a longer daylight period in order to also simultaneously run the geyser from my PV without needing any grid input (except when it's really cloudy, of course...).

4 minutes ago, HennieL said:

I fully agree with @Denns

Although many manufacturers rate their batteries as "1.0C" (or even higher) as an advertising gimmick, they don't refer to their own small print that normally state something like "... if operated at 25ºC". The service life of Lithium ion batteries depends on charge and discharge temperatures, depth of discharge, and rate of charge or discharge, and any deviation from any one (or worse, two or all three) or these parameters from the optimum values will have an effect on the total number of cycles that your batteries can provide. Now, given that our batteries are our single most expensive hardware, to my mind it just makes sense to look after the batteries by keeping them close to their optimum parameters.

I have a 12kW Sunsynk inverter and two 10kWh Sunsynk batteries, and my charge rate set in the inverter is 0.15C and the discharge rate is set at 0.25C. This not only nurse the batteries (and I do realise that I'm over-doing this...) but also allow me to be "virtually off-grid" by spreading the charging over a longer daylight period in order to also simultaneously run the geyser from my PV without needing any grid input (except when it's really cloudy, of course...).

My Omnivolt 5kW/5kWh all in one inverter is set to charge at 0.1C. But I do discharge very rarely a bit over 0.5C from it depending on loads. It is a 1C battery.

Yes, the batteries are rated 1C charge according to the spec sheets, to take 105A each, so then if you charge at 100A that the inverter can handle, they will will still be charging at around 50A each, ie. well within in the battery manufacturer's spec. Basically at a 0.5C rate.

But I'd set the inverter charge rate to 80A as a balance between going easy on your system (batteries as well as inverter), and extracting useful performance.

That's around 0.4C or 4kW charging power, in your setup, on a panel set of just over 5kW. Any less, like if you're using a 50A charge rate on the inverter, then you'd be negating a fair bit of the benefit of having that many panels in the first place.

Edited 1 hour ago1 hr by GreenFields