| Author | Message | ||
| Larry & Lynne Dixon (Larry_d)
Registered Member Username: Larry_d Post Number: 88 Registered: 7-2005 Posted From: 71.111.184.211 Rating: N/A |
Here we go again I would like to put four new 125 golf cart batteries with two 1 year old 105 batteries any pros and cons to this. I relize I should buy all six new. Just being a cheap scate. 4905 Larry | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1098 Registered: 5-2001 Posted From: 209.145.114.134 Rating: N/A |
Larry, the 105s are less efficient than the 125s in charging and discharging. If you check them for full charge periodically, and the 105s are getting fully charged, they will add capacity to your system. When they start taking too much recharge time to suit you, you could chenge them to 125s then. If the 125s are still in good condition when you do that, then you can probably get some savings from delaying the change. If they are getting tired when you replace the 105s, you will probably lose out, overall. Try connecting the 105s nearest the loads and charge system and connecting the 125s to them. This will mean that they will carry a slightly greater share of the workload and recharge. Be sure to desulfate them when they are fully charged to keep them working well. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| Larry & Lynne Dixon (Larry_d)
Registered Member Username: Larry_d Post Number: 89 Registered: 7-2005 Posted From: 71.111.184.211 Rating: N/A |
Thanks Tom, we have been fighting a longevity time with batteries since we bought the bus. Even with the six batteries lucky to get six hrs with just the refrigerator a lite and TV. Even driving down the road not over 5 or 6 hrs. Don't know what we should get but doesn't seem like enoough. Thank you for your help larry | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 176 Registered: 8-2006 Posted From: 207.231.81.59 Rating: N/A |
Morning L & L, Maybe an explanation of the electrical math might help diagnose the [problem] if you have one? Watts, the electrical unit of work, is Amps, the electrical unit of quantity, multiplied by Volts, the electrical unit of pressure. Watts used to be called Watts, now you will see them called VA, (same thing.) Deep cycle batteries are rated in Amp-hours, which is just how many Amps they can put out, or take in, for how many hours. So, if you charge a battery at 10 amps for one hour, you have 10 amp-hours. Now, six-6 Volt batteries will have to be wired in three groups of two in series, (positive to negative between the two batteries) then the groups wired in parallel, (all three positives connected, all three negatives connected.) Make certain you put the two 105s in one series pair. Now, your total AVAILABLE amp hour rating will only be the sum of ONE 105, plus TWO 125s, because they are 6 Volt, and have to be wired in series groups. So, lets say they are rated at 105, and 125 amp hours respectively. That means you will have 355 amp-hours available at theoretical perfect, which we know won't happen. You probably won't get more than about 70% of your charge back out of your batteries, and your inverter probably won't exceed 90%. Now, remember Watts=Amps X Volts? Well, 10 Amps at 120 Volts=120 Amps at 12 Volts, @ 100% inverter efficiency! So, a 5 Amp 120 V load would run your batt bank down in six hours. You say your house batteries go dead after 5 or 6 hours of use while DRIVING? Or do you mean you only get 5 or 6 hours of inverter while parked AFTER driving? If you lose them DURING driving, they are not being charged by the bus alternator, and I assume, are being charged by the inverter while hooked up to shore, before you start out? Do you have a voltmeter? 12.5 V across two fully charged 6 V batts, ABOUT 14.2 V across the same two under charge, if they weren't just run flat. Remember, it WILL take a 10 Amp charger 35.5 HOURS to fully charge your six flat golf carts! Needless to say, a 200 AMP or so bus alternator will do it much more quickly. Write and tell us what you find, please. George | ||
| Jerry Liebler (Jerry_liebler)
Registered Member Username: Jerry_liebler Post Number: 247 Registered: 3-2005 Posted From: 71.31.3.204 Rating: N/A |
Larry, It sounds like you are hurting for capacity. Can you put batteries that are 16" tall instead? If you could try 4 new L16s ( they have the same footprint but are taller) which would give you about double what you have now or 6 which would almost tripple your storage capacity. L16s are, while not cheap, about the most capacity per unit volume. If you stay with the shorter batteries you'll be much better off replacing all at the same time. If you kept the smaller older batteries they would actually be being discharged more deeply than the newer batteries and would have a much shorter life. When one battery fails it'll likely damage the others. Regards Jerry 4107 1120 | ||
| Jerry Liebler (Jerry_liebler)
Registered Member Username: Jerry_liebler Post Number: 248 Registered: 3-2005 Posted From: 71.31.3.204 Rating: N/A |
Larry, I see you have a 4905 which is a 24 volt bus and since you have 6ea 6volt house batteries your house system is 12 volts. To charge your house battery while driving, from the huge gear driven alternator you have, you need an equalizer on the bus battery system, a wire to your house battery and a contactor wired so it's on when the alternator is charging, such a setup could easily give you 100amps charging while driving. Or you could add a 12 volt alternator dedicated to the house battery. By the way the L16s are available with ratings froom 350AH to 420AH. Regards Jerry 4107 1120 | ||
| Jerry Liebler (Jerry_liebler)
Registered Member Username: Jerry_liebler Post Number: 249 Registered: 3-2005 Posted From: 71.31.3.204 Rating: N/A |
George, I beg to differ with you about watts and VA. Watts is absolutely a modern unit and is quite different from VA which only applys to AC. In AC systems the phase of voltage and current waves may differ. The watts in an AC system is actual power and attributable to the in phase component of the voltage and current waves. The out of phase component is called 'volt amps reactive' or VAR. The product of RMS voltage and RMS curent ignoring phase is called VA. Regards Jerry 4107 1120 | ||
| joe padberg (Joemc7ab)
Registered Member Username: Joemc7ab Post Number: 117 Registered: 6-2004 Posted From: 66.38.159.33 Rating: N/A |
Sure nice to have some engineering types here to get the definitions just right. Joe. | ||
| Larry & Lynne Dixon (Larry_d)
Registered Member Username: Larry_d Post Number: 90 Registered: 7-2005 Posted From: 71.111.184.211 Rating: N/A |
Thanks so much everyone here is a little insight to this old lady. Thhe chassis is 24V and the house is 12V, the chassis is charged by engine only, The house is charged by shore or by genset, genset is charged by genset only I think. I haave 2amp charge float on chassis and genset. I also have a 2K or 2500 inverter. Chassis 2 8D and house 6 6V Trogen. I think I will spend some time looking for the L16s, may have to go to large town. Thanks again Larry | ||
| Gary Pasternak (Cessna5354)
Registered Member Username: Cessna5354 Post Number: 26 Registered: 2-2007 Posted From: 152.163.100.13 Rating: N/A |
L & L, I have a (4) 8D AGM house set of batts, with a similiar load. I do have a Vanner equilizer which is connected to the coach batts. via a contactor( electro mech switch) That 200 A contactor was original equip. from the bus OTR A/C. As George and Jerry have posted, the coach alternator will more than adequately charge the house batts with 5 - 8 hours drivinng time. When I am traveling I rarely use the gen set due to this. You may have already made the decision to replace the batts, but may I suggest you look at the equilizer to charge OTR. BTW, the equilizer is utilized so as to "pull" 12V from the coach batts "equally" as the alt. chages @ 24V. If the coach batts were not exactly alike (and never will) the one with the lower internal resistance will take most of the load and fail. Best of luck, Gary | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1099 Registered: 5-2001 Posted From: 206.116.245.127 Rating: |
Larry, you already know that I don't see some things quite the same way as some of the other posters here. The reason that I said that you might get some value from adding batteries into a mixed system is that I have been doing it successfully for some time, but it is tricky. Two things I would add to what has already been said. One is that heating or cooling with electricity in a coach requires some care to balance the charging needs and loads on the batteries. If you don't have quite a bit of experience, you are going to be running a generator a lot. One of the reasons that this happens is that newcomers to living on DC power tend to see batteries the same as fuel tanks; if they get low, just fill them back up. The actual behavior of batteries is quite different than that. They will meet their specifications only if fully charged and discharged they way the maker tests them. But, that's not the way they are used. Instead, people use them until they are partially discharged and then find out that they will neither charge or discharge like they did when they were new and fully charged. This is true of deep cycle batteries, as well. They simply are not as easily damaged by deep discharges. If you can keep your batteries mostly fully charged, they will behave pretty well. If you can't, you will be very disappointed. To get there, go very heavy on battery capacity and recharging and metering and very light on your discharges. If you do that enough, you will get to the point that you can see what it will take to keep your system working right. Your golf cart batteries are only good for about 1.3 kwh until fully discharged and you're only going to want to use about 1/2 kwh each between recharges. This means that 4 golf carts are going to give you about 2 kwh between recharges, and a household refrigerator takes 10 per day if it is fairly efficient. The charging and discharging are going to have losses and the inverter is going to take 10% for sure, so you're looking at recharges every 3 hours. That won't work very well. Compare that to 3 ounces of propane replacing one golf cart battery; if you want to stay with a household refrigerator, you are going to need to figure out what you need for house batteries and charging sytem. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 177 Registered: 8-2006 Posted From: 207.231.81.59 Rating: N/A |
Hello again L & L, The difference between the voltage phase and the current phase of an AC circuit has been called "Power Factor" since Edison or somebody way back then figured it out. I am well aware of the characteristics of AC power, I am a licensed electrician, and what I end up doing is making the stuff the engineers design WORK. This wasn't constructive, the correction wasn't constructive, so lets move on! I asked you to check the charging voltage on your house batteries, with the engine running, suspecting that you had a charging failure between the chassis and the house batteries. I never thought that your coach wasn't equipped to do that. I also try very hard to explain the whole system simply, and I'm not "talking down" to anyone. I greatly appreciate Joe's sense of humor, obviously he GOT IT immediately. Since then, Tom has also gone to great lengths to make a CONSTRUCTIVE post! Please, read his whole post, slowly, and take it to heart. IMNSHO, he has explained the holy grail of storage batteries. I was going to do that here, I wouldn't have done it as well, now I don't have to. So, I am going to beat you up about your electrical system instead, sorry. Remembering the above, deep cycle batteries will only deep cycle a finite number of times, and each DEEP cycle reduces their capacity very slightly. The way I see it, your coach is set up so that you leave your 'house' after being plugged in all night, which MAY give you a full house charge, (more on that in a minute) and drive all day on the house batts and the inverter. That's one deep cycle. Some time in the afternoon, you start the gen, until you reach your destination, or get some charge, and incur another half cycle? Overnight, you're re-charged, fridge is cold, and you go again. Another DEEP cycle. The alternative is charging off the main alt, thru an equalizer, with an interlock to only allow charging while the main eng is running. The difference? At the end of the day, you arrive with FULLY charged batts, a cold fridge, and NO cycle. If you have shore, what you do next is obvious, if you don't, you have fully charged batts instead of flat ones. In other words, you will only incur cycles when boondocking. Remember the amp-hour math from the first post? If you buy 6 L16s at 420 Amp-hours each, you will have 1260 Amp-hours of theoretical 12V capacity. That means that it will take 12.6 HOURS to fully charge those flat batteries at a 100 AMP CHARGE RATE! How much DC does your inverter put out? The other little problem, is that batteries don't like being hit with a huge charge rate for a short time, the math is the same, but the reality isn't. A slower charge, at least for the last 20% or so is better, which is why many of the inverters have 3 charging stages. The bottom line of that is time, you won't actually get 1260 amp hours in 12.6 hours of charging, it will take longer. (Divide your present charging output into half of your total battery Amp-hour rating, that will give you a guess of minimum hours required for a "full" charge.) As you can see from my first post, I also agree with Tom on battery matching, as long as you keep the pairs matched, all will be well. George | ||
| Richard Bowyer (Drivingmisslazy)
Registered Member Username: Drivingmisslazy Post Number: 1916 Registered: 1-2001 Posted From: 75.108.87.165 Rating: N/A |
Well said George. And if someone really wants to charge the flat batteries at 100 amps until they are fully charged they had better have a good supply of water to keep adding and a big tub of ice to set them in to try and keep them cool. LOL Richard | ||
| Jerry Liebler (Jerry_liebler)
Registered Member Username: Jerry_liebler Post Number: 250 Registered: 3-2005 Posted From: 71.31.3.204 Rating: N/A |
L & L, Your goal should be to have enough house battery capacity so that you'll only use less than half of it between recharges. Using more than half of a battery's capacity significantly shortens it's life. Enabling charging while driving can reduce the needed capacity. Generally charging from the engine will take longer to top off the house battery because it isn't what is called 3 state charging. Most inverter chargers use 3 state charging so they top off charge much quicker. Regards Jerry 4107 1120 | ||
| Larry & Lynne Dixon (Larry_d)
Registered Member Username: Larry_d Post Number: 91 Registered: 7-2005 Posted From: 71.111.184.211 Rating: N/A |
George and all the explanations have helped my understanding a whole bunch. Have not had time to put meter on batteries yet. The inverter meter on the wall say 1145 and I am recharging again. My understanding is the 4905 should have had an equalizer on it, where mite it have been mounted. In the morning I will go out test under shore power and cut it off and test with engine running. Am sure I did this before but can't remember. I still haven't decided what I am going to do. I have printed all this off and maybe will have better insight with postings and system in hand. It is so nice to have everyone so helpfull and will keep you posted. larry | ||
| Glenn Williams (Glenn)
Registered Member Username: Glenn Post Number: 42 Registered: 6-2006 Posted From: 216.163.56.125 Rating: N/A |
Does anyone know what a factory installed equalizer may have been labled as in a 4905? I would love to know where it is on the bus so I could put it to better use. | ||
| captain ron (Captain_ron)
Registered Member Username: Captain_ron Post Number: 711 Registered: 1-2005 Posted From: 75.206.239.161 Rating: N/A |
I have been using six batteries that cliff gave me about 3 years ago. everybody on here said I was wasting my time. These batteries are now on their last legs but only because I didn't practice proper battery care. When first installed I could go for 4 1/2 days running a fridge, lights, computer, tv and occasional microwave use. Now I can only go a day and a half. I abused these batteries by running them completely down and charging them at 40 amps repeatedly. I would like to try and get them reconditioned and see if I can get another year out of them. | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1100 Registered: 5-2001 Posted From: 206.116.245.127 Rating: N/A |
Captain Ron, a desulfator is probably the only thing that has a chance of helping those batteries, now. A cheap choice on eBay is the Wizbang. If you're running 24 volts, you will want a minimum of two. Two would be good, even with 12 volts. I think that those run all the time. There are some designs that only run if the battery is up to around 13 volts, so that they shut off when there is no charge. We're running some pretty old batteries. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| David (Davidinwilmnc)
Registered Member Username: Davidinwilmnc Post Number: 168 Registered: 7-2005 Posted From: 152.20.216.103 Rating: N/A |
From above: This means that 4 golf carts are going to give you about 2 kwh between recharges, and a household refrigerator takes 10 per day if it is fairly efficient. The charging and discharging are going to have losses and the inverter is going to take 10% for sure, so you're looking at recharges every 3 hours. This seems way too short of a run time for the 'fridge. I've run a much smaller manual defrost refrigerator from an old and abused group 24 battery for over 24 hours. It was still running when I plugged it back into the hoouse outlet. I had the temp on 'max' and opened and closed the door quite a bit. Is my experience not 'typical'? David | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 594 Registered: 12-2000 Posted From: 205.142.19.91 Rating: N/A |
David, Here is our "real world" experience. We have eight 6 volt golf cart batteries feeding a Heaert Interface 2500 waqtt inverter/charger. Our refrigerator is a 15 cu. ft. house type, along with TV, lights, coffee maker, etc. When dry camping, we run our generator 2 hours in the morning and 2 hours around supper time. Our batteries never go below 12 volts. Just our experience, YMMV. Jack | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 149 Registered: 7-2006 Posted From: 4.240.214.81 Rating: N/A |
Tom...thanx for the heads up on the Wizbangs. I contacted the fellow...very responsive and also helpfu;. He says 2 units for three start batteries (group 31) and 5 house batteries. Says it will take abut 4 weeks for things to even out. Seems like $50 well invested. Thanx again. RCB | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1101 Registered: 5-2001 Posted From: 206.116.245.127 Rating: N/A |
David, I believe that you caught the best of two extremes. One is that the manual defrost refrigerators take much less power than typical self defrosting units. The other is "the refrigerator was still running" and it was not my example. The recharge period that I mentioned is what would be required to prevent the batteries from gradually becoming sulfated. If you run the batteries until they die on a single charge, you are looking at a lot more time. I was trying to point out the limitations of trying to do heating or cooling on batteries; they really don't like it and you need to do some optimizing to get away with it. I don't like running a generator unless I really have to. With 220 rated watts of solar panels, I can go a week without other power if I conserve. And then, I am only looking at two or three hours of generator time. I couldn't do that if I was heating or cooling with electricity. Jack's example is a good one. Before we had solar panels, we would run the generator morning and evening. What we found ourselves doing is that we would take the biggest draws of power when the generator was already running, so the batteries never saw those loads. If well managed, there is no reason that wouldn't work just fine. In any case, you wind up with a balance between needs and supplies. The most successful, I believe, are those that manage to get the batteries back up before piling on more loads. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska |
