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Old 09-13-2015, 12:26 PM   #1
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Anyone make a 100 amp converter/charger to replace parallax 7345 for boondocking?

Hello..

My batteries (2 trojan T105's) rarely get charged (parallax 7345) from shore power, as I remove them and store them inside after I return from boon docking 2 weeks per year.

My parallax converter/dumb charger provides 45 amps but takes to long while boon docking and running my honda EU2000i. The parallax "could" boil them but I never run the generator long enough.. I think..

Id like to have a smart charger/converter with a minimum of 90 amps (20% of the rated 20 hr capacity) but would also consider a 100-110 amp charger because Iv heard plenty of people charging at 25%.

Does a converter/charger in this amp range exist? Or should I continue to make sure my batteries never drop below 12.3v and hope I don't run the generator to long if we watch a movie or something?

Thanks
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Old 09-13-2015, 01:13 PM   #2
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Hello..

My batteries (2 trojan T105's) rarely get charged (parallax 7345) from shore power, as I remove them and store them inside after I return from boon docking 2 weeks per year.

My parallax converter/dumb charger provides 45 amps but takes to long while boon docking and running my honda EU2000i. The parallax "could" boil them but I never run the generator long enough.. I think..

Id like to have a smart charger/converter with a minimum of 90 amps (20% of the rated 20 hr capacity) but would also consider a 100-110 amp charger because Iv heard plenty of people charging at 25%.

Does a converter/charger in this amp range exist? Or should I continue to make sure my batteries never drop below 12.3v and hope I don't run the generator to long if we watch a movie or something?

Thanks
You could add Airstream's current Univolt that charges at 55 amps maximum.

Your 45 and the 55 make up your 100.

Also. you could put a switch in the 120 volt line going to the 45 amp charger, and shut it off, when not needed.

Andy
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Old 09-13-2015, 02:05 PM   #3
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I don't think your math is correct. If your 20% figure is derived from the C/5 calculation for charging amperage, then you would need a 45 amp charger.

Your T-105s are 220 amp/hours at 6 VDC but they stay at that amperage when connected in series for 12 VDC operation. 220/5=44.

The direct converter replacement for your Parallax is the Progressive Dynamics PD-4655, which is a 55 amp converter with 3-stage charger. It will do a good job for your T-105s.


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Old 09-14-2015, 05:27 AM   #4
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I don't think your math is correct. If your 20% figure is derived from the C/5 calculation for charging amperage, then you would need a 45 amp charger.

Your T-105s are 220 amp/hours at 6 VDC but they stay at that amperage when connected in series for 12 VDC operation. 220/5=44.

The direct converter replacement for your Parallax is the Progressive Dynamics PD-4655, which is a 55 amp converter with 3-stage charger. It will do a good job for your T-105s.


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
Master Tech Energy Systems, Inc.
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Lifeline Batteries**Magnum Inverters
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Thanks for pointing out my mistake.

I thought my charging amperage wasn't enough, but turns out its pretty close to max with the 7345. The 7345 just doesn't have the float mode and could over charge the T105's. But how long that would take is the question with only my refrigerator and occasional light in the bath as a load.

Is there a device which I can monitor the charging conditions with the 7345 to warn me while I run my generator for warming microwave meals? Or is a smart charger the only way to prevent over charging?

Thanks again.
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Old 09-14-2015, 10:54 AM   #5
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Originally Posted by rebar View Post
Thanks for pointing out my mistake.

I thought my charging amperage wasn't enough, but turns out its pretty close to max with the 7345. The 7345 just doesn't have the float mode and could over charge the T105's. But how long that would take is the question with only my refrigerator and occasional light in the bath as a load.

Is there a device which I can monitor the charging conditions with the 7345 to warn me while I run my generator for warming microwave meals? Or is a smart charger the only way to prevent over charging?

Thanks again.
The problem with the Parallax is not only the lack of a float mode, it is the continual 13.6VDC output. If you check with Trojan, they recommend 3-stage charging with much higher voltages for both bulk and absorption phases more in the area of 14.4-14.6VDC.

Your Parallax will never attain these voltages, and your batteries will never be completely charged, causing premature failure. Your best solution is to junk the Parallax and install the Progressive Dynamics.
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Old 09-15-2015, 06:05 AM   #6
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My T-105's spend two weeks a year in the trailer. The other 50 weeks they sit in my basement and I charge them once a month with a batteryminder smart charger.

So, I was only concerned with the two weeks where my battery load is my fridge and a evening shower. I run the generator twice a day for a hour or two for microwave meals and I know the batteries never went below 12.5v , but wasn't sure if they had reached full charge.

Iv been told not to worry and cant justify buying a Progressive Dynamics unit for my two weeks a year. And now understand why the first single battery died when I left it on shore power..

Thanks!
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Old 09-26-2015, 05:43 PM   #7
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I've got the original Univolt charger on my 1990 Excella 29' and only one battery. I need to replace the battery next towing season and am thinking of replacing the Univolt with the Progressive Dynamics charger. Am also thinking of having JC add an additional battery box and wiring. Would the PD 4655 be the right one, or one lower or higher?

As is, the Univolt is plugged to shore power most of the time because we use the AS a lot, and when home we are unpacking, then repacking. So I add distilled water to my current battery monthly and over all six cells it takes a total of about 6-8 oz, so I know that the Univolt is cooking the battery.
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Old 09-26-2015, 05:58 PM   #8
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I've got the original Univolt charger on my 1990 Excella 29' and only one battery. I need to replace the battery next towing season and am thinking of replacing the Univolt with the Progressive Dynamics charger. Am also thinking of having JC add an additional battery box and wiring. Would the PD 4655 be the right one, or one lower or higher?

As is, the Univolt is plugged to shore power most of the time because we use the AS a lot, and when home we are unpacking, then repacking. So I add distilled water to my current battery monthly and over all six cells it takes a total of about 6-8 oz, so I know that the Univolt is cooking the battery.
Airstream' current Univolt is 55 amp.

That is more than enough to keep 2 and for that matter even 3 batteries charged up for you.

If you have 3 batteries at 100 amps per hour, it would take that charger about 7 hours to recharge all 3 if they were all dead.

Going to a 100 amp, to me, would be a waste of time, and money.

Your current Univolt, would take a little longer, but I would keep it until it says goodbye, and then update, unless you absolutely have to have full charged batteries quickly after total run down.

Andy
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