| Author | Message | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 491 Registered: 11-2008 Posted From: 66.87.1.215  Rating: N/A |
Somewhere in my travels, I picked up a 24v to 12v stepdown converter. Forgot I had it until I finally emptied a bay (to figure out my Vanner) and have no idea why I got it (must have had something in mind but darned if I can remember what?). The unit's brand new, so trying to figure a good use for it. Wondering if I could change my (4) Trojan batts from 12v to 24v and run household through the converter? Then (maybe) I could charge both household and start batts with the engine alternator (or is it generator?). I am SUCH a klutz when it comes to electronics! Any advice greatly appreciated. Nellie Wilson | ||
| Jim Sanders (Sandy)
Registered Member Username: Sandy Post Number: 11 Registered: 1-2011 Posted From: 69.199.96.250  Rating: N/A |
nellie I am not sure what you are trying to do? Is your bus 24 or 12 volts? The best? way to charge all batteries when you are driving(12 volt alternator)Use isolators. dozen different ones made | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 1190 Registered: 3-2007 Posted From: 71.55.4.4  Rating: N/A |
Nellie, I believe your coach is set up for 24 volts. The step-down can be used for lights,electronics,and anything you need for 12-volts. I wired clearance light with mine and radios,interior lighting, bay lights and etc. 24 volt bulbs are sometimes hard to find let alone pricey,so having 12 volt stuff is easier to find too. My Thoughts Gomer | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 493 Registered: 11-2008 Posted From: 66.87.1.198 Rating: N/A |
Thanks for info guys! Jim, sorry I wasn't as clear as I should have been. As Gomer mentions, my bus is 24v with OEM (24v) generator. But (also like Gomer) my interior stuff is 12v. All works fine off my g.c. batts which are presently wired for 12v. Trouble is, I don't want the hassle and expense of installing a 2nd (12v) generator.. would rather use the existing gen. to charge everything (which is why I'm thinking of rewiring house batts for 24v and using the converter). But would I need an 'isolator' for that too? Gomer, love your idea of running clearance & bay lights on 12v. Big job? Would I need to completely rewire or just splice in appropriate pigtails and sockets? Like I said, I'm the original electronic klutz - got to either go to school or get a tutor! Thanks to both of you... Nellie | ||
| Bruce Henderson (Oonrahnjay)
Registered Member Username: Oonrahnjay Post Number: 673 Registered: 8-2004 Posted From: 98.233.187.50  Rating: N/A |
Nellie, a couple of thoughts (which aren't complete but may help). You have a 24V generator and your batteries are set up for 24V. You have a couple of "quick options"; you can use your converter to pull 12V off your system. But unless you have (or install) a way to separate a set of "house batteries" from the "start batteries", you may run into a situation where you drain the batteries with the 12V items. So, one way to go would be to set up separate systems; you'd charge your start batteries off the 24V generator (or alternator, not that it really makes much difference) and use excess charging capacity to charge a separate set of house batteries with a properly setup isolator. Then you could pull your 12V off the house batteries with the converter: if you're running down the road, you will always be charging your house batteries and you can use that power to run your 12V items. But this way, you'll never discharge your start batteries by using your 12V electrical loads when the engine isn't running (and making 24V through the generator). Or, do you already have a separate house battery system? Do you have an inverter for DC (direct current from the bus generator) to 120 AC? Tell us more about what you already have and how it's set up. | ||
| Derrick Thomas (Thomasinnv)
Registered Member Username: Thomasinnv Post Number: 9 Registered: 10-2010 Posted From: 69.19.14.17 Rating: N/A |
I'll probably get slapped for this, but you could use the vanner to charge the house batteries while under way, and just run your 12v stuff (chassis and house both) off the house bank. very simple setup and serves multiple purposes. I used the existing a/c solenoid (rewired to the master switch) for the 24v side of the vanner. that way when the bus engine is off the 24v and 12v systems are isolated. Has worked fine for me for months, and i got the idea from another busnut who has used this method for years with no problems or issues. | ||
| Bruce Henderson (Oonrahnjay)
Registered Member Username: Oonrahnjay Post Number: 674 Registered: 8-2004 Posted From: 208.84.199.36 Rating: N/A |
Derrick, if the 12V loads are things that are only used "on the road", that would work great. (I.e., any time you're using 12V, you're also making 12V through the Vanner as the engine is generating 24V.) | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 497 Registered: 11-2008 Posted From: 66.87.0.60 Rating: N/A |
Geez Louise... See what I mean? You guys are talking quantum physics while I'm stiil learning trig. Think I'll hit Dal's Tejas rendevous and get some good ol' greasy hands around this mess. BTW, I'm not ignoring Bruce's question... "Tell us more about what you already have and how it's set up." Just too tired (and happy!) right now - Packers won and Steelers won! Obama, Emanuel, Bloomberg and Schumer bit the dust... all in one glorious afternoon! (But then again, what's new about that  ) Anyway, looks like I've got all the gear... just no knowledge. Nellie | ||
| Derrick Thomas (Thomasinnv)
Registered Member Username: Thomasinnv Post Number: 10 Registered: 10-2010 Posted From: 66.82.9.80 Rating: N/A |
Bruce, it really doesn't matter if the 12v loads are over the road usage or not, there is always 12v available whether the engine is running or not. the house bank is connected to the 12v side of the vanner so there is always 12v available. I have a combination of 12v loads. some are otr such as a few guages, towing relays etc. and some that are not otr such as 12v plugs in the cockpit and elsewhere. by utilizing a solenoid in the 24v side, the chassis batteries cannot be discharged when the engine is not running. | ||
| Bruce Henderson (Oonrahnjay)
Registered Member Username: Oonrahnjay Post Number: 676 Registered: 8-2004 Posted From: 208.84.199.36 Rating: N/A |
Yes, Derrick, that's right. What I meant to say (and didn't say clearly) was that the 12V batteries could get discharged even if the 24's don't. But it's a good setup -- even if the 12's are run down, you can still start the engine to charge them up again and that's the advantage of the isolated 24's. | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 1434 Registered: 10-2006 Posted From: 64.241.37.140  Rating: N/A |
The system (24 coach charging 12V house)will work fine on the road, BUT the real question is how much 12V battery will you need while camping . If you plug in all the time darn little is needed , but if you boondock with a DC fridge or propane furnace you will need a big batt pile. Our solution was 24V starts , with a solenoid to charge 4 -6V deep cycle batts for 24V as the house supply. The Vannier takes 2 of the house batt set and alternates between them to give 12V as needed. Couldn't figure our a simpler way , tho the purists will complain the Vanner is only 90% efficient , but my Sat car radio with 10% more juice is still not a biggy. FF (Message edited by FAST FRED on January 25, 2011) | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 500 Registered: 11-2008 Posted From: 66.87.2.115 Rating: N/A |
So, Fred, you run 24v household? "...with a solenoid to charge 4 -6V deep cycle batts for 24V as the house supply." Or do I misunderstand? Going to Bruce's question, I have: 1) 24v start system (typical MCI OEM setup); 2) 4 X 6v Trojan g.c batts. Presently, I'm using only two (wired in series), the other two (also connected in series) aren't yet online (call them 'backups'). Presently, I can only charge household batts from a batt charger, so I'm reliant on AC power. 3) My household lights are 12v, the appliances are 120v AC (except for RV type 3-way fridge); 4) a 24v-12v stepdown converter (see first post). 5) I also have: A Vanner; An AC to 12v converter; A tiny inverter (1000 watts; A little (2 amp) trickle charger. Neither the Vanner nor the 12v converter are presently hooked up. I do NOT have an onboard generator - still trying to find one I can afford. In the meantime, need to charge my household batts (when not plugged in) with my engine alternator. Considering what I have, what's the best (easiest?) way to do this? I'd like to avoid adding a 2nd (12v) alternator... I don't have the tools (or know-how) for that. But I'd love to be more independent and able to boondock awhile. Thanks again for your infinite patience. Nellie (Message edited by vivianellie on January 26, 2011) | ||
| Len Silva (Lsilva)
Registered Member Username: Lsilva Post Number: 433 Registered: 12-2000 Posted From: 72.187.35.208  Rating: N/A |
We are missing a critical piece of information, and that is how big your DC-DC converter is. My guess is that it is probably quite small, less than 10 amps at 12 volts, thus only good for a few lights or maybe a radio. | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1975 Registered: 12-2000 Posted From: 174.89.174.161  Rating: N/A |
My bias is the same as FF. House bank voltage matches the start bank. Use the Vanner equalizer on the house bank so you can use the existing 12 volt equipment. Two inexpensive regular battery chargers can be hooked up to each of the pairs of Trojans to charge until you need a more elegant 24 volt solution. Down the road, the big alternator takes care of both banks. Sell or horse trade the unused equipment to get the pieces you need. happy coaching! buswarrior | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 1436 Registered: 10-2006 Posted From: 64.241.37.140 Rating: N/A |
The house is 12V as most Vanniers were made to operate a 12V bus system and are usually 50A or so. Mine came from the DD Series 50 donor transit bus. It operated all the lights etc, even the big draw of a Hyd power pack for the handicap lift. The old FLX is 12v so all origional and camping systems are simply 12V output of the Vannier.. FF | ||
| Tom Phillips (Fortyniner)
Registered Member Username: Fortyniner Post Number: 36 Registered: 2-2010 Posted From: 66.93.216.253 Rating: N/A |
I know it takes quite a while to top off deep cycle batteries. I was planning on wiring the generator to the 24v house batteries and feeding the starts from a solid state isolator. The small isolator voltage drop would help prevent over charging the starts. A 24v inverter connects to house batts directly and a vanner supplies smaller 12v accessories. BTW. the pinball suppliers use lots of 24v bulbs and are super reasonable. -Tom P. |