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ron_dittmer's avatar
ron_dittmer
Explorer III
Oct 13, 2014

Batteries: Two-6V In Series, or Two-12V In Parallel ???

Before spring I will be replacing our two 12V Walmart coach batteries. Our 7 year old rig has it's original Tripplite 2000 watt inverter/charger similar to THIS ONE. I was thinking of replacing the ...
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DiploStrat's avatar
DiploStrat
Explorer
Apr 30, 2015
pnichols wrote:

I'm curious about the PD multi-stage units: How are they at automatically dropping down from their boost voltage to their bulk voltage?


First some terminology. The three, commonly accepted stages for lead acid charging are:

-- Boost/Bulk: Max voltage and current until the battery reaches 80-90% charged.

-- Absorb/Accept: Max voltage, declining current until the battery reaches 100% charge. (This basically allows a surface charge to spread throughout the battery.)

-- Float: Reduced voltage and current. Holds the battery at full charge.

(Some chargers offer a fourth, equalization charge cycle.)

My gripe with the specs on the PD line is that they drop the voltage so much that they basically skip the absorb stage; one reason that their charge times are so long. I know from experience that if my Magnum Inverter/Charger drops out of absorb before the batteries are fully charged they will never reach full charge. This means that you have to pay a bit of attention to the absorb setting, either time or amperage flow, to assure that your batteries are getting a full charge. One reason that lots of folks keep a TriMetric around so that they have an independent opinion of the state of charge.

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