Pushing the limits of electric cooking

[Pete7]

Originally Posted by Na Mara

That is a good point well made. I also tend to eat cold alfresco meals for lunch in the cockpit if it’s hot. Maybe I shouldn’t count on solar charging helping out the batteries when I cook.

If its hot so 25c+ then for evening means we are probably going to cook fish or steak with a salad type meals, plus curries etc. We had 30c for a couple of days earlier in September, that was uncomfortable on board, even with the sun shades up. Lunches are fresh crusty bread, cheese, salami and crunchie salad items.

However, now the weather is starting to turn, it will be jacket potatoes filled with butter and topped with tuna.

What I do like is induction heats the pan, not the cabin.

Pete

[fxykty]

Originally Posted by Na Mara

I had a similar experience with my setup. The BMS is set up to prevent my 600Ah LFP bank from going lower than 12.8V. If that happens it first sends a signal to the inverter to cut it off and if that doesn’t fix the problem it pulls the ATD signal low on all the loads cutting them off and if that doesn’t work it throws the contactor totally isolating the batteries.



The 2.4kW inverter is enough to run my two 1.2kW hobs simultaneously but it pulls the voltage down on the batteries by about 0.2-0.3V when it does it. Fully charged this isn’t a problem as I’m pulled down from 13.5 to 13.2. I’m even ok at the 75% charge mark at 13.2V. But as the batteries get down to 50% or lower charge, the pull down on the voltage from running both hobs results in less than 12.8V at the battery terminals and the inverter turns off.



There’s no drama, and the inverter restarts after 30s by which time I’ve turned one of the hobs off and it’s all fine. The situation should improve after I’ve fitted the 600W of solar Im planning (higher average state of charge, less pull-down whilst charging). Ultimately, I could also just add one more battery as well to reduce the pull down.



Discharging continuously at 0.3C + just is going to drop your battery voltage and with a good system that will lead to cutoffs to protect the battery under certain conditions. That’s just a fact of life with electric galleys without generator power supplies.

12.8V is pretty high - our inverter cut off is set at 11.8V, which is still well above the low voltage knee. Why 12.8V?

We have a 5KW inverter and it suffices running two hobs, just, though our dual hob is rated for 3.5kW. Our inverter will trip if a third AC load comes on while the induction bobs are pulling full power, which isn’t very often. So we can generally also use the oven, or toaster, or blender while cooking with two pots.

[wholybee]

Originally Posted by Na Mara

I had a similar experience with my setup. The BMS is set up to prevent my 600Ah LFP bank from going lower than 12.8V. If that happens it first sends a signal to the inverter to cut it off and if that doesn’t fix the problem it pulls the ATD signal low on all the loads cutting them off and if that doesn’t work it throws the contactor totally isolating the batteries.

12.8V is quite high for a LVD. You can discharge to 11.5V with no ill effects. This isn't lead-acid, you can use the whole capacity of the battery without problems.
You can safely set the LVD at 11.5V, and set an alarm on your SOC meter at 12V to warn you before it gets that low so you can start charging.

[Na Mara]

The 12.8V value was set by the installers. I think it’s the recommended least value for my Victron smart cells as it corresponds to an SOC of 5% or something like that. But that is the unloaded voltage at that SOC of course. I think the manual specifies 2.8V per cell as the min safe cell voltage so 11.2V is the absolute floor on the battery according to the manual. Not sure why the installer specified the higher level. Should be easily changed though.

[wholybee]

Originally Posted by Na Mara

The 12.8V value was set by the installers. I think it’s the recommended least value for my Victron smart cells as it corresponds to an SOC of 5% or something like that. But that is the unloaded voltage at that SOC of course. I think the manual specifies 2.8V per cell as the min safe cell voltage so 11.2V is the absolute floor on the battery according to the manual. Not sure why the installer specified the higher level. Should be easily changed though.

Reading the manual it looks like voltage parameters are not adjustable on a Victron BMS, instead there is a "discharge floor" which is based on SOC and defaults to 10%. 10% is about 12V(maybe 12.1V). 12.8V is about 17%.

[koyote]

Originally Posted by wholybee

12.8V is quite high for a LVD. You can discharge to 11.5V with no ill effects. This isn't lead-acid, you can use the whole capacity of the battery without problems.
You can safely set the LVD at 11.5V, and set an alarm on your SOC meter at 12V to warn you before it gets that low so you can start charging.

My understanding is that dropping below 20% SOC (12.7V) has some negative impact on life of the battery. Is this no longer the case?

[Na Mara]

Originally Posted by wholybee

Reading the manual it looks like voltage parameters are not adjustable on a Victron BMS, instead there is a "discharge floor" which is based on SOC and defaults to 10%. 10% is about 12V(maybe 12.1V). 12.8V is about 17%.

I have a lynx BMS that allows you to set the discharge floor in terms of SOC. I believe the BMS then sets a voltage limit on the batteries that corresponds to this SOC. Discharge is then prohibited if that threshold is crossed due to discharge or load. My SOC threshold is set at 20% so the voltage limit is set at 12.7-12.8 V.

There is a further under voltage alarm that is hard coded into the BMS, that limit is between 10.4V and 11.2V.

Cooking on both jobs I was no where near the latter so I must have been bumping up against the former and it can be lowered easily and safely to say 10%.

[fxykty]

Originally Posted by koyote

My understanding is that dropping below 20% SOC (12.7V) has some negative impact on life of the battery. Is this no longer the case?

It was never the case. Look at any voltage curve and you can see that it is almost flat between 2-5% of SOC at either end of the curve. Here’s the discharge curve for Winston LFP batteries:

[koyote]

Originally Posted by fxykty

It was never the case. Look at any voltage curve and you can see that it is almost flat between 2-5% of SOC at either end of the curve. Here’s the discharge curve for Winston LFP batteries:
Attachment 281460

I do see that for the LFPs. the curve is very flat. And I am being told that flatness of curve proves that there is no difference in lifecycle of a battery based on DoD. 40% 60% 92% all same-same. Nothing I've found yet is explaining why flatness of curve proves that.

I'm looking at a pile of sites right now and I'm getting "flat curve means no internal effects because the curve is flat" but not "because we measured" - if the companies are just using legacy setting of 12.8 or 12.7 volts because they don't like change, then they are. That's cool. Guess we'll find out in ten years.

[YachtBoyRMK]

Originally Posted by Pete7

jacket potatoes filled with butter and topped with tuna.

Tuna on a jacket potato? When I read this I thought of the phrase "Tell me you're British without saying you're British"

[Pete7]

I am actually English

Oh and a cup of tea is to die for but you know that coming from the smoke.

[more]

my induction is little old i think 6 year now AEG uper class but i buy old model 1/2 price i think be 600€

if sombody help i have average energy spend by day,week ,month year
only induction
for example
Consumption
Time, Watt/h day
21.Oct , 415.19
22.Oct , 2509.28
23.Oct , 236.54
24.Oct , 129.23
25.Oct , 332.48
26.Oct , 445.66
27.Oct , 216.59
28.Oct , 487.97
29.Oct , 51.42
30.Oct , 125.07
31.Oct , 395.12
01.Nov , 1439.9
02.Nov , 655.11
03.Nov , 2752.55
04.Nov , 307.03
05.Nov , 292.8
06.Nov , 434.84
07.Nov , 416.27
08.Nov , 0
09.Nov , 120.21
10.Nov , 973.64
11.Nov , 650.57
12.Nov , 1761.98
13.Nov , 801.64
14.Nov , 855.87
15.Nov , 531.26
16.Nov , 144.16
17.Nov , 184.05
18.Nov , 564.84
19.Nov , 1593.38
but i think best data is for winter,booring, no restaurant on island

Consumption
Time, Wh
01.Mar , 507.46
02.Mar , 317.16
03.Mar , 346.87
04.Mar , 119.86
05.Mar , 2326.76
06.Mar , 295.79
07.Mar , 717.43
08.Mar , 2050.58
09.Mar , 451.96
10.Mar , 203.99
11.Mar , 178.87
12.Mar , 459.61
13.Mar , 1004.46
14.Mar , 658.34
15.Mar , 700.08
16.Mar , 608.39
17.Mar , 120.66
18.Mar , 1085.56
19.Mar , 165.9
20.Mar , 3.38
21.Mar , 43.08
22.Mar , 3844.59
23.Mar , 1651.63
24.Mar , 132.74
25.Mar , 601.63
26.Mar , 212.09
27.Mar , 105.53
28.Mar , 279.78
29.Mar , 1346.54
30.Mar , 571.57
31.Mar , 146.78

today i cook dinner 16 to 18.00 beef steak in vine 2 hour cooking, lunch 14.00 pasta but with ready bolognese. tea and coff lot
Consumption
Time, Wh
21:00 , 0
22:00 , 0
23:00 , 0
00:00 , 0
01:00 , 81.16
02:00 , 0
03:00 , 0
04:00 , 0
05:00 , 0
06:00 , 0
07:00 , 0
08:00 , 0
09:00 , 0
10:00 , 0
11:00 , 38.79
12:00 , 0
13:00 , 0
14:00 , 63.25
15:00 , 0
16:00 , 529.11
17:00 , 672.37
18:00 , 130.37
19:00 , 78.33
20:00 , 0

this is for me ,everybody cook different. i eat only MED italian /croatian food.

red meet file minion 2 minute max, vegetable cook 10-15 minute,lot high pressure cook 10-20 minute , fish 10-15 minute, but ragu,tomato souce is cooking 4-5 hour but on minimum around 300w big pan,beef cook soup or other 2+ hour. mostly veal meat 10 minute.

aeg induction cook is totaly silent no sound, for testing before i buy this cheap rom lidl is ok if work 60% and up power under killing inverter. because jump 400w to 700 w also my AEG is not good under 300W this jumping is 100-299w
i now search for new induction but with only 2 spot i think . oven i don't need ,becouse gas oven maybe i use couple time and burn food. but also wife forbiden me use becouse is hard to clean.

[poiu]

Originally Posted by Loredo

Earlier in this thread I showed a link to a Foster three burner induction hob.
Well, I ended up installing one in my boat. I simply installed it on top of the already existing gas hob. On top of the frame where the pot holders would normally be. Since I still consider electric cooking experimental, the good thing is that I can convert back to gas in about half an hour. I hope to never have to but hey, it's a boat and stuff goes wrong... Time will tell.


Should there be lack of inverter power...

A nice feature of the Foster hob is, one can limit the total power it uses from 1.8 KW to 5.5 KW in several incremental steps. For the inverter, I think I went a different route than most others. There already was a 2.5KWA Mastervolt one on board. After several considerations I went with a relatively cheap 5 KW Chinese inverter that powers the galley only. With all three hubs on max power the inverter's fan does not even run constantly. OK, after having tested the first one, I ordered a second one as a spare. I have still spend way less than with a Victron or Mastervolt.
I've had Victron inverters on previous boats, my experience with them had been less than stellar. They fail exactly like the cheapo ones do. It's now a long time that I use cheap inverters none has left me down thus far. Knock on wood.
So far the experience with induction cooking has been fabulous, granted I had to throw away all my old pots and get new ones. I've spent more in new pots that in the hob but that's another story.

That's nice. Can you say where you bought it?

[GILow]

Originally Posted by more

….

if sombody help i have average energy spend by day,week ,month year
only induction
for example
Consumption
Time, Watt/h day
21.Oct , 415.19
22.Oct , 2509.28
23.Oct , 236.54
24.Oct , 129.23
25.Oct , 332.48
26.Oct , 445.66
27.Oct , 216.59
28.Oct , 487.97
29.Oct , 51.42
30.Oct , 125.07
31.Oct , 395.12
01.Nov , 1439.9
02.Nov , 655.11
03.Nov , 2752.55
….

Finally, a cruising budget I can relate to.

[Loredo]

poiu,


I can't even remember which site I bought the hob from... I'm in Europe, you're in the Caribbean, right? Attention, the "Foster S-1000" is a 220V unit, I don't know if they make a 110V version. Another thing worth of notice is that the very same unit is sold under different brand names. Pick the one with the lowest price... The one I purchased is branded "Plados Telma" which is a Spanish company. (Saved me a hundred bucks or so) The MFR of those hobs is "Foster" which is an Italian company.
Here is a link to one of the many vendors (I might have bought mine there?)
https://www.vieffetrade.eu/sale/cook.../pbim430/55990