Generator Newbie-How long to charge?

[RobertDS]

Originally Posted by GLBCamper

OK, so I get that there are a lot of factors involved, but how long do YOU run your generator during the day to recharge?



I have a Ryobi 2300/1800w generator charging two 6v GC batteries via the onboard converter. Let's say I wake up to my batteries showing 12.2 (60% charge state.) I have no clue what to expect. 2 hours? All day??



Is there a way to know if I've achieved float mode?

The way that I read this. As a newbie to another newbie. The OP asked three questions.

1. How long do YOU run your generator ...

2. Is there a way to know if I’ve achieved float mode.

If I filter through all of the response, I gather the answer to Number 2 is no but I can only infer that because no one answered it directly. One poster replied that the assumption was the OP had a volt meter since he stated he had 12.2 volts.

No one answered his question Number 1 directly. I again infer no one did because of so many variables. He omitted a lot of info?

I will google the article cited. Maybe it will answer #2 and maybe the poster knew that but did not state it.

Now, his third question... “Let’s say...” I know there is no practical way of answering that question because we don’t know if it is cloudy, i.e., daylight use of lights, summer with long days, playing the radio, etc., way too many variables. But then again, I have no experience to draw on so, GLBCamper, I think got a good dose of opinion filled in with some knowledge. Let’s see, what was that article... something 12 volt ...

[latner]

Originally Posted by GLBCamper

can someone suggest which "good quality charger" to buy rather than going through my wfco converter, which is at least 20ft. From the batteries?

This is what I use:
https://www.walmart.com/ip/Diehard-8...&wl13=&veh=sem

I always have this in the truck for other purposes, so it is just easier for me to use this instead of upgrading the converter and wiring.

[dbledan]

Originally Posted by RobertDS

The way that I read this. As a newbie to another newbie. The OP asked three questions.

1. How long do YOU run your generator ...

2. Is there a way to know if I’ve achieved float mode.

If I filter through all of the response, I gather the answer to Number 2 is no but I can only infer that because no one answered it directly. One poster replied that the assumption was the OP had a volt meter since he stated he had 12.2 volts.

No one answered his question Number 1 directly. I again infer no one did because of so many variables. He omitted a lot of info?

I will google the article cited. Maybe it will answer #2 and maybe the poster knew that but did not state it.

Now, his third question... “Let’s say...” I know there is no practical way of answering that question because we don’t know if it is cloudy, i.e., daylight use of lights, summer with long days, playing the radio, etc., way too many variables. But then again, I have no experience to draw on so, GLBCamper, I think got a good dose of opinion filled in with some knowledge. Let’s see, what was that article... something 12 volt ...

I think post 12 is as close as you can get to answering with the information provided and a lot more complex math.

Lets say that 2 GC 6 volt batteries will give you 200 AH total capacity. Unfortunately you cannot see what your charge current is, nor the actual SOC of the batteries. You are kind of blind and, in addition, we don't know what kind of converter you have so we don't know what the charge amperage is.<br />
<br />
Let's take a flyer and assume that you can get 20 amps from the converter at a 50% SOC. That means that you have used 100 AH and, simplistically, it would take 5 hours (actually it would take much longer since it tapers down as the SOC goes up.)<br />
<br />
I would never go to the trouble of starting a generator and not let it run at least 2 hours, in the case above maybe 3. You can't get to 100 SOC with a generator because it will take days...not hours.

[RobertDS]

Thumbs up! Now, most of that I can understand.

“Flyer,” a flying leap, a WAG (wild as_ guess), a hypothetical situation?

[dmdomokos]

Originally Posted by 510Rick

Sounds like you should get solar .lol.
I have no idea how long two GC batteries should take but my single battery doesnt take more then 2 hours .

I have the same confusion over this issue. I have 2 - 6v GC2 batteries but it takes a long time to charge them up either from shore power or generator. The WFCO converter is in the middle of my trailer. So I got 160w of portable solar and it will fully charge my batteries in a day on medium usage. Before that, I would run my generator for 3-4 hours and still never get fully charged, by day 4 I was less and less charged. Using both Solar and a generator solved our power issue.

[ependydad]

Would a battery monitor like the Victron BMV-702 take the guesswork out of this?

I just ran my new battery bank (400Ah) down to 56% (196Ah used). I was able to watch the Bluetooth display on my phone as it recharged.

I know lead batteries are different than my lithiums in that you have to push back in more slowly as the battery gets more full.

When I got to the camper:


And then periodically while he converter/charger refilled the bank:

[ScottBrownstein]

Yes, a battery monitor takes the guesswork out of it all. Victron, Trimetric, etc. See the SOC, see the charge voltage and more importantly, see the charge current. Running a genny for 5 amps from a converter is a waste of time.

[camaraderie]

Originally Posted by carlsbad

Sure you can, with the right charger. The charge time is solely dependent on the charger and the type of battery. There is some internal resistance but the math is simple. In my example above, a 10amp charger will take 2.5 times as long. I have a pretty good 40amp bulk charger that can mostly charge batteries in two hours.

Nope. You only think you're getting them to 100%. You can't measure real charge with a voltmeter till 24 hours of non use has happened or you take the charge off with a pile. Charge Acceptance at BULK charging stage is between 20-25% of capacity. As the battery becomes more full acceptance drops until it is only an amp or two...even with a 100amp single stage bulk charger. It will take at least 4 hours to put 100% back into the pair of golf carts the OP has if discharged to 50%.

The OP...if out for a week or so can give up a LITTLE battery cycle life for less charging time if he so chooses. Simply charge normally and monitor charging voltage... when is drops to 13.6...then you're at about 80% and it will take just as long to get to 100%. So shut down after you reach this stage and cycle between 50 and 80% for a few days and then put a 100% charge back in. Just don't leave the battery in a partially discharged state for too long and always get to 100% after the trip before you close her up for a while. This advice is for flooded cell batteries. Always charge AGM's fully.

[GLBCamper]

Originally Posted by latner

This is what I use:
https://www.walmart.com/ip/Diehard-8...&wl13=&veh=sem

I always have this in the truck for other purposes, so it is just easier for me to use this instead of upgrading the converter and wiring.

I've looked into chargers like this and they are not sold in Oregon (my home state) or California. Severely limits my choices.

[babock]

Originally Posted by GLBCamper

I've looked into chargers like this and they are not sold in Oregon (my home state) or California. Severely limits my choices.

That's why you go buy them from a different vendor than Amazon or Walmart. Oregon and California have stupid energy laws...I am from California.

[GLBCamper]

Originally Posted by babock

That's why you go buy them from a different vendor than Amazon or Walmart. Oregon and California have stupid energy laws...I am from California.

There are other vendors besides Walmart and Amazon?!?

[babock]

And not sure why you would use that over your convertor. Your convertor will charge way faster than that battery charger.

[boondocking]

Originally Posted by GLBCamper

can someone suggest which "good quality charger" to buy rather than going through my wfco converter, which is at least 20ft. From the batteries?

I use a 40A Schumacher charger when it has been cloudy for a few days and the solar isn't up to par. Great charger, has a de-sulfate mode also and it doesn't cost an arm and a leg.

[latner]

Originally Posted by babock

And not sure why you would use that over your convertor. Your convertor will charge way faster than that battery charger.

Not true. At least on my camper, the combination of wire size and distance between the converter and batteries makes for a slow charge rate.

[babock]

Originally Posted by latner

Not true. At least on my camper, the combination of wire size and distance between the converter and batteries makes for a slow charge rate.

With a discharged battery , what's the voltage at the convertor and at the battery?

Personally, if that's your issue, I would be fixing it. I have a new trailer and I am going to be removing the WFCO that comes with it and buying a PD convertor and putting it near the batteries.

[jimmoore13]

According to Forest River tech support, a 35 amp BASIC converter won't charge at 35 amps....more like 10 amps or so.
Depending on where you are, I'd suggest that you go solar. No noise, no effort.

My solar experience.
This is boilerplate...a response to another thread. I have a single 100 watt panel, but my charge controller can handle up to 4 panels. So, your "mileage" will vary, but solar has proven to be a no-brainer.
Your camper may already be setup with a ZAMP adapter. If so, buy enough panels to ensure they can charge your batteries.

My experience...excuse the length.
On solar: I bought this: https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1
Outstanding! One panel keeps my battery topped off indefinitely. I can use 12-Volt power with "reckless abandon" during the day - running the "car" stereo in the camper, and whatever else, and by the end of the day, the battery is showing 12.8 volts and about 116 amp-hours on the charge controller display...full up! But...as the day wears on, I go into frugal mode and resort to my mantle and LED lights to save power for, wait for it, my electric blanket!!

I also installed this inverter: https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1
My dual zone blanket needs a total of 360 watts. We run the blanket for about 20 minutes to warm the bed, then turn it off. Zero issues with 12-volt power to run the furnace, fridge, hot water heater, and the occasional pump run to flush and wash hands (I'm 68, and the old guys know what I'm talking about. )

How do I know how long my battery will last with the inverter? Calculator:
Voltage current resistance and electric power general basic electrical formulas mathematical calculations calculator formula for power calculating energy work equation power law watts understandimg general electrical pie chart electricity calculation
Input 12 volts and 400 watts, and you get 33 amps.
The battery at full charge will deliver over 100 amps for an hour (its rated amp-hours).
If I run the inverter at full load for an hour, I'd use up 33 amp-hours of the 100 I have available. But a safe rule of thumb is that you can use about 1/2 of the battery's capacity...40 to 50 amp hours. If I run it for 20 minutes, I use up about 10 to 12 amp-hours. Negligible if the battery if fully charged.

About solar: As I looked into it, I think I discovered that all comparable systems use the exact same panel, no doubt made by one factory in China. Also, according to Windy Nation, there is little difference between monocrystaline and polycrystaline...except price. Poly used to be inferior, but no longer.

BUT THERE IS A HUGE DIFFERENCE in the charge controllers. You don't need a $200 charge controller, but if you go too cheap, they fail, they're inflexible, they're "stupid," and they might not be expandable. Mine may be the "Goldilocks" controller - just right. It can accept up to 4 panels - massive overkill for one battery - and it has the LCD display to tell you how you stand.

As I experimented with my system, I used a lot of power (the stereo and interior lights) one evening. We listened to music for about 3 hours using the built in Kenwood stereo. This thing has a display that has lit-up, animated LEDs in addition to the amp. It's a power hog. Then I checked the battery status on the LCD display of the solar charge controller. 11.8 volts and about 70 amp-hours left. Great info. A dead battery is 10 volts. Went to frugal mode and woke up with plenty of power to spare, then the sun went to work. Also note that we had a mix of clouds and sun with some thunderstorms. Still plenty of sun to charge the battery.

As I said, I have a PUP. I ran the wire from the panel to the charge controller 'outside' the camper, and I purchased a waterproof box and mounted the charge controller in the box just above the A-frame. I could have mounted it inside, but space is at a premium, and I wanted as few holes as possible in my tub. (There's one to get wire to the 400 watt inverter.)
Your installation could probably save about $50 compared to mine, but all-in, it cost me about $250 to install the Windy Nation kit - panel, connectors, wire, charge controller, and my accessory items - (which I bought during a sale for $150).
All-in, the inverter cost about $55 including longer connecting wire, crimp on connectors and already-open tube of silicone (used for the solar install) to seal up the hole in the tub for the wires to get into the cabin.

So, for $300, I have all the 12-Volt power I need to boondock until I run out of water, supplies and the black tank (all 12 gallons of it) is full. On our maiden solar voyage, we stayed 5 days and 4 nights, and we came home with a full battery.

IN SUMMATION: Install an appropriately sized solar array, and your days of listening to a generator droning on for hours will be over. I have a generator, and I use it to run the microwave and espresso maker...and I have it to back me up if something goes wrong with the solar...like 4 days of driving rain. Otherwise, silent bliss.

[boondocking]

The numbers your charge controller is showing seem inaccurate.
At 11.8 V your battery is at 30% SOC, that would be 35 AH left not 70 AH. At 11.8 V (30% SOC) you need to put back 81 AH into the battery for a full charge of 116 AH.
Your 100 watt panel will produce 6 amps max, so you would need at least 2 days of full sun to bring the battery back up to 100%.

[rsdata]

jimmoore13,

neither of your amazon links work... can you provide a product and model other than those old links?

thx

[jimmoore13]

Originally Posted by rsdata

jimmoore13,

neither of your amazon links work... can you provide a product and model other than those old links?

thx

Ah, a "flaw" in how the forum converts URLs into shortened strings with "embedded tags" (or whatever they are called.)
I will revise the original and correct the URLs.
Thanks for bringing this to my attention.

[jimmoore13]

Originally Posted by RobertDS

<<snip>>
No one answered his question Number 1 directly. I again infer no one did because of so many variables. He omitted a lot of info?

<<snip>> ...

Partly, perhaps. There ARE tons of variables:
1) type of converter and CHARGE AMPS of the converter. A multi-stage converter will bulk charge at the beginning and as the battery is topped off, it will step down (usually 3 total charging levels). But some converters are not just simple, they also don't charge at their stated rate. According to Forest River tech support, the 35 amp converter in my PUP does not charge at anything like that rate. So, regardless of the output of the generator, the converter may limit the charge rate.
2) Other loads (e.g. the fridge) will be addressed first by the converter. So, if your fridge is on "auto" it will run on AC as soon as you fire up the generator. It's possible to use enough of the CONVERTER'S capacity (with microwave, etc.) to cut down on the charging considerably.
3) If I recall, the generator is a Ryobi...an unknown compared to say a Honda. Assuming the generator is running at low speed (stepped down rather than at full speed), it is likely delivering only the power demanded by the converter...whatever that may be. Unlike a 30 amp shore power connection, the generator only delivers its full, rated 15 amps continuous (+/-) at high speed. What it delivers at idle speed is an unknown...whatever the converter wants.

More to the point, MANY respondents suggested better options than relying on a 2K inverter generator to handle boondocking battery charging. Early in the thread, someone suggested conducting a test: starting with a discharged battery, use a multi-meter and test the voltage. Charge the battery with the generator, checking regularly to see when the voltage increases from discharged (about 10.5 volts) to charged (about 12.5 volts). That's the benchmark for that generator/converter combination.
And that's a good recommendation.

Others suggested getting a dedicated battery charger, with a known charge rate, plug it into the generator, and calculate the time based on the charger's output rate. This assumes the charger will force the generator to deliver the charger's full output. A typical group 24 can hold about 80 amp hours---perhaps as much as 100. Assuming a discharged battery uses about half of that, then assume you need to put 40 amp hours back into the battery. If your automobile-grade charger delivers a 15 amp charge rate, that comes out to about 3 hours to charge a "dead" battery. If your auto charger can deliver 45 amp hours, then it will take an hour.

Too many variables.