DonMichUP
MI
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Joined: 03/28/2011
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Hello all! I've really enjoyed this group and have found some tremendous people willing to give their suggestions and opinions. I've had a little lapse in my goals and plans for my van, but a unique opportunity arose and I'll be into the mods as much as time will allow while working a full time job and no garage.
I'm getting ready to prepare my '95 GMC Vandura for a 12,000-20,000 mile photojournalist road trip beginning this June. This will be a 3 to 6 month tour, and, who knows, maybe even be a permanent thing   .
Is there anyone out here knowledgeable about coach batteries and alternators? Not that it matters, maybe, but here are some specifics:
I already have one 30A DC inlet, and one 15A DC inlet. I'll have a generator in time. I'll install 2 to 4 high Ah coach batteries (thinking Trojans). I'm considering installing a 250A alternator (current one is stock 105A). I'll have a continuous duty solenoid. I'll have a charger/converter (thinking of Progressive Dynamics Minny Max I think it's called).
The 250A alternator is a lot of power. So my question is, do I need to worry about the coach batteries charging too quickly or overcharging? I was told that the batteries will only accept the charge (amps) that is needed and no more. I don't know if this is correct. Seems to me that the batteries would be charging all the time, when ever the engine is running. Maybe I'm missing something with that logic tho.
Any and all advise is appreciated .
Moved to Tech Issues forum from DIY
* This post was
edited 02/06/12 07:50pm by an administrator/moderator *
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fltioga89
oviedo, fl.
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Joined: 01/19/2011
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from what i have heard and experienced its true that the battery will only take what it needs. i changed my cars alternator from the factory 60 amp to a 100 amp and have had no problem at all. the volts gauge does read a charge voltage of 14 or so when running now. it used to read just 12 with the old alternator .
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pianotuna
Regina, SK, Canada
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Joined: 12/18/2004
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Hi,
I'd add a small pure sine wave inverter to your wish list. Morningstar makes a super duper one that is 300 watts. Just perfect to run a laptop and recharge batteries. Generators are noisy.
It would be a good idea to consider upgrading the charging path from the Alternator to the house battery bank from the puny OEM wire.
Costs for materials for a solar installation are below $2.00 per watt.
Regards, Don
Kustom Koach Class C 28'5" 256 watts solar, 875 amp hours in two battery banks 12 volt batteries 2500 watt inverter.
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Normk
Canada's Wet Coast
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Joined: 01/24/2010
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A battery's charging rate depends on the voltage being applied. The higher the voltage (above the battery's voltage at the time) the greater the charging rate. Your 105 amp and a prospective 250 amp alternator will both have the same voltage set point so charging rate will be the same from either alternator unless the system load and charging current match the 105 amp output of the smaller alternator in which case the 250 will have the advantage.
In practice, the 250 amp alternator may not recharge faster than will the 250 amp unit. One advantage the 250 amp may have is the ability to provide sufficient charging current in the event of a diode or even stator leg failure.
If you are trying to run a huge number of loads and to charge the batteries at the same time, the 250 amp unit may be an advantage.
Some possible down sides to the 250 are larger mounting area required and potentially higher belt loading. If using the same belt for both units, it may be found that the required belt tension in order to prevent the alternator puller from slipping may cause bearing life issuwater pumperpump, or other components.
HIH
Norm
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Normk
Canada's Wet Coast
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Oh, forgot to mention: the larger battery capacity the better. A larger battery capacity will sustain loads longer between charges and will generally recharge faster.
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DonMichUP
MI
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Wow! Such QUICK replies! Thank you everyone . Love this forum, all good info, as expected. Good to know that a higher amp alternator wouldn't be a problem with overcharge. I was really worried about that. And as for the extra strain on the belt and water pump, I hadn't thought of that, but makes sense! I agree that the more capacity the better, and I'm known for overkill rather than being conservative. There will be times of heavy load, too, so if the alternator will help with that while running the engine, so much the better.
I will mostly be boondocking... maybe staying somewhere with park power once or twice a week. There 'will' be extended periods of dry camping though, and I want to be as self sufficient as possible. The generator is a Yamaha... very quiet... and will be used at times to enjoy some "comforts of home" as well as charge up the batteries. Solar may be an option later down the road, we'll see.
To give you a better perspective of this tour, I'll be in National, state, local, and private parks, dry camping from 9K+ elevations in the Rockies to -0 elevations in the deserts. The goal is to experience and share with others articles and photos of various locations, histories, cultures, events, and scenery. I'm going to have topics on my website relating to RV/van travel and living. Reviews and installation of the products, gear, and equipment used. Prospecting. And more. If anyone would like to follow along with me my url is in my signature I think(?).
I'll be starting to order my equipment and gear soon. First mod will be to tear out my conversion interior, insulate, and reinstall that or another interior. Lots to do! But sooo excited to do it . I got off track, sorry.
I'm going to go with the 250A alternator. I'll be needing to replace the water pump anyway, so I'll look for a heavy duty one for that. I'll also see what I can do to lessen the strain on the other pulleys and belt as well. Thanks again everyone, you're awesome!
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RJsfishin
Winston Or.
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Joined: 10/16/2007
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IMO, you are asking for trouble running a 250 amp alternator.
I also don't believe more battery is always better. Whatever you discharge, you must recharge. More batteries are more apt to spend more of their time in more of a discharged state.......which is a no no for any battery,.....it will shorten their life aq bunch.
Rich
'98 Flair, 454, Onan Microlite 4k, Intel PD 9155 w/ wizard, Sta-power 1500 watt Inv, 2 6v batts, ammeters, KingDome/sat, Two Oly Cat heaters, and towing a '05 Jeep Liberty, or sometimes towing a New Lowe fishing boat.
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DonMichUP
MI
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Rich: What sort of trouble? The discharge state makes sense, but I'll be charging while driving as well as idling, and also charging while the generator is being used.
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mena661
Southern California
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Joined: 03/21/2009
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RJsfishin wrote:IMO, you are asking for trouble running a 250 amp alternator.
I also don't believe more battery is always better. Whatever you discharge, you must recharge. More batteries are more apt to spend more of their time in more of a discharged state.......which is a no no for any battery,.....it will shorten their life aq bunch. A larger battery bank will last as long as a smaller one as long the proper maintenance is being done. Also, smaller banks experience progressive capacity loss quicker than larger banks simply because you hit lower SOC's faster. Smaller banks tend to be overdischarged more frequently due to not sizing for realistic usage. You can delay the onset of PCL by running a larger bank.
To the OP, you need to plan a full charge with equalization once a week or once every other week depending on battery capacity. Your battery capacity will drop with successive 50% to 90% recharges (the PCL I was mentioning). I would plan a drive once a week and let that 250 amp alternator do the heavy lifting and maybe a decent sized solar panel to top them off. Get yourself a portable Black and Decker VEC1093DBD and use the equalization feature on it after you get your batteries to a full charge. Also buy a hydrometer, you're going to need to know when your batteries need equalizing. That's the easiest way to tell. If I were in your situation I might get an external 3 stage voltage regulator for your alternator to make best use of that unit. Mexbungalows and some others know more about those than I do. You might want to get the attention of the fulltimers here that boondock. It's a totally different setup than us weekend warriors.
2006 Ford F250 Lariat 6.0 PSD 2WD
2010 Keystone Outback Super-Lite 285FL 5er, Reese Signature Series 18K w/Manual Slider
Four Trojan L16 6V's (740Ah)
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Normk
Canada's Wet Coast
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Rich's caution regarding the need to maintain batteries to the higher end of charge is very valid. For this reason I prefer to have a voltmeter with more resolution than the typical 5 or 6 bars which indicate some rough idea of the state of charge. If one is boondocking, having more battery capacity, IME, has usually been best.
As for the alternator drive, you will need either a poly V belt or at least a double V belt configuration in order to drive a 250 amp alternator. Having a larger drive surface such as in a poly V or multiple belt set-up will be far superior to trying to achieve enough tension to drive through a single belt.
You may wish to check to see if there are belt listings for your engine configuration in ambulance service since these typically have the huge alternators. That belt sizing will serve as a back-check to ensure that you are sizing adequately.
We used to see many water pump failures because people installed large output alternators with inadequate belt drive capacity and were trying to compensate for belt slippage by over tensioning the belt.
Sounds like you have an interesting project in preparing the rig and an even more interesting trip planned. Best of luck with both!
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