Renogy DCC1212 connection time

When I connect the ignition wire to a Renogy DCC1212-20 and start the engine will it directly connect the 2 batteries or is there some delay in connecting ?
I prefer a delay of a few seconds.

It never directly connects them; however, per the manual:


It will use the starter battery to begin charging the house battery at up to 20A.

I understand that, D+ connecting and ignition on will activate the DCC even the engine is not running
But what I wnat to know is when the D+ is connected and ignition is on will the DCC directly turn on ?
Isn´t it better when the DCC turn on a few seconds later ? Just for the alternator ?

I think it's safe to assume there is no significant delay regardless of what you think is better. In any case, a 20A charge current is going to be a very small fraction of the current pulled during start.

Thanks I was worried about that

An other off topic question, I also want to buy the AC-DC 20A charger for self build 280Ah Lifepo4 battery.
I take out ±60A eache day
I also have a 265Wp solar panel on the roof with the MPPT 75/15
The charger is just for emergency
Do you think 20A charger is enough ?

It depends on what you actually need. It's good for 20Ah/hour of charging. If you need 200Ah, then it's 10hr of charging... then it might not be enough. 3 hours is enough for your current usage, and you have over 4 days of capacity.

Your 265W panels could push up to 265W/12V = 22A. With only 15A available for charging, you are over-paneled and can't capture your full panel output. You can't harvest more than about 15A * 14.4V = 216W from your current panel in perfect conditions as the battery voltage peaks.

12V * 15A = 180W

If you use 12.8V * 60Ah = 768Wh, you need 768Wh/195W (something in between 180 and 216) = 4 hours of solar charging. And that's not 4 hours of being in the sun, that's 4 hours of insolation, i.e., after charging all day, you get the equivalent of 4 hours of full power charging.

With panels presumably flat on the roof, I suspect that you will need regular charging from the alternator, particularly in cold months where your equivalent hours may only be 1 or 2.

An upgrade to a larger (20-30A) controller, or a second 265W panel IN SERIES with the first will notably up your solar harvest.

Thank you. I keep your advice in my mind