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Old 12-13-2017, 12:27 AM   #1
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2011 23' FB International
1975 Argosy 30
Santa Barbara , California
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Any charger around with a high voltage absorption phase?

My AS came with a parallax converter and it's time to replace it with better. I have two Trojan T-105's and the manufacturer recommended charging (@25C) is:
- bulk phase (constant current) at up to 25A up to 14.8v
- absorption phase (constant voltage) at 14.1 to 14.7v
- finish phase ramping the battery up to 16.2v
- float phase at 13.5v
see table 4 in

I have solar and try hard not to go below 70% and I want a charger that uses a minimum of generator time to go from ~70% to 90%+. I've looked at progressive dynamics chargers and powermax chargers and neither can run the absorption phase at more than 13.6v and both have too low a float phase (sometimes in winter the solar doesn't cut it and I stay plugged in for long). Does anyone know of chargers that are programmable and can run the absorption above 14v and keep float at 13.5v? (I have a Trimetric and the Bogart SC-2030 solar charger, so I'm spoiled...)
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Old 12-13-2017, 06:08 AM   #2
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I'm not sure if all the specs, but I've heard good things about the BlueSky equipment, a few people complain it's too complicated, which to me implies it must have more controllable functions than simple ones. Might be worth a look
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Old 12-13-2017, 06:29 AM   #3
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Chelsea , Michigan
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Many Airstream owners replace their factory chargers with one from Progressive Dynamics. They have models that are essentially "drop in" replacements for the one Airstream uses. Start your research here:
Bob Martel
WBCCI# 5766
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Old 12-13-2017, 09:12 AM   #4
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Pleasanton , California
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I would ask why bother? You already have a decent solar charger, so simply make sure you're not connected to your parallax for extended durations by selecting the "store" position when connected to shore power. Let your solar charger do the bulk, absorption and equalization and even the float and use your parallax to charge when you're in cloudy conditions - does this occur in Santa Barbara
Al, K6IV
2015 30' Classic, "Chez Nu"
2014 RAM 2500 w/Cummins Diesel
ProPride Hitch, 400 W Solar
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Old 12-13-2017, 12:10 PM   #5
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2011 23' FB International
1975 Argosy 30
Santa Barbara , California
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The bluesky gear is all solar chargers as far as I can tell. I need a shore power charger.

The progressive dynamics does the absorption phase at 13.6v, which is lower and thus I fear slower than necessary. I'm exactly trying to shorten the absorption phase 'cause that's the relevant one when we're in cloudy or forested conditions and I need to run the generator to go from ~70% to 90%+. I just did that with the parallax and it starts at ~10A @74% charge and drops to 8A within a couple of minutes and it's downhill from there. From there to to 90% takes forever and goes at perhaps 3-4A avg, if that.
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Old 12-13-2017, 03:43 PM   #6
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Originally Posted by tvoneicken View Post
-- snip -- I need to run the generator to go from ~70% to 90%+. -- snip --.
The PD Charge Wizard has an over-ride button that pushes the charge to 14.4 volts boost mode until 90% and then backs down to complete the charge.

What charger did Trojan recommend? Pat
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Old 12-13-2017, 07:17 PM   #7
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Carlisle , Pennsylvania
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If you have a button labeled "charge to full fast", put a little label under it that reads "boil batteries".

There really isn't a good way to get to > 90% charge fast. Lead acid batteries don't work that way. If you are going to try, be sure to get a charger with a temperature probe on it. You very much want the charger to adapt as the batteries heat up.

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