# Inverter and batteries

#### InternetLuddite

##### Expert Member
Sorry for cross posting.

My maths is sh i te, but how many 104ah batteries is a pylontech 3.5kw battery equivalent too?

#### Messugga

##### Honorary Master
Sorry for cross posting.

My maths is sh i te, but how many 104ah batteries is a pylontech 3.5kw battery equivalent too?
3-4, give or take. But you'll kill the lead acid batteries if you discharge them as far as the lithium battery can go without significant damage, so you'll probably need closer to 8 to get close to the Pylontech.

#### howardb

##### Expert Member
Sorry for cross posting.

My maths is sh i te, but how many 104ah batteries is a pylontech 3.5kw battery equivalent too?
Each of my 2.4kw pylons is 50ah, but can discharge to almost zero without effect. Have 4 to give me 200ah.

##### Honorary Master
Sorry for cross posting.

My maths is sh i te, but how many 104ah batteries is a pylontech 3.5kw battery equivalent too?
104Ah at 12V is 1048Wh.
Pylon 3.5kwh @80 percent DoD is 2800Wh usable.
Lead acid is max 50 percent DoD so 524Wh per 104Ah battery.
So about 6 lead acid cells to match the Pylon for practically usable capacity.

#### InternetLuddite

##### Expert Member
Thx guys. It's just confusing to work out whether to buy lead acid batteries or lithium ion and whether its worth it Now more educated

##### Honorary Master
Thx guys. It's just confusing to work out whether to buy lead acid batteries or lithium ion and whether its worth it Now more educated
Lithium will give you thousands of cycles. Lead will give you hundreds if you look after it exceptionally well

#### Dairyfarmer

##### Executive Member
Thx guys. It's just confusing to work out whether to buy lead acid batteries or lithium ion and whether its worth it Now more educated
You have to calculate the Rands per cycle or Rands per Kwh over the life of the batteries.

I went with lead acid because I didn't know how many batteries I would need and how long they would last. My 4 x R1300 batteries are still going strong almost 18 months down the line. When we don't have a power outage I do run the system once a month just like you would run the gennie. We normally have, at least, 2 or 3 outages a month that last over an hour. My batteries perform almost as they did the day I bought them. DoD, lowest volts and recovery time are almost identical. I would guess that they have another 18 months left in them. Consider also that we did have a fair amount of load shedding at one stage. The prediction for this year is lighter than last.

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#### Retro1337

##### Well-Known Member
so i got a 2000w pure sine wave inverter and a 100ah gel battery and i noticed while the inverter is plugged in to power ( to charge the battery) its fault light is on but when power is off and running of the battery the fault light doesn't come on? anyone know what might be causing the issue? faulty inverter?

#### howardb

##### Expert Member
so i got a 2000w pure sine wave inverter and a 100ah gel battery and i noticed while the inverter is plugged in to power ( to charge the battery) its fault light is on but when power is off and running of the battery the fault light doesn't come on? anyone know what might be causing the issue? faulty inverter?
Which inverter? Is it a 12v or 24v model?

#### Dairyfarmer

##### Executive Member
while the inverter is plugged in to power ( to charge the battery) its fault light is on but when power is off and running of the battery the fault light doesn't come on?
Could in not maybe be the charge light rather than the fault light? Make and model of the inverter would help.

#### Lupus

##### Honorary Master
You have to calculate the Rands per cycle or Rands per Kwh over the life of the batteries.

I went with lead acid because I didn't know how many batteries I would need and how long they would last. My 4 x R1300 batteries are still going strong almost 18 months down the line. When we don't have a power outage I do run the system once a month just like you would run the gennie. We normally have, at least, 2 or 3 outages a month that last over an hour. My batteries perform almost as they did the day I bought them. DoD, lowest volts and recovery time are almost identical. I would guess that they have another 18 months left in them. Consider also that we did have a fair amount of load shedding at one stage. The prediction for this year is lighter than last.
Oh my batteries ran well for well over 2 years, than suddenly bam

#### Retro1337

##### Well-Known Member
Could in not maybe be the charge light rather than the fault light? Make and model of the inverter would help.

its one off takealot - seems they are sold out as the page is not available at the moment

This is when its plugged into the wall to charge the battery (charge light is green which means battery is full. but the fault light is on):

This is when you switch off at the plug to simulate a power outage (fault light is off):

#### Dairyfarmer

##### Executive Member
Oh my batteries ran well for well over 2 years, than suddenly bam
Maybe you discharged too much the last few cycles, the water was low, batteries got too hot, .....

#### Lupus

##### Honorary Master
Maybe you discharged too much the last few cycles, the water was low, batteries got too hot, .....
Possible

#### Dairyfarmer

##### Executive Member
If your inverter has the option, set it to turn off when the battery voltages gets to a certain point. That way it is less likely to discharge the batteries too far.

#### TheChamp

##### Honorary Master
its one off takealot - seems they are sold out as the page is not available at the moment

This is when its plugged into the wall to charge the battery (charge light is green which means battery is full. but the fault light is on):
View attachment 867147

This is when you switch off at the plug to simulate a power outage (fault light is off):

View attachment 867149
Looks like those cheap ones, ignore it if it works.

#### joker08

##### Expert Member
Bought a Mercer inverter 720w 1200va with a 100ah calcium batteries.
Question : can I connect another battery in parallel ?
How to connect it in parallel? I mean what connectors and cables is best for this purpose.
Will the inverter charge both properly?
Does the battery have to be the same brand and type?
Also I bought a "rough tote" storage box but the battery is too heavy for it. What's the best box on wheels i can buy for this purpose?

#### TheChamp

##### Honorary Master
Bought a Mercer inverter 720w 1200va with a 100ah calcium batteries.
Question : can I connect another battery in parallel ?
How to connect it in parallel? I mean what connectors and cables is best for this purpose.
Will the inverter charge both properly?
Does the battery have to be the same brand and type?
Also I bought a "rough tote" storage box but the battery is too heavy for it. What's the best box on wheels i can buy for this purpose?
Yes, you can connect another battery in parallel, look for ready made cables with lugs, they should be the same size as the ones the battery is connected with.

Yes the inverter will charge both.

Yes, same brand and type.

#### joker08

##### Expert Member
Yes, you can connect another battery in parallel, look for ready made cables with lugs, they should be the same size as the ones the battery is connected with.

Yes the inverter will charge both.

Yes, same brand and type.

Oh that's expensive.
Drilled holes in the plastic box. I think I am good for now.

Inverter's fan making noise. Very annoying.

#### Lupus

##### Honorary Master
Oh that's expensive.
Drilled holes in the plastic box. I think I am good for now.

Inverter's fan making noise. Very annoying.
Inverter should stop making noise after batteries are charged.