battery upgrade questions

[Gary M]

I just ordered 2 VMAXTANKS 225ah 6V AGM batteries for my 2018 21BHS, and I'm about to order a battery charger as well. The onboard WFCO 8735 converter/charger is below specs for properly charging these batteries. Batteries will be on the trailer tongue and connected to the existing 8awg wire currently installed by the factory. In addition, I will be running some 4awg welding wire under the trailer straight to the charger located about 14' away in the compartment under the bunk. Problem is that all my circuit breakers in my WFCO are being used, so I'm guessing I will have to wire in a sub panel, new breaker, and AC receptacle to power the charger? I'm assuming people have done this with inverters? Looking for solutions or ideas on how others have done this. Also looking for recommendations on parts to order(sub panel. breaker. romex size?). Any suggestions would be much appreciated!

This setup is a temporary battery capacity upgrade for this season, until I have a full solar system installed next year. At that time I will probably be having the charger replaced with an inverter/charger along with the rest of the system. For now, this is the charger I will be using...

COTEK CX1250 12 VOLT 50 AMP 4 STAGE 3 BANK AUTOMATIC BATTERY CHARGER / POWER SUPPLY

https://www.amazon.com/gp/product/B00F9DSQAO/ref=ox_sc_act_title_7?smid=AWPBFTW0ZXVPR&psc=1

[DavidM]

I think you are going off the deep end here. The existing WFCO converter won't harm your new AGM batteries. The charging profile might not be exactly what the AGM battery manufacturer recommends but it is probably close enough. Do you know the numbers of what the manufacturer specifies and what the WFCO puts out?

If you must install this new charger, then use one of the 120V breakers that supplies the house outlets to power your new charger. The new charger probably draws a max of 7-8 amps AC so you need to keep whatever you plug into the house outlets less than 7 amps to keep from tripping that circuit breaker.

Use 14 gauge romex to wire your new charger up, assuming it is on a 15A breaker.

David

[Gary M]

Thanks for the reply David, and I think you're right about the WFCO "possibly" being good enough. The WFCO is a 30 amp charger, and the batteries recommend 30-110a at 14.4 to 14.7 charging voltage, with float at 13.2-13.8v. I've never seen my WFCO go above 13.7v. There's also a 15' run of 8awg wire to the batteries on the tongue that's probably contributing to a lot of voltage loss.

I guess my biggest concern was having to run my generator forever to recharge the batteries with the WFCO, and not soo much on hurting the batteries. After looking into all this though, I think I might just give the WFCO a try for now and hold off on ordering the charger. Thanks again for the input!

[Steve Sanders]

If the 110 volt breakers are single circuit breakers, you can replace them with split breakers to add additional circuits. It won't increase the total amp rating for the panel, but it can provide the additional circuit.

Sent from my SM-G950U using Tapatalk

[Gary M]

If the 110 volt breakers are single circuit breakers, you can replace them with split breakers to add additional circuits. It won't increase the total amp rating for the panel, but it can provide the additional circuit.

Sent from my SM-G950U using Tapatalk

Thought about that but I don't see any more room in the panel to add one.. I guess if the WFCO turns out to be under par, Ill run some romex to the existing outlet breaker labelled as "Gen" as DavidM suggested and just keep it simple.

[DavidM]

I guess my biggest concern was having to run my generator forever to recharge the batteries with the WFCO, and not soo much on hurting the batteries. After looking into all this though, I think I might just give the WFCO a try for now and hold off on ordering the charger. Thanks again for the input!

Ahh, I see! You may be right. RV converters don't seem to charge as fast for their amperage rating as others like marine chargers. You might also look at IOTA chargers. This 55A one should work and is only $206- https://www.amazon.com/DLS-55-AUTOMATIC-BATTERY-CHARGER-SUPPLY/dp/B0074JVO0A/ref=sr_1_1?ie=UTF8&qid=1525559795&sr=8-1&keywords=iota+55

You could go a little bigger with AGM batteries. Conventional wisdom is to limit FLA chargers to 25% of the amp hour rating, but I think you can go a little bigger with AGMs, probably 33% or 75A. Here is a 75A IOTA- https://www.amazon.com/DLS-75-AUTOMATIC-BATTERY-CHARGER-SUPPLY/dp/B0074JVO8C/ref=sr_1_fkmr0_1?ie=UTF8&qid=1525560011&sr=8-1-fkmr0&keywords=iota+75+amp+charger

But what generator are you using. A Honda EU2000 will work with the 75A IOTA, but a Honda EU1000 won't.

I see the fifth AC breaker position is labeled "Gen". It will power an auxiliary charger just fine. But never connect an external power source to that breaker like an inverter or a generator. If the shore power cord is connected it will fry the generator or inverter and if the shore power cord is not connected it will fry you because the terminals will be hot.

David

[Gary M]

But what generator are you using. A Honda EU2000 will work with the 75A IOTA, but a Honda EU1000 won't.

I have one of the new Honda EU2200I gens that I'll be using. It's pretty good, and can run my AC on eco mode with a Micro-air EasyStart kit that I installed.

I see the fifth AC breaker position is labeled "Gen". It will power an auxiliary charger just fine. But never connect an external power source to that breaker like an inverter or a generator.

There's another issue with this "General" breaker. Not only does it power all my AC outlets, but it also powers the charging portion of my WFCO converter. I would like to seperate the 2, so i can disable the WFCO charger (while using a better charger), and not lose all my outlets at the same time. I was thinking of moving the AC outlets to join the microwave breaker since i hardly use the microwave. thoughts?

[Gary M]

The IOTA charger you linked looks great, but someone in the amazon review section said this...

"Be aware that this bad boy pulls 18 amps. A lot of installed breakers are 15 amps.
Does not play well with GFCI outlets typically found on boats. We had to install non-GFCI just for this charger."

Only 20 amp breaker I have is for the Air conditioner. So I would be back to the circuit breaker dilemma again.. LOL

[Steve Sanders]

If the 110 volt breakers are single circuit breakers, you can replace them with split breakers to add additional circuits. It won't increase the total amp rating for the panel, but it can provide the additional circuit.

Sent from my SM-G950U using Tapatalk

Thought about that but I don't see any more room in the panel to add one.. I guess if the WFCO turns out to be under par, Ill run some romex to the existing outlet breaker labelled as "Gen" as DavidM suggested and just keep it simple.

All double breakers already. No options there...

Sent from my SM-G950U using Tapatalk

[Gary M]

All double breakers already. No options there...

Yea I think I may be back to the idea of installing a sub panel with a 20 amp breaker to power the aux charger. I would just have to wire the sub panel to the main 30 amp breaker on the WFCO distribution panel right?

[Merlin]

I hope that all your AC outlets are not on the same CB as the converter in your power control center. Double check that. The AC outlets should be on the CB labeled GFCI and the power control center should use a separate 15A AC breaker to feed the DC converter. I have no faith in the labels LL put on the panel, so double check everything!

Where is the refrigerator breaker for its operation on AC?

Before you double up on AC circuits (such as moving all the outlets to the microwave CB), you may want to reconsider the plan. I like the idea of just using the existing converter output to charge the 2 new batteries for this season, then doing it all new with an inverter/charger when you install solar next year. You won't hurt the batteries in just one camping season and next year you'll be able to get things just right with a new CB panel and wiring. This summer, just gas up the Honda and charge away!

[DavidM]

You are correct. The IOTA 75A charger pulls 18A max and that is too much for the 15A breaker. So back to the 55A IOTA which pulls 13A. Wiring it to the microwave breaker will work as long as you don't use both at the same time.

But Merlin is right. Use the WFCO for the season. It won't hurt your batteries. It may take a little longer to charge up the batteries though.

David

[Gary M]

I hope that all your AC outlets are not on the same CB as the converter in your power control center. Double check that. The AC outlets should be on the CB labeled GFCI and the power control center should use a separate 15A AC breaker to feed the DC converter. I have no faith in the labels LL put on the panel, so double check everything!

I just went out and re-verified and Yes all 4 of my AC outlets are on the same 15a breaker that the charger is on labelled "Gen". When I turn it off, my DC voltage dropped from 13.2v down to 12.6, and I lose all power on the AC outlets.. Turning it back on brought the voltage back up to 13.7v

From what I could tell, The GFCI breaker only controls the GFCI alone. I'm assuming they connected the AC outlets to the wrong breaker? It wouldn't surprise me as I've already found my back up camera "pre-wired" bracket wiring to be backwards, along with my black flush tank check valve to be installed backwards too. This is on a 2018 21BHS.

Where is the refrigerator breaker for its operation on AC?

It's a 2 way dometic, that runs on propane or 12v. No breaker for it.

[Diversteve]

The IOTA 75A charger pulls 18A max!
75*12=900 watts. 900 watts /120 VAC =7.5 amps.
That is one horribly inefficient charger!
Your existing charger will not fully charge the batteries but you will probably be OK until you complete the project with solar.
jmho.

[Steve Sanders]

[I would just have to wire the sub panel to the main 30 amp breaker on the WFCO distribution panel right?
/quote]

I don't think so. The 30 amp breaker is typically acting as the (reverse fed) main breaker for the system. The black wire from the shore power cable is probably connected to that breaker.

I would replace that double breaker with a double 30 amp breaker. Feed the subpanel from the right side of the double 30, and move the circuit that's currently on the other side of that split breaker to the subpanel.

Sent from my SM-G950U using Tapatalk