solar regulator

flywire

New Member
I have a small panel
Typically a small panel has a small controller and I'd expect peak load amps for your gear would probably exceed controller load capacity. Realistically I suppose a small controller load terminal is probably only good enough to run a relay.
 

Bru9

Member
I wonder what you guys think.

I have a small panel and MPPT on the 4wd, which pretty much keeps my 75L DZ Fridge / System fed all day long, which is great.

One thing I have noticed is that it very frequently re-enters an bulk > absorption charging mode when it sees the voltage drop due to the Fridge compressor kicking in (the fridge is not wired into the "load" terminals).

I know there's a design flaw in the way I've done things in so much as my MPPT can't differentiate between battery or load, but i wonder, am I likely doing any damage by re-entering a charge mode a half-dozen times or more during the day?

It doesn't seem to re-enter for long ... i suspect the fridge only cycles on for a few minutes, reaches temp and pulls out - then the MPPT shortly after flicks back to float too. If / When the battery is actually down on charge, it will stay in bulk / absorption (of course).

I'm not overly worried, but chewing the fat ...
Prob best to upgrade the firmware & fine tweak the settings.
Just a guess, the panel is quite small, or at least it's amps are, so when the controller sense a lower terminal voltage it raises
it's constant voltage to absorb (~14.4v) there by given the batt the chance to max it's current out briefly going back to bulk.
Can't see a fridge causing that much vdrop, but I can only guess here. Maybe the batt is unhealthy?

the way a charger knows the diff between the battery & the load is simply by ohms law. constant current/constant voltage with the appropriate
absorb timer setting, that is after all what 3stage charging is.

If your charger is in float, it shouldn't really be going back into absorb, it should be smart enough to stay in at the float level even when
clouds roll in breifly, over absorbing is only harmful to AGM/GELs/Li and really for weekend warrior stuff probbaly won't make any diff.

actually the proper way to wire is all loads at the battery terminals, I have about 20 wires all going to my pos terminal (via busbars).
the load ouput is just a poor mans LV cutout.

cam04 is on the money... some actually have a 1,2,OFF switch setup tapping the alternators raw output first for speed & then switch over
to the DC-DC to give the final proper voltages... Youd have to be a fool to charge off direct with quality AGMs & potenially miss out
on the last 15% capacity because of a low volatge... Even more foolish on a big trip sulphating the battery in as little as 10-20cycles. Some wet cells can be charged to 14.9 to actually speed things up... Buy the thing once & you can charge any battery chem without worrying about voltages.
 

darb

Well-Known Member
Prob best to upgrade the firmware & fine tweak the settings.
Just a guess, the panel is quite small, or at least it's amps are, so when the controller sense a lower terminal voltage it raises
it's constant voltage to absorb (~14.4v) there by given the batt the chance to max it's current out briefly going back to bulk.
Can't see a fridge causing that much vdrop, but I can only guess here. Maybe the batt is unhealthy?

the way a charger knows the diff between the battery & the load is simply by ohms law. constant current/constant voltage with the appropriate
absorb timer setting, that is after all what 3stage charging is.

If your charger is in float, it shouldn't really be going back into absorb, it should be smart enough to stay in at the float level even when
clouds roll in breifly, over absorbing is only harmful to AGM/GELs/Li and really for weekend warrior stuff probbaly won't make any diff.

actually the proper way to wire is all loads at the battery terminals, I have about 20 wires all going to my pos terminal (via busbars).
the load ouput is just a poor mans LV cutout.

cam04 is on the money... some actually have a 1,2,OFF switch setup tapping the alternators raw output first for speed & then switch over
to the DC-DC to give the final proper voltages... Youd have to be a fool to charge off direct with quality AGMs & potenially miss out
on the last 15% capacity because of a low volatge... Even more foolish on a big trip sulphating the battery in as little as 10-20cycles. Some wet cells can be charged to 14.9 to actually speed things up... Buy the thing once & you can charge any battery chem without worrying about voltages.
Cheers , have mostly got this resolved ... the issue is mainly when the fridge pulls 4-5amps and the solar input isn't enough to supply, so it dips into battery for a little while and thus kicks the mppt back into a charge mode. It's shortlived and been fine

Plus these days I mostly work from home and its sitting on an AC float charger ... solar only gets used camping these days!

Additionally, my setup is not ideal in that the the MPPT is wired into the system too deep in the system and shares the same 6BS feed from the auxillary battery

next car will be better done
 
Top