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Worthwhile to change out my Parallax 7300 Converter/Charger?

Woodtroll
Explorer
Explorer
Hello folks,

For years I have read that the factory converter/chargers on most RVs don't usually charge the storage batteries very well. With tax returns I finally have a little money to change out my power unit if I decide to, but I am wondering if it is worthwhile?

We often camp where there are at least electrical hookups, but frequently boondock, and for that I have solar panels run through a charger control that works well. At home between trips, I maintain the batteries with a Xantrex SureCharge 10 that has three different charging levels along with a periodic high charge to keep the plates clean. My batteries consist of one deep-cycle group 27 12-volt that we usually use while on shore power, and two 6-volt GC-2s that we use off the grid. I seldom have to add water to either, maybe a little bit twice a year or so.

I was considering changing out my OEM Parallax 7345 for a Progressive Industries PD4645; it is pretty much a direct replacement for the charger portion of my power center that has multiple battery charging levels, an charge level indicator light with an override switch for manual mode, and comes with a new DC fuse panel that has the "blown fuse" indicator lights, all for about $200. However, while researching my options, I ran across some information on Parallax's website that made sense. They said basically that the variable-rate chargers with the high-voltage modes work well for batteries, but when they also supply power to the trailer lights and accessories on the same outputs as the battery charger (as the PD4645 does), there is no "buffer" to deliver more consistent voltage to the trailer itself, meaning that some appliances will be subjected to higher voltage at times. I had wondered about this myself, but had never seen it in writing before.

So, really, I have no need for the faster recharging times that the Progressive Industries unit can provide, since I have a charger especially for the batteries at home and don't use a generator while boondocking. The only advantage I can see at this point to changing the module out is possibly(?) longer battery life, and the blown fuse indicators that I don't have now.

I'd value your input and experience- would I be wasting money to fix something that doesn't seem to be too badly broken, or will my much longer battery life eventually pay for this upgrade? Are there any other pieces to this puzzle that I am missing?

Thanks, safe travels!
Regan
2003 F250XL 4WD 7.3L Crewcab LB, 6 speed; Prodigy brake controller; Big Tex grille guard/ deer deflector. Canoe hauler and camping truck extraordinaire!
2003 Layton 242 Scout- Extra batteries, solar panels, LED lighting, and propane for boondocking.
37 REPLIES 37

LuvMT
Explorer
Explorer
Nice. My Class C with the Parallax came with #4 wiring to the battery. I know this because I bought thinner wire to connect the new 6V GC batteries in series before looking and had to go back and get #4 to match the leads to the coach.

tenbear
Explorer
Explorer
LuvMT wrote:
tenbear did you notice a considerable difference?


Yes. The battery charges much faster. I don't have numbers but it is a very noticeable change. The Parallax charges at 3.8v, or something less due to the resistance of the wiring between the converter and the battery. The PD charges at 4.4v when the battery is low. I replaced the existing #8 wire with #4 to reduce the resistance.
Class C, 2004/5 Four Winds Dutchman Express 28A, Chevy chassis
2010 Subaru Impreza Sedan
Camped in 45 states, 7 Provinces and 1 Territory

LuvMT
Explorer
Explorer
tenbear did you notice a considerable difference?

tenbear
Explorer
Explorer
I replaced my Parallax 7345 with a PD 9260 because I wanted faster charging times when using the generator. If you are happy with what you have, there is really no reason to change.
Class C, 2004/5 Four Winds Dutchman Express 28A, Chevy chassis
2010 Subaru Impreza Sedan
Camped in 45 states, 7 Provinces and 1 Territory

LuvMT
Explorer
Explorer
Thank you Pianotuna. Great info for thinking about solar...

Because we are still worker bees in the daily grind, we can only get out about 3 or 4 times a year at a few days at a time. WHEN we are finally able to spend a lot more time out there, I think solar would be the way to go. We generally don't stay at sites with power, as around here it is the exception not the norm (considered a luxury site). As long as the old OEM converter is doing its job, we will stay status quo. I am really hoping these new 6V batteries will really improve our boondocking experience. I have an acquaintance who uses them WITHOUT a generator (just charges at home before he leaves) and he is able to go almost a week. He does not use a furnace at night, however, in his travel trailer.

Thanks again guys!

pianotuna
Nomad II
Nomad II
Hi LuvMT,


Here is a simple flow chart.

Budget-->Energy Audit-->Battery bank size-->number of watts-->PWM or MPPT. What ever type of controller is choosen, make sure it has adjustable set points and a temperature probe that is on the battery.

One rule of thumb is between 60 and 150 watts of panels per 100 amp-hours of storage. The smaller the battery bank the higher the wattage needed (per 100 amp-hours). Here is a link to the rather special spreadsheet which includes an energy audit, that N8GS has created to help size solar battery charging systems!

Solar Spread Sheet N8GS

For a nice explanation of solar, try this link:

Golden rules of solar

LuvMT wrote:
Or maybe think about solar.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

wa8yxm
Explorer III
Explorer III
Regarding appliances running off the higher "Bulk" charge voltage.. not really a problem.. You can do this two ways.. But First let me tell you about the layout in my, rather poorly in my not very humble opinion (And well educated I might add opinion) RV.

The batteries are under the steps, Front, entry side, the power leads then run up to the very front where the BCC (Battery control center) and isolator/boost relays are then ALL THE WAY to the rear of the 37'7" RV, I mean the very back wall, stopping amidships to connect to the fuse block, and there.. Thats where they put the PDI 9180 with wizard.

A much better way would have been to put the IntellaPower converter next to the batteries, then run lines to the batteries and then on back,

Or if you want it on the house side of the disconnect switch, Put it next to the BCC and hook it in there.

In both of these arraingments the load of the battery will tend to protect the house from over voltage.

In my case... not so lucky

So, how much problem have I had in 9 years of running most of the time with the 9280 operating?

NOT A ONE. I have lost some electronics,, but in no case do I suspect over voltage on the 12 volt side of doing the damage.. (Poor quality and bad design yes, excessive voltage no) which by the way is why I push Dinosaur Borads for your 12 volt appliances... Much better quality, and in some (At least) Cases design as well.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times

BFL13
Explorer II
Explorer II
Your two new 6s need to be "base-lined" now so you know what is "full" in the future. Also this makes sure they get a full charge right away after being on the shelf for a while and are likely undercharged a bit.

You must have an hydrometer--use the glass tube bobber type not the fat little plastic type with the sideways arrow. The SG should be 1.275 or higher. If not charge them up.

Here is more bad news! The 7300 at 13.8 cannot fully charge those 6s and they will die an early death. They need to be charged to 15 volts or so to get the SG all the way up--you need a special old time manual charger that lets the voltage keep climbing until you shut it off---NOT an "automatic" that shuts itself off when it thinks the batts are full (it is set to shut off when they are not quite really full) Of course you need a voltmeter to know when to shut off the manual charger.

So the 7355 will be good to float them on shore power after you do that full charge with the other charger. Read this and weep

http://pdf.wholesalesolar.com/battery-folder/charging_instruction_2011_2.pdf
1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
See Profile for Electronic set-ups for 1. and 2.

time2roll
Nomad
Nomad
LuvMT wrote:
Charging from the generator is my biggest concern. When I get home I just plug the RV into the house and the batteries get their charge for next time, but when out in the sticks I need to recharge the batteries as quickly as possible without running a 4000 watt generator for 5 hours. Why is the charging different when running the genset compared to being plugged into a house outlet? Does the 4K gen not put out enough juice? Or did they wire it up differently? I was under the impression that the converter/charger does not know where the 120v is coming from (house or generator) and that it converts and charges the same either way?


The difference is TIME. Three days at home no big deal. Running a generator over three hours for a 65% charge is hopelessly weak.

Introduce 14.4+ volts and you are in the 90% zone in 2 to 4 hours every time.

pianotuna
Nomad II
Nomad II
Hi,

You could do as BFL13 has done and use additional chargers. 4000 watts is going to run a LOT of charger! There is an annoyance factor, however.

Make sure to plug in for several days before your next trip. A week would be super.

Another route to consider is solar panels.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

LuvMT
Explorer
Explorer
Cool info. Thanks BFL13!

I just installed to new batteries last week so have not had the RV out yet with them. I guess I will see how it goes. I really don't want to run the genset much more than a couple of hours per DAY (for many reasons to include not wanting to waste the gas, or be a noisy neighbor to people wanting to camp in the woods for the serenity not to hear a combustion engine all day long). I guess if that couple of hours is not enough for 4 days, I will have to upgrade the converter/charger. Or maybe think about solar.

Thanks!

BFL13
Explorer II
Explorer II
Here is what to expect for recharge times from a smart charger on your two batteries starting at 50% SOC, using various charging rates.

Do not imagine the 13.8v 7345 will do anything close to this! ๐Ÿ˜ž



You can see how tapering starts sooner at lower SOC the higher the charging rate using the same voltage 14.5ish. but that early tapering still has the amps higher than the constant lower amount, so it is winning until they become the same. After that the time is all the same. Time savings is all up front and to get that you have to start at a low enough SOC or there is no point in having a higher amp charger.

Your problem is if you only want to replace 50AH (not amps, it is AH) and your have a 50amp charger, then you must start at 50% but in an hour you have only put back 23% of that 220 so now you are up to 73% when you stop the gen. Unfortunately, you can't just keep doing that!

Leaving the batteries undercharged lets them sulphate, so they get you coming and going. Good news is that for a few days camping , like a long weekend, you can do that.

On the generator vs shore power, it usually doesn't matter. However, some gens like the 4000 Onan (and maybe only some of them) have a "dirty" waveform so it is not "clean power" like shore power and then some (but not all) converters will not run as well (not to fuill rated amps) but they will still run. The usual inverter-generators like the Honda 2000 etc are clean power.

Then of course you have to have enough generator power to run the charger where a high amp charger wants lots of input power, so there are limits there.

To achieve a desired generator time to do x AH back in, you need the right charging rate for that size battery bank at the right voltage, to start at the right SOC, and have a generator that can run that charger that long. Now all you need is to be in a campground that allows you to run that generator that long. Some don't allow that.
1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
See Profile for Electronic set-ups for 1. and 2.

LuvMT
Explorer
Explorer
Thanks to everyone for their input. It is greatly appreciated!

I have a class C that I have upgraded the batteries to 2 6 volt GC batteries. My estimate is they give me 200 solid amps when fully charged for my trip. Minus 50% of that so that I don't discharge my batteries too much, I have a solid 100 amps to use while boondocking. Our trips are usually 4 days. I estimate using 50 amps per day at most. That means a solid 2 days before the batteries need a charge. I was just hoping to run the genset for an hour and half per day to recharge most of the 50 amps I just used the prior 24 hours.

This seems simple, but after reading numerous forums and then the manufacturer's website and the resulting contradictions, I was getting confused as to just how "simple" it would be. I think I am OK with my theory that an hour and a half a day will replenish most of that 50 amps (I am figuring it will put at least 30 amps back in). My question now is, does my converter/charger "care" whether the power is coming from my 4K genset or shore power, as someone here stated? Or is the battery charging capability the same either way?

Thanks again for the responses! It is good to hear from experienced folks.

KJINTF
Explorer
Explorer
"Charging from the generator is my biggest concern"

If indeed this is your BIGGEST concern a multistage converter with remote pendant will decrease the generator run time.
How much? Well that depends...

For any of us to make a proper suggestion we need lots more info regarding your power requirements, battery bank size and type, etc....

As stated by the others - The 7345 is a good quality single stage converter. There are many quality multistage converters available or you could simply take along a 120Vac portable battery charger - hook it up to the generator and have both the 7345 and the charger top off the battery.

Many many options available