Battery link correct ?

[markus19]

Hi guys obv fully new to all this stuff
I have 4x 6v 200ah deep cycle batts
if i link them the way i have in the image will i get 12v 400ah ?

Many thanks

 

[sunshine_eggo]

No.

You have created 3 6V batteries the outer two are 200Ah and the inner forms 400Ah. You will get 18V.



This is a more typical 2S2P arrangement for 12V.

 

[markus19]

Ahh ok thanks for your help so linking like
you have done that would give me a 12 volt bank with 800ah yeah obv only 400ah useable with lead acid

 

[littleharbor2]

You'll get a 400 ah 12 volt bank with 200 ah useable.

 

[sunshine_eggo]

You'll get a 400 ah 12 volt bank with 200 ah useable.

Yes. this.

 

[markus19]

So if each battery is 200ah and i link them like we have said why do i only get 400ah when i have 4 batterys ?

 

[sunshine_eggo]

So if each battery is 200ah and i link them like we have said why do i only get 400ah when i have 4 batterys ?

Ah is voltage dependent

Ah in series doesn't add. Voltage does.
Ah in parallel adds. Voltage does not.

to make 12V, it takes two in series, so now you have a 12V 200Ah battery.

Parallel another two in series with the first pair, and you have 400Ah.

 

[markus19]

Thanks for the reply i get it now so yeah i the battery i have are 6v 200ah but the 200ah is at the 6v if you make it 12v by the link of series it stays at 200ah not double the only way to make the ah double was link the 2 batts parallel but this would only give 6v

 

[littleharbor2]

Thanks for the reply i get it now so yeah i the battery i have are 6v 200ah but the 200ah is at the 6v if you make it 12v by the link of series it stays at 200ah not double the only way to make the ah double was link the 2 batts parallel but this would only give 6v

4 in parallel gives 800ah @ 6 volts. 4800 watt hours or 4.8 kwh.
4 in series gives 200 ah @ 24 volts. 4800 watt hours or 4.8 kwh.
2s2p gives 400 ah @ 12 volts. 4800 watt hours or 4.8 kwh.
See how that works? You still have the same amount of power, regardless how you configure them.

 

[markus19]

Lol yeah i think im sort of getting it taking about of getting my head round , its the same with the solor panels ive been looking at getting 6x panels giving a max of 1560watt at 12v im told i would need 130amp charger controller at 24v a 65amp and at 48v a 32.5 amp which is obv alot more affortable however my question would be say i bought 4x 12v 100ah lithium battries and linked them in a 48v way would i then only have 100ah of use ? Rather then the 400ah at 12v or have i got lost again

 

[littleharbor2]

Yep, lost again. At 48 volts you're using 1/4 the current to do the same task as you need at 12 volts. Again, you have the same amount of energy in the batteries regardless how they are wired.

 

[sunshine_eggo]

Can't believe I haven't blathered about it yet, but you can always normalize to Wh to make storage independent of voltage.

If you have 6V 200Ah, that's 6 * 200 = 1200Wh of storage. It doesn't matter how you arrange them. Each 6V will add 1200Wh of storage.

If you put 4 in series for 24V, that's still 4 * 1200Wh = 4800Wh of storage. If you want to know Ah, divide by voltage, 4800Wh / 24V = 200Ah.

 

[littleharbor2]

Can't believe I haven't blathered about it yet, but you can always normalize to Wh to make storage independent of voltage.

If you have 6V 200Ah, that's 6 * 200 = 1200Wh of storage. It doesn't matter how you arrange them. Each 6V will add 1200Wh of storage.

If you put 4 in series for 24V, that's still 4 * 1200Wh = 4800Wh of storage. If you want to know Ah, divide by voltage, 4800Wh / 24V = 200Ah.

I had eluded to it a couple posts ago.

 

[sunshine_eggo]

I had eluded to it a couple posts ago.

Indeed you did!