Charging question

[mark98012]

We only boondock so power is always a problem. We usually go for a minimum of a week which means at least re-charging. I have a Champion 2000 watt generator, I have also read that charging using the 12v output is not very efficient (which I can attest to). I have 2013 Creekside 22RB with a WF-8955PEC control panel, I'm thinking about buying a smart charger powered by my generator. DOES ANYONE KNOW IF HOOKING MY GEN TO THE SHORE POWER CABLE WILL CHARGE THE BATTERY AS FAST AS DIRECTLY AS HOOKING UP A CHARGER TO THE BATTERIES? I know this is long but I need an answer from somebody with experience as opposed to guesswork.  Thanks,

Mark R.

 

[darsben]

So if you hook up the genny to your shore cable then plug in the charger to your RV to charge your battery it should make NO DIFFERENCE. Unless you overload the genny

 

[John From Detroit]

Short answer is Perhaps.
Longer answer is it depends on the add-on "Smart Charger"

Your existing charger is likely a smart charger. (3-stage) 55 amps.

NOW Depending on how much battery you have (150 amp hours of battery that's about two Group 24's  Would take a 55 amp charger at the maximum.)  and how big the external is.. Matters.

Xantrex, in the Prosine 2.0 manual suggests a maximum charge rate not more than 30% the C/20 Amp hour rate..
SO a Group 27/29 battery is a bout 30 amps per battery
A pair of GC'2.s is 60-66 amps per pair (You put two in series to mak,e a bit 12 volt batter)

If you have say 450 amp hours of battery then  a 100 amp charger is good.

The Progressive Dynamics 9200 series of converters make very good smart chargers. Pick the size that matches your battery bank.

That said. 6 hours to re-charge fully is about the mininum no matter the size of the converter/charger.

But so long as it is workign the WFCO 55 amp is a good unit

 

[Gary RV_Wizard]

I suspect you would choke at the price of a separate "smart charger" that could produce anywhere near the continuous 45-55 amps that your WFCO 8955 can put out. Think in terms of $350+.  Those 50A chargers you see in the auto parts stores for $79 aren't continuous duty or "smart" (3-stage). They will be 50A "engine starting", meaning about 10 seconds out of each minute. The rest of the time they put out about 10A. A truly smart charger that can run at 50A for hours would be more like this one:https://www.batterystuff.com/battery-chargers/12-volt/samlex-america-12v-50-amp-2-bank-automatic-smart-charger-sec-1250ul.html

Plug in  your shore cord, turn off all unneeded 120v and 12v items and let the WFCO do the job.  About the best you can hope for is to get back to around 80% charge in a couple hours. It will take several hours or more to reach 100% charge, no matter what charger you use.

 

[Frank B]

In addition to the answers already given, have you considered adding some solar to your RV?


The problem with lead acid batteries is that while they will charge quickly to about 80%, they take forever for the last 20%  Not charging that last 20% for an extended period will shorten the life of the batteries considerably. Doing the bulk of the charge with a generator, and then letting the solar do the remainder over several hours is a good hybrid solution.

 

[mark98012]

I guess the best way to ask the question is: Which is best AND most efficient, an external battery charger (powered by my generator) or just hook up my 2000w generator to my shore input power cable?

 

[John From Detroit]

As I said. unless the existing converter is defective or you have added a whole lot to the battery bank. Best option is just plug the RV in and let teh WFCO do the job. They are good while they last.

SOme prices
I have a Battery Tender Plus that can do 1-2 amps "Float" charge  20 amps BULK and 70 Cranking. about 100 dollars at Auto Zone NOTE the ABOUT)

My Progressive Dynamics 9180 Refurburished was 236 FACTORY DIRECT without the Charge Wizard (I already had one) it does 80 amps.  So for a decent 3 stage charger you are looking at at least 150-200 dollars.. Might a well just use the WFCO that's what it is there for.

 

[darsben]

So if you hook up the genny to your shore cable then plug in the charger to your RV to charge your battery it should make NO DIFFERENCE. Unless you overload the genny

See above  ) )

 

[mark98012]

I guess that my question was answered, buying a decent battery charger on Amazon ($100) would be NO BETTER than just plugging in shore power to my generator. My problem was (is) that the batteries last for 3 days (with being very conservative) and can't get my batteries fully charged by my generator (12v output) running for several hours. going to buy new batteries and start charging (when needed) using the shore input. May even go to golf cart batteries (anybody have ANY comments at all on that?) Got a 2 week trip boondocking trip planned for next month and trying to get all my ducks in a row.    Thanks,

                                      Mark

 

[John From Detroit]

A pair of six volt Golf Car batteries is about 220 Amp hours give or take and you can safely run 'em down 50% before re-charge (But don't dwaddle) your WFCO will need 76 to 7 hours to re-charge fully on with a pair of 'em.

Group 24 is about 75 AH
Group 27/29 just under/over 100
Group 130

But you can only use about 25% before re-charging less you like buying batteries.  (or less).

I would just plan on a six hour generator run when you need a recharge if they are lasting 3 days betwen charges the amount of power you are sucking off the converter won't make 15 minutes difference.

 

[Gizmo]

The Progressive Dynamics 9200 series of converters make very good smart chargers. Pick the size that matches your battery bank.

You have to be careful about swapping out an existing charger for a higher amperage unit, because the wiring in the coach may not be rated for a higher amperage unit. 

 

[Gary RV_Wizard]

Gizmo is correct, but it's only the wiring between the charger and the battery that needs to be rated high enough for the DC amps. The required input power is moderate, even if you double the charging amps.  Even 100 charging amps @  14v takes about 12A @ 120v and that rate wont be sustained very long either. Rarely will a 100A charger actually put out more than 75-80A.

 

[John From Detroit]

I am aware of the wiring limits. but you will notice I was suggesting using one as a "Smart Charger" not as the converter in the RV. His WFCO (wile it works) is good.

But if you want a Stand alone charger for a lead acid battery the 9200 line. of the proper size (NOTE: don't get one too big) is an excellent choice they come in both hard wired and plug in models. YOu get the plug in type and take a good set of jumper cables or heavy wire (lke 4ga or 0ga depending on the converter) with battery clamps and hook it up.

It takes almost no time at all to hook the cables to the unit.. Just ust the biggest cable that fits the clamps.

 

[mark98012]

I appreciate all the replies, I'm planning on going with 6v golf cart batteries and will charge using the WFCO. Right now I'm verifing if I have the room. once again I appreciate all the replies.

            Mark