Born Free Leap'n Lions RV Club

I, like many of you, have read the material and discussions on replacing Parallax and Magnetek Converters with the Progressive Dynamics PD4655 units. My older BF (24' RB) is of 1982 vintage and in this coach, the factory installation was a Progressive Dynamics PD765Q, rated at 45 amps. I recently found that the Charge Sentinel (battery charging) light was not illuminated on hookup to shore power, so I went through the system to determine the problem. It turned out to be a poor contact to the battery charge board by the connecting wiring harness.

I then decided to look into the upgrading of the battery charging system and examined all the current offerings from several manufacturers. To my chagrin, I found that the cutout footprint of all more current units was far smaller than my current PD765Q. While going through the electronics didn't give me pause, redoing the cabinetry to accommodate a smaller front face certainly intimidated me! I quickly found that the AC panel system of the PD765Q was fully functional, as was the DC converter. The old unit did have a hum at the transformer, the battery charger was a single stage unit and the system only charged the coach battery (my 1982 E350 based BF has dual batteries under the hood and no obvious area available for additional battery packs.)

After a bit of searching, I found that the PD9245 from Progressive is a virtually drop-in replacement for the converter/charger on the original PD765Q. The PD9245 has the built-in Charge Wizard 3-stage battery charger and delivers the same level of DC support and charging current as the original unit. After installation I found that the previous transformer hum is now gone and the the power center runs a bit cooler than the older system. I found the new PD9245 on eBay for $106 plus $12 shipping. I enjoyed not paying CA sales tax on the transaction.

I also found that a Trik-L-Start module would add charging of the chassis battery whenever the charger was supplying current to the coach battery. When no charger current is applied to the coach battery, the chassis battery is fully isolated. The Trik-L-Start has no electrical interference with the alternator relay circuit that charges both batteries when the engine is running. I have now experimentally verified that the PD9245 goes into the correct 13.2V float charge mode with the Trik-L-Start unit in place and both batteries up to charge. (I'm using two Interstate Deep Cycle Wet Cell Batteries.).

Finally, I have just purchased a 100W monocrystalline solar cell panel and controller for mounting on the BF. Although its not yet mounted, I have been testing the electrical hookup. I have wired it into the PD765Q/PD9245 DC distribution panel and find the Trik-L-Charge works just as effectively to distribute charge between the two batteries. I one test, I ran the coach battery down to 10.7V, had the chassis battery at 12.6V and brought on the solar cell current. The current going into the coach battery was 5.22 amps (direct LA mid-day sun) and that going to the chassis battery was 130 ma. It appears that the control circuitry in the Trik-L-Start module is far more sophisticated that I would ever expect at at retail price of $48. I got it for $38 and $10 shipping at RVupgrades.com. Once again, I was deeply pleased to forgo any contribution to the fiscal state of CA.

I'm sure this is quite uninteresting for the majority here, but I hope there are a few lurkers with older versions for which this might be helpful.

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Frank and Paula
1982 BF 24' RB

Very good info and good detailed writeup. Having the 3 stage battery charger feature in the Progressive converter makes it 500% better than the normal converters which only have a single stage. The single stage is, 1st-- slow to charge, 2nd-- will overcharge the battery if left on too long.

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Al & Sharon
2006 Winnebago 29' Class A MH
Chevy Colorado Toad
Former BF owners.

Dear Frank,

Seeing this meticulous description, I am sure that you have an equally good analysis of the length of time you can dry-camp with the utilization of 100 watts solar panel?

In addition, how long does it take to fully recharge your house batteries with the new charger/converter?

BTW(1) - Why is it called "converter" - probably because it "converts" 120 VAC to 12 VDC for the house loads excluding the battery charge. If this is the case, does the converter maintain constant 12 VDC for the house loads separately from the battery charging voltage level?

BTW(2) - I fully share your pleasure for the fiscal deprivation of the state of CA

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Oliver P Smile
2005 26ft RSB

Oliver,

Some good questions! I can't answer the question as regards full recharge time as I have not fully discharged the batteries after the PD9245 installation. Initially, I had run the coach battery down to 11.2V which is rather heavily discharged. It was up to the 90% charge indication in about 1.2 hours and fully charged in about 356 hours, although I wasn't recording the voltage profile carefully. The old PD765Q had a battery charger circuit that was limited to 10A maximum. The PD9245 will actually deliver up to its rated 45 amp current capacity if the battery can accept the current load (this is at the 14.4V full boost stage). Of course the delivered current is limited by how many other DC sources you have drawing on the converter.

The term converter is appropriate because the PD9245C is converting the 120VAC shore power or generator power to nominally 12VDC.

Actually, I have found that the Motorhome DC circuits are supplied at 13.4 to 13.6VDC at all times regardless of the output voltage of the charger circuit. The PD765Q supplied 12.8 to 12.2VDC under similar terms.

As to the dry camping lifetime of the system, the result depends on the various drain sources, of course. For my selection of the single 100 Watt panel, I went through the following analysis. I disregarded the details of toilet use, water pump running to support the sink, ignition currents for the water heater and zone heater. I lumped these together with water pump usage during showers as a total of 7.5 amp-hrs per day. I've converted all the interior lights in our BF to LEDs. The total current draw when I turn on all 12 fixtures is 2.016 amps. For my calculation, I budget 1.0 amps for lighting with a net usage of 8 hours per day for 8.0 amp-hrs. My TV/DVD system draws a total of 1.8 amps with audio amplification. Using the Satellite antenna and the Direct TV receiver requires a total of 3.270 amps with the Direct TV receiver and dish driven by my full sine wave inverter and supplying the TV from the direct 12VDC source. I assume that TV entertainment is an average of 4 hrs per day and therefore entertainment takes an average of 10 amp-hrs. My Mac Powerbook Pro 17 consumes 22.5 watts and the iPad 2 uses 3.8 watts per hour. I assume that we will use these no more than 8 hours per day, for a computer budget of 16.8 amp-hrs. The vent fan draws 1.6 amps at its maximum speed, so I assume 8 hours of forced ventilation per day for 12.8 amp-hrs. With these estimates, I have a daily electron expenditure of 55.1 amp-hrs per day.

The capacity of Interstate Deep Cycle battery I'm using as the coach battery is 107.5 amp-hours for discharge to 11.5 volts which is the load cutoff point that the solar panel controller uses. Consequently, I could live for two days on the coach battery without consideration of the solar panel. The 100 watt monocrystalline cell solar panel delivers 5.0 amps at typical midday mid-latitude illumination. The average current delivered per summer day with typical Pacific Northwest cloudy days is 3.6 amps average during the illumination period. This is a literature number and I haven't yet mapped the panel response in LA as yet. Assuming a best case mid-summer day, there are about 13 hours of useful illumination. Therefore, the panel would supply about 47 amp-hours of charge leaving a deficit of 9 amp-hours optimistically to 20 amp-hours more realistically. This says that the dry camping window should range from 5 to 12 days without firing up the engine or generator. If I assume that the will be used for several hours on a given day for the AC or the microwave, then no-engine fire-up should extend to weeks with the charging capability of the PD9245C. Should we forgo computer use or extended satellite entertainment, the dry camping period easily extends to weeks.

Of course, your mileage may vary. Hope this helps.

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Frank and Paula
1982 BF 24' RB

I spent 3 months in Florida last winter all of which was dry camping. I have a 125 watt solar panel and only had to run my generator about 6 times to charge my batteries. The panel will typically supply 6 to 7 amps in direct sunlight. I haven't done the converter upgrade but I do have a separate 40 amp battery charger. I don't have a satellite receiver so that saves a bit of power.

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Tom
2005 24' RB
Towing 1978 VW Bug convertible
New Hope, MN

What some people do about recharging their batteries is to run the generator for about 1 hr in the morning to bulk charge the battery and then let the solar panel finish charging the battery.

With your 3 stage converter/charger the 1 hr of gen time should put 35 amp hours or so of charge back in the battery, and then the solar will top off the batteries.

If you only have a single stage charger this won't work nearly as well.

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Al & Sharon
2006 Winnebago 29' Class A MH
Chevy Colorado Toad
Former BF owners.

Just gotta jump in here with warning that routinely taking that battery down to 11.2 V will greatly compromise battery life. !2.1 V is a more appropriate cut-off point.
Ralph

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Ralph
2011 24RB
Former 2001 23RK

Instead of running your generator just to charge batteries, why not start the engine to charge your batteries (both coach and chassis at the same time) at much higher amps than any converter/inverter can supply? Wouldn't this charge the batteries faster?

Just asking. This is what I do.

Now if you need to run your microwave or AC, you'll need to run your generator if not connected to shore power.

Bill

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Barb & Bill
2004 Born Free 22' Built for Two (Sold)
no longer towing a 2008 Smart ForTwo

Escondido, CA

At this point the drain down cutoff point is hard to monitor. In the 11.2V case I cited, there was a 255 ma. current drain in coach from the Magellan GPS system I installed. I had foolishly assumed that the off switch switched the thing off! When the BF is in storage, I have no power input for the batteries. This is one of the things I intend to correct with the solar panel.

But your suggestion is well taken. I am considering a battery voltage triggered alarm or sentinel signal to alert me during dry camping when the usage has exceeded reasonable limits.

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Frank and Paula
1982 BF 24' RB

As long as you just dry camp or boondock overnight or for a couple of days and just use the lights and water pump, running the engine for an hour or so works just fine.
However if you run the furnace in 35*-45* or lower temps for 12-16 hours, just running the engine for an hour won't charge the batteries well enough.

Additionally if you have an inverter and run a TV & satellite receiver, and a couple of laptops in addition to the lights for several hours, running the engine for an hour won't recharge the batteries enough. Do this for 2-4 days and you will have dead batteries. Repeat this process for 20-30 times and you will kill your batteries so they won't accept a full charge and you will need new house batteries.

Doing either of the above will use 50 to 90 amp hours (AH) in one day.

To quickly charge a lead acid battery pack you need to apply 14.6 volts (Bulk Mode charging voltage) at about 25% of the total battery capacity. My Born Free house batteries have a capacity of about 200 AH. So I can charge at 50 amps. If you push say 100 amps at 14.6V or even 13.8V for the needed hour or so you can damage the batteries.

To get 50 AH back into the batteries you need have the 50 amps at the 14.6V continuously for 1 hour.

Auto or truck alternators put out about 13.6-13.8, possibly 14, volts and are designed to recharge the starting battery, and are not set up to quickly recharge the house batteries. This means it will take even longer to recharge than if it was at 14.6V

We probably have #10 wire from the alternator to the house batteries. With that small wire going to the house batteries, pushing high current down that wire causes a voltage drop. So instead of getting the 13.6-13.8 volts you could be getting 13 volts at the battery. Now it takes many hours to get 50AH back into the house batteries. Running #0 or #00 (one "0" or two "0") wire, which is 5-10 times a thick as #10 would really help.

If you want more info here is a link to very good RV battery info
http://www.rvcruzer.com/electrical/chapter7.php

Here is a link to Trojan Battery's website where they detail the proper daily (bulk mode) charging voltage as 14.8V.
http://www.trojanbattery.com/BatteryMai ... rging.aspx

Lots more info about batteries & RV electrical system on the above websites.

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Al & Sharon
2006 Winnebago 29' Class A MH
Chevy Colorado Toad
Former BF owners.