Converter/Charger Question

[Appalachian Ed]

I see many of you upgrading your converter/charger. Many to the Progressive Dynamics. Sometimes to a 55 AMP (which is what my OEM is) sometimes to a 65 AMP. Why? I have a WFCO WF8955 in mine. I am not challenging you, just trying to understand what the advantage is. Is it due to a high failure rate or is there some other advantage i.e. with the charger? (I am hoping RodeoGeorge is listening as I was reading your mods that made me wonder, but I have read of a few others doing this as well. And thanks RodeoGeorge for the details in your mods. They are very helpful.)

Thanks for your expertise.

[Kenny kustom]

I'm installing a magnum hybrid inverter.

It's a 3k inverter, plus it's a 120amp charger!

Best of both worlds.


2016 Sabre 36QBOK
2015 Ram 3500 CUMMINS

[Appalachian Ed]

Originally Posted by Kenny kustom

I'm installing a magnum hybrid inverter.

It's a 3k inverter, plus it's a 120amp charger!

Best of both worlds.

I have a basic question on that. Is there a problem installing an inverter with a charger while having a converter with a charger built in. Are 2 chargers ok or do you disable the OEM charger when you install the inverter?

[Kenny kustom]

My converter is out board from the panel.

With the built in ones, I would assume you just remove the dc lines going to the battery.


2016 Sabre 36QBOK
2015 Ram 3500 CUMMINS

[Flybob]

To answer the original question,

The Progressive Dynamics converter offers a much better charge management system which will prolong the life of your batteries and reduce potential for premature damage ( ie cell evaporation).

The PD converter is also a higher quality unit which in theory is less likely to cause problems when you need it.

The main electronics panel in most RVs consists of two sub units, the converter and the distribution/fuse/breaker panel. The replacement is fairly simple as you just replace the converter assy. In most cases they are same size ( or very close). Think the PD sizes are 45A and 65 A ( no 55A) hence the switch to 65A

[pgandw]

frwright2A 65A converter is overkill in most situations. Converter size should be driven by battery bank size (max charge rate = 25% of battery capacity in AH), and other camper DC loads (not including any inverter) that would be used while hooked up to shore power or generator.


For my little A-frame with a standard single size 24 battery (80 AH), max charge rate is 20 amps. Fridge in DC mode doesn't count because I use AC mode while camping with electric. Remaining DC items are lights (5A total), heater fan (4A), and vent fan (3A). Both fans would not be running at the same time. So max DC load is about 8A. The stock 30A converter is fine, a 45A converter would not change charge times at all.


I installed 2 size 24 batteries to dry camp for 4 days/nights using heater at night. Yes, I could now use a 45A converter. But the whole point of the 2nd battery was to keep the batteries above 50% of capacity. Bulk charge can only be used to 80% of battery capacity, then the charge rate needs to drop and then taper as charge slowly climbs to 100%. With 1 battery, it takes 75 minutes (1.25hrs) in bulk mode to get to 80% from 50% - and at least 4 more hours to fully charge. With 2 batteries, it takes 2.5hrs in bulk mode to get to 80% - and the same 4 hours to get to full charge. I would save 1 hour 15 minutes in charge time (of a total 6.5hrs plus) by replacing my 30A converter with a 45A converter. The time savings with the bigger converter is only significant if I'm using a generator to charge my batteries. And then, it only matters if I'm taking my batteries down to 50% before charging. If I start charging when the batteries are at 80%+, I gain nothing with the bigger converter.


Since we are setup for short-term dry camping (4 nights), and have a camper that stores in the garage, I don't carry a generator. Battery recharging that does not happen while driving is done by plugging in when we get home. An overnight charge time to 100% is not an issue, so again the 30A converter does just fine.


just my thoughts and experiences
Fred W
2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan

[spock123]

I have in my Cedar Creek a 55amp converter/charger, I have 4 6 volt batteries. I plan to install a Progressive Dynamics converter, what amp should I go with? I looked at a 60amp, 70amp, and a 80amp. On the 80amp it said something about a 20amp plug. I am thinking maybe the 60amp or 70amp. I need advice


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[Kenny kustom]

Anything past 70 amp will need another feed from the panel.


2016 Sabre 36QBOK
2015 Ram 3500 CUMMINS

[Bluepill]

Originally Posted by spock123

I have in my Cedar Creek a 55amp converter/charger, I have 4 6 volt batteries. I plan to install a Progressive Dynamics converter, what amp should I go with? I looked at a 60amp, 70amp, and a 80amp. On the 80amp it said something about a 20amp plug. I am thinking maybe the 60amp or 70amp. I need advice


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Assuming that your batteries are 225 Amp hours, you have a total of 450 AH at 12 volts. For true deep cycle batteries, you can discharge down to 20% state of charge. That means you recharge with 360 amp hours to full. Based on a C/8 maximum charge rate, a 55 Amp. converter/charger would do. Personally, I would go to 65 amp so that it doesn't run at full power.

[spock123]

They only come in 60amp and 70amp. I'll get the 70amp. Many thanks


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[PokerDealer]

My understanding is, for the longest life of deep cycle batteries they shouldn't go below 50% of capacity, whenever possible . That changes things signifantly.

[spock123]

Originally Posted by PokerDealer

My understanding is, for the longest life of deep cycle batteries they shouldn't go below 50% of capacity, whenever possible . That changes things signifantly.

You are right, you don't want to ever discharge your batteries below 50%


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[Skyliner]

A triple rate charger such as a Progressive Dynamics one will charge your batteries faster than the power converter that came with your unit from the factory.

I almost feel guilty selling my factory power converters on craigslist when I upgrade mine each time I buy a new camper.

[Bluepill]

From Trojan Battery website:

Discharging batteries is entirely a function of your particular application.

However, below is list of helpful items:

Shallow discharges will result in a longer battery life.
50% (or less) discharges are recommended.
80% discharge is the maximum safe discharge.
Do not fully discharge flooded batteries (80% or more). This will damage (or kill) the battery.
Many experts recommend operating batteries only between the 50% to 85% of full charge range. A periodic equalization charge is a must when using this practice.
Do not leave batteries deeply discharged for any length of time.
Lead acid batteries do not develop a memory and do not need to be fully discharged before recharging.
Batteries should be charged after each period of use.
Batteries that charge up but cannot support a load are most likely bad and should be tested. Refer to the Testing section for proper procedure.



This applies to TRUE Deep cycle batteries, not "RV/Marine" types which should NEVER be discharged beyond 50%

[PokerDealer]

My point exactly, I have 2 T105's. As per Trojan, they will last the longest it they are only discharged 50% or less

[PokerDealer]

They're not like the old ni cads that have memory. You would be using a "discharge cycle" it you used 80% of their capacity. Batteries only have so many cycles and then need replaced

[Skyliner]

Not entirely accurate and my rebuttal has a manufacturer weblink to validate my comments.

Lead acid batteries have greater discharge/cycles based on lower depth of discharge.

Trojan batteries can last about 2900 cycles if discharged only 20% and 500 cycles if taken to 80% discharge. Reliant AGM | Trojan Battery Company It is to your advantage to use as many batteries as you can fit/afford to reduce depth of discharge and extend battery life.

I've had batteries last only a season when I abused them by discharging them too much too often.

[Bluepill]

Originally Posted by Skyliner

Trojan batteries can last about 2900 cycles if discharged only 20% and 500 cycles if taken to 80% discharge.

If accurate, those numbers would argue for fewer batteries and deeper discharge.

Basis: 1 pair of T-105 batteries in series giving 12 volts and 225 AH capacity.

Discharging 20% = 45 AH used. Times 2900 cycles, total "Lifetime" AH delivered is 130,500 AH.

Discharging 80% = 180 AH used. Times 500 cycles, total "Lifetime" AH delivered is 90,000 AH

To get the same 180 AH capacity per charging cycle that the 80% discharge gives, you would need 4 times as many batteries for the 20% scheme.

If you boondock for 50 days a year and recharge daily, the 80% discharge scheme should give you 10 years of use.

Just sayin'

[Witch Doctor]

Originally Posted by Flybob

To answer the original question,

The Progressive Dynamics converter offers a much better charge management system which will prolong the life of your batteries and reduce potential for premature damage ( ie cell evaporation).

The PD converter is also a higher quality unit which in theory is less likely to cause problems when you need it.

The main electronics panel in most RVs consists of two sub units, the converter and the distribution/fuse/breaker panel. The replacement is fairly simple as you just replace the converter assy. In most cases they are same size ( or very close). Think the PD sizes are 45A and 65 A ( no 55A) hence the switch to 65A

I changed out my charger/convertor from the WFCO 8955 to a direct replacement progressive #PD4655/ progressive PD 4600 series. The progressive is a true 4 stage charger a WFCO 8955 is a 3 stage charger. The reason I changed was because of a fan failure. I choose Progressive because of the charge wizard. I can controll what my charger is doing. Also the added 4 th stage of desal mode which it will go into every 24 hrs for 15 mins. I have not had to add water since my change out. In hind site I should have went to the PD4665. It still would have been a direct replacement but 10 more amps. The progressive also comes with 2 fans for cooling not 1 fan like the WFCO unit. I use to beable to hear the WFCO fan but not the progressive with both going. See attached: Also after 2 WFCO either one would drop to float at 13.1 Progressive can read parasites and still drop to 13.1, as stated in the WFCO manual it will only drop to 13.1 if it will not read a draw for 48 hrs. So I was always in 13.5 not good for batteries unless you check your water weekly. It's a very easy change out, just wire from the old to wiring to the new board.