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Old 11-28-2013, 07:35 PM   #71
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It works! At least the first test without the trailer hooked up. I still need to make an umbilical to wire the trailer batteries up. But it fires up and the control panel is putting out useful info about the alternator and truck batteries.

The unit said the truck batteries were getting about 30 amps at first but that quickly dropped to about 20-22. All this is just at idle. I suspect the batteries don't need much at the moment, just a quick boost to recover from starting. Turning on the headlights caused a 10 to 12 amp increase in both alternator output and amps going into the truck electrical system.

Now the real test will be with the trailer hooked up. I'm very curious what I will get at idle back to the trailer bank. This charging system is supposed to put a load on the alternator, so just like turning on the headlights, it should have no problem pulling a decent amount of amps back to the trailer even at idle.

That's kind of one of my ultimate scenario for doing this -- being able to idle at rest stops or whatever to juice up the batteries if I need power to watch satellite! Currently, I keep one eye on the tv and one eye on my voltage meter and there are times I have to shut it down if I haven't collected enough solar power during the day. Especially if I have to run the furnace.

With this system, I should never be at a loss for power. Well, except in the case of the AC.
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Old 11-28-2013, 09:59 PM   #72
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Back from a test drive... Couple of surprising things watching the control panel and data from the shunts.

One, there was absolutely NO discernible difference in alternator output based on speed of the vehicle. Of course, this may (probably) change if the alternator was being taxed. Basically, as the specs on alternators show, the capacity depends on higher rpms. But I was surprised that there wasn't any difference from idle for normal loads. The only impact to the amps was based in loads, which brings me to my second point...

These little alternator devices are pretty remarkable! I was shocked at how it seemed to almost instantly react to any load put on it! Brake lights, windows, etc all nearly instantly showed up in current crossing the shunts! In fact, I could see a difference between rolling the windows down vs up! It was so fast that I'm almost surprised I didn't see vacillation in blinkers.

Well so far, so good. Tomorrow I should have a chance to finish trailer wiring so we'll see what it does with that connected. I'm hoping for at least 25 amps at idle, and based on what I've seen so far, I don't think that will be a hard target to beat. I figure headlights and trailer lights alone must pull 20 amps, which the alternator certainly handles at idle just fine. So that capacity (and hopefully much more) should be available for trailer charging when at idle and those systems off.
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Old 11-30-2013, 08:09 PM   #73
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HOLY cow! 96 amps at IDLE!!!! Yes, that's right! NINETY SIX amps at IDLE!

(DOM is for "domestic" which is what the unit calls the trailer battery bank)

Just like the unit advertised, it pulled down the truck battery voltage to 12.9 or something and that made the alternator work close to capacity. I just was surprised to see the full effect even at idle.

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Old 11-30-2013, 11:03 PM   #74
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Have you had a chance to measure the voltage delivered to the battery bank? That appears to be outstanding performance. How long does output stay high before the current begins to taper?
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Old 11-30-2013, 11:37 PM   #75
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I have not measured at the bank in the trailer yet but it is supposed to compensate for voltage drop. There is a sense wire running back to the unit so it knows how much the drop is, then it boosts to compensate. I did press the "full/empty" voltmeter button on my 70s control panel and the needle went all the way to the right like it does when the regular charger/converter is working.

Today I just started the truck and let it idle for 30 minutes or so. It has a routine it goes through -- I think the first 5 minutes of run time are focused on making sure the truck/starter batteries get what they need, then it switches over to focus in trailer batteries. I think it was about 60 amps to the trailer for the first 5 min then it went to 96. The first 5 minute think can be overridden if desired to immediately go I to trailer charging.

Every 20 mins it is supposed to pause and check the starter batteries to make sure they are full. It also has temp sensors on the alternator and trailer batteries so it can adjust what it is doing if either seems to be getting too much action.

The charger runs a multistage charging program to take good care of the batteries. I think towards the start of the tread I posted a marketing graph from the company. I don't think the detail level is great on it, however. It didn't show the 20 minute pauses for example.
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Old 12-01-2013, 12:12 PM   #76
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Well I may need a bigger alternator! I made an assumption when buying the 210 amp charger vs the smaller 160 amp charger that it would work fine with my smaller alternator for the time being, and I would just have extra capacity if I decided to upgrade the alternator later. Well, the system is VERY effective in milking amps from the system so today when I hooked up the trailer to do more testing I decided to rev the engine (the trailer is up on blocks in my workshop at the moment). The amps jumped up (140 to the trailer!) and it seemed like the alternator was working AT capacity. The temp probe on it soon showed it was overheated.

Now, I think there is a workaround for now so it isn't the end of the world. The system also kicked in and disengaged as it is supposed to.

Also, keep in mind my batteries are far lower than they normally would ever be while underway, so this situation may not present itself very often anyway. Glad they were low for this testing, however, so I can understand this better.

And, consider that this was revving at idle, so there was no extra airflow through the engine compartment like there would be underway. I don't think it is going to overheat the alternator at normal idle and 100 amps or so charging to the trailer (it started off today at 110).

One thing that surprised me is that when the system disengaged, the trailer was still drawing like 60-70 amps! I thought system disengaged meant that the batteries would be disconnected and the truck would revert to only handling it's own needs. My theory, which I need to confirm with the maker, is that it acts as a combiner when it isn't doing the voltage boost thing in normal operation. And the high amps going back was a result of the beefy wiring I've done.

That gets back to the point of the system anyway -- it's really designed to speed up charging to get the max benefit when the engine is running. And, to be able to fully charge the batteries with the voltage boost whereas you can never fully charge with an alternator and long wiring run otherwise. It seems there is still plenty of charging that can happen without the boost when you have this extra big wiring and low battery levels.

So my workaround for the undersized alternator may be to just turn off the system when batteries are very low like this to let them come up with some bulk charging and equalizing with the truck batteries. That will hopefully keep the alternator working at no more than 60-65% capacity. This may ONLY be needed while underway and when batteries are at an exceptionally low state of charge. Then I can turn on the system to charge beyond where this workaround is effective and the batteries won't need to suck as many amps. Again, I think the normal boost will be fine with my alt capacity for charging at idle.

I had been counting on a disconnect function, however, for times such as climbing mountains when I didn't want any extra load on the system. Well, I guess I can always manually unplug if I really really am desperate.
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Old 12-02-2013, 09:26 PM   #77
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Probably mentioned and likely already known by the PO is that some OEM's offer dual alternator packages for some light duty and medium duty trucks (4500 -5500 series) and not just an oversized alternator. I've bookmarked the "ambulance package" single alternator for my pickup R&R at some point. The aftermarket offers some dual alternator packages as well, but I'd sure prefer an engineered approach (as I'd be as worried about bracketry as about alternator quality). This thread will help determine my path.

LEECE-NEVILLE was part of the DODGE Police Pursuit Package in the late 1960's and forward. I recall some RV'ers wanting that just for this kind of purpose . . but the price can be daunting, now as then (and another reason big engines [440, 454 & 460 cid] were popular with the trailering crowd: could easily run air-conditioning and had the biggest alternator. Which back then was the mind-blowing 60A configuration, ha!)

Great thread, good work, and look forward to more.

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Old 12-16-2013, 10:56 PM   #78
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Thanks Slowmover - good to hear your thoughts on Leece-Neville. I had come across a DIY on how to install one of those into a Dodge Cummins but I have not learned a whole lot more about them.

I've been meaning to come back to post some follow up about the system now that I have about 1500 miles experience with it. This was pretty much a "lets get there" trip scenario with overnights in rest stops and walmarts so there are certainly many other scenarios still to be tested.

The unit performed quite nicely and provided the quick charging of the battery while parked on those nights. The weather was quite cold (you may have heard about the texas ice storms) so it was nice not to have to worry about 12v power. The furnace was blasting and I had my TV on many hours, even leaving the Dish Hopper DVR on overnight to collect some recordings. I did go out and run the truck engine for about 30 minutes to recharge the batteries before bed and while out walking the pooch.

That was the main scenario I was envisioning when going all out to setup this crazy system. It was clear to me, watching the control panel numbers, that the system capacity is FAR above what someone would need to get good charging of batteries over slightly longer periods -- or with a smaller battery bank. My large battery bank was getting fully charged in about 2 to 3 hours of driving in the morning. I'd say maybe 90 to 95% charged in the first hour alone.

I'd also estimate that probably 90% of the improvement I've seen is from the beefy wiring I've done. Inserting the charge controller into the mix really only benefits the setup in very specific scenarios like being able to top up the batteries in those rest stops as quickly as possible. If you are like me and have reasonably long driving days when the trailer can get long periods of charging, there isn't as much need for super ultra fast charging (just the complete charging that these types of units can provide).

One thing I ponder is how the system would have worked with less beefy wiring and a less beefy charge controller. For anyone else considering stuff like this, you might look at the Balmar Duo Charge (30 amp rating), Xantrex Echo Charge (15 amps), the CTEK D250S (20 amps base but they have an expansion module) -- and of course, I recommend people check out the Sterling products (also sold under ProMariner brand). Sterling has units at 40, 130 and 210 amps.

You could probably insert one of the smaller units into your 7 way connector to get faster and more complete charging of your trailer batteries. The larger units should be run through a separate connector. The main problem to solve would be setting it up to limit the amount of current that can be pulled by the trailer at once as appropriate for the size wire you want to use.

One thing I also wonder is how its possible that these 7 way connectors are not melting when people have them hooked up to directly connect a big battery bank in a trailer to the tow vehicle charging system. I was SHOCKED by how many amps were being pulled through my fat cabling even when my charging system was deactivated. I know the wiring does limit how fast the current can move, but wow, my batteries wanted to suck many, many amps down my fat wire and it would seem that any big battery bank would still want to pull those amps over a 7 way! So if you have a big battery bank, you might want to think about this.

I know that some of the smaller units I mentioned, in particular the Balmar, have ways to hook up a solenoid so if a big battery bank wants a lot of amps at the start, that just activates to parallel the truck/trailer batteries. Then the Balmar unit kicks in once the amp draw comes down to handle the tail end charging. I could see how that could work pretty well. Still wouldn't have the fast charging I get with the 220 amp sterling unit, but I'd think it would work pretty well (but I'd think you would still need pretty big wiring unless you can limit the current draw somehow). And Sterling does have smaller capacity units as well but I can't tell you how they handle that scenario.

Anyway, just wanted to get some of that info dumped out of my head in case anyone was wondering how it was going. Feel free to ask questions in this thread and I should be around to answer them now and into the future.
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Old 12-17-2013, 10:07 AM   #79
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Quote:
Originally Posted by CA_Tallguy View Post
I'd also estimate that probably 90% of the improvement I've seen is from the beefy wiring I've done.
+1

Quote:
One thing I also wonder is how its possible that these 7 way connectors are not melting when people have them hooked up to directly connect a big battery bank in a trailer to the tow vehicle charging system. I was SHOCKED by how many amps were being pulled through my fat cabling even when my charging system was deactivated. I know the wiring does limit how fast the current can move, but wow, my batteries wanted to suck many, many amps down my fat wire and it would seem that any big battery bank would still want to pull those amps over a 7 way!
The 7 way connectors are rated for 30 amps.

Typically, the alternator delivers 14.4 volts and the battery charges at around 12.5 volts. When enough current flows that the voltage drop in the charge circuit wiring (tow vehicle and trailer combined) reaches 2.1 volts, the system is in a state of equilibrium. With stock wiring that will usually occur at less than 30 amps with some occasional brief excursions up to higher currents that don't last long enough to cause the connector to overheat. The exact voltages involved vary based on a whole bunch of things but the overall effect is usually the same.

When you upsize the wiring, there is a greater risk of overheating the connector. I have 6 gauge wire on my main tow vehicle and have switched from a 7 way to a 6 way connector because of the slightly higher current rating. The 6 way connectors have their own problems and I don't recommend them, and will switch to a 7 way pin type (the kind used for semis) when it fails.
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Old 01-12-2017, 11:05 PM   #80
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Well folks, looks like I may dismantle this system and sadly I didn't get all that much use out of it over the last few years. Some health issues (now behind me) along with building a man cave type thing at Texas Airstream Harbor have kept me off the road. I just purchased a Mercedes GL350 and am looking to set it up as my new tow vehicle and I don't think that I want to try to modify that electrical system to the extent I did for the system described prior to this post in my Dodge truck.

Instead I may go for a "battery to battery" type charging system with the goal of getting maybe 60 to 100 amps back to the trailer over smaller wiring. The HUGE amperage of my prior system is too much. I do have a 220 amp alternator in the Mercedes vs 140 in the old Dodge but I just feel like it would be good to max out at drawing around 100 amps from that. Maybe 120/140 for the first few minutes of bulk charging. But in any case, a far more reasonably sized system.

I do want to be able to top off my batteries quickly by idling the engine for short periods. So still some hefty amps, but not insane. One nice thing is I can start the Mercedes with an app on my phone so I'll be able to kick off charging without even leaving the trailer. Hmmm.... I wonder if I can kill the engine though? I have not yet tried this app so will have to find out. Guessing that they probably didn't implement killing the engine because I can see how that might present safety issues if someone on an app tried killing the engine of a vehicle that someone else was using.

Anyway, I'll likely be updating this thread with some new info in the coming weeks/months... depending on how soon I decide on what I want to do.
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Old 01-13-2017, 11:02 AM   #81
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Good to hear you're back, looking forward to your project(s)...

Are you still in the 1977 31' Excella 500 you refurbished a while back?

Edit: I glommed onto enough 300AH lithium cells (at can't refuse prices) to make three 12V banks or one 12 & one 24V bank from them, have been in a holding pattern trying to smooth out details to use them safely, I think about your upgrade from time to time. Thanks for posting.
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Old 04-22-2017, 12:47 PM   #82
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I've decided to start a new thread for my Mercedes project, which will be a bit of a continuation from this thread. It is located here:

http://www.airforums.com/forums/f37/...ml#post1939574
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