Battery charging from 2000 W generator

[unyalli]

2000 watts is probably surge capacity not sustained. 1600 watts is probably more like it. 1600 watts at 120 volts is 13.3 amps. If your battery is the typical group 24 that RV dealers install you have around 60 to 70 total amp hours. If this battery was charged by a proper charger (which you don't have, more later.) at 14.6 to 14.8 volts you shouldn't see more than around 14 amps which will taper off quickly. 14 amps at 14.6 volts is 204 watts. Your generator is adequate.

If you have a WFCO power center and converter you will never see volts in the 14's and charging in the 13's takes a while.

Do you have a 12 volt round power outlet in the camper? One of these is simple to use. Cigarette lighter volt meter.





- Jeff

[MNtraveler]

Sorry, I think people are making it too complicated. When we boondock, we usually charge up (2 deep cycle batteries) one hour at breakfast and an hour at dinner. Before charging, test battery voltage and see where your state of charge is. If low, you may need more charging. If high, you may need less or even none at that time. Follow the attached charge chart.

There is all kind of math and physics you can learn about and apply but I think it’s better to KISS.

Now you didn’t say what kind of “charger” you are plugging into the generator. (A lot of people, including me, have built in chargers and genrators so our comments should be read with that in mind.) If you happen to be using a trickle charger, that’s a whole different story and may take much longer than I suggested which is based on a multi-stage charger that starts with a boost charge at 14.4V.

[MNtraveler]

Sorry, here is the chart.

[TitanMike]

I think far too many don't understand battery charging. It's not a linear process
You may see 90% recharge after a couple hours but recharging that last 10% can take many hours more.

You also can't rely on cheap "zero sum" monitors that nearly measure power consumed then have their display count back up to 100% as you run your charging source.

The voltage charts are usually going to give people a false sense of security, thinking their batteries are fully charged, unless the voltage readings are taken quite a while after charging has stopped. 30 min's is minimum. Temperature of the battery also has an effect on voltage so a chart without temperature correction is really worthless.

Best way, if you dont have a good battery monitor, is to keep charging until the charging voltage from your converter drops below 13.5V. Above that means your battery is still absorbing charge. When you hit 13.25v on most chargers the battery is full.

Again, that last 10% can take a long time after the LED tree says 100%.

[MNtraveler]

I recommended checking battery voltage BEFORE charging.

In the chart I provided, there is a caveat about testing voltage soon after charging.

It may be nice to have a 100% charge but isn’t necessary in many if not most cases. As you say, the extra 10% may take several hours. It’s happens routinely when on shore power, but may be a futile effort with a generator.

[dward51]

I would add that if you can get it to 80-90% charge on your generator schedule and not draw it below 50% before the next recharge, you will still need to give it an extended 100% proper charge every so often to keep the battery healthy. Camping for a week or so with 80-90% charges should not hurt it, just don't forget to give it an extended charge at the end (or whenever you can).

And MNTravler is right, you want to know the battery voltage before charging and 30 minutes after charging (after generator is off). The battery will read higher right after charging and it will settle down for a more accurate reading in about 30 minutes once the "surface charge" has dissipated.

[TitanMike]

Originally Posted by MNtraveler

I recommended checking battery voltage BEFORE charging.

In the chart I provided, there is a caveat about testing voltage soon after charging.

It may be nice to have a 100% charge but isn’t necessary in many if not most cases. As you say, the extra 10% may take several hours. It’s happens routinely when on shore power, but may be a futile effort with a generator.

Certainly best but many think they're done when they shut down generator and voltmeter reads voltage indicating 100%.

I'd prefer using a chart like this:
https://images.app.goo.gl/h8DA152k9DfHzxFk6

Note how it recommends a 4 hour "sit" and an air temp gauge along with voltmeter.

Yes, that last 10% can be handled when hooked to shore power but for some (like me) that may not happen for a couple weeks.

Longer a battery sits only partially charged the more capacity it loses over time.

It's a little like cutting 1/2 inch off your shoelace every day. Will still be able to tie your shoes for quite some time but one day you wont. With the battery, same thing. May still be able to light the lights and run water pump but one day they wont.

[NMWildcat]

We boondock anywhere from one to three weeks at a time. I abuse our batteries terribly, especially by this forums standards
I buy 'inferior' Interstate Marine 27 series batteries (2) for less than $100 a piece. I frequently discharge them more than 50%. I don't always run the generator long enough to get back to 100% each day. I use a 'terrible' WFCO converter. I use a total battery disconnect on the negative side when necessary.
The batteries last on avg 4.5 to 5 years, run everything I need overnight just fine (like heater).
I don't spend a lot of time and energy worrying about them

[babock]

Originally Posted by TitanMike

I think far too many don't understand battery charging. It's not a linear process
You may see 90% recharge after a couple hours but recharging that last 10% can take many hours more.

You also can't rely on cheap "zero sum" monitors that nearly measure power consumed then have their display count back up to 100% as you run your charging source.

The voltage charts are usually going to give people a false sense of security, thinking their batteries are fully charged, unless the voltage readings are taken quite a while after charging has stopped. 30 min's is minimum. Temperature of the battery also has an effect on voltage so a chart without temperature correction is really worthless.

Best way, if you dont have a good battery monitor, is to keep charging until the charging voltage from your converter drops below 13.5V. Above that means your battery is still absorbing charge. When you hit 13.25v on most chargers the battery is full.

Again, that last 10% can take a long time after the LED tree says 100%.

X2

[tc cruiser]

Originally Posted by NMWildcat

We boondock anywhere from one to three weeks at a time. I abuse our batteries terribly, especially by this forums standards
I buy 'inferior' Interstate Marine 27 series batteries (2) for less than $100 a piece. I frequently discharge them more than 50%. I don't always run the generator long enough to get back to 100% each day. I use a 'terrible' WFCO converter. I use a total battery disconnect on the negative side when necessary.
The batteries last on avg 4.5 to 5 years, run everything I need overnight just fine (like heater).
I don't spend a lot of time and energy worrying about them

NMW
I like your line of thinking. I'm new to this and if your getting those results with experience , that is good enough for me.
Sometimes reading this forum puts fear in me that I should have never got a TT. For a new guy this can be overwhelming with everything from wheel bearings, to heaters etc.

Tom

[popeye59]

Originally Posted by tomkatb

When sitting in storage you need a battery disconnect. Or the parasitic loads will wipe the battery out.

When my trailer is in storage, my 6VDC batteries are in my shed because otherwise the parasites in my neighbor hood will swipe them.

[tomkatb]

These rv’s are complicated.

This forum is great. Far exceeded what you get in dealer support.

Read and learn every day. Some opinions may disagree.

Part of the fun.

Course, I’m handy.

The wife is starting to think about full timing! Too nice a life.

[gbaldwin]

Originally Posted by NMWildcat

We boondock anywhere from one to three weeks at a time. I abuse our batteries terribly, especially by this forums standards
I buy 'inferior' Interstate Marine 27 series batteries (2) for less than $100 a piece. I frequently discharge them more than 50%. I don't always run the generator long enough to get back to 100% each day. I use a 'terrible' WFCO converter. I use a total battery disconnect on the negative side when necessary.
The batteries last on avg 4.5 to 5 years, run everything I need overnight just fine (like heater).
I don't spend a lot of time and energy worrying about them

I feel the same. Post prompted because I stumbled on the fact that people recommend not letting battery fall below 50% .

For 3 years I have been running one 12 and just run generator when battery gets low and whenever I find it convenient. Many times to 25-33% only using the charge indicator as a guide. Have not had problems that I have known of.

[extremebike]

Originally Posted by gbaldwin

I noticed last year a TT camper neighbor had his 2000w generator positioned near his battery compartment, had a small battery charger plugged into it and hooked to his battery (s) ? also had generator plugged into his trailer plug. He said it was to get a quicker and fuller charge. Whats anyone think about this? effects on battery life, charging, ....

Yes, I use a 25 amp automotive charger and disconnect the converter at the electric panel using the breaker. When boon docking you don't need the converter and it is a the internal battery charger is best for long term charging which is not the case with generator charging.

I have two 220 amp 6 volts and charge twice a day, for 1 1/2 to two hours at a time. I plug in the trailer so my wife can use the 120 VAC and two auto chargers, one for the trailer and one for the boat battery.

when I first started boon docking I let the batteries really run down. Then it took forever to charger up. Hope this helps.

[NJKris]

Originally Posted by TitanMike

It's a little like cutting 1/2 inch off your shoelace every day. Will still be able to tie your shoes for quite some time but one day you wont. With the battery, same thing. May still be able to light the lights and run water pump but one day they wont.

What a great analogy.

[aeblank]

Originally Posted by NMWildcat

We boondock anywhere from one to three weeks at a time. I abuse our batteries terribly, especially by this forums standards
I buy 'inferior' Interstate Marine 27 series batteries (2) for less than $100 a piece. I frequently discharge them more than 50%. I don't always run the generator long enough to get back to 100% each day. I use a 'terrible' WFCO converter. I use a total battery disconnect on the negative side when necessary.
The batteries last on avg 4.5 to 5 years, run everything I need overnight just fine (like heater).
I don't spend a lot of time and energy worrying about them

X3.

Surprised people have time to camp worrying about their batteries and flushing out their black tanks.

I just think about "back in the day" abuse we did to the batteries. The lights got awfully dim and the tube TV screen kept getting smaller. We still had fun though.

[510Rick]

So I have 1 battery . I also have solar.(which is awesome). If we winter camp and there isn't much sun to charge the battery we usually run the generator for our morning coffee and evening movies for the kids and that seems to be more then enough to keep our battery charged to run the heater all night. If for some reason we are blocked by trees and the solar is struggling I will use my old school battery charger to bring up the battery to keep from getting cold over night. The last thing you want is the heater to crap out on a cold night .

[Martsing]

But I know what makes sense. Personally I subscribe to NMWILDCAT's attitude. I have two lead acid deep cycle batteries and a Ryobi 2200w Inverter generator. I did add this outlet to one of our 12v outlets: https://www.amazon.com/Linkstyle-Cha...e%2C206&sr=1-8

I am fully aware that this is not an accurate gauge but it gives me a peek into the status of the battery bank. The THREE times that I have been boondocking at Assateague here is what I noticed.......

When I shut everything down in the evening at about 10pm the batteries are at about 12.8. I set the thermostat at 60 (it was approx. 30 degrees outside) and by the morning the gauge indicated 12.4v or so. There was no rush to recharge in the morning. I would start the generator and run that for about 1.5 hours and when I was finished the batteries would hover at 12.8 to 12.6 for the day. I would start the generator at about 7pm for TV and charging. The cycle would then start over.

I do envision a portable solar charge for the day but that has not been needed so far.

I was very happy and very comfortable with that.

Marty

[babock]

I used to be an engineer on the GM EV1 back when it used lead acid batteries. It took a full 8 hours to charge using the same battery technology that are used in flooded lead acid batteries today. There is no magic bullet that allows you to do a charge of 50% discharged flooded lead acid batteries in 2 to 4 hours. Just not going to happen. Lead acid batteries can only accept a certain amount of charge current unless you bring the voltage up to levels where you get boiling of the electrolyte. Since most campers are only putting in partial charges, their batteries are never getting fully charge while camping. Do that over multiple times and you get sulfation and reduced battery capacity. The great analogy that Titan Mike said was cutting your shoe laces down one half inch at a time. That is exactly what is happening. Some people claim they replace their batteries every 5 years. What they don't tell you is that they have no idea what capacity is left. May be less than half! The simple solution for them is to run their generator more often during the day so that the battery is actually being used less...there just isn't much capacity left.

There are always the "works for me people" that claim what they claim.

Few things you can do to make your batteries last longer.
1) Make sure your converter is putting out at least 14.4V to 14.8V AT the battery at the the end of bulk charge. This means you may need to upgrade your converter and/or make sure the cable between the battery and the converter drop at most 2% voltage between them. Many converters are in the back of the RV while the batteries are in the front. I replaced my converter and put it right next to the battery. Many converters, fall out of bulk charge too early as well
2) Never discharge below 50%. Your battery has a finite number of charge discharge cycles at 50% and much much less for discharges more than that. Charts are available at all battery manufacturers showing this.
3)Try to get your batteries 100% charged if you can and make sure they are at 100% charge when you store them. Anything less than 100% charge and you are sulfating your batteries. This greatly reduces its capacity.

If you can't go full solar, at least get a small system that can bring your batteries up to close to full charge after you run your generator in the morning.

[Papadave]

Generator for quick charge then solar for topping off. Disconnect the coach wiring if possible when not around. Lots of parasitic drain even when you are not actively using stuff. Solar will get you to 13.5.