Quote:
Originally Posted by mikeloretto
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So I bought new 12 volts today, installed them around 1pm, and the In-Command panel showed something like 12.6 volts. I decided to wait to plug in to shore power and to let it sit without anything on (except whatever phantom power is being drawn), and by 9pm it was down to 12.2 volts, which if I read my charts right is something like 60%???
We're planning to get solar anyway, which I saw earlier in this thread was one person's solution. And will probably install a battery cutoff, too. But it still doesn't seem right that it would go down that fast with totally new batteries.
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The battery may not have been fully charged. New batteries may need a long charge to start.
It takes 14 to 18 hours to fully charge a lead acid battery. It does not matter what size it is or what the charger capacity is. It takes a long time to fully charge. The dealer may not have fully charge it.
To test, disconnect the battery so no charge or discharge for 4 hours (cheat a little use 1 hour). Measure the voltage. Get the battery discharge chart from batteryuniversity.com. Read the state of charge (SOC) from the chart. 13 volts for a new AGM is fully charged. 12.7 volts is sometimes used for older flooded cell batteries.
One test reported in another thread demonstrated a full charge reduction time switching from 30 amp to 60 amp charger. It reduced charging time by 22 minutes. The batteries still need 14 hours for full charge.
There will be large or small parasitic loads present. How large depends on the appliances in your TT. Even a low parasitic load with large batteries will run the batteries down eventually (2 or 3 weeks). Overnight is very quick. Maybe a refrig is on.