New to site, could use some insite

[WhisperingAngel]

Live off grid: 2 (24 v 500ah) lead acid batteries, 7000 w solar panel system, use sine wave inverter, multiple charge controllers and back up diesel generator. Unable to get battery reading above 24.9 underload at end of day and 25.2 open cell, unable to equilize because unable to reach full charge. Charge controllers are set up based on 40-60 amp. The controllers go through bulk and float, as well as the inverter when use generator, but at the end of the day, still no higher. Hydrometer readings on all cells are 1.250 and voltmeter 2.1 per cell.

[Mike90250]

I'm not clear ( and maybe you aren't either ) but it looks like you have two 500ah 24v banks, creating a 1,000ah 24v bank ????

That size battery needs 100A to properly be charged, because the electrolyte needs to be bubbled vigorously, to keep the acid from stratifying.
(or if it's 500ah, needs 50A to be charging well)

700w of solar @ 30V (charging voltage) only gives you 23 amps of possible charging, so you are seriously undercharging the batteries.

Your course out of this, is to use the generator from 3AM to 9AM to charge the batteries and run your morning loads, and hope that at 9am, the sun comes up and you can use the solar to finish charging the batteries.

What sort of amps can the generator and charger provide to the battery bank ?

[SunEagle]

I'm not clear ( and maybe you aren't either ) but it looks like you have two 500ah 24v banks, creating a 1,000ah 24v bank ????

That size battery needs 100A to properly be charged, because the electrolyte needs to be bubbled vigorously, to keep the acid from stratifying.
(or if it's 500ah, needs 50A to be charging well)

700w of solar @ 30V (charging voltage) only gives you 23 amps of possible charging, so you are seriously undercharging the batteries.

Your course out of this, is to use the generator from 3AM to 9AM to charge the batteries and run your morning loads, and hope that at 9am, the sun comes up and you can use the solar to finish charging the batteries.

What sort of amps can the generator and charger provide to the battery bank ?

I think the OP has 7000 watts but even with a 24V battery system there needs to be multiple Charge Controllers which may or may not work well together on the same battery system.

That may be why the battery system is not getting fully charged.

[WhisperingAngel]

Thank you Mike and SunEagle! Yes, 1000 ah 24 v because batteries are parallel. Have multiple charge controllers with each set to a bulk and float of 28.027. Unfortunately, have noticed charge controllers are in float mode by 10:00 am.

Solar panels: 16 (220w 8.32 ah), 14 (305w 8.99ah). These are all parallel and 2 (130w 7.39ah), 2 (120w 7.45ah), these are in series.

Going to try disconnecting one battery pack to see if it makes a difference, but concerned our controllers aren't allowing high enough voltage to reach full capacity. Will be verifying this tomorrow.

I attempted to upload photos, but kept getting error message.

[WhisperingAngel]

Disconnected one of the battery banks, left charge controllers on, ran generator from 4:30 am till 8:30 am then turned off and left to controllers. Got 29.7 v during most of the peak hours, sundown 24.8 v. Does anyone have an idea of a controller that can push in what we need? We are using xantrex c-series 40s and 60s.

[littleharbor]

I'm going to guess that your 220 watt panels are 60 cell panels. What cell count are the 305 watt panels? Can you give specs of both 220 and 305 watt panels? The voltage of 60 cell panels isn't high enough to properly charge a 24 volt battery. I have a feeling that, even if the 305 watt panels are 72 cell panels the 220 watt panels are dragging down the input voltage to the point that you're not getting high enough voltage to fully charge your battery.

[WhisperingAngel]

I checked and you are correct about cells. Recommendations?

[littleharbor]

I checked and you are correct about cells. Recommendations?

Get a good MPPT controller and series wire your 60 cell panels is strings of two or 3, depending on the max Voc. of the controller. Keep the 12 volt panels for another project.

[WhisperingAngel]

Thank you, Little Harbor. This was very helpful! Currently rewiring, might have to live with PWM controllers for a bit. But will be upgrading as soon as able. Hoping the rewiring will help with the issues. Looking at using atleast one of the 12v panels for the battery on our trackers.

[littleharbor]

Without a MPPT controller you wont get very good performance out of a PWM controller. If it can handle that high of voltage (two in series) then you will at least get the charging voltage high enough but will only get the same amperage coming out as you're putting in to your cc.

[WhisperingAngel]

Yeah, figured. Any idea if battery packs are going to be damaged using at max 24.9 v till I can install mppt controller?

[littleharbor]

If the best you can get is 24.9 then, yes. Get a new controller asap. You need to bring those batteries up to the 28.8 range just for proper charging. Equalizing will require higher voltage still.

[WhisperingAngel]

It is very frustating because we easily get 29V during the day, but our current controllers peak out and enter float mode. Rewiring complete, 12 V panels have been disconnected for use somewhere else and the remaining ones are being utilized for our solar well. I have attached a diagram of solar configuration of panels being used to charge our 24V battery banks and could use recommendation on mppt, looking at the Morningstar 60A and the Outback 80A. One advantage to the 80A is it would allow us to put our two trackers on the same controller.