Renogy batteries and charging

Almot wrote:

Groover wrote:

This is what is in the manual on-line: "• Standard Charge shall consist of charging at 0.2C constant current rate until the battery reaches 14.6V.
The battery shall then be charged at a constant voltage of 14.6V while tapering the charge current.
Charging will terminate when the charging current has tapered to a 0.02CA."

Make sure this is a manual for your particular battery. Since Renogy is in batteries business now, God knows what other batteries they might sell.

Applying charging current after full charge is not very common with Li. In fact, applying any current after 90-95% of full charge is not a good idea with Li, the detail that manufacturers prefer not to mention. Get a charging graph V vs SOC% for your battery and stay within 30-90%. 40-50% while in prolonged storage.

That came from their online manual for the battery. It seems to call for limiting amperage until full voltage is reached then limiting voltage from that point on. I called Renogy a few days after posting that and the tech guy I talked with acted like he had never heard of the .2C limit and thought that the 50amp charging limit was more realistic.

My next question if I do this is how to handle the battery isolator that charges the house batteries when the main engine is running. My alternator produces 14.1V. It appears that I am going to have see what the lithium battery voltage does when the Magnum charger is turned off. If it drops rapidly to or below 14.1 there won't be an issue. If the batteries try to stay above 14.1 they could run themselves down backfeeding into the chassis circuit. That shouldn't be too hard to figure out. The worst case would be that I disable the house battery charging from the alternator until the voltage drops.