Electrical Invertor Calculator

Drover

Drover

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With so many folk wanting to bring their household kitchen with them here at long last is a reasonable calculator to show what is really needed to run the stuff, may surprise many, Im assuming that the battery size is actual usable not the total capacity of the battery...... the amount wasted by the Invertor is also interesting...........

www.caravanrvcamping.com.au

Inverter Calculator - Caravan RV Camping

Inverter Calculator - Inverter Calculator
www.caravanrvcamping.com.au www.caravanrvcamping.com.au
 
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Boots in Action

Boots in Action

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Drover said:
With so many folk wanting to bring their household kitchen with them here at long last is a reasonable calculator to show what is really needed to run the stuff, may surprise many, Im assuming that the battery size is actual usable not the total capacity of the battery...... the amount wasted by the Invertor is also interesting...........

www.caravanrvcamping.com.au

Inverter Calculator - Caravan RV Camping

Inverter Calculator - Inverter Calculator
www.caravanrvcamping.com.au www.caravanrvcamping.com.au
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Hi @Drover, as you have said before "oils aint oils Sol"! Daughter's new Network RV van had a rated 200ah lithium battery installed and a 3000w inverter. (All Victron equipment). Trouble was that the (non Victron) 200ah Lithium was only capable of OUTPUTTING 150 amps, so 3000w inverter could never be used at full capacity, only up to approx 1500w . Company decided it was cheaper for them to provide a second 200ah Lithium connected in parallel to be able to provide max demand of inverter, than it was to provide another different Lithium with greater output performance. So size does not matter- it is output power than is the most important.

Very interesting to note how domestic 240v fridges work (don't work so well!) in a van when connected to batteries and an inverter. Looks like the 12v van fridge wins out comfortably!
 
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Drover

Drover

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I'm yet to see how it comes out when I run my data through it, be interesting to see if my guestimate is close..............

Most vans I have looked at seem to have the bling Invertor and other gear but fall down on battery capacity and panel size, looks the goods in the brochure but for any serious off grid camping be a failure .... If you can't get your battery up to speed in 3 hrs before lunch when camping, remembering its being used all the time then your system isn't up to it ...... and will rarely see anything near the stated charging rate or solar output ......

I can imagine the size of the battery bank needed for a 240v fridge nice spring day by the river and its 30c ...................
 
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Drover

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jazzeddie1234 said:
I've seen some very creative solutions that add a new thermostat from the fridge to the inverter on switch so it only turns on when the motor needs it. A domestic fridge wouldn't last 5 min in my van though :oops:
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My son has something like that to run his fridge which he uses to brew his keg beer, it turns on and off to keep the temp at a stable temp for ferment ....... but then a normal household fridge only fires up when needed anyway, it doesn't run all the time ... If you had kids swinging off the door I imagine the battery would slowly die in line with the sun going down.....
 
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Hitting the road

Hitting the road

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Boots in Action said:
Hi @Drover, as you have said before "oils aint oils Sol"! Daughter's new Network RV van had a rated 200ah lithium battery installed and a 3000w inverter. (All Victron equipment). Trouble was that the (non Victron) 200ah Lithium was only capable of OUTPUTTING 150 amps, so 3000w inverter could never be used at full capacity, only up to approx 1500w . Company decided it was cheaper for them to provide a second 200ah Lithium connected in parallel to be able to provide max demand of inverter, than it was to provide another different Lithium with greater output performance. So size does not matter- it is output power than is the most important.

Very interesting to note how domestic 240v fridges work (don't work so well!) in a van when connected to batteries and an inverter. Looks like the 12v van fridge wins out comfortably!
Click to expand...
Very interesting Boots...I don't yet have an Inverter in my van, but will likely install one down the track. I currently have 2 x 135 amp Lithiums in the van...both have 150amp BMS output capacity. I have them wired in parallel of course for 12 volt but giving 270amps...my theory was that I could draw up to 300amps if need be as each battery could supply 150amps...would I be right or wrong on that one?
 
Boots in Action

Boots in Action

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Hitting the road said:
Very interesting Boots...I don't yet have an Inverter in my van, but will likely install one down the track. I currently have 2 x 135 amp Lithiums in the van...both have 150amp BMS output capacity. I have them wired in parallel of course for 12 volt but giving 270amps...my theory was that I could draw up to 300amps if need be as each battery could supply 150amps...would I be right or wrong on that one?
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Hi @Hitting the road , the 135 amp hour lithium batteries you speak about in your van does not refer to the OUTPUT capacity of your lithium batteries. It only refers to the amount of stored electrical capacity that is available to use when fully charged. Amp hour capacity refers to storage whilst OUTPUT refers to the rated max draw in amperes at any one time. However, just because your amp hour capacity is only 135ah each (or 270ah in parallel) does not mean that your combined OUTPUT power is not capable of reaching 300 amps at one time, as that depends on the BMS of the lithium batteries. If they were capable of outputting such a high rate , all it means is that the batteries will not be able to output such a high rate for as long as say 2 X 200ah lithiums in parallel. The comparison of different brand types as set out by @Drover in earlier messages gives an indication of the different OUTPUTS. In theory anyway!!!
 
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Drover

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Yep, theory plays a big part in it all these things ........................ of course if you ran the draw at max rating the battery would probably go legs up very quickly, like most of this stuff I look at 30% less than what they say as being realistic ................................
 
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Boots in Action

Boots in Action

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Fair comment. As I understand it, you have UP TO 200 AMPs (in total) available as output for heavy demand loads through the BMSs. What sort of amp hour storage do you have and how long do you maintain a 150 A draw? Big currents in use there!!
 
Drover

Drover

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On the odd/rare times we've needed the microwave,I just fire up the Honda .................. I imagine if we had a 3000w invertor instead of a 600w someone would be wanting to thaw out the frozen dinners in the Nukavator instead of slowly on the bench,............. it aint gonna happen ...
 
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Hitting the road

Hitting the road

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Boots in Action said:
Hi @Hitting the road , the 135 amp hour lithium batteries you speak about in your van does not refer to the OUTPUT capacity of your lithium batteries. It only refers to the amount of stored electrical capacity that is available to use when fully charged. Amp hour capacity refers to storage whilst OUTPUT refers to the rated max draw in amperes at any one time. However, just because your amp hour capacity is only 135ah each (or 270ah in parallel) does not mean that your combined OUTPUT power is not capable of reaching 300 amps at one time, as that depends on the BMS of the lithium batteries. If they were capable of outputting such a high rate , all it means is that the batteries will not be able to output such a high rate for as long as say 2 X 200ah lithiums in parallel. The comparison of different brand types as set out by @Drover in earlier messages gives an indication of the different OUTPUTS. In theory anyway!!!
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Yes, the 135 amps is the rated capacity of each battery = 270amps in total storage...theoretically. Yes I could have I suppose installed 2 x 200amp batteries, but in my case would be a total overkill.
Being both batteries are capable of 150 amp max output according to their BMS specification, I figured that in the event an Inverter drew say even 200 amps at any point, then the 2 batteries would likely give 100 amps each, as their inbuilt BMS would balance the output to protect the batteries. The stored capacity would be fine for running a microwave oven, hair dryer or similar.
I have the formulas on hand for calculating total amperage requirements to run 240v appliance from a 12v supply, so no problem, was really just confirming my thoughts...
 
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Boots in Action

Boots in Action

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Hitting the road said:
Yes, the 135 amps is the rated capacity of each battery = 270amps in total storage...theoretically. Yes I could have I suppose installed 2 x 200amp batteries, but in my case would be a total overkill.
Being both batteries are capable of 150 amp max output according to their BMS specification, I figured that in the event an Inverter drew say even 200 amps at any point, then the 2 batteries would likely give 100 amps each, as their inbuilt BMS would balance the output to protect the batteries. The stored capacity would be fine for running a microwave oven, hair dryer or similar.
I have the formulas on hand for calculating total amperage requirements to run 240v appliance from a 12v supply, so no problem, was really just confirming my thoughts...
Click to expand...
@Hitting the road , a very easy way to calculate in your head for a 12 volt draw (in amps DC) when using an inverter to change output to 240 volts AC , is to check the listed wattage on the item (at 240v AC) and just remove the last 0 (zero). For example, if electric jug is rated as 2000w, the ball park draw from a 12 volt DC source would be approx 200 amps. Similarly a 1800 watt hair dryer or toaster would draw approx 180 amps at 12.0 volts, and for the coffee drinkers, a 3000w unit would draw approx 300 amps at 12 volts between the 12 volt battery/ies and the inverter. Big power means very heavy cabling and good battery supply!! And not for too long either!!!!
 
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Drover

Drover

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Boots in Action said:
@Hitting the road , a very easy way to calculate in your head for a 12 volt draw (in amps DC) when using an inverter to change output to 240 volts AC , is to check the listed wattage on the item (at 240v AC) and just remove the last 0 (zero). For example, if electric jug is rated as 2000w, the ball park draw from a 12 volt DC source would be approx 200 amps. Similarly a 1800 watt hair dryer or toaster would draw approx 180 amps at 12.0 volts, and for the coffee drinkers, a 3000w unit would draw approx 300 amps at 12 volts between the 12 volt battery/ies and the inverter. Big power means very heavy cabling and good battery supply!! And not for too long either!!!!
Click to expand...

Well thats very cool, easy to remember and really ball park figures is all you really need ................................... I wonder if I knew that once and forgotten as its my sort of science/electric theory ......................................... not forgetting the power tax required by the Invertor......

Last trip I was seriously contemplating an upgrade as I dislike instant coffee and plunger is so messy and a water waste
, thankfully the Scots blood fired up when I saw the cost involved ................ The Honda grunts a bit when I hook the pod machine up to it but it works.....
 
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