Do I need an extra Lithium battery?

[Take2]

I have a100Ah Lithium, 200W Solar and had 2kW inverter. Used it fine for 3 years with 800w kettle 1.5kW instant pot.
But I want to change to a pure sine wave 3kW so I can use my 1.8kW induction hob for short heating jobbies.
During my research I discovered a possible issue in that using a single Lithium battery instead of two paralleled up, that I might suffer a voltage drop on input to inverter!!
Anyone have experience of such an issue.
Be kind with suggestions

 

[Guigsy]

I suspect the Battery Management System built into the battery will shut down if you try to pull too much current for too long. You're going to need about 170 amps of sustained current for the hob!

 

[Lenny HB]

No info on your battery but most Lithium's the max current you can pull out of them is the C1 or C2 rate however even if they state C1 if you want them to last best to keep to C2.
C2 for a 100ah battery is 50 amps a 1.8kw load allowing for inverter efficiency is going to draw around 165 amps so you need 2 more batteries. Not all Lithiums can have more than 2 in parallel, so you need to check.
Also as Guigsy the BMS may limit it.

 

[Minxy]

I suppose the question that no-one is asking is if you only want it for short heating jobbies, and due to the massive cost involved in order to have enough electric to do what you want, it is really worth it? If you want to conserve gas and don't already have an underslung tank that would be a way of 'eeking' it out for less cost.

 

[Lenny HB]

Another point the main advantage of Lithium is the fast recharge, not much point in having Lithium with only 200 watts of solar to charge them, you really need to at least double that.

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[BillandHelen]

We have 2 100amp NDS lithium (150amp max draw) with a 2000w NDS pure sine invertor. Use it to power, nespresso machine, induction job, microwave, hairdryer/straighteners, even the roof aircon for short periods. Obviously only one at a time. Draws 140/160 amps as it does but only uses limited amps as short duration.

 

[BillandHelen]

As Lenny HB says, recharging is the trick. We only have room for one 120amp panel and rely more on our 60amp b2b.

 

[Lenny HB]

We have 2 100amp NDS lithium (150amp max draw) with a 2000w NDS pure sine invertor. Use it to power, nespresso machine, induction job, microwave, hairdryer/straighteners, even the roof aircon for short periods. Obviously only one at a time. Draws 140/160 amps as it does but only uses limited amps as short duration.

It will work but it will shorten their life probably not enough to worry about but when giving advice I like to err on the side of caution.

 

[Lenny HB]

As Lenny HB says, recharging is the trick. We only have room for one 120amp panel and rely more on our 60amp b2b.

Blimey that panel must be huge.

 

[Raul]

Even C/2 discharge will tire a lithium, throw in a bit of heat, and you got the perfect recipe for accelerated degradation. For short bursts of 10mins or so it’s ok. For long sustained loads of 30mins upwards a C/3 discharge should never be exceeded.
Take2, you are on the edge already with the 1,5kw load, theoretically you are exceeding a100a draw as it is. For that kind of load I upgraded from 200ah to 400ah. The heat in the summer with a large load will degrade your battery much faster than a lower load. My car revs to 6,5k rpm and is deemed safe by the manufacturer. But I drive most of the time at 2k rpm. Same with your battery rating. It’s safe to 1C but, does not mean you will not pay for it if you keep on it. The max I would push on long loads, even for 15mins, is C/2. As 50amps for every 100ah. Batteries are the most expensive piece in the system so needs max care.

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[Jimbohorlicks]

I have a100Ah Lithium, 200W Solar and had 2kW inverter. Used it fine for 3 years with 800w kettle 1.5kW instant pot.
But I want to change to a pure sine wave 3kW so I can use my 1.8kW induction hob for short heating jobbies.
During my research I discovered a possible issue in that using a single Lithium battery instead of two paralleled up, that I might suffer a voltage drop on input to inverter!!
Anyone have experience of such an issue.
Be kind with suggestions

Why not use a microwave rather than a 1.8kw induction hob for quick heating. Your existing set up would accommodate an 800 w microwave and it would be far cheaper than buying a lithium battery.

 

[Littlewheels]

As Lenny HB says, recharging is the trick. We only have room for one 120amp panel and rely more on our 60amp b2b.

Are you absolutely sure you cannot get more solar up there? Check out Photonic Universe they have some very interesting sizes that makes it possible to squeeze more on.

 

[autorouter]

You've got good advice answering your question so far, but maybe look at the big picture. Apart from the inverter, your 12V requirement is probably 20A or less. That's 240W.

There comes a time when the disadvantages of 12V outweigh the advantages, and if you're considering a 3kW inverter you are definitely in that area. For that power, you'll need a second 100Ah battery. If you're doing that you could set it up as a 24V system, with a 24V 3kW inverter/charger, and a 12V-to-24V B2B. The solar controller will probably do 24V automatically anyway.

A 24V-to-12V converter can power all your 12V habitation loads. The amps requirement for a 2kW load drops from 167A to 83A, which is more manageable. For 3kW it drops from 250A to 125A.

 

[Take2]

No info on your battery but most Lithium's the max current you can pull out of them is the C1 or C2 rate however even if they state C1 if you want them to last best to keep to C2.
C2 for a 100ah battery is 50 amps a 1.8kw load allowing for inverter efficiency is going to draw around 165 amps so you need 2 more batteries. Not all Lithiums can have more than 2 in parallel, so you need to check.
Also as Guigsy the BMS may limit it.

I'll check max current with battery Co. Thanks

 

[Take2]

Why not use a microwave rather than a 1.8kw induction hob for quick heating. Your existing set up would accommodate an 800 w microwave and it would be far cheaper than buying a lithium battery.

It was you cook foods rather than reheat but thanks