AGM Batt on Trickle Charge?

Almot wrote:
My mistake, sorry. 40% minimum SOC for AGM is for self-discharge only. When they cycle daily, there is no minimum SOC (I think). But the deeper you cycle, the fewer cycles you'll get. At 100% discharge you'll still get 200 cycles (vertical axis are cycles, horizontal - depth of discharge):



But this is for AGM (or any other deep cycle battery). Car starter battery won't take deep discharge too well.

So, you can abuse AGM and draw - don't know - 13 or 14 AH a day, out of 18 AH battery. Maybe you should consider lithium battery.

That is the ubiquitous Lifeline chart. Let's read that chart.

Look across the bottom of the chart to find 80%, then look up to see the intersection at 500 cycles.

This means that you can get 500 discharge/recharge cycles when discharging by 100% of capacity. Now what do you think will be the capacity of the battery at this point?

Well, the chart is designed to show where the battery will have 80% of the original capacity! Then, it is time to consider battery replacement.

Now, using the 18AH battery, we see that we can discharge/recharge 80% of 18AH, or 14.4AH, 500 times and the remaining capacity of the battery is 14.4AH.

The complete info can be found here.

Here is the authentic chart.

HTH;
John