Flanders
Well-Known Member
@ShadowsPapa I didn't mean to offend you. I am asking what, specifically, would cause the PCM to register a fault with the AUX battery replaced by a capacitor bank. FCA's language is vague.
Suppose, for the sake of discussion, we replace the AUX with a LICAP SM0062-018-P-1 ($116 at Digikey). This is a 62F 18V passive-balancing module with initial ESR < 22 milliohms and leakage < 30mA.
What happens when a 20A load is placed on the SM0062-018-P-1? You'll see an instaneous IR drop of 0.022 * 20 = 0.44V plus about 0.33V per second due to capacitor discharge. Both of those are lower (better) than a brand new AUX battery, for the first few seconds. The AUX is never isolated that long. From the PCM's point of view, the capacitor module would look like a really good AUX battery.
The 30mA leakage is a little problematic, roughly twice what the JT draws while sitting. But that's not going to cause a fault. A lot of people add accessories with parasitic draws greater than that.
There are bigger and better options. The Eaton XLR-18R0507B-R is 500F, ESR < 1.7 milliohm and leakage < 8mA. This one could cold start the JT several times on a single charge. The PCM might register a fault with this as its AUX because the voltage wouldn't fall enough when isolated.
Suppose, for the sake of discussion, we replace the AUX with a LICAP SM0062-018-P-1 ($116 at Digikey). This is a 62F 18V passive-balancing module with initial ESR < 22 milliohms and leakage < 30mA.
What happens when a 20A load is placed on the SM0062-018-P-1? You'll see an instaneous IR drop of 0.022 * 20 = 0.44V plus about 0.33V per second due to capacitor discharge. Both of those are lower (better) than a brand new AUX battery, for the first few seconds. The AUX is never isolated that long. From the PCM's point of view, the capacitor module would look like a really good AUX battery.
The 30mA leakage is a little problematic, roughly twice what the JT draws while sitting. But that's not going to cause a fault. A lot of people add accessories with parasitic draws greater than that.
There are bigger and better options. The Eaton XLR-18R0507B-R is 500F, ESR < 1.7 milliohm and leakage < 8mA. This one could cold start the JT several times on a single charge. The PCM might register a fault with this as its AUX because the voltage wouldn't fall enough when isolated.
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