DC loads on battery

[LucianM]

Hi,
This is my setup ( 24V off-grid system):
- two 410W solar panels
- EaSun SMH 3k inverter with MPPT charger
- home built LiFePO4 7KW battery with JK BMS

I added DC loads directly on the battery, fused of course, is this a security issue?

Also I'm not sure how charging works.
The charger is set to user mode, the charging algorithm according to the manual is constant current until charging voltage of 27.8V is reached (bulk), then constant voltage for the absorption time, then float at 26.5 V.
Since I added the DC loads, the charger will "think" that the current is going into the battery.
Will this influence the absorption? When does it stop charging, when the current is lower than a certain value? when it's constant for some time?

For those of you wondering why I did this: during the winter time the system may need to survive 5-7 days with no production.
Since the inverter itself uses quite a lot of power in stand-by, I turned it off and now I only run DC loads directly on the battery.
I have hooked up a DC heater foil for the battery, an internet router and some security cameras which together use 15 to 100 W.

 

[chrisski]

I added DC consumers directly on the battery, fused of course, is this a security issue?

If the DC loads are connected to a battery directly through a fuse and perhaps on a busbar to prevent lug stacking, no issue.

I’d also recommend a properly rated switch to either disconnect all the batteries for storage, or disconnect the DC loads in case you get too many cloudy days and want the battery to get some charge but take the loads out of the system.