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merlin avatar image

Inverter maximum battery capacity

Could someone be so kind as to tell me the maximum battery capacity that both the 48v 3kw and 5kw multiplus inverter charger can handle? (Intend I’m using Pylontech 48v us2000).

Phoenix InverterPylontechbattery capacity48v battery
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dayandnight answered ·

Hello @Merlin,

I have done an installation with a 3-phase ESS, 3x Multiplus-II 3000, a grid based PV 6 kWp and 8 Pylontech US2000B. This works perfect, nevertheless in summer the batteries with 17,2 kWh capacity are at SOC 100% charged before noon, when started in the morning with 40 - 50% SOC. As feed back into grid is not welcome, PV power is switched to 0 at SOC 100% and possible energy performance is wasted. In such a scenario I think it would be no problem to increase total capacity to 26,4 kWh (12 x 2,2 kWh ) or even 34,4 kWh ( 16 x 2,2 kWh) if there is a need and usage for the saved energy during the following night or might be the following days with less or no sun.

Based on the DC charging setup, which is in my example only grid-based PV, the bottleneck of charging the batteries is the max charging current of the Multiplus-II 3000 which is in a 3-phase installation 3 x 35 A = 105 A, but only when PV is well balanced over 3 phases. It doesn't help that 16 pieces Pylons can be charged with 400 A, when three Multiplus-II 3000 can do together only 105 A. ( 3 x 35 A )

When your target is to store as much energy in batteries as possible and there is more PV power available as grid-based PV can do in combination with Multiplus you have to use bigger Multiplus or additionaly DC based PV.

When discharging the Pylons you will have a similar scenario in the other way round. For discharging normally the only way is through the Multiplus Inverter which will limit the discharging current with a Multiplus-II 3000 to 2.400 W AC maximum per phase. I have seen up to 170 A DC discharging current with a 3-phase AC geyser running. For this you need for an ESS Multiplus-II setup already 8 pieces Pylon ( 8x25 A = 200 A ) if you want to use the "small" Multiplus-II 3000, 3-phase at full possible AC power.

So the answer to your question is not a figure of xyz kWh. It is more a combination of what is your target, how much energy you want to store, how much PV energy is available AC-based, DC based and how much max AC energy has to be available for AC consumers.

Hope this helps you a little bit. Cheers!

DayAndNight


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Thanks for the reply.
Sorry, I should have given more detail about my intended setup. Only one inverter on a single phase 240v hookup.

wkirby avatar image
wkirby answered ·

This is a little bit difficult to answer. It is similar to asking "How much money can your bank account handle"?
The more battery capacity the better, right?
The limitation is how quickly can the battery bank be recharged. Is the MultiPlus the only charging source or is there solar also? If so, how big is the solar array? Will the charging sources be able to fill the battery each day.

If you have some more information about the design of your system as a whole then I think we can give a better answer.

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Thanks for the reply.

Intended system to power the 12v and 240v electrics on a barge. (all the comforts of a house). Mostly moored in a marina but do often take out during the summer. Have 1260 watts of solar but intend on increasing to 1890 watts. I currently have a Mastervolt 3kw combi ultra with 4 x 12v 220ah agm Batteries.

Batteries struggle with high loads and are painfully slow at recharging.

As I mainly cruise during the summer months, I want to heavily rely on the solar.

Will be looking at a generator to back up charging on not so sunny days.

Power usage (read from shore electric meter is on average 7.5kwh per day.

Hope this makes it much clearer.