jbenini
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Post by jbenini on Oct 19, 2017 8:10:45 GMT -8
Greetings all, working on a 1976 Shasta 1750 electrical system; I need to buy and install a battery, but I can't find anything that tells me how many amps I need. If the electric brakes run from the on board battery, I'm guessing I will need something large enough to handle the current draw when the brakes are applied? Any suggestions ? Thanks! JB
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Post by Ross on Oct 20, 2017 3:58:51 GMT -8
I am no expert or even know much about batteries, but the electric brakes, running and brake lights that are on your Shasta will pull from your tow vehicle, not the battery in your camper.
As for your 12V system inside the camper, how is it setup now? Is there a converter in place? Was there a specific place for a battery or two, built into the original camper layout from the factory? Sorry for the questions, but I don't know much about the later models of Shasta's.
Hopefully someone will jump in, who has a lot more battery knowledge.
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Ten
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Post by Ten on Oct 20, 2017 6:12:59 GMT -8
Control of the brakes does come from the tow vehicle. An onboard battery of some type is necessary for operating the emergency breakaway switch. You should find either a separate rechargeable battery for that, or a direct wiring to the storage battery from that switch.
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jbenini
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Post by jbenini on Oct 20, 2017 6:21:59 GMT -8
Hey Ross and Ten, the trailer has a Phillips 30 amp converter, the wiring has been damaged/hacked, looks like there might have been a battery box on the tongue at one time, but there's plenty of room for one under the seat next to the converter. What was left of the breakaway switch was dangling under the trailer (told you the wiring was a mess!) I guess I need to know how many amps I need to activate the brakes if there ever is a breakaway. My worry is I'll buy a rechargeable battery and it won't have the ooomph to do the job if it ever happens. Based on that, any ideas? Thanks!
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Post by Ross on Oct 20, 2017 10:02:17 GMT -8
This is a very good Break away system and very reasonably priced...at least to me it is: Hopkins Engager
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jbenini
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Post by jbenini on Oct 20, 2017 17:48:16 GMT -8
OK, this helps! So the breakaway system uses a small, 50 amp battery with it's own recharger...cool! so now I just need to figure out what size battery to hook up to the converter, because it has to have a battery connected to it in order for the DC part of the system to work properly. What do you guys use for total amperage? Is it all in one battery, or are you stringing a pair of 6 volt golf cart batteries together in series? JB
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Post by vikx on Oct 20, 2017 22:19:12 GMT -8
You will need a Deep Cycle battery, either series 24 or 27. 27s are a little larger and give a little more oomph but not a lot. Some trailers will support 2 batteries; if you'll be off grid a lot, twins and solar are a consideration.
Also, Ross' system above is great for the break away if you don't want to buy a battery(s) right now. The little batteries don't last forever but would give you a year or two to decide.
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cowcharge
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Post by cowcharge on Oct 23, 2017 8:29:53 GMT -8
"House" battery size is determined by your planned electrical usage between charges. You need to add up all the loads and run times for everything you'll use between charges to get an accurate assessment.
Example: 3 12v light bulbs. They draw about 2 amps each. If you want to run them all for 6 hours every night, that will take: 2a x 3 bulbs x 6 hrs = 36 amp-hours per day.
Propane hot-air furnace. I have a '76 Shasta 2250, its Suburban 22k btu furnace draws 4 amps at a duty cycle of about 50% in a Maine winter. That makes, for calculation purposes, a constant 2-amp draw (.5 duty cycle x 4 amps = 2 amps constant). Running day and night, that makes for 48 amp-hours per day (2amps x 24 hrs = 48 amp-hours).
So to run lights and furnace (in Maine, at least), you'd need 84 amp-hours of usable capacity. For long battery life, you should avoid discharging it below 50%. So for lights and furnace, you'd need a battery with 168 amp-hours of capacity to make it one day without charging.
That means that neither a single Group 24 or Group 27 battery would be big enough. It adds up quickly. A 90 amp-hour Group 27 battery would run just those three light bulbs for a day with only an extra 9 amp-hours to run anything else (.5 discharge x 90 ah - 36 amp-hours for lights = 9 amp-hours).
Every appliance is supposed to have either amp or wattage requirements on its data plate, but those are usually higher than they actually use, so it's more accurate, and probably will save some money on buying batteries, if you actually measure their draw with a ammeter.
If you plan to run any 110v stuff through an inverter, every AC amp drawn by the appliance will take 10 amps DC out of the batteries, so make sure you don't forget to multiply the AC draw on the fridge label by ten when calculating your battery capacity.
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jbenini
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Post by jbenini on Oct 24, 2017 8:15:00 GMT -8
Wow, that's great information cowcharge, thanks! I did just buy a series 24 battery rated at 550 cca, but at this point I'm not planning on camping off-grid, so plugged in the converter should keep things charged....assuming it's working properly. It seems to be, but the wiring is a mess (PO touched it with tools) so it's too soon to tell if the charging circuit is working. Once I get the battery installed (need to get a box for it) I'll know for certain. Replaced all the 12v lamps with warm-white LEDs, less draw and slightly brighter than the originals.You own a '76? Any idea where I could find a stone guard and front eyebrow for my '76 1750? Let me know, thanks!
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cowcharge
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Post by cowcharge on Oct 24, 2017 17:19:19 GMT -8
Yup, I have a '76, same orange stripe, but mine has dual axles. Does yours have the lovely brown and yellow plaid cushions and the babysh- I mean Harvest Gold tub and sink?
No idea where to find a rock guard, mine was still there so I haven't had to look.
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jbenini
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Post by jbenini on Oct 27, 2017 13:06:28 GMT -8
I have the harvest gold toilet and shower base, and the cushions that I think are original are green and gold stripes. The dinette cushions have been recovered in a red white and blue nautical theme. That project will probably happen over the winter. I started digging into the DC side of the electrical this afternoon; I have the PC-401-A-1 power converter/battery charger, found a wiring diagram for it on line, and found some suprises in the trailer: the three heavy wires coming out were red, white and black, not red, blue and white as labeled on the diagram. The white is definitely trailer ground, the red looks like it went to the battery (everything is ripped apart, like with a chain saw by the PO) and so does the black. Is the black wire the supply for the trailer load like interior lights, range hood fan, etc.? There are also four other wires not shown on the diagram, all smaller gauge than the "big three", two blue wires, a yellow and a black. I'm guessing these are DC supplies as well, but I have no idea where they go or what they are for. Can you shed any light on this mess?
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jbenini
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Post by jbenini on Oct 27, 2017 18:36:14 GMT -8
I discovered the front of my converter op ens, which allowed me to figure out most of what I needed to know, like the fact that it's not a 401, it's a 201, and that the red and white wires go to the battery, the heavy black wire has no fuse connecting it to the battery input so there's no "pure" DC going out (not hooked up to anything anyway, PO cut it for some reason) Still wondering where the two blue, the yellow and the black wires go, guess I'll have to start pulling apart things and look for those colors!
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Ten
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Post by Ten on Oct 27, 2017 18:53:50 GMT -8
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jbenini
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Post by jbenini on Oct 28, 2017 9:14:38 GMT -8
Thanks, that helps! Now, if I could just find a wiring diagram naming which wires go to the interior DC stuff, water pump, range fan, etc.!
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m
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Post by m on Apr 21, 2019 6:16:26 GMT -8
Yup, I have a '76, same orange stripe, but mine has dual axles. Does yours have the lovely brown and yellow plaid cushions and the babysh- I mean Harvest Gold tub and sink? No idea where to find a rock guard, mine was still there so I haven't had to look. Greetings, I’ve got the 2 dual axle 1976 model with the plaid cushions and harvest gold tub and sink! The bathroom walls have an almost wallpaper like pattern. I’ve owned it for 2 days! It’s got original bedroom window stripped orange and white awning but no awning along the front. I’m researching wings for that model. I see the holes where they were installed. Does yours have awning and wings? Would love to see a photo. Also, my previous owner painted the interior except for the bathroom. Do you have a shot of the wood look? We’re just trouble shooting the dc now, there are two grounds, one to the chassis...
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