24volt Upgrade

[JOKER34]

Last year I built an off grid solar system for my pond, its a 2.4kwh system with four 380 amp hour 6v batteries. Originally i had it set up on 12v but the charge controller could only produce a max of 1.2kwh which is half of what its capable, but by upgrading to 24 it can produce all of it. The pump on the pond is 250 watts on 120v, so my 12v DC load was about 25 amps and it would make it the entire night without the batteries dying, but now that I upgraded to 24v my DC load is about 12 amps but the batteries keep dying every night shutting the pond down. I did not increase any draw any where, its the same 250 watt pump, any one know why the storage capacity is so terrible now?

Now I already know this, at 12v my battery bank amp rating was 760 amps, and at 24v its half that at 380, but the difference is my DC load is also cut in half, so the run time should be exactly the same.

Anyone have any input?

[SunEagle]

Last year I built an off grid solar system for my pond, its a 2.4kwh system with four 380 amp hour 6v batteries. Originally i had it set up on 12v but the charge controller could only produce a max of 1.2kwh which is half of what its capable, but by upgrading to 24 it can produce all of it. The pump on the pond is 250 watts on 120v, so my 12v DC load was about 25 amps and it would make it the entire night without the batteries dying, but now that I upgraded to 24v my DC load is about 12 amps but the batteries keep dying every night shutting the pond down. I did not increase any draw any where, its the same 250 watt pump, any one know why the storage capacity is so terrible now?

Now I already know this, at 12v my battery bank amp rating was 760 amps, and at 24v its half that at 380, but the difference is my DC load is also cut in half, so the run time should be exactly the same.

Anyone have any input?

First off you have the same load in watts (250w) regardless of the voltage. Going to a higher voltage only reduced your amp draw allowing you to use smaller wire and fusing but it will not reduce your load.

It is possible that one reason you no longer can run the pump all night is that the batteries are not being fully charged or they can no longer hold a full charge since you have been running them almost empty prior to the voltage upgrades.

Doing that will shorten the lifespan of any battery even a deep charge one.

[Mike90250]

I'm assuming you rewired the panels to be in series also ? And that you are completing a full charge cycle daily ? Odd, because with longer days (or are they foggy and cloudy?) should give you more charging hours and fewer night hours.

[Beanyboy57]

Last year I built an off grid solar system for my pond, its a 2.4kwh system with four 380 amp hour 6v batteries. Originally i had it set up on 12v but the charge controller could only produce a max of 1.2kwh which is half of what its capable, but by upgrading to 24 it can produce all of it. The pump on the pond is 250 watts on 120v, so my 12v DC load was about 25 amps and it would make it the entire night without the batteries dying, but now that I upgraded to 24v my DC load is about 12 amps but the batteries keep dying every night shutting the pond down. I did not increase any draw any where, its the same 250 watt pump, any one know why the storage capacity is so terrible now?

Now I already know this, at 12v my battery bank amp rating was 760 amps, and at 24v its half that at 380, but the difference is my DC load is also cut in half, so the run time should be exactly the same.

Anyone have any input?

Have you kept any record of the voltages or SG levels of your battery bank over the last 12 months? If so, when running the pump all night what did the batteries read in the morning before the panels started to kick in? Also your battery bank was configured in series/parallel initially to give you 12v. Now you have a 24v setup. How are they wired now, as in where and how are the leads connected to the batteries? Do you have a photo you could upload or a diagram?