off.the.grid
New Member
- Joined
- Dec 26, 2021
- Messages
- 124
I was doing a bit of a stress test on my battery bank yesterday after setting up my new install to test its limits.
I had boiled the kettle and used the toaster a few times during the day and put the dishwasher on that night.
My bank has 540Ah capacity at 24V which gives me close to 6.5kwh of usable capacity. My panels can supply up to 1600W.
Anyway, that evening when I had the dishwasher on, near the end of the cycle i noticed the battery voltage was around 23V, I know that this is OK under load.
The inverters cut off voltage is set to 21.6V under load, so I was not concerned over the system over draining going by those figures, however, it must have dropped off quite fast, as in about another 20 mins, the inverter shut off.
The battery voltage bounced back quite close to 24V after the load was removed, so that gave me some reassurance. I feel that it was probably just more current than what the battery bank could cope with as it was getting low.
I have no idea how much I had drained the batteries, but my maths goes that I would have only used about 2.5KWh of power that day that I could account for.
Im not sure how much charge the bank had that day, but it was showing what appeared to be a full charge at normal float level voltages in the morning.
What I dont know is how long does it typically take to charge a bank if its down to say 70 - 80%? I have no idea who low it even was the night prior, and measuring the capacity is not always accurate either. I was a bit concerned how my epever controller said it was at 30% capacity remaining, but things were under a small load, but nonetheless I fired up the genset for an hour before bed.
How does the boost phase work with these anyway? Its set to charge for 2 hours during the boost phase in the morning and stay at float voltage for the rest of the day, but those 2 hours might not be necessarily enough to top the battery right up to 100% all of the time?
I have no idea how to tell the capacity while its in the float range, i guess the only thing to look out for is the reading on how much current the batteries are being fed?
If i switched on the kettle during the day, you can see a good amount of current feeding into the system from the panels, so I know that it shouldnt have been using much of my batteries when the sun is up.
Am I better getting a 48V inverter to reduce current demand from the battery bank?
I had boiled the kettle and used the toaster a few times during the day and put the dishwasher on that night.
My bank has 540Ah capacity at 24V which gives me close to 6.5kwh of usable capacity. My panels can supply up to 1600W.
Anyway, that evening when I had the dishwasher on, near the end of the cycle i noticed the battery voltage was around 23V, I know that this is OK under load.
The inverters cut off voltage is set to 21.6V under load, so I was not concerned over the system over draining going by those figures, however, it must have dropped off quite fast, as in about another 20 mins, the inverter shut off.
The battery voltage bounced back quite close to 24V after the load was removed, so that gave me some reassurance. I feel that it was probably just more current than what the battery bank could cope with as it was getting low.
I have no idea how much I had drained the batteries, but my maths goes that I would have only used about 2.5KWh of power that day that I could account for.
Im not sure how much charge the bank had that day, but it was showing what appeared to be a full charge at normal float level voltages in the morning.
What I dont know is how long does it typically take to charge a bank if its down to say 70 - 80%? I have no idea who low it even was the night prior, and measuring the capacity is not always accurate either. I was a bit concerned how my epever controller said it was at 30% capacity remaining, but things were under a small load, but nonetheless I fired up the genset for an hour before bed.
How does the boost phase work with these anyway? Its set to charge for 2 hours during the boost phase in the morning and stay at float voltage for the rest of the day, but those 2 hours might not be necessarily enough to top the battery right up to 100% all of the time?
I have no idea how to tell the capacity while its in the float range, i guess the only thing to look out for is the reading on how much current the batteries are being fed?
If i switched on the kettle during the day, you can see a good amount of current feeding into the system from the panels, so I know that it shouldnt have been using much of my batteries when the sun is up.
Am I better getting a 48V inverter to reduce current demand from the battery bank?