Mecer 2400VA Inverter (Community Support)

wingnut771

Executive Member
Joined
Feb 15, 2011
Messages
7,822
But if im correct due to 12v now and not 24v, the equation shows that less hours are gained on the battery?
Example: side note, i suck at math
12x180ah(one 12v batt)/wattage 650/2 x0.85=1.412
24x180/650/2x0.85=2.824
now that you only have one battery, you should double it's size to compensate because you're coming from 2 batteries to make 24V.
you were getting 2 x 150ah, now only 1 x 180ah, you should be getting 1 x 300ah battery to get the same use out of 12v.
24V x 150ah (2x12V150ah)=3600 watt hours (remember, parallel batteries, voltage doubles, current stays the same)
12V x 150ah (1x12V150ah)=1800 watt hours (here you would do series (if you can't find a big enough battery) and add batteries which keeps the volts the same but doubles current)

one thing to note going 12V is more current where:
700W @ 24V = 700 divide 24 = 29.16666666666667 amps from your battery.
now 700W @ 12V = 700 divide 12 = 58.33333333333333 amps from your battery.

so you can see there is more load on the battery which will shorten the amp hour rating:

lead_acid_discharge_curve2.gif

"A 1C rate means that the discharge current will discharge the entire battery in 1 hour. For a battery with a capacity of 100 Amp-hrs, this equates to a discharge current of 100 Amps. A 5C rate for this battery would be 500 Amps, and a C/2 rate would be 50 Amps. Similarly, an E-rate describes the discharge power. "

Think you'll need at least a 300ah battery @ 12V and thicker battery cables and bigger fuse.
 
Last edited:

Leno

Expert Member
Joined
May 15, 2005
Messages
1,243
Yeah its mainly as in PE we have 12 hours on average for stage 3 and then there is not enough time between to charge, so ill give 20A a try, maybe only if its stage 3

Edit: just to clarify I have 2x 105 Ah batteries
 

Gaz{M}

Executive Member
Joined
Feb 9, 2005
Messages
6,159
Yeah its mainly as in PE we have 12 hours on average for stage 3 and then there is not enough time between to charge, so ill give 20A a try, maybe only if its stage 3

Edit: just to clarify I have 2x 105 Ah batteries
20A is way less than what 2 x 105ah can handle. Go for it. Why suffer needlessly.
 

Verde

Expert Member
Joined
Aug 16, 2006
Messages
1,424
But if im correct due to 12v now and not 24v, the equation shows that less hours are gained on the battery?
Example: side note, i suck at math
12x180ah(one 12v batt)/wattage 650/2 x0.85=1.412
24x180/650/2x0.85=2.824
I assume you are looking at 12V batteries.
So for a 24V system you need 2 x 12V batteries
In series the voltage is doubled, the capacity stays the same so 2x12V180Ah =2x12Vx180Ah/2x.85/650 = 2.8Hr
In parallel the voltage stays the same and the capacity doubles so 2x12V180AH = 12Vx2x180Ah/2x.85/650 = 2.8Hr
 

thechamp

Honorary Master
Joined
Feb 26, 2011
Messages
27,124
I assume you are looking at 12V batteries.
So for a 24V system you need 2 x 12V batteries
In series the voltage is doubled, the capacity stays the same so 2x12V180Ah =2x12Vx180Ah/2x.85/650 = 2.8Hr
In parallel the voltage stays the same and the capacity doubles so 2x12V180AH = 12Vx2x180Ah/2x.85/650 = 2.8Hr
If he uses two batteries in the 12V system.
 

COMPUTEK

Executive Member
Joined
Apr 7, 2009
Messages
6,230
now that you only have one battery, you should double it's size to compensate because you're coming from 2 batteries to make 24V.
you were getting 2 x 150ah, now only 1 x 180ah, you should be getting 1 x 300ah battery to get the same use out of 12v.
24V x 150ah (2x12V150ah)=3600 watt hours (remember, parallel batteries, voltage doubles, current stays the same)
12V x 150ah (1x12V150ah)=1800 watt hours (here you would do series (if you can't find a big enough battery) and add batteries which keeps the volts the same but doubles current)

one thing to note going 12V is more current where:
700W @ 24V = 700 divide 24 = 29.16666666666667 amps from your battery.
now 700W @ 12V = 700 divide 12 = 58.33333333333333 amps from your battery.

so you can see there is more load on the battery which will shorten the amp hour rating:

"A 1C rate means that the discharge current will discharge the entire battery in 1 hour. For a battery with a capacity of 100 Amp-hrs, this equates to a discharge current of 100 Amps. A 5C rate for this battery would be 500 Amps, and a C/2 rate would be 50 Amps. Similarly, an E-rate describes the discharge power. "

Think you'll need at least a 300ah battery @ 12V and thicker battery cables and bigger fuse.
you have this completely wrong o_O
 

Gtx Gaming

Gtx Gaming
Joined
Aug 25, 2008
Messages
19,084
Is this site legit?

Its on back order, so not worth it anyway. All the stock comes from mustek, but seems pclinkshop is getting first dibs on the stock.
 
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