I think the alternator is buried in my Toyota Sienna, so I’m not going to mess with it, or a second battery I guess.
I’ll just live with the combined 100-120w restriction on all the outlets in my car combined. I suspect the alternate is bigger than norm just because of that allowance given to the two AC plugs and DC plugs. I might try and sneak in a 50W computer for serving videos. Or maybe an Xbox One S that I think runs around 50-60W. As long as the kids aren’t all charging their devices at the same time, lol! From: Af [mailto:[email protected]] On Behalf Of George Skorup Sent: Tuesday, July 11, 2017 11:28 PM To: [email protected] Subject: Re: [AFMUG] OT: Road Trip Battery Alternator rating = rotor speed, not engine RPM. Crankshaft pulley to alternator pulley ratio is usually like 3:1. So 2k engine RPM = 6k alternator RPM = max power. Probably varies by model/mfg. Yeah, idle is usually gonna be a little bit less. A high-output alternator is the better choice. You can screw around with pulley ratios for more power at idle, but you run the risk of over-driving the alternator at higher engine RPM. IIRC, ~18-20k RPM is ungood for it. My '11 Silverado has a 145A alternator. Dual rectifiers. Maybe triple. I forget. Idle=600 RPM. Still produces at least 110A based on my clamp-on ammeter and a bad battery that always pulled about 90A. Probably bad cells. Made it 7 years. New battery pulled around 100A for 10 minutes or so to top it off. The typical commute of 15-30 minutes should be ample time to maintain a battery that's in decent shape/age. The law of averages, that's what the auto mfgs aim for. Most people don't need 180A at idle, just like most of our customers don't need 1Gbps, or 100Mbps, all the time.. or ever. On 7/11/2017 9:05 PM, Adam Moffett wrote: My '04 Hyundai Accent has a 90 amp alternator. ....though I never did figure out how many RPM's they assume when giving you that rating. I read some conflicting facts on that. Anyway, I have 1000 watt inverter and I've had approx 600 watts on it while idling for several hours. I can't prove whether the alternator kept up or the battery was slowly draining. ------ Original Message ------ From: [email protected]<mailto:[email protected]> To: "Animal Farm" <[email protected]<mailto:[email protected]>> Sent: 7/11/2017 8:49:23 PM Subject: Re: [AFMUG] OT: Road Trip Battery If you install the isolation diodes, then yes. But that only prevents a dead starter battery. If you have 3-4 devices all using 50 watts, and you have a 50 amp alternator, you only have 600 watts total. The air conditioner blower is going to take probably 200 watts, the onboard electronics perhaps 100 watts. So maybe 300 excess. I wouldn’t count on even that much. I have seen aux connectors fused at 15 amps so that is 180 watts. My dell has a 90 watt power supply. So two of those running non stop? From: Jaime Solorza Sent: Tuesday, July 11, 2017 6:32 PM To: Animal Farm Subject: Re: [AFMUG] OT: Road Trip Battery Not at all...Pep Boys and others sell a simple to install dual battery inverter and heavy duty fuse system. A good quality inverter would work well and no big thing to install. I use this for wiring up inverters for vans and buses to a solenoid to start inverter when vehicle is started. Prevents draining battery.. Jaime Solorza On Jul 11, 2017 6:14 PM, "Sterling Jacobson" <[email protected]<mailto:[email protected]>> wrote: I've got a cross country family trip from Utah to New York coming up and I want to wire up a secondary battery to my Toyota Minivan. I know, maybe I'm crazy, but I want to be able to run all our electronics on the trip, including maybe a computer for serving up video (another topic). I want it on a secondary system so I get more power and don't kill the main car battery. From what I gather I would need a sealed battery to avoid fumes (mostly). I would need a some sort of control system so the battery can charge from the alternator, but not drain the main battery. I need high gage wire between the batteries/alternater along with fuse, and also between secondary battery and large inverter for AC power. Probably not possible to shove another battery under the hood of the mini-van, but I haven't checked. Is this a silly idea?
