The Regalia 1550 says 2.44 kWh means 50AH x 48V
These lithiums run at 48V not 12V
So a 50Ah battery at 48V is the equivalent of a 200AH battery at 12V
But you need to de-rate that lead acid battery as you ain't getting 200AH out of it with regular use.
If its C20 then that's 10A for 20h which means can deliver a a measly power draw of 120W for 20h. Who can manage with such a low power load. Most load requirements are more which which means its worth less than 200AH
If its C10 then its 20A for 10h for twice that power draw or 240W, but battery costs go up for a C10, though i was quoted around 15k for a 200AH C10 battery a few months back
I was looking for 4h backup. If you flatten a C20 battery in 4h, the derating formula for tubulars is approx 65% of 200AH = 130AH this means to get 200AH worth of battery you really need 300AH.
With C10 you could get away with a 270AH as C10 derate at 75% for a 4h draw
Next you need to take into account the inverters efficiency. cheap means 60%, better means approaching 80%
The cruze was rated at close to 80% efficient so let's take that.
With the C20 i now need 400AH ie 400 * 0.65 * 0.8 ~ 200AH
With the C10 i need 330AH ie 330 * 0.65 * 0.8 ~ 200 AH
These figures might seem inflated but there's good reasons for it. I've purposely over sized my load requirement by 50%. I don't want to run around the place switching things off. My real load is likely in the 400+W range but i calculate based on 600+W. You could get more out of the battery by decreasing the load, this means your run time is longer and the de-rating will be less aggressive as a result. But for my uses with lead acid to get real 200AH requires at least 350AH
I also over sized my time requirements by 100%. Worst case i need 2h but i said 4h run time. A tubular will give you a thousand cycles if discharged down to 80%. Well, what happens if you only discharge it 50% then your cycles double. If you discharge less you get still more cycles. Result is a longer lasting battery.
Right sizing means changing batteries every 3-4 years this way i figured i could double the life of lead acids by over sizing. I'd rather pay all in one go now than in the future with inflation on top. And this all is provided I don't get an aged battery ( i would not buy a battery that was older than 4 months due to sulphation) or a defective battery (QC on consumer batteries isn't great hence the warranties) and water maintenance is kept to religiously. Any slip ups and the battery is shot.
Call it 30k+ for 2 x C10 200Ah
So, now what about the lithiums. The efficiency of the inverter is 90% say. The 50AH becomes 45AH.
What about load characterisitcs for lithum ? i don't have any data for that as yet.
50AH is 50AH under what draw. There are no C ratings for lithiums AFAIK. The vendors calculations are based off the battery ratings and ignore load. More load less power that's just how batteries work. Question is how much less power.
So if i have a 600W load then my current draw is 12.5A with a 48V battery. Four times lower than if the battery was 12V. That's got to help things.
Battery university says lithium phosphate has a flat discharge curve. Lithiums are known for being able to deliver high power so i'd imagine there isn't a whole lot of derating going on to begin with.
So how much does a 50Ah lithium cost ? i don't know. Apparently the price of spare batteries for the Regalia hasn't been made known by Luminous as yet.
