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Thread ID: 58621	2005-06-06 11:06:00	An electrical problem for my new home :D	personthingy (1670)	PC World Chat

Post ID	Timestamp	Content	User
361696	2005-06-06 11:06:00	I've not that long ago bought a cute wee 3½ ton twuck. I plan to not only use it for work lugging my favourate toys about, but also fit it out as a simple mobile home. :thumbs: Being the size of vehicle it is, the electrics are predictably a 24volt system with 2 batterys, which is fine for the truck it self, but seeing 24V triples the cost of audio systems, little flouresant lights, and all the other nice bits, i figure it might be simpler to have a third battery for the "house" and the cab accessorys, in short, a dual voltage system. Not everywhere i park will be able to supply 230volt power, so a 12 volt system is essentual. So what i need is some device that allows the 12 volt system to be run and charged while the engine is running. Something that takes the 24+volts, and produces the 13½ volts needed to charge the third battery. Part of the logic for the third battery is the fact that it will basicly be provided by charity from people who find a battery that only holds a charge for less than a month substandard, plus if i drain battery 3, i can still start the twuck itself. I'm open to other ideas, but hope someone can either tell me where i can get a suitable voltage reduction device, or how to make one. Also i'd like to be a bit more efficiant and precise than a resister and a diode :p .	personthingy (1670)
361697	2005-06-06 11:16:00	24V DC to 12V (13.8v) DC Converter, 20 amp continuous. www.dse.co.nz $137.31 trade. $143 retail	godfather (25)
361698	2005-06-06 13:06:00	Get a 12volt alternator as well and run it to the "house" system. Two totally seperate systems.	|llus|oN (645)
361699	2005-06-06 22:27:00	Get a 12volt alternator as well and run it to the "house" system. Two totally seperate systems.That was my first thought, then i lifted up the seat and had a look at how much room there was and what i could bolt alternator #2 to. :eek: That was the end of that idea! Thankyou Godfather. That looks just the ticket! :thumbs:	personthingy (1670)
361700	2005-06-07 20:43:00	Not all that familiar with the 24V systems, but what I have seen seems to be 2 x 12V batteries are used in series to provide 24V. Why not tap your 12V off 1 battery, connect to the positive pole on the battery closest to the negative earth connection, that way you can still use the chassis as the common ground for your 12V wiring. Alternatively you could try connection the 3rd battery in parallel with the same battery, with a fat switch (or relay controlled switch) on one cable to isolate it from the main battery when the engine isn't running to charge it.	BoboTheClown (5652)
361701	2005-06-07 23:00:00	Not all that familiar with the 24V systems, but what I have seen seems to be 2 x 12V batteries are used in series to provide 24V. Why not tap your 12V off 1 battery, connect to the positive pole on the battery closest to the negative earth connection, that way you can still use the chassis as the common ground for your 12V wiring. Alternatively you could try connection the 3rd battery in parallel with the same battery, with a fat switch (or relay controlled switch) on one cable to isolate it from the main battery when the engine isn't running to charge it. the problem with tapping just one battery to get 12v is it stuffs up the charging system, exspecially with high drain devices.	tweak'e (69)
361702	2005-06-07 23:36:00	the problem with tapping just one battery to get 12v is it stuffs up the charging system, exspecially with high drain devices.What do i expect to run? Baby pairs or flouo lites, one each end of the main bed, 2 over the bench, 1 or 2 in the main areas, (mainly for loading purposes when i/we pack up the gig and leave), possably one over a mirror, as this is in my friends truck that we used to use, and she found it very usefull when using the truck as a dressing room before playing. Maybe one little bank of colored LEDs as nite lights if sleeping a whole crew. Total Load = 7 pairs of flouros +LEDs + the little light that stays on by the RH brake lite. Also 1 x flaptop 1 x Amplifier brick (2 nice speakers with any spare subs from concert PA) Chargers for cellphone(s) Water pump for sink Other things i haven't thought of yet :D Duration of Load = Probably over night, but could be till the 2nd battery runs out.. I expect to go through a few, but they will be the last use of ones to sick for cars. Even if there wasn't problems with imbalance, i think the chances of getting the elgrunto diezil motor going again after draining the chassis-12v battery would be low. A seperate house battery is required. My friends smaller 12V truck used the same battery for all functions, and sometimes had to be jump started after being used as a camper overnight. I'm quite happy to learn from her mistakes without repeating them :p I dont want a dead battery in the morning, particually with a 24V vehicle.	personthingy (1670)
361703	2005-06-08 06:03:00	Chris, wander into the Public Library and look at the boat electrics, and alternative energy, solar energy, books . This is all standard stuff . You definitely need a "house battery" . But just any battery won't do . Unfortunately, your "overnight" loads are going to be a problem . A standard automotive battery won't live long if you run fluorescents, a laptop, a water pump . . . for hours . It's designed to supply perhaps 5Ah in 5 seconds to start the motor . The alternator supplies the loads . A few fluorescents, a laptop, etc will kill a battery in a few hours . An amplifier (how many watts?) will make things worse . You need a deep cycle battery . A "charity" battery which is already "dead" won't hack it . Deep cycle batteries can tolerate discharge to 10 or 11 volts repeatedly . Automotive batteries are not designed to do that . They are designed for very shallow cycling . The killer thing is that watts are volts*amps . If you use 1 amp at 230V ac (through an inverter), you are pulling about 20 A at 12 volts . A 40 Ah (e . g . ) battery can't provide 20 A for 2 hours . It will, if fully charged (a rare event), supply 2A for 20 hours . Mostly you are lucky to have more than 40% of the rated Ah of a battery available .	Graham L (2)
361704	2005-06-08 06:30:00	Unfortunately, your "overnight" loads are going to be a problem. A standard automotive battery won't live long if you run fluorescents, a laptop, a water pump ... for hours.The water pump, if i get one would only be for when i want water at sink, but apart from that, and the possable audio gear, what i'm doing is pretty much modelled on my friends truck, which she has had for years. :D So far, the only time shes drained her battery to the point where she can't start her engine has been when kids have left a light on overnight. She gets over 2 years life from each battery. I of course will be running a seperate "house" battery. I can only try it, and if the charity batterys dont hack it, then i'll get a deep cycle one. I should point out that i do expect to be conservative with the use of electrical items in the truck, and that i'll only be running 230v lights all night, but be taking it easy when off the mains, and under no circumstances will i be providing 230v power via an inverter for anything!	personthingy (1670)
361705	2005-06-09 03:11:00	I have heard of a seperate alternator being driven from the driveshaft, should be plenty of room under the deck somewhere for it.	rmcb (164)
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