Having looked at the tech sheets for the H1 and EP batteries I can't quite figure out the peak output numbers.
The H1-5 seems capable of outputting 6kWh with batteries, but I don't understand the EP battery specs to know the max output for each model EP5/EP11.
I am in the early stages of researching a solar and battery installation to accompany my 9kWh heat pump. I need to ensure my inverter and batteries can output at least 5kWh to cover the heat pump and other household electricals through normal use.
Thanks
Battery and Inverter Peak Output
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Dave Foster
- Posts: 1328
- Joined: Thu Oct 13, 2022 7:21 pm
The H1-5 can never output on it's AC interface any more than 5kW to meet export regulations (it's a little different when running off grid but you won't be) - there is an H1-6 that will go up to 6kW, the price difference is marginal, size and weight are the same - if you can do, go with the larger one.
It's a more complicated answer with the batteries, as you have maximum recommended discharge current although it can provide more for peak demands - the main consideration with batteries is the battery voltage (dc) as the potential max power they can operate at is limited by that.
The EP11 has a max recommended discharge of 27A and battery volts between 348V and 438V (10-100% SoC) so at 20C they would be able to output at between 9,396 watts and 11,826 constantly - You will lose a couple of hundred watts in the conversion but very capable of meeting your demands.
The EP5 has a max recommended discharge of 27A and battery volts between 179V and 219V (10-100% SoC) so at 20C they would be able to output at between 4,833 and 5,913 constantly. Again, you will lose a couple of hundred watts in the conversion so for constant use of 5kW you would be better to consider the EP11 although the EP5 can go to 65A for 60S to meet short peak demands.
Looking at that i'd recommend the EP11 as the batteries will have reduced performance as the temperature falls below 15C and they will comfortably still be capable of supplying what you need.
If you are installing outside be aware that at 0C the batteries will no longer charge, they will carry on discharging down to -10C but performance is severely limited at low temperatures - this is true of all LFP & Li-ION batteries. You mentioned using these with a heat pump so I would recommend that if mounted outside you build some kind of enclosure, preferably that you can insulate with sheets of 50mm Kingspan in winter so they remain operational even during a cold spell.
It's a more complicated answer with the batteries, as you have maximum recommended discharge current although it can provide more for peak demands - the main consideration with batteries is the battery voltage (dc) as the potential max power they can operate at is limited by that.
The EP11 has a max recommended discharge of 27A and battery volts between 348V and 438V (10-100% SoC) so at 20C they would be able to output at between 9,396 watts and 11,826 constantly - You will lose a couple of hundred watts in the conversion but very capable of meeting your demands.
The EP5 has a max recommended discharge of 27A and battery volts between 179V and 219V (10-100% SoC) so at 20C they would be able to output at between 4,833 and 5,913 constantly. Again, you will lose a couple of hundred watts in the conversion so for constant use of 5kW you would be better to consider the EP11 although the EP5 can go to 65A for 60S to meet short peak demands.
Looking at that i'd recommend the EP11 as the batteries will have reduced performance as the temperature falls below 15C and they will comfortably still be capable of supplying what you need.
If you are installing outside be aware that at 0C the batteries will no longer charge, they will carry on discharging down to -10C but performance is severely limited at low temperatures - this is true of all LFP & Li-ION batteries. You mentioned using these with a heat pump so I would recommend that if mounted outside you build some kind of enclosure, preferably that you can insulate with sheets of 50mm Kingspan in winter so they remain operational even during a cold spell.
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Dave Foster
- Posts: 1328
- Joined: Thu Oct 13, 2022 7:21 pm
The EP series batteries are connected in parallel so if you had 2 * EP5 batteries the maximum theoretical output would be 54A but unfortunately you would then be limited by the H series maximum 40A battery connection - so approx 50% more power than a single battery. (I’ll just mention it but if you go up to the KH series inverters they are bigger starting at 7kW, 8, 9 or 10kW and they have a max battery current of 50A)
You can’t mix 5 & 11 batteries, again because they are connected in parallel the EP11’s higher voltage would do a lot of damage to the EP5.
Having a higher voltage is usually the best place to start as you tend to avoid any temperature limitations, the only real downside to the EP11 is it is very, very heavy (100kg)