Huntindog wrote:
wrvond wrote:
First, any tow vehicle with a factory tow package is going to have an upgraded alternator to handle the increased load experienced when the TT is plugged into the truck's connector. If you feel the need to connect your camper to the truck because the batteries are low, simply plug it in near the hitch, and it will charge them just fine.
Second, The way a vehicle's charging system works is, the vehicle actually runs off the battery for all it's electrical requirements, and while old fashioned generators had to run at higher rpm's before the charging started, today's alternators produce electricity at very low rpm's, so no need for high idle to charge the battery.
Purpose built generators provide nearly all their generated electricity for such things as battery recharging, which makes them much more efficient than your TV for recharging. Even at that, it takes several hours to recharge batteries to 100% with one.
hope this helps.
This goes against everything I have known to be true....
But I figured that maybe you were right and things have changed.... So I googled it. I can find nothing to back up what you just said.
Plenty out there about automotive altenators needing high rpms to produce signifiganant power.
I even found some info about lower powered altenators producing more at lower rpms than their higher powered counterparts... So much for the upgraded tow package altenators being better for this...
My mind is still slightly open to the possibility (mostly because I would like it to be true) so if you can please post up some links to back up your claims... I'd be grateful.
I actually tested this once with a meter. I got about 1.6 amps of charge.. Not worth the effort.
Sorry, I re-read my post and see that I was really not very clear.
My statement about upgraded alternators was in response to an earlier statement, to whit: "Other than putting one heck of a load on your alternator by asking it to do something it was not designed for". I was trying to say that today's higher capacity heavy duty alternators on factory tow package equipped vehicles actually are designed (would "intended" be a better word?) for the increased load of battery/batteries included in the TT.
Also, the reference to the efficiency of alternators vs. generators, I'm sure you remember that before alternators, whenever we wanted to jump a dead battery in another vehicle, we'd hook up the jumper cables, then have to rev the engine above 1500 rpms or so before it would start putting out enough voltage to charge the dead battery. By the same token, even with a voltage regulator, headlights dimmed whenever the vehicle idled for any period of time, or boiled the battery dry on long cross country drives. That's why we drove with our headlights on, to keep a constant drain on the battery so it wouldn't over charge. By contrast, today's alternators put out voltage at around 700 t0 900 rpm's (idle speed for many vehicles, not necessarily significant voltage, but still useable. I haven't jumped to a dead battery and had to rev the engine in many, many years. Nowadays I simply connect, let it idle for five minutes or so, and the dead vehicle invariably starts. It would be more correct to say that DC generators require a specific rpm to generate useable electricity, while AC alternators (or alternating generators) create useable electricity within a wider rpm range.
Finally, the statement that the batteries will charge "just fine" with the umbilical plugged into the TV was not to imply they would charge
betterthan a charger connected directly to the TV battery. Just that simply plugging in the umbilical would work "just fine".
While I may feel that my statements are empirical, I am willing to grant that the observation is at least somewhat subjective, since no real methodology was employed.
Ultimately, I still feel, and I think anecdotal evidence supports this, connecting a TT with dead batteries to the TV through the umbilical, and allowing the TV to idle will charge the TT batteries (without having to employ direct connection to the TV battery with a charger). That doing so will not result in any increased wear to the heavy duty alternator (due to increased load), but that a purpose built generator connected directly to the TT batteries will charge them more efficiently.
Hopefully this is a lot more lucid than what I originally posted. Again, apologies for the lack of qualifying criteria.
