[Coniac]

I have the original, stock alternator in my 2006 S model. After some searching it looks like it is rated at 110amps. I'm guessing that's max ouput under the best conditions, revving high. I'm building an off grid power system for a small offroad teardrop. I was planning on integrating a dual alternator / solar charger from Redarc to charge a 100ah lithium battery on the trailer. Redarc provides 3 different models for the BCDC charger: 25, 40, or 50 amps. I have a 300 watt RMS total 4 channel amp, 4 led cube lights, and aftermarket fog lights on the truck as extra load.

I'm going to run some heavy gauge, probably 4awg, back to trailer from the battery for charging. I'm wondering if anybody has experience with this type of load on the X electrical system? I'm trying to avoid a smoke show on the alternator, but would also like to charge that thing AFAP. I dont really want to upgrade to a high current component if I dont have to. Thanks in advance.

 

[curt86iroc]

i mean, think about it like this. my x, while running, can charge a group 24 deep cycle house battery (92ah i think) AND fully support the entire electrical system in my camper (which pulls a max of 30 amps, i think). the volt meter in my camper shows a full 14.2v from the truck even with everything on and running.

i'm not really sure how long it takes to fully charge the house battery in this configuration, as i keep the battery hooked up to 120w of solar that trickle charges it (end up being more like 80w). i also never let the battery get below 11.5v.

edit: just a side note on stock alternators. my daily driver ('09 jetta sportwagen) has a fair bit of electronic gizmos hooked up that pull an extra 30-40 amps from the car's electrical system...and I've never had any issues at all..

 

[Brunnie]

I'm going to run some heavy gauge, probably 4awg, back to trailer from the battery for charging.

And just how are you going to get this BIG wire through the connector at the hitch?? The usual wire from the tow vehicle to trailer is an 8 or 10 ga wire.

 

[Coniac]

And just how are you going to get this BIG wire through the connector at the hitch?? The usual wire from the tow vehicle to trailer is an 8 or 10 ga wire.

I'm going to run it separately from the 7 pin wiring and terminate it with an Anderson connection that will marry up with the same connection from the trailer side. Essentially it will be a second connection to make when hooking up the trailer. The stock wiring cant support that amount of amperage, so it will have it's own system.

 

[Coniac]

i mean, think about it like this. my x, while running, can charge a group 24 deep cycle house battery (92ah i think) AND fully support the entire electrical system in my camper (which pulls a max of 30 amps, i think). the volt meter in my camper shows a full 14.2v from the truck even with everything on and running.

i'm not really sure how long it takes to fully charge the house battery in this configuration, as i keep the battery hooked up to 120w of solar that trickle charges it (end up being more like 80w). i also never let the battery get below 11.5v.

edit: just a side note on stock alternators. my daily driver ('09 jetta sportwagen) has a fair bit of electronic gizmos hooked up that pull an extra 30-40 amps from the car's electrical system...and I've never had any issues at all..

Thanks for the insight. Much appreciated.

 

[Lowcountry idn]

I don't know all the specifics of X's alternator - but the generic answer is yes - if your running your alternator near full capacity all the time it will die quickly. The biggest issue is near idle. Modern alternators are designed to produce a lot of current at or near idle - because modern cars need a lot of current and spend a lot of time in traffic. So if your current needs are high, it will product max current it can at idle, and this will heat up a lot of components in the alternator where the internal fan of the alternator is providing the minimum amount of cooling. So all the internal components will heat up. Electronics, brushes, armatures, and high heat don't mix well.

Its less of an issue at speed - because there is more cooling air. But its still not wonderful.

You should measure your current load at idle without the charge system to see where your starting and go from there. 110A is pretty wimpy by todays standard. I would suggest upgrading your alternator to a mean green or something with more current, depending on how close to max current you think your going to be. I know you say you don't want to - but you can upgrade now, or at some very inconvenient time at a later date.

Or lower your expectations and find a way to limit the alternator load to a reasonable level rather than AFAP.

 

[mojavedesertman]

Later years of the X had a 130 amp alternator that is what I have in my '05 is the alternator for a '15 I run a 750 watt amp a 40" double row light bar a 12" double row light bar 2 6" single row lights and 2 cubes with no issues

 

[N.Fl.X]

Im having a lot of excess corrosion build up on the top of my battery. I just recently replaced the alternator and the positive terminal but im still having corrosion build up. An army mechanic friend of mine said my battery may be too small and that the alternator is overcharging it. Would a bigger battery be the answer to my problems or am i wasting my time?

 

[Lowcountry idn]

Im having a lot of excess corrosion build up on the top of my battery. I just recently replaced the alternator and the positive terminal but im still having corrosion build up. An army mechanic friend of mine said my battery may be too small and that the alternator is overcharging it. Would a bigger battery be the answer to my problems or am i wasting my time?

Corrosion is usually from the battery venting caustic gas (which can happen more often if the battery is too small or too old and needs a lot of charge). It can also happen if your charging at too high of voltage - which is unlikely with our smart charge system but possible. An additional very likely reason is leaky battery top - which all lead acid batteries seem to do now days.

What I would do, and I would do all of them because all are cheap, easy and smart:

1) have your current battery tested. See what the tester says for CCA and how it compares to what the battery is rated for.
2) check your charge volts after start up. When charging it shouldn't exceed 14.2 volts or so. Just to make sure that's not your issue.
3) clean your battery top and terminals with a baking soda/water solution - WEAR SAFETY GOGGLESS!!! - to remove any acid, then use the little felt rings under the terminals - they really do work, and coat the terminals in di-electric grease.

If you do need to replace your battery, there is no downside to going with a larger size as long as it fits.