Blue Solar going straight to float. Thus voltage based load output not turning on

Question

question

joeoffgrid asked Jun 5, '19

Blue Solar going straight to float. Thus voltage based load output not turning on

I know it has been reported a few times that the chargers go into float (too?) quickly. I cannot judge whether this will hurt my battery in the long run or not. But my problem is this: I want to give priority to make sure the battery is fully charged before turning on the load. So I choose voltage based load settings. Since my chargers are now all sitting idle at float they won't turn on the load. Some people suggested excess power calculation. I don't know whether something like this will be introduced and when.

I simply suggest more parameters to calibrate for this setting. Like the timers and solar voltage and a couple of dependecies.

MPPT Controllers charger

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Modifications Space

Node Red Space

Answer 1 · 2019-06-05T08:45:41Z

adev answered · Jun 05, 2019 at 08:45 AM

which particular model are you using, and what type of batteries? Using the batteries whilst charging shouldn’t be an issue at all, however if you really want to do this, then setting your upper load voltage limit to just above your float voltage should do the trick. Once the battery is charged it will always stay in float so long as the PV voltage is greater than the battery voltage and there’s no load pulling the voltage lower. (ie during most of daylight hours).

3

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

joeoffgrid commented · Jun 05, 2019 at 11:37 AM

I'm using several 75/10 and 75/15 chargers to charge lead acid. Priority should always be to keep the batteries full.

I just want to make use of the excess solar energy. When turning the load on too early I think it is very likely to have a hunting phenomenon and/or have the battery not charged on cloudy days.

Shouldn't be hard to implement like "turn load on if Ubatt > w V for Tbatt x sec AND Usol > y V for Tsol z sec." Just to add x, y, z in the menu.

I chose solar for high voltage output so that the battery is charging even in poor light conditions. Voltage is often high but power output not necessarily.

0 ·

adev joeoffgrid commented · Jun 05, 2019 at 12:07 PM

Priority really depends on a specific application and the needs of the user. If your priority is to keep batteries full and the need to use your loads is flexible enough to allow for that then that’s fine but there’s no harm in using the loads while the battery is charging.

0 ·

joeoffgrid adev commented · Jun 05, 2019 at 09:51 PM

Absolutely agree.

I might add that I have different priority loads. High priority is taken directly from the battery - of course they are used while charging as well.

Last couple of days sun was awesome. I can manually (every day set voltage to float as a work around) turn on the excess power loads and it will run all day (e.g. strong fan for cooling the van). So could get away with setting the on voltage near float. But on clowdy days the power drawn would be too high thus the load turning on and off while the battery may never fully recharge.

0 ·

question