I have one of those "one RPM fits all" gensets too; it came built in. I also use my rig as a portable office and have four 6-volt GC size batteries. I have a PD9160 instead of a Prosine 2.0. I do have a Link-10 battery monitor.
To minimize genset run time, I let the batteries get down to ~50% charged and then recharge them to 80%. Keeping the batteries at 50% or above lengthens their life. Charging to only 80% (as Sam stated) keeps you in the bulk charging mode (maximum amps). After the first couple of days, I run my genset about 1.75 hours per day to stay in the 50% to 80% range. We run the microwave off the batteries if the run time is 5 minutes or less, and off the genset if more than 5 minutes. About 20 minutes of the 1.75 hrs/day is running the microwave for our dinner.
As for only discharging a small amount and keeping the batteries in a high state of charge (>90%), you would burn a lot of gas doing that.
Okay, just so I understand, does that mean letting it run on the default bulk (14.4v) and then disconnecting it as it falls off into absorption mode--this will get me 80% or 90% of the way there?
And then every week I do a full, leisurely charge?
What if I just do the bulk but change it to 14.8v?
greenrvgreen wrote: Okay, just so I understand, does that mean letting it run on the default bulk (14.4v) and then disconnecting it as it falls off into absorption mode--this will get me 80% or 90% of the way there?
More likely you will get to 75% or 80%. Usually at ~80% you go from bulk to absorption.
Quote: And then every week I do a full, leisurely charge?
Yep. Once a week to 100%. This is where solar comes in really handy.
Quote: What if I just do the bulk but change it to 14.8v?
If you're getting the full 100 amps out of your Prosine, it won't make much difference. It might get you to 85% instead of 80% before you fall off into absorption, but you'll use more water. As Sam mentioned, be careful of doing this in hot weather.
There is no way you can charge to 100% with a larger generator without going broke. You would have to run it for 24 hours straight. If you follow my instructions you should be OK for up to 3 weeks. I have done it several times and my batteries are 5 years old and still going strong. By the end of the third week your batteries will be sulphated enough where you will have a hard time charging them.
If you did this for 6 months without going on the grid the batteries would be destroyed. This is why long term boondockers have solar. Two to trhee weeks is OK and I have even gone a month a time or too, but at that point, you have to charge those batteries for at least 48 hours to get the sulfate back into solution.
Don't think that the constant speed generator is all bad. A constant speed generator still uses less fuel or more fuel, depending upon the load on it - just like an inverter generator does. The only difference is the little more extra fuel that it takes to overcome the additional friction of the genny engine when spining at it's faster average speed. Most folks prefer the inverter Hondas for low average noise because most of their use turns out to be at less than full output - not necessarily for an over-whelmingly low fuel consumption rate per se.
A small constant speed genny sized just right for charging will only use a very little more - or even maybe no more - fuel than a perhaps too-big inverter generator that is running throttled down.
For instance I have an ultra-quiet (53dB) Honda constant speed 650W (~45 amps at 12 volts) generator that runs about 8 hours at full load on 1/2 gallon of gas. It will charge my battery bank in about 3 hours or less, so I use less than 1/4 gallon per charge. My battery bank is only 200 amp hours so 45 amps is fine, making this genny perfectly sized for it and thus very efficient in gas consumption dealing with my particular charging needs. It being constant speed is really not an issue. (.... counting noise too, as a bonus in this example)
To treat a 440 AH wet cell battery bank correctly and also do it at minimum gas consumption .... probably about a 1000 watt constant speed (or 1000 watt inverter genny running at near full rpm) driving your Prosine programmed down to 60 amps max output during bulk charging should just about be the best combination for you.
* This post was
edited 06/20/08 08:54am by pnichols *
It's a big constant-speed generator that's "bad". A 4kva Onan Microquiet uses more fuel at zero load (0.3 gph) that an eu2000i at it's 1,600 watt rated load (0.275 gph). The eu2000i at 500 watts uses 0.073 gph, about 1/4 what the Microquiet uses at zero load. At 2,000 watts, the Onan uses 0.5 gph, 82% more fuel for 25% more power than the Honda at 1,600 watts. If there was an Inverter generator sized for 4,000 watts rated load, I believe it would have roughly the same full-load fuel consumption as the Onan.
Absolutely Wayne.. And the OP has a 3500W constant speed generator to use for battery charging. This is much larger than necessary to do the job and as a result, uses much more fuel. According to the published figures, the Champion 3500W uses over 1 gal per hour at 50% load and the Honda gets 15 hours on 1.1 gal at 1/4 load.
Yes, my Honda is only running at about 1/4 load when battery charging, even at bulk charge rates with my PD9260. The Champ 3500 would be at less than 1/2 load, but I was unable to find any other consumption specs for it. Greengreen says less than 1 gal per hour, but still that does not compare to less than 1/10 gal per hour.
One thing brought out on this string was the importance of adding solar to the system if you are a long term boondocker, and the need to fully charge the batteries at regular intervals to avoid sulfating.. Personally I keep my TT plugged in when it is stored, so this is not a problem.
Great information here though...
* This post was
edited 06/22/08 07:23pm by Dixonmatco *
One thing brought out on this string was the importance of adding solar to the system if you are a long term boondocker, and the need to fully charge the batteries at regular intervals to avoid sulfating.. Personally I keep my TT plugged in when it is stored, so this is not a problem.
Great information here though...
I agree. I started reading these forums in February 2005. There are a few select topics that I am very interested in, batteries and charging specifically.
For the first time I see the value of solar. Since I only weekend camp, I have great flexibility using my Honda 2000. However, as the OP pointed out, it is not economically viable to fully charge batteries using a generator. Since I can top off the batteries when I go home at the end of the weekend all is well for me. But for extended trips, you need some affordable means of topping off the batteries some of the time. Solar, it seems to me, is a great solution for this problem.
Wayne in San Jose
TV1:2002 Chevy 1500HD 4wd Crew Cab,Valley Odyssey brake ctlr,McKesh mirrors
TV2:2008 GMC 2500HD long bed 4wd Crew Cab,GMC brake ctlr,GMC mirrors
TT:Trailmanor 2720
Honda 2000
Yamaha WR250R,Polaris Sportsman 700 X2,Polaris Scrambler 500
PopBeavers wrote: For the first time I see the value of solar. Since I only weekend camp, I have great flexibility using my Honda 2000. However, as the OP pointed out, it is not economically viable to fully charge batteries using a generator.
Your Honda 2000 beats solar on economics unless you camp a lot. You may want the solar for pollution reasons - noise and fumes - but the generator is ahead on economics.
For the price of the panels, you can buy a LOT of gasoline, and the EU2000 sips gasoline under light load so that's a lot of hours of gen time for the price of the panels.
As for the Honda eu2000, I think if you have only one charging method, it is certainly the best one and "possibly" the most economical over time. However, two things work against it, IMO:
#1. That other generator with significantly lower purchase cost. We all agree the Honda runs more efficiently, but there are no hard figures yet--YET.
#2. Solar-generated float charge. It looks like roughly $1300 will buy you a couple of Kyocera 135-watt panels and a charge controller. Reduce outputs for efficiency loss and you're still getting an 8-amp charge, it seems.
So. I've already got a generator to run my A/C and everything else (all at the same time). But it slurps gas and could be quieter and better-loved by potential CG neighbors. Do I spend $1,000 on a quieter second generator that uses less gas, or $1300 on a silent generator that uses NO gas? Remember, I've still got that honkin' yellow thang.
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