Charger selection help please

[hammick]

I'm thinking about buying a Noco Genius G26000 26a smart charger for when the sun isn't getting my batteries charged.

I have a FR Stealth Toyhauler with two Interstate GC2 208ah batteries. They do everything I want and more when I am able to get them fully charged. 99% of our camping is boondocking and our solar system will get the batteries fully charged during the summer assuming it is sunny and we aren't in the woods. I have a crappy 55a Wyco converter that never gives more than 13.7a to the batteries.

We boondocked for four days over Thanksgiving and it got quite old hauling out my Schumacher 25a cart charger to get the batteries fully charged. Plus the Schumacher gets the batteries over 16v when in absorb.

When charging I use a 2000w Yamaha inverter. I do have a built in 4000w Onan if needed.

I've read about all the threads on replacement converters, the Meanwell power supplies and other options. But I keep coming back to the Noco for it's many charging options and convenience.

Can I get these batteries fully charged using the Noco in a reasonable amount of time or should I go with something like the Powermax Boondocker with adjustable voltage or a Megawatt. I'm willing to pay the premium for the Noco but not at the expense of hours of extra generator time.

[BFL13]

"To do this you will need a power factor corrected charging device. The Magnum 3012 inverter/charger can do up to 125 amps of charging on a 15 amp shore power supply. For a 2000 watt Yamaha that would have to be "dialed down" on the Magnum ARC remote from 15 to 13 amps and that would limit charging to about 109 amps"

I do not understand how all that can possibly work. My PF corrected 100 amper draws 1910VA by Kill-A-Watt when output is 100 amps at 14.x volts.

So howinheck can you run a PF corrected 125 amper from a "15a" circuit? The 100 amper was drawing 15.57 amps. (The VA was with 122.7v/15.57a) A PF corrected 125a is going to need a 20a circuit would think. ????

The 75 amper Kill-A-Watt figures are:
123.8v, 13.64a, 1693VA, 1241w, PF 0.73

So I can see there that if you dial down the Magnum which is still then PF corrected, you could do more amps output than 75 with a draw of 13a, but I don't know about 109a--seems like a lot.

[hammick]

MEXICOWANDERER wrote:

It is EZ to the extreme to fit a 4-hour Intermatic timer to that wheeled charger.

Agreed but even after one hour it has the batteries over 16 volts. This is essentially equalizing the batteries every time they get charged from the generator. That's bad, right?

[pianotuna]

Hi,

To do this you will need a power factor corrected charging device. The Magnum 3012 inverter/charger can do up to 125 amps of charging on a 15 amp shore power supply. For a 2000 watt Yamaha that would have to be "dialed down" on the Magnum ARC remote from 15 to 13 amps and that would limit charging to about 109 amps.

Unfortunately the battery bank, once it reaches 85% state of charge will only accept about 26 amps. That will be approximately 1/4 load on the generator.

Practically speaking, with such a small bank, it may not require dialing down anything at 50% state of charge. I truly doubt that a 208 amp-hour bank is going to draw at a c/2 charge rate.

In truth, the only time I've seen over 108 amps of charging for my surplus acid AGM bank was when I deliberately took it to 50% state of charge as a test.

hammick wrote:
Priorities are:

Getting 208ah batteries fully charged from 75% SOC to full quickly
Able to use my 2000w Yamaha without maxing it out
Hopefully avoid rewiring and difficult install
Portability if going the stand alone charger route (wheeled charger is cumbersome)
Price

[theoldwizard1]

BFL13 wrote:

IMO you have all the information needed, but a conflicted set of priorities. It is up to you now. 🙂

Concur ! (See my last post.)

[BFL13]

"If I'm only going to 90% SOC when using the generator then the Noco can surely do that"

Yes, and so could a 3 amp charger. It is all about how long you want to run your generator. You have the timing information for various amp chargers, so just make your choice.

If you want to, go ahead and pay big bucks for a measly 26 amp charger--it's only money 🙂

An RV on solar is not the same as a stick house/cabin on solar. Different operating routines. "When in Rome---"

BTW, the 75ADJ pulls 1693VA from a Honda generator. (measured with a Kill-A-Watt) The Honda 2000 is rated at 1600VA but it does run the 75ADJ at sea level. Must be some wiggle room in the specs. However at altitude, it loses VA so at some altitude above sea level it won't run the 75ADJ anymore.

IMO you have all the information needed, but a conflicted set of priorities. It is up to you now. 🙂

[theoldwizard1]

hammick wrote:

Priorities are:

Getting 208ah batteries fully charged from 75% SOC to full quickly (<1-2 hrs ?)
Able to use my 2000w Yamaha without maxing it out
Hopefully avoid rewiring and difficult install
Portability if going the stand alone charger route (wheeled charger is cumbersome)
Price

Meeting #1 and #2 is pretty difficult !

With a 2000W generator, you are going to be limited to about a 600W power supply. A Mean Well SE-600-15 is only going to give you 40A @ 15v. That is going to seriously impact #1.

If you want "fast" charging, you are going to need 1000W-1500W and the in rush current of that big of a DC power supply will likely bog down/stall/trip the breaker of your generator.

Either a) abandon #1, b) get a bigger generator or c) figure out how to use the alternator (probably good for 100+A) on your TV to charge your house bank via a good battery isolator and some VERY LARGE (0 gauge ?) battery cables.


EDIT : After more thought ...

Forget c). Most (all ?) "modern" (built in the past 10-15 years) light and medium duty vehicle charging systems are OPTIMIZED to recharge the starting battery. The PCM controls the voltage regulator and you will NEVER be able to get the proper voltages to do a 3 stage charge with a fast (high current) "bulk charge" cycle.

Conclusion : Buy a high current (1000W-1500W) 3 stage battery charger AND buy a second 2000W Yamaha generator (I assume it is an inverter generator like a EF2000iS that you can run 2 in parallel to increase the available current).

You still may NOT succeed in achieving #1 BECAUSE once a 3 stage charger goes from "bulk" to "absorption" mode the voltage stays constant and the current ramps down (i.e. charging SLOWS DOWN).

[MEXICOWANDERER]

That particular off grid 80% protocol should yield 3-5,000 cycles if a strict float - destrarltification and top charge exercise is adhered to. Conscientuous management encourages use of Rolls wet or Lifeline VRB. Trojan is also fine IMHO.

It is EZ to the extreme to fit a 4-hour Intermatic timer to that wheeled charger.

[hammick]

BFL13 wrote:


With no solar, let the batts run down until your "morning voltage" is 12.2ish. Then do a 50-90 on gen and get as high in SOC as you can after that on solar till dark.

You don't have to recharge every day. The batts will recover to 100% next time you have shore power or some longer times with good solar conditions.

Note--
A.you will not be recharging to 100% on generator, just to 90% unless you are crazy 🙂

B. You can rig any deck mount converter as a portable charger simply by using a set of cut-off jumper cables (4 AWG though--not those skinny wire ones) in the terminals with the clamps to go on the battery bank (that's what I do with my 75ADJ )

I have a 48v system at my off grid place with 370ah Trojan RE batteries. I rarely take those below 80% SOC and hope to get 12 years or more from them. They are not cheap batteries. I guess that's why I like to charge every day in the trailer. On the other hand the Interstates are cheap at Costco and I'll probably spend more on gas than replacing them more often.

I'f I'm only going to 90% SOC when using the generator then the Noco can surely do that. On the rare occasion that I have to use my generator at my cabin I go to 90% and let the CC take over the absorption and finish.

[BFL13]

hammick wrote:

time2roll wrote:

hammick wrote:
Does your opinion change if I am unlikely to be under 75-80 SOC each morning?

Charge every other day.

Too anal for that. My Blue Sky solar charge controller is in the bedroom and it's hard to sleep when I see 12.5v or lower on the display :E

With no solar, let the batts run down until your "morning voltage" is 12.2ish. Then do a 50-90 on gen and get as high in SOC as you can after that on solar till dark.

You don't have to recharge every day. The batts will recover to 100% next time you have shore power or some longer times with good solar conditions.

Note--
A.you will not be recharging to 100% on generator, just to 90% unless you are crazy 🙂

B. You can rig any deck mount converter as a portable charger simply by using a set of cut-off jumper cables (4 AWG though--not those skinny wire ones) in the terminals with the clamps to go on the battery bank (that's what I do with my 75ADJ )

[hammick]

MEXICOWANDERER wrote:
All modes of charging are compromises in one form or another. You need to arrange in ordinal your list of priorities then seek the least offensive manner of charging.

Priorities are:

Getting 208ah batteries fully charged from 75% SOC to full quickly
Able to use my 2000w Yamaha without maxing it out
Hopefully avoid rewiring and difficult install
Portability if going the stand alone charger route (wheeled charger is cumbersome)
Price

[hammick]

MEXICOWANDERER wrote:
Many variables. Innumerable permutations. Curious as to why ypu did not employ the motor driven timer on your wheeled charger? Would have prevented overly high finishing voltage.

A fully programmable charger will shut itself off. Leaving the batteries at whatever state of charge is present. Have no surf access cannot read Noco opetating specs. Are the charge modes timed? If yes how does it know when to quit? Raised my eyebrows with the AGM modes voltages.

Try to avoid jumping from the frying pan into the fire. All modes of charging are compromises in one form or another. You need to arrange in ordinal your list of priorities then seek the least offensive manner of charging.

The wheeled charger is a Schumacher manual charger. Doesn't have timer or any auto mode. Once my batteries reached 15.3v I let the charger go for another hour. Volts went to 16.2 and the batteries were disconnected. So essentially I equalized the batteries.

The Noco manual doesn't go into details about whether absorption is timed or not. I will call them tomorrow and see if I can get any details.

I may just buy it and if it doesn't do a timed absorption I'll send it back and get a Megawatt and a timer.

[MEXICOWANDERER]

Many variables. Innumerable permutations. Curious as to why ypu did not employ the motor driven timer on your wheeled charger? Would have prevented overly high finishing voltage.

A fully programmable charger will shut itself off. Leaving the batteries at whatever state of charge is present. Have no surf access cannot read Noco opetating specs. Are the charge modes timed? If yes how does it know when to quit? Raised my eyebrows with the AGM modes voltages.

Try to avoid jumping from the frying pan into the fire. All modes of charging are compromises in one form or another. You need to arrange in ordinal your list of priorities then seek the least offensive manner of charging.

[hammick]

time2roll wrote:
Maybe just add another solar panel?

Wouldn't do any good for the camping we did the last several days. Camping in the woods at Cove Lake on Mt. Magazine, AR.

[time2roll]

Maybe just add another solar panel?

[hammick]

time2roll wrote:

hammick wrote:
Does your opinion change if I am unlikely to be under 75-80 SOC each morning?

Charge every other day.

Too anal for that. My Blue Sky solar charge controller is in the bedroom and it's hard to sleep when I see 12.5v or lower on the display :E