Extra batteries January 27, 2005, 09:52:02 pm Yahoo Message Number: 49978Hope I do not sound DUMB but I do not have the skills of Bumper. Anyway, I am wondering if extra batteries could not be mounted on the rear bumper? Trailers carry batteries outside on the tongue in battery boxes and could this sort of arrangement work with the LD's? Wiring length might become an issue but heavier gauge could handle that. Any chance of such a hook up working??? I am not an LD owner so do not know where the present batteries are located. It would be best to keep them close together but I doubt if very many individuals could do what Bumper has accomplished.
Extra batteries Reply #1 – January 27, 2005, 10:52:34 pm Yahoo Message Number: 49980QuoteHope I do not sound DUMB but I do not have the skills of Bumper. Anyway, QuoteI am wondering if extra batteries could not be mounted on the rear bumper? Not dumb at all.Remember the Pinto? The gas tank would rupture on even a relatively mild rear end collision. Batteries may not be quite as dangerous as spilt fuel in an accident, but they do provide a ready source of ignition if the terminals or wires (before the fuse) get shorted. Aside from the increased risk in a rear ender, The wire length would be an issue, although this could be mitigated with heavier wire as you suggest. Still, if running a larger inverter with current demand of say 150 amps while running heavy loads like a microwave, the logistics of heavy enough wiring becomes an issue.From a handling standpoint, the very back of the coach is not the best spot to be adding a lot extra weight. I'm sure it could handle it though, but it would probably subtract some from the allowable hitch loading.Before I'd go with the rear bumper location, and assuming one did not want to build or go with a frame mount rack, then perhaps using an outside compartment would do? The MB has an excellent one just below the original battery compartment. I would maybe reinforce it some, add a plywood floor to further distribute the load, and add vents.all the best,bumper
Extra batteries Reply #2 – January 28, 2005, 01:20:48 am Yahoo Message Number: 49981QuoteHope I do not sound DUMB but I do not have the skills of Bumper. Anyway, QuoteI am wondering if extra batteries could not be mounted on the rear bumper? Trailers carry batteries outside on the tongue in battery Ours is an older model that was equipped only with one coach battery - a 12V group 27 mounted under the hood. I added an extra one on the rear bumper, and it has worked well there. Of course, the wiring must be pristine and extra-heavy gauge to avoid voltage drops. Extra care must be paid to ground wiring as well - run cables from the batteries to the main frame rails. Additionally, anytime there is more than a few inches separation between parallel-connected battery positives, close fusing is required at BOTH ends.There are some downsides, such as vulnerability to damage in a collision, but I don't consider that a likely safety issue. More significant is the exposure to a different environment than the other battery (bank). This will cause voltage and charge differentials between the batteries, as well as different aging factors. It is particularly important to keep an eye on the condition of all the batteries for these reasons. Still, this arrangement has worked well for ~11 yrs now.Steve
Extra batteries Reply #3 – January 28, 2005, 08:10:03 am Yahoo Message Number: 49984That is the exact location one should use on a MB. Adding a frame or support reinforcement and ventilation would be relatively easy. Any competent RV shop can do that
Extra batteries-Rear bumper Reply #4 – January 28, 2005, 02:49:01 pm Yahoo Message Number: 50016"More significant is the exposure to a different environment than the other battery (bank). This will cause voltage and charge differentials between the batteries, as well as different aging factors. " This a good reason for installing all the batteries in the same place rather than splitting them up. Having two batteries mounted under the frame or on the rear bumper, while the original battery(s) still resides in the battery box, exposes the batteries to different operating environments. In cold weather, the Factory battery box will remain much warmer than the batteries mounted outside. The Factory battery box is exposed to the interior temperature since the wall between the battery box and the interior is not insulated, there is just a thin piece of sheet metal and the 1/8" interior paneling separating the box from the interior.Another solution is to split the one battery pack into two separate batteries, using a battery switch and adding another battery isolator. It is easier to mount all the batteries in one place, if space is available. On the newer Fords, there is plenty of space under the floor. On the older LDs, like Steve's, space is very limited. Our 1983 FL had a single series 27 battery that was much too small. I built a new battery box behind the front barrel chair so I could use two T-105s. The box was sealed and vented to the outside.Larry
Extra batteries-Rear bumper Reply #5 – January 28, 2005, 09:26:52 pm Yahoo Message Number: 50046Quote"More significant is the exposure to a different environment than the other battery (bank). This will cause voltage and charge differentials between the batteries, as well as different aging factors. "This a good reason for installing all the batteries in the same place rather than splitting them up. Having two batteries mounted under the frame or on the rear bumper, while the original battery(s) still resides in the battery box, exposes the batteries to different operating environments. In cold weather, the Factory battery box will remain much warmer than the batteries mounted outside. The Factory battery box is exposed to the interior temperature since the wall between the battery box and the interior is not insulated, there is just a thin piece of sheet metal and the 1/8" interior paneling separating the box from the interior.Another solution is to split the one battery pack into two separate batteries, using a battery switch and adding another battery isolator. QuoteIt is easier to mount all the batteries in one place, if space is available. On the newer Fords, there is plenty of space under the floor. On the older LDs, like Steve's, space is very limited. Our 1983 FL had a single series 27 battery that was much too small. I Quotebuilt a new battery box behind the front barrel chair so I could use two T-105s. The box was sealed and vented to the outside.Larry Larry, I agree it would be easier to have all the batteries together - - if there was room. And, if that spot was located close to where the large inverter/charger is installed (in my case a Prosine 2.0). I don't think there is any such spot in the '05 MB.Okay, lets look at the issues of separate battery banks. I have the banks connected with 4 gauge welding cable with a wire run of less than 6 feet. At any reasonably low current flow there is essentially no meaningful voltage drop in the wire. This would not be the case when running the microwave on the inverter, but even then, voltage drop on the this length of 4 ga is insignificant. When the current draw drops to lower levels, the battery banks will "equalize" (not the same as an equalization charge of course).On the temperature issue: The LD battery box is well vented to the outside with louvers cut in the door. I suspect that any "heat" that makes it through the cabinetry and ABS box (and I agree there will be some) will quickly be lost through the louvered door. In other words, unless the batteries are working hard, being charged or discharged and thus raising their internal temperature, I suspect the battery box will be close to ambient temperature. The Blue Sea marine battery box I used is just as substantial as the LD box, and has way less vent area. I see no reason for the battery temperatures to be much different. In fact, I am only planning to monitor the temperature of the original LD bank. (I will, however, check both in different environmental conditions to validate or disprove my assumptions.)It would be good if LD made the battery box large enough to hold 4 105's. There's room to do it, no question. I don't think they have the customer demand though, as mostly it would appeal to boondockers and those who rarely connect to shore power. The 2 Trojans LD installs are better than what most similar sized SOBs get.all the best,bumper
Extra batteries-Rear bumper Reply #6 – January 28, 2005, 11:50:36 pm Yahoo Message Number: 50061"I don't think there is any such spot in the '05 MB. The Blue Sea marine battery box I used is just as substantial as the LD box, and has way less vent area. I see no reason for the battery temperatures to be much different. In fact, I am only planning to monitor the temperature of the original LD bank. (I will, however, check both in different environmental conditions to validate or disprove my assumptions.) I suspect the battery box will be close to ambient temperature."Bumper Trust me, I know that every project is subjected to many compromises. Your two-battery tray will work fine. Battery life may or may not be slightly shorter but so what. Ideally all the batteries should be changed at the same time but sometime this just isn't practical. I will probably hold off and get some more use out of our two-year batteries before adding two more. If the cost difference isn't too high, the two T-105s will be replaces with four T-145s.It would be interesting to install thermometers in both battery locations, to see what differences occur. I think you will see a difference in very cold weather, as long as the interior is heated to a comfortable level. I can feel the cold coming off the interior table on cold evenings. This cooling effect is warming the batteries, how much, who knows? The other time there will be a great difference will be while driving in the summer. The frame-mounted battery is subjected to road heat and to whatever heat radiates off the MH's exhaust. Since a battery's maximum charging voltage decreases as its temperature rises, I wonder if frame-mounted batteries will overcharge on long drives in the summer. You may need to add water a little more often. If I move the battery pack to the frame, the charger's temperature sensor will be move to the new, frame location.Doubling the size of the battery pack has an advantage that many do not know about. The bigger battery allows the battery charger, engine alternator, converter or a inverter, to charge at a high rate for a much longer period of time before the charge rate tapers off; thus enabling shorter generator run time over the long term. Another reason why I would like to have the battery frame mounted is to free up the original battery box. The 23.5's have a small, 8-gallon propane tank, half of what the 26.5's have. With a little reconfiguration, I can store an additional 20 lb propane can in that space. Our 1983 FL had its propane can located in the same location. Using a `extend-a-stay, will enable us to delay refueling in the winter. We can easily carry the 20 LB can in the toad to get refilled if we do not want to move the LD.Larry
Extra batteries-Rear bumper Reply #7 – January 29, 2005, 01:03:33 am Yahoo Message Number: 50066Quote Trust me, I know that every project is subjected to many compromises. QuoteYour two-battery tray will work fine. Battery life may or may not be slightly shorter but so what. Assuming they are not abused, the longevity of lead-acid batteries is based in part on the depth and number of discharge cycles. Deeper discharge cycles, more than 50% of capacity, shorten lifespan. One advantage of more amp hour capacity is not having to run the batteries down so far. Of course the resultant longer battery life is partially offset by having to replace more batteries when the time comes.bumper
Re: [Life With A Lazy Daze RV] Re:Extra batteries-Rear bumper Reply #8 – January 29, 2005, 02:44:56 pm Yahoo Message Number: 50106In a couple of other brands, I've seen the batteries installed in the space under the floor at the entry step. There was a hinged 'trap door' that gave access to the batteries. In our coach, the 26' RB, this would be very close to the coach batteries. I haven't looked under there to see if there's space. Whadda ya think?Sarah Back in Quartzsite - going to try to find the SKP Boondockers at N 33 45.518 W 114 11.005
[Life With A Lazy Daze RV] Re:Extra batteries-Rear bumper Reply #9 – January 29, 2005, 08:41:49 pm Yahoo Message Number: 50122QuoteIn a couple of other brands, I've seen the batteries installed in the space under the floor at the entry step. There was a hinged 'trap door' Quotethat gave access to the batteries. In our coach, the 26' RB, this would be very close to the coach batteries. I haven't looked under there to see if there's space. Whadda ya think? The SOBs are probably basement models, and that's how they get the room under the step. My friend with the Minnie Winnie has them there. No room under, behind, or near the step on a MB LD.bumper
Topic: Extra batteries (Read 2 times)
previous topic - next topic
Topic: Extra batteries (Read 2 times)
previous topic - next topic