| Author | Message | ||
| JackInKC (24.166.167.152) Rating: |
Can anyone tell me if it is possible to hook up two alternators in parallel? When I bought my bus it had an alternator for the coach batteries and an alternator for the engine batteries. I want to use a big battery isolator and some 4-0 cable so I can run a roof air off of the alternator and my inverter. It seems like the challenge would be getting the regulator to tell the alternator(s) when to work hard. Could I use one regulator for both alternators? If I use two regulators it seems like the charge from one alternator would confuse the second alternator. Any other problems, advice, or suggestions? Thanks in advance to all for help. JackInKC | ||
| Stan (216.95.238.97) Rating: N/A |
The regulator only tells the alternator what voltage to put out. With two in parallel the one set for the higher voltage will do most of the work. No current will be drawn from the lower set alternator until the battery voltage is below that set point. Under heavy load the alternator set for the higher voltage will run at maximum load continuously and the other one will only start to work when the first one can't keep up. This may be an acceptable situation but the first alternator better be a super good one. | ||
| Stephen Gutknecht (Roundsparrow) (66.174.34.123)
Rating: N/A |
I believe there are ways to link the two alternators together so you don't have voltage regulation problems. Just like some inverters can be linked together for similar reasons. Some Bluebird Wanderlodge (1992 and later?) have Detroit Diesel engines with dual alternators... so you could run roof electric AC off engine while driving. I suggest posting on the http://www.wanderlodge.org/ mailing list (Yahoo Groups) and seeing if someone can tell you what brand alternator/hookup they used. It could just be that you have two banks of batteries and charge each with an alternator. Not a bad idea in a solar install. | ||
| Johnny (67.241.166.117)
Rating: N/A |
Well, I know it's possible--since the F-550 at work has factory dual alternators. As to how...no idea...but a late-model Ford Super Duty is a good place to start. try www.thedieselstop.com for info. | ||
| Stan (216.95.238.99) Rating: N/A |
I did a search on the dieselstop site but didn't learn anything about their dual alternator system other than that they have one. Probably 30% of bus conversions use a dual alternator sytem. They use one alternator to charge engine batteries and one alternator to charge house bateries. This is very simple and quite foolproof. To tie two alternators to the same battery is entirely different. It is technically possible with eltronics and custom built equipment but that is usually not practical for a bus conversion. On the dieselstop site I found a reference to Fault code P1108 as it relates to dual alternator warning lamps so I assume they have extensive electronics in their system. In fact, I can't find Ford's reason for dual alternators. The alternator is a very reliable device and is readily available is sizes up to several hundreds of amperes, so what is the purpose of having two? | ||
| Johnny (67.241.232.34)
Rating: N/A |
I don't know why Ford has 2 alternators--except maybe so they'll onlyy need one part number? Ask on the TDS boards--there are plenty of experts there among the regulars. I'm no expert, but I'm Johnny96 there.  Please say hi. WHD507 has several converted buses, in fact. | ||
| Greg (207.174.177.204) Rating: N/A |
If you use alternators that have external regulators (ie, a regulator that mounts on the bulkhead, rather than an internal/independent regulator in each alternator), you might be able to connect the field winding circuit of the alternators in parallel. Use identical alternators, along with the recommended voltage regulator. DC doesn't have a phase like AC, so the two alternators simply feed into the same stream. I'd suggest you consult with someone that specializes in automotive electrical systems, and see what they know. What you are trying to do might be a recipe for disaster. Here's how it might work well: The single regulator would tell both alternators to operate at the same time. If a big load is put on the battery pack, the regulator runs the alternators at a high charge rate. Once the load drops off, the regulator backs off the charge rate. It would be like one big alternator working instead of two smaller alternators. You might also investigate a single wire alternator (just one wire between the alternaltor and the rest of the electrical system). They might be set up in such a way that two can work in parallel. They are often used in marine applications, and I've seen a few on off-road jeeps and trucks, as they have a reputation for being very reliable. Now, all this begs the question WHY would you want to use two alternators to charge the same battery pack? There are a multitude of good, heavy duty, high amperage alternators (both 12v and 24v) out there that should last as long as you own your rig. Two inexpensive units kluged together are probably less reliable (and maybe just as expensive) than one good unit. Let us know what you find out. Greg (no bus, yet...) | ||
| Darryl (68.184.122.103) Rating: N/A |
Jack, you didn't mention what bus you have, so I don't know what voltage you're wanting the output to be. However, if it's 24 volt you might consider the setup that the military CUCV (military blazer) has. It has two 100 amp delcos in series, which gives you 24 volts. Since you mentioned parallel, not series, I'm assuming you're looking for a 12 volt output. In this case, the above wouldn't work for you. | ||
| R Johnstone (Chilebrew) (63.106.39.35)
Rating: N/A |
Check www.balmar.net for a $200 device to control two alternators. | ||
| Stephen Fessenden (Sffess) (65.154.176.107)
Rating: N/A |
Running two alternators in parallel sounds complicated. Just use a one big alternator. If you can run a second alternator you could use it as a back up or to charge the bus batteries. The 400 amp 24 Volt alternator I have listed in the Flea Market is an exteme example of a big alternator. I have seen postings of other belt driven alternators up to 275 Amps. Steve Fessenden |
