why generators are bad battery chargers
- Thread starter Mwilliamshs
- Start date
pugslyyy
Expedition Vehicle Engineer Guy
Sorry, I'm an electrical engineer so I tend to be a bit pedantic about stuff like this!
dwh
Tail-End Charlie
pugslyyy,
Can I make a request? I would dearly love if you would put together and post an in-depth review of that generator that Doug Hackney bought for the Fuso. Man, I saw the pics of that thing on Doug's site and fell in love with the design and layout of that unit, but I've never been able to find any full-on wring-it-out review of the thing.
Pretty please? With sugar on top?
dwh
Tail-End Charlie
Then I guess it's a good thing that I covered my butt with that qualifier of "appears to".
Mwilliamshs
Explorer
Then I guess it's a good thing that I covered my butt with that qualifier of "appears to".
Actually if you'd moved the "appears" before the "misleading" you'd be covered. Or if you'd read more closely or done the math or independent research of your own you'd be less of a foot-muncher, or at least it would appear so.
pugslyyy
Expedition Vehicle Engineer Guy
pugslyyy,
Can I make a request? I would dearly love if you would put together and post an in-depth review of that generator that Doug Hackney bought for the Fuso. Man, I saw the pics of that thing on Doug's site and fell in love with the design and layout of that unit, but I've never been able to find any full-on wring-it-out review of the thing.
Pretty please? With sugar on top?
It's a Next Gen 3500W diesel marine generator (single cylinder water cooled Kubota), consuming 0.1-0.2 gph. It is sized for the inverter/charger (Xantrex 3000W) and that combination can push up to 150Amps into the AGM bank during bulk charge.
PROs: It's a bulletproof, highly efficient generator - built to be run continuously for long periods of time.
CONs: It's noisy, not small, noisy, not light (160lbs dry), noisy, and not quiet. Also, it was designed to operate at sea level so does not do as well at very high operations. (I changed the air filter to a much larger K&N that helps it to breathe a lot easier.)
I use it as a backup generator for my home - if we lose power during the winter I can just crank the generator and let it run. 0.2 gph from a 100 gallon tank means that I'm probably not going to run out of fuel before power comes back on.
DiploStrat
Expedition Leader
That genset is simply incredible; it is 100% efficient in turning tiny amounts on diesel fuel into incredible amounts of noise.
Haf-E
Expedition Leader
That genset is simply incredible; it is 100% efficient in turning tiny amounts on diesel fuel into incredible amounts of noise.
Actually its 100% efficient at making a lot of heat, noise and a little bit of electricity...
DiploStrat
Expedition Leader
It makes electricity? Wow. Missed that part.
(Sorry, but having camped with Robinson Fuso, I just had to take some cheap shots!)
Now, if you want to discuss the amazing outdoor grill and plug in camp fire ...
(Sorry, but having camped with Robinson Fuso, I just had to take some cheap shots!)
Now, if you want to discuss the amazing outdoor grill and plug in camp fire ...
dwh
Tail-End Charlie
It's a Next Gen 3500W diesel marine generator (single cylinder water cooled Kubota), consuming 0.1-0.2 gph. It is sized for the inverter/charger (Xantrex 3000W) and that combination can push up to 150Amps into the AGM bank during bulk charge.
PROs: It's a bulletproof, highly efficient generator - built to be run continuously for long periods of time.
CONs: It's noisy, not small, noisy, not light (160lbs dry), noisy, and not quiet. Also, it was designed to operate at sea level so does not do as well at very high operations. (I changed the air filter to a much larger K&N that helps it to breathe a lot easier.)
I use it as a backup generator for my home - if we lose power during the winter I can just crank the generator and let it run. 0.2 gph from a 100 gallon tank means that I'm probably not going to run out of fuel before power comes back on.
So it actually does get the advertised 0.2 gph under full load?
pugslyyy
Expedition Vehicle Engineer Guy
Don't forget that the genset includes an insect fogger at no extra cost. It's also good for ensuring nobody else camps too close to you.
Mwilliamshs
Explorer
Insect fogger, neighbor deterrent, noise, AND electricity? Tell me it's heavy, has its own liquid cooling system and fluid/filter maintenance schedules and I'm SOLD...
on the idea of NOT having a generator. Especially that one.
on the idea of NOT having a generator. Especially that one.
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1stDeuce
Explorer
It appears you guys are trying to justify a generator as the 100% solution, or 100% problem for battery charging... I think the reality is that for certain things, the generator (Large or small) is the right answer, but for total battery charging, probably not... If you want A/C in a mobile rig, then your best bang for the buck by far is a generator. But if you're just trying to charge batteries that ran some lights, a heater, and perhaps an ARB fridge overnight, then a generator (of any size) is probably not so ideal.
If you are pulling more Ah out than a moderate solar setup can replace, then a generator is needed, but there is a better way than running a generator for hours to get the batteries to 100%... As someone pointed out already, a little "quiet" generator can output 15A of 12v power, but charging a battery to 100% takes a long time as the charge current tapers as the battery gets closer to 100%. It would be wise in this case to use the generator until the current fell to perhaps 5A, which might take only an hour of run time in the morning, and then let a small solar panel, perhaps 80W or so, do the final charging over the rest of the day. You wouldn't need 600W of solar, just enough to get 4-5A of output, and you'd be using the generator at closer to its max output, which provides better efficiency.
I'll tell you this from my own experiences though... My 85 watt solar panel and Group 31 battery do a fine job of keeping the house battery topped off in my truck camper for summer fall and spring camping, and it's the only charge input to the battery. In the winter, if it's a bit cloudy, I can start to pull the battery down about 5%/day if the weather is cold and the heater runs a lot. (3A heater draw @ ~20min/hour at 30F outside) If I tilted the panel, I'm sure it would be fine. Or if I had put a 100W panel up there. I don't normally stay in one spot for more than 3-4 days, so I don't worry about it, and still run the heater/tv/lights plus phone and computer charging duties. When I get home and stop drawing from the system, the battery is at 100% by the end of the following day. If I winter camped more, I'd fix it, but I don't.
So... If you're limited on how much solar you can run, then using a small gen set to bulk charge early in the day, and then 80-100w of solar to do the rest of the job over the next 5 hours is probably the best of both worlds, minimizing fuel usage while getting the batteries to 100%, which is VERY important if you don't want to replace a lot of batteries.
I think many people have been led to believe that you need hundreds of watts of solar, and that just isn't the case if you install the system correctly. The biggest issue with solar setups is that many systems are not supplying proper voltage to the batteries to charge them. That can be because of voltage drop over long wire runs, charge controllers too far from the battery (which leads to the previous) or because your charge controller is simply not letting the batteries charge at higher voltage for long enough. (Many drop to float mode as soon as the charge voltage gets to 14.4, and this is WRONG.
Earlier in this thread, I saw a picture of a portable setup showing 14.4V AT THE PANEL, and someone responded about the battery being full... That's most likely WRONG. The battery may be at 85-90%, but for daily drain and recharge with solar, you need to be getting the battery up to 14.65 or higher for it to be at 100%. 14.4V with 10' or more of wire between the charge controller and the battery means the battery is probably in the high 13's, and that is NOT a fully charged battery.
Read HandyBob's blog. Then read it again. Heed his words. He lived on 345 watts of solar for YEARS in an RV that didn't have a generator, and he ran a toaster, coffee maker, tv, sewing machine, etc with no problems. It can be done. It's not that hard. You probably don't need a generator. And by all means STOP looking at pre-packaged solar kits... They are almost all overpriced, and full of poor components. OMG I'm starting to sound grumpy and I'm only 41... I'll be kicking puppies by the time I'm 50...
Now get out and go camping, and use your solar, or a generator, or whatever your little heart desires, and post a nice trip report so I can live vicariously through you!!
If you are pulling more Ah out than a moderate solar setup can replace, then a generator is needed, but there is a better way than running a generator for hours to get the batteries to 100%... As someone pointed out already, a little "quiet" generator can output 15A of 12v power, but charging a battery to 100% takes a long time as the charge current tapers as the battery gets closer to 100%. It would be wise in this case to use the generator until the current fell to perhaps 5A, which might take only an hour of run time in the morning, and then let a small solar panel, perhaps 80W or so, do the final charging over the rest of the day. You wouldn't need 600W of solar, just enough to get 4-5A of output, and you'd be using the generator at closer to its max output, which provides better efficiency.
I'll tell you this from my own experiences though... My 85 watt solar panel and Group 31 battery do a fine job of keeping the house battery topped off in my truck camper for summer fall and spring camping, and it's the only charge input to the battery. In the winter, if it's a bit cloudy, I can start to pull the battery down about 5%/day if the weather is cold and the heater runs a lot. (3A heater draw @ ~20min/hour at 30F outside) If I tilted the panel, I'm sure it would be fine. Or if I had put a 100W panel up there. I don't normally stay in one spot for more than 3-4 days, so I don't worry about it, and still run the heater/tv/lights plus phone and computer charging duties. When I get home and stop drawing from the system, the battery is at 100% by the end of the following day. If I winter camped more, I'd fix it, but I don't.
So... If you're limited on how much solar you can run, then using a small gen set to bulk charge early in the day, and then 80-100w of solar to do the rest of the job over the next 5 hours is probably the best of both worlds, minimizing fuel usage while getting the batteries to 100%, which is VERY important if you don't want to replace a lot of batteries.
I think many people have been led to believe that you need hundreds of watts of solar, and that just isn't the case if you install the system correctly. The biggest issue with solar setups is that many systems are not supplying proper voltage to the batteries to charge them. That can be because of voltage drop over long wire runs, charge controllers too far from the battery (which leads to the previous) or because your charge controller is simply not letting the batteries charge at higher voltage for long enough. (Many drop to float mode as soon as the charge voltage gets to 14.4, and this is WRONG.
Earlier in this thread, I saw a picture of a portable setup showing 14.4V AT THE PANEL, and someone responded about the battery being full... That's most likely WRONG. The battery may be at 85-90%, but for daily drain and recharge with solar, you need to be getting the battery up to 14.65 or higher for it to be at 100%. 14.4V with 10' or more of wire between the charge controller and the battery means the battery is probably in the high 13's, and that is NOT a fully charged battery.
Read HandyBob's blog. Then read it again. Heed his words. He lived on 345 watts of solar for YEARS in an RV that didn't have a generator, and he ran a toaster, coffee maker, tv, sewing machine, etc with no problems. It can be done. It's not that hard. You probably don't need a generator. And by all means STOP looking at pre-packaged solar kits... They are almost all overpriced, and full of poor components. OMG I'm starting to sound grumpy and I'm only 41... I'll be kicking puppies by the time I'm 50...
Now get out and go camping, and use your solar, or a generator, or whatever your little heart desires, and post a nice trip report so I can live vicariously through you!!
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