How much gas does your genny use? And a charging question

[Naio]

After generous advice and hand-holding from folks here, I experimented with running my van engine to charge house batteries when dry camping, as I do not yet have a genny or solar. I used an MSW inverter and a 30 amp 'smart' charger. Now I have results to post and subsequent questions.

I did this for a total of 7 days at two campgrounds. At the first cg, I felt bad because my van engine was louder than the neighboring gennys. At the second cg, I did not, because some gennys were louder than my van, so I felt I was fitting in with social norms :).

It's hard to estimate, but it seemed to take about 1/2 gallon per hour, idling the van. Seems like a lot of wasted energy. How much does a small generator use? OTOH, the van gets nice and warm for sleeping at night!

Charging this way took a LOT longer than plugging in to 120v. I don't have an ampmeter yet, but it took around 3x as long. Same charger. Is there anything I can do to speed things up? My alternator is 105v, so I don't think that is the problem.

[SoundGuy]

Almot wrote:
Who said anything about portable? 🙂

I did :R ... and I'm just illustrating the fact that we all have different views on the subject. I agree with others who say NO WAY to using their only way home as a charging station for their trailer. Obviously the OP can do whatever he wants but for myself and clearly others the answer is a definitive "no thanks". Same for solar in my case - I'm not going to babysit a portable system but I likewise refuse to restrict myself with a permanently mounted system to always parking in full sun just so I can charge the batteries regardless of where I may be camping. The OP's arguments for doing otherwise may make total sense to him but that in no way lessens the validity of how I handle the same problem of battery recharging.

[Almot]

Who said anything about portable? 🙂

Yes, when camping often in deep shade, permanently mounted solar won't be much useful. The OP are snowbirds, and those are after sun. Snowbirds camps are out in the open. To get plenty of shade, they need to travel pretty far South, like Mexican tropics, and those places are more densely populated and (usually) have electricity. Farther South though, on-grid camps disappear, locals don't camp and most gringos don't go that far either.

Summer in Ontario (or BC) is a different thing. Still doable without a generator, for 4-5 days, if you carry enough batteries. Without A/C of course.

[SoundGuy]

Almot wrote:
The way I see it, solar is a must for an offgrid snowbird, generator is optional.

I've been on / off with the genset / solar issue for several years now and came to the exact opposite conclusion - genset first, solar second. I did get my first EU2000i to run a 13.5 BTU A/C reliably until the temps got into the 90s (ironically when I'd want A/C the most), then concluded I wouldn't bother with it anyway as running A/C all day means running the genset all day which in turn means dragging along copious amount of fuel ... which ain't happenin'. OTOH I am very much interested in the freedom having a genset on hand provides in terms of being able to dry camp at any time, for as long as I want, a particular advantage here in Ontario where getting an electric site during the busy summer months of July / Aug is pretty well impossible without reserving months in advance. By dry camping I can get a last minute site, without reservations, with little difficulty at all ... but I need a way to recharge the battery. Yes, I did consider solar but there's no way I'm going to babysit a portable system to follow the sun and to avert theft issues ... a system permanently mounted on the rig wouldn't work either because we so often camp in deep shade, especially if we're dry camping and have to rely on fans for cooling. For sure, genset noise can be an issue, even with a so-called "quiet" inverter genset, but I think I've managed to dull that down to the point where I'm confident most people walking by our site would hardly notice. Pics and a couple of vids are here for anyone who may be interested.

[Almot]

SoundGuy wrote:

Naio wrote:
Boy, I cannot believe how much gas those little generators use.

"How much gas ..." ?? :h Geez, my Honda EU2000i is rated to run anywhere from ~ 3.4 to 9 hrs, depending on speed, on just 3.6 litres (~ 0.9 US gal) of gas. I'd call that miserly...

According to Naio post, his truck engine is running from 2 to 4 hours on a gallon. A bit more than 2000W generator, but not unacceptably more, if this makes for less noise. Yes, there is a matter of wearing out more expensive truck engine, but then, not all of them are that expensive.

To me, it sucks either way - fumes and constant humming/rumbling of even the quietest generator is not what I'm looking for, when going out there. People are learning now - though slowly - all these basics, i.e. that charging at the end is very slow, and solar can finish the charging off silently, and that with enough solar you may not even have to run this machinery at all, or on most days. And that generators noise levels and lifespan are overstated by manufacturers. I still see people running it a few hours to charge a cell phone or watch a small TV - don't even understand why, when a small $30 inverter would do this without making a dent in battery SOC.

For somebody who doesn't have a generator yet - and spending winter in some place warm - there is a lot to think before buying it. Upfront cost of generator - don't forget about charger as well - exceeds the cost of a midsize solar system a few times, and then there is a fuel and maintenance costs. If truck can do, I would wait and see. The way I see it, solar is a must for an offgrid snowbird, generator is optional.

[pnichols]

I'd sure like to see some curves showing wattage output versus RPM for a Honda EU1000i generator.

Honda EU1000i (and Honda EU2000i) low noise and low fuel consumption rates of course only apply at the low ends of their RPM ranges. I'm finding it very hard to digest that the little Honda can put out enough watts into a moderately sized multi-stage charger for just a few hours so as to bring a 200 amp hour or larger RV battery bank from 50% up to a 90% state of charge ... while at the same time just putt-putting along sipping little fuel and making little noise at speeds close to Eco-idle.

Our little (obsolete model) single speed Honda will run 5-6 hours on 1/2 gallon of fuel at it's low-ball sound level (54dB), but the charger it's powering during this time period only ranges from ~15 amps down to ~5 amps into our 200 amp hour AGM batteries.

It seems like the EU1000i either has to be rev'ing up to power a good charger (and sucking fuel and being louder), or staying near idle (and sipping fuel and being quiet) powering a lesser charger and therefore not really be charging larger battery banks up that well ... one or the other. :h

[NinerBikes]

I've run my Honda Eu1000i on Eco mode charging batteries, and 6 to 7 hours on .45 gallon of gas seems to be about my regular consumption rate, if charging with it for an hour first thing in the morning, and topping the battery off with solar the rest of the day. Charger is a Switch charger power supply unit rated at 30 amps and set at 14.8V.

This set up lets the generator do the quick and dirty part of the charge cycle, the 50 to 80% section. The solar does the 80 to 95-98% SOC section.

I do warm my generator up for 3 or 4 minute before I turn on the Power Supply Unit. Important if you want your generator to last, to warm it up properly before putting it under heavy load.

[Naio]

landyacht318 wrote:
Do you have a quality set of jumper cables?

Pretty good. 4 or 6 gauge.

Many vehicles idle speed Alternator amperage output is pathetic but some are pretty good. If it can do 30+ amps and maintain 14.4+ volts over some 4 awg cabling then hooking battery to battery with engine running will be more effective than using an inverter to power a 30 amp smart charger.

I did not try the direct jumper cable method and I should, to compare.

Also when batteries are cycled heavily without an intervening full recharge, one cannot really compare charge times requirements as to how depleted they were to begin with.

Even less trustworthy is when an Automatic charger flashes the green full charge indicator light. They all stop applying absorption voltages and revert to float way too early on a heavily cycled battery, and when fed by a MSW inverter, I bet this is even more a case of wildly premature efloatulation. Scumbag 'smart' charger liars.... grumble grumble

The first night at each of two campgrounds, when the previous charge had been from a wall plug, it still took ridiculously long for the charger to turn green. So my guess would be that it it not turning off prematurely (or not more prematurely than with a wall plug).

But it could be doing who-knows-what-all weird stuff because of the MSW. I was charging at night, when tired from hiking all day, or in the morning, when antsy to get going, so I did not get off the surface charge, put on a small load on the batteries and then test their actual voltage after charging.

In your case, assuming the house battery bank is well grounded to the frame, I'd order a 2awg cable, or thicker, from Genuinedealz with ring terminals on one end and an alligator clamp on the other, and hook one to the house battery and the other directly to alternator (+) output and hold the engine at 1000 rpm for an hour, when needed, and not worry about getting the batteries past 80% charged. Bypass that too thin original alternator to engine battery circuit and more amps will flow, and the voltage regulator will likely allow higher voltages, and thus higher amperages, for longer.

But if the VR only allows or reverts prematurely to 13.7v, forget this plan.

Thank you 🙂

[SoundGuy]

Naio wrote:
Boy, I cannot believe how much gas those little generators use.

"How much gas ..." ?? :h Geez, my Honda EU2000i is rated to run anywhere from ~ 3.4 to 9 hrs, depending on speed, on just 3.6 litres (~ 0.9 US gal) of gas. I'd call that miserly, especially since mine rarely runs much off it's slowest ECO speed, even when re-charging the trailer battery. Heck, I don't even bother taking extra gas if we're going camping for up to 3 days ... just fill the tank to capacity and call it good! :B

[64thunderbolt]

well, my toy hauler came with an onboard onan and I only have a small inv for tv/dvd. Since it is there I use it when needed. I would never run my trucks engine to recharge. Not putting hours on that $12K engine to charge batt. But to each his own.

[landyacht318]

I have seen 5 amps during a rain event from my 198 watts of solar, but on another rain event at high Noon there was not even enough light for my charge controller to turn on.

Lots of variables on this obviously and no hard numbers can be applied across all locations and all rain events as to what solar can or cannot provide during one.

I personally don't use any electricity to make coffee, or food, and am always a little surprised that those living on battery power choose to do so. Especially when they do not have enough charging sources to meet their needs most of the time.

The second my vehicle parks, the engine is off, I can't imagine idling to recharge, or run an engine at all to recharge, but again, that is a personal choice, and not one for everyone.

[Almot]

64thunderbolt wrote:
The solar is the key & are getting reasonable. I bought 2 100w panels & 30a controller for $319. Even in low light they will recharge the following day. On a rainy day they will produce about 5/6a.

5-6A from 200W array under rain is a lot. 5-6 AMP-HOURS a day is more like it. Water film on the panel is blocking most of the solar radiation. My flat 500W barely generates 1A-2A in the rain. As soon as it stops raining, amps climb up.

In low overcast with none or very little wet time, and if the only loads are lights and some electronics, 500W would charge to Full the same day. So 200W charging the next day sounds about right. Solar is a must for a snowbird. The more - the better. Microwave and coffeemaker are power hogs, without them a 200W array would suffice on most days.

My situation is easier since I don't drink coffee, and with 500W array and 300 AH AGM bank I can afford 25-30 AH daily for microwave. As soon as I convince myself to spend $200 on a big inverter for microwave. Most common MW task is reheating leftovers, and a $10 double-wall boiler on a stove top is doing it so far. Generator? What generator...

[landyacht318]

Do you have a quality set of jumper cables?

Many vehicles idle speed Alternator amperage output is pathetic but some are pretty good. If it can do 30+ amps and maintain 14.4+ volts over some 4 awg cabling then hooking battery to battery with engine running will be more effective than using an inverter to power a 30 amp smart charger.

Also when batteries are cycled heavily without an intervening full recharge, one cannot really compare charge times requirements as to how depleted they were to begin with.

Even less trustworthy is when an Automatic charger flashes the green full charge indicator light. They all stop applying absorption voltages and revert to float way too early on a heavily cycled battery, and when fed by a MSW inverter, I bet this is even more a case of wildly premature efloatulation. Scumbag 'smart' charger liars.... grumble grumble

In your case, assuming the house battery bank is well grounded to the frame, I'd order a 2awg cable, or thicker, from Genuinedealz with ring terminals on one end and an alligator clamp on the other, and hook one to the house battery and the other directly to alternator (+) output and hold the engine at 1000 rpm for an hour, when needed, and not worry about getting the batteries past 80% charged. Bypass that too thin original alternator to engine battery circuit and more amps will flow, and the voltage regulator will likely allow higher voltages, and thus higher amperages, for longer.

But if the VR only allows or reverts prematurely to 13.7v, forget this plan.

[64thunderbolt]

you do what you gotta do. The solar is the key & are getting reasonable. I bought 2 100w panels & 30a controller for $319. Even in low light they will recharge the following day. On a rainy day they will produce about 5/6a. I only use my inv for tv/dvd so my consumption is low unless it warms some & I have to use my 2 fantastic fans. I use my onboard 4K onan for coffee maker & microwave. A good batt bank is also a key item. I have 2 gc2's @ 232a

[Naio]

Thanks, folks!

Boy, I cannot believe how much gas those little generators use. It sounds like my van at idle does not use much more, maybe not any more. I do not have an accurate count on how much it is using -- but it looks like about 1/2 gallon for 2-4 hours.

As for SOC and how do I know: I ran the same loads on multiple days, and charged till the charger shut off. This was 3x faster when I charged by plugging into the wall. Surprised me!

If money was not an issue, I would get everything: genny, solar, more batteries, fat wire to alternator, PSW inverter... but all that would cost me about what I bought the van for, and I have had a lot of expenses this year. I'm looking at my usage patterns, and what will give me the most bang for the buck.

[John___Angela]

Although we rely principally on solar for our Little class C for batter charging, in bad conditions we routinely run the V10 when under high inverter loads (like Microwave, toaster, coffee maker etc) and then usually let it run for 15 to 30 minutes after. However, we installed 2 gauge cables directly from the alternator to the two AGM group 31 batteries. We installed an inline meter and routinely see high charge current of mid 30 amps for the first little while or even higher when the inverter is under load. The v10 is quieter than ANY generator I have heard. Our scan gauge registers between 1/3 and 1/2 gallon per hour on idle with AC off.

Wear and tear are not a concern for us. No where for a generator and don't want to pack fuel. Having said all that, like I said, solar is our primary charger with 320 watts flat mounted on the roof.