greenrvgreen
open road
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Joined: 09/05/2007
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With gas prices such as they are, I want to maximize the fuel efficiency of my battery charging when boon docking, even though it wears out the batteries quicker. I have searched and found mentions of altering the charging pattern to INCREASE the time spent in bulk mode. Could somebody enlighten me on this?
I have a Xantrex Prosine 2.0 and a certain generator that runs at a fixed RPM. I have 4 gc2 batteries, 440 ah total.
When I charge, unless I have a competing load, the charger goes to 100 amps and holds there in bulk mode. After a couple hours, it descends through absorption mode.
--As it is now, what % of total charge is achieved in bulk mode? Or is it just time-based?
--How much more charge is gotten through "absorption mode"?
--Does "float charging" add a charge or just maintain a charge?
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ejforwood
Littleton (Denver) Colorado
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Joined: 04/26/2006
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How many hours can you run the gen on the cost of a ruined set of batteries?
Jerry, Dottie & Chan, "the little furry one"
98 Bounder 34V, 99 F-53 Ford V10 chassis
06 Saturn VUE 4I
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Hurricaner
Hurricane Utah
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Joined: 02/17/2007
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Are we talking a weekend, a few weeks or are you full time?
Sam
Sam & Kari
Hurricane, Utah
2004 34' Damon Challenger 315
Damon owners forum
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greenrvgreen
open road
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Joined: 09/05/2007
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I will go out for 1-3 weeks at a time, no services, no neighbors. I truck in gasoline and water and I am never too far from a McDonalds, just in case.
I will run a computer and related devices all day on battery power--this is my "portable office". Twice a day I fire up the generator and it gets to be expensive. My thinking is that using less gas more than makes up for decreased battery life.
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RCMAN46
NorthWest
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Joined: 02/24/2008
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The way I see it is for every amp hour you remove from a battery you will have to replace that many amp hours plus a small percentage for losses. Since lead acid batteries do not like deep discharges I would charge the battery often when I have access to a generator. It does not make sense to deep discharge when you have access to a generator. The cost of a good battery will buy more fuel than you will probably use for the life of the battery.
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greenrvgreen
open road
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Let's start with "float charging". Do I gain any charge by this? Because I'm turning around and IMMEDIATELY discharging the battery.
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RCMAN46
NorthWest
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greenrvgreen wrote:I will go out for 1-3 weeks at a time, no services, no neighbors. I truck in gasoline and water and I am never too far from a McDonalds, just in case.
I will run a computer and related devices all day on battery power--this is my "portable office". Twice a day I fire up the generator and it gets to be expensive. My thinking is that using less gas more than makes up for decreased battery life.
At the end of the week, month or what ever your trip time is will require about the same amount of fuel regardless of the method you use to charge the batteries. It would make sense to use a method that will give maximum battery life. Batteries are not perpetual devices. A good battery will give you about the same energy out as you put in. Good batteries have very small losses.
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ejforwood
Littleton (Denver) Colorado
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RCMAN46 wrote:The way I see it is for every amp hour you remove from a battery you will have to replace that many amp hours plus a small percentage for losses. Since lead acid batteries do not like deep discharges I would charge the battery often when I have access to a generator. It does not make sense to deep discharge when you have access to a generator. The cost of a good battery will buy more fuel than you will probably use for the life of the battery.
I agree, and I don't see how using the battery longer between recharging is going to shorten the length of time to recharge. Only shorten the life of the batteries and eventually you will have to charge longer to get then to to accept the same amount of charge. But then I could be wrong!
All I know is that my T-105's are 9 years old because I have respected them. At $250 a pair I could have at least 60+ hours of run time even at $4.00 per gallon X 5 or more sets of ruined batteries. JMHO!
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PopBeavers
San Jose, CA
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Joined: 03/19/2005
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Try this algorithm:
1. Never allow the batteries to discharge below x percent. Choose x to be a number between 50 and 70.
2. When running the generator, turn it off when the charge current has dropped off significantly. At this point you are burning gas at the same rate, but the battery is absorbing less than it did before.
Depending on your battery bank capacity and the discharge rate, you might be running the generator several times a day, or you might run it once every few days.
If you let the batteries get too low it is damaging to the batteries. If you run the generator when the batteries are already full, or "close enough for government work" to being charged, you are loosing efficiency, "wasting gas".
A good meter would be helpful.
Wayne in San Jose
2002 Chevy Silverado 1500HD 4x4 Crew Cab
2005 Trailmanor 2720
Valley Odyssey brake controller, Honda 2000 generator, McKesh mirrors
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Hurricaner
Hurricane Utah
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Joined: 02/17/2007
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For 2 to 3 weeks you don't want to do anything but bulk charge. I would set the voltage at 14.8 to 15 volts. You need a battery monitor if you don't have one. Do not let the batteries go below 50 percent charge and charge them to 80% at least every other day. I would also bring them up to 90% once a week. Only use this method for 3 to 4 weeks max before you go on the grid and get a good 24 to 48 hour absorption charge at somewhere around 13.8, but the Prosine will take care of that.
Sam
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