I finished my 300 amp alternator/isolator/cabling upgrade today and thought I would post some pictures. Following Acousticart's recommendation, I bought a FTZ crimper and used FTZ heavy duty "power" lugs from Bay Marine Supply. I used Ancor Marine Grade adhesive lined heat shrink tubing to cover and seal the lug joints, using a Wagner 1200 watt heat gun to shrink the Ancor tubing.
Previously when doing heavy cabling I have always soldered the lugs, using a good crimper and heavy duty lugs produces a very clean professional result.
I used 2/0 gauge wire for the alternator B+ to the isolator, and for the alternator NEG to the starter negative post (this is then connected to the battery bank NEG with OEM 4/0 cable). The WestMarine ampacity chart rates 2/0 gauge wire at 330 amps.
From the 3 diode 300 amp isolator I used 3 - 2 gauge cables to connect directly to the battery bank, 1 - 2 gauge wire to the chassis battery, and 2 - 2 gauge wires in parallel to the house batteries. The WestMarine ampacity chart rates 2 gauge wire at 210 amps.
I disconnected and left the OEM isolator and cabling in place as a backup.
Peter,
Nice job.
Assume this has an external sense wire-- and I see a small-gauge red wire coming from the alternator. Where is it connected?
Peter, looks great.
Brett:
Yes, the sense wire is connected to the starter + post with a 5 amp fuse. I took out the resistor bridge I posted about previously, that was more of an experiment. Now I have 14.0 volts at the batteries - the stock Delco 40si set point.
Want to make it a "smart" alternator?
http://www.xantrex.com/power-products/power-accessories/alternator-regulator.aspx
We use one on the sailboat. That way we can fast charge (bulk mode), but, if motoring all day, will not overcharge the batteries by keeping them at 14 VDC.
I have one of the Balmore versions of this regulator new in the box from a previous project...
If a person was to set it up for our application would it be better to optimize for the chassis bank or the house bank?
( I already run a Yandina ACR so the voltage drop of the isolator is gone...)
I have
Chris,
Assume you mean Balmar.
Good question about which bank to use for the sense wire. Conventional wisdom would suggest chassis batteries, but I would probably use the house bank.
The reason for using the house bank to provide the regulator with its sense voltage is that if discharged, following a good bulk/absorption/float regime is better for them and starting at 14.2 or so will not harm the chassis batteries and once float voltage is reached you won't continue to over-charge both banks if driving all day.
I have had several questions about how to wire up the ignition excite wire when changing from a L-N alternator to a Delco alternator. I did a quick schematic showing the additional diode required. The diode can be purchased from Radio Shack for $2. The stock Foretravel excite wire should already be fused in the dash fuse block (it was in my coach). If you are installing a new excite wire (or aren't sure if the existing wire is fused) it wouldn't hurt to add a fuse.
Peter,
So no separate excite terminal? And the excite wires goes to the B+ terminal??
Brett:
Yes, see attached DelcoRemy Application Engineering Bulletin. I underlined the key points. The diode circuit I posted is what is done within the isolators that have an excite post (a diode is connected from the excite post to the B+ post). The external diode allows you to use a standard isolator without the excite post feature - like I used in my Delco 40si upgrade.
Peter,
Great write-up, excellent photos, very professional looking wiring job! ^.^d
Question: Is the isolator OK with the high temps present in the engine compartment?
Excellent, thanks Peter.
And, yes, that diode is necessary, or the alternator output would be trying to push through that small excite wire and would quickly burn it or what it is connected to.
Peter,
Interesting updates on your project! We look forward to additional updates as you start using the new system. Thanks!
In my testing so far, I drove for an hour or so with headlights on and fridge on the inverter - a draw of approx 100 amps. I lifted the bed and the isolator was warm, but I could hold my hand on it. I'm thinking at the front of the engine room there is outside air coming in from below, and with the rear radiator the heat is going out the back.
For a winter project I am going to upgrade from the Delco 40si to the Delco 55si. This is the best deal I have found, it is a "real" Delco alternator, not a China imitation:
Delco 55si Alternator (http://firetruckparts.com/remy-inc-55si-12v-420a-alternator.html)
I have designed a J-180 to pad mount adapter and will be using the double V pulley. My brother (a machinist and a welder) is going to help build the adapter.
Will post progress and plans for the J-180 to pad mount adapter.
Update:
I located a Canadian company Dixie-Electric (http://www.dixie-electric.com/alternators.html) that manufactures high capacity DelStar alternators (I called and verified - not made in China). They make direct replacements for the Delco 40si and Delco 55si, and both with a J-180 mount option. The DelStars actually have higher idle and running amperage ratings than the Delcos.
Delco 40si replacement
DelStar 170 series (http://dixiehdalternators.com/pdf/170/170-SBS-COM.pdf)
D100-17102 J-180 Alternator (http://dixiehdalternators.com/pdf/170/D100-17102.pdf)
Delco 55si replacement
DelStar 180 series (http://www.dixie-electric.com/pdf/180/180-SBS-COM.pdf)
D100-18101 J-180 Alternator (http://www.dixiehdalternators.com/pdf/180/D100-18101.pdf)
They sell through US distributors. The one in Minneapolis is C&J Bus repair (http://www.cjbusrepair.com/). For their Delco 55si version the price is $1,358.00, quite a bit cheaper than the Delco 55si. I didn't price the Delco 40si version but I'm thinking they will be competitive. For a self-installed purchase they offer a 1 year warranty.
Is there a ballpark total cost to this upgrade?
Good find! Looks like the ultimate alternator upgrade... Using two alternators offers redundancy, but I like the simplicity of the single option. Less belts, half the moving parts...
Don
As Krush asked – just how much does it cost to upgrade the 12V charging system in a coach?
Let me start out by saying that this is not an "incremental" upgrade, i.e. just replacing a 160 amp alternator with a 200 amp alternator, wiping your hands, ah, that should do it!... This is an overhaul of the entire 12V charging system. Like adding high capacity 12V compressed air, a high capacity 12V charging system WILL cost some money, and is a fair amount of work.
Some are asking "why on earth would you want to do this?" Well with the higher power 12V inverters , and higher capacity 12V air compressors, adding additional batteries, etc. its nice to have some reserve alternator capacity.
I also agree that upgrading a system with one alternator and one isolator is simpler and much easier to implement, using stock mounting brackets, engine drive pulleys, etc.
In the research I have done, I would say there are 2 levels of 12V charging system upgrades, roughly doubling the stock charging capacity to approx 350 amps. Or, roughly tripling the stock charging capacity to approx 435 amps.
The more I read about the DelStar alternators, the more I like them. I called Dixie-Electric (http://www.dixie-electric.com/alternators.html) today and got the pricing on the DelStar version of the Delco 40si.
These prices are what I have found by researching and calling for information and are ballpark estimates. The super flexible welding cable prices are estimates – you may need more or less wiring depending on your coach layout. Also, tinned Marine flex cable is much more expensive. You do want to run upgraded cables from the isolator all the way to the battery terminals. I left my OEM isolator and wiring installed to use as a backup.
Note that the DelStar pricing came from the Minneapolis distributor. The distributor in your area may have different pricing.
I didn't include the cost of the FTZ crimper. My thinking is when you do the work yourself, the tools pay for themselves.
350 Amp 12V system upgradeDelStar 350 Amp J-180 Alternator (http://dixiehdalternators.com/pdf/170/D100-17102.pdf) $1125
SurePower 300 Amp Isolator (http://www.ase-supply.com/Sure_Power_3003_Battery_Isolator_p/sp-3003.htm) $525
Super flexible 2 and 2/0 gauge welding cable $150
Heavy Duty FTZ cable lugs $40
Heavy Duty Ancor shrink tubing $40
Total $1880
435 Amp 12V system upgradeDelStar 435 Amp J-180 Alternator (http://www.dixiehdalternators.com/pdf/180/D100-18101.pdf) $1420
PowerLine 400 Amp Isolator (https://www.emarineinc.com/400-amp-1-alternator-2-batteries-w-excitation-term) $770
Super flexible 3/0 and 4/0 gauge welding cable $400
Heavy Duty FTZ cable lugs $80
Heavy Duty Ancor shrink tubing $80
Total $2750
Peter,
Have you had enough experiences with 4/0 cable to discuss the differences between standard, welding cable, and marine grade 4/0 cables? It seems like standard 4/0 may work from batteries to the bus bars and possibly from there to the isolator. But any more complex routing would definitely benefit from more flexible cable.
How about the price differences? Anybody know how the prices compare for, say 50 feet of the three types of 4/0 cabling?
BTW, I noticed that your two upgrade systems specified a lower isolator rating than the alternator ratings. I am sure it is supposed to be higher. Unless you are implying that your alternators will never run at their rated outputs.
Thanks,
Trent
Peter,
Thanks for all the information and links.
One thing i noticed from the graphs is that the alternators were based on an idle speed about 2000 rpm, and go up to 8000 rpm. Newer Foretravels may be different, but mine idles about 800, with fast idle at 1200 rpm. I haven't paid that much attention to my tachometer, but it seems like my cruising speed is about 1600 rpm. The new alternators do not seem to reach their peak rating until about 5000 rpm.
I am not sure how this applies to our Foretravels, but it sure seems we would not really generate 350 amps, for example. Or is there something I am missing here? Don't get me wrong, brushless certainly seems the way to go, and you seem to have found the best prices out there. Just wanted to point out you may not be able to achieve the rated amps in your Foretravel.
Trent
To translate engine RPM to alternator RPM you need to know the circumference of the crankshaft pulley and alternator pulley. Many give more than 2X the engine RPM for the alternator.
Brett,
Ah, sooooo!
As I was finishing up that message, I started thinking of the pulley size. I was wrestling (in my mind) about whether a larger or smaller pulley would speed it up. Having reached the limit of my brain activity for the day, I clicked post.
Thanks,
Trent
Big crankshaft pulley and small alternator pulley= much higher alternator RPM than engine RPM. Virtually all engines are set up this way.
It's like simple 1-speed bicycle gearing. Big primary sprocket (crank pulley) plus a small secondary sprocket (alternator pulley) makes the rear wheel (alternator) spin really fast. :o
EDIT: DANG! Brett beat me to the draw by <1.0 minute.
Trent:
I was wondering the same thing and wanted to check the RPM after putting in the 40si. I ordered this Digital Tachometer (http://www.amazon.com/gp/product/B000I5LDVC?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00) from Amazon a couple of weeks ago and took some measurements on my Delco 40si alternator (http://www.delcoremy.com/documents/brochures/40si-brochure.aspx). At 650 RPM engine idle the alternator was spinning at approx 2000 RPM so the engine shaft/pulley ratio is 3 to 1. So this means at 1800 engine RPM (highway speed) the alternator should be spinning approx 5400 RPM which puts it near the maximum rated output on the graph.
Trent:
I think the SurePower 300 amp isolator is heavy enough for the DelStar 350 amp alternator, and here is why: It would be rare to run continuously at the full rated current of 350 amps (that is almost 5000 watts of power). The more usual case will be occasional intermittent current at that level, say when house batteries are low after dry camping. Diodes have intermittent (peak) current ratings several times higher than their continuous current ratings, and intermittent over-current won't damage them.
If one wanted to be very conservative, you could go with the more expensive PowerLine 400 amp isolator.
For the PowerLine 400 amp isolator, the company says their isolators are designed to supply the full rated current to each battery bank. For the 400 amp isolator that would be a combined current of 800 amps, so the PowerLine 400 amp isolator should be able to easily handle the 435 amp DelStar alternator, as current will be split to each battery bank.
Trent:
I have only used the untinned copper super flexible welding cable.
Here are the approx prices I have paid:
4/0 - $6.00 / ft
2/0 - $3.20 / ft
2 - $1.50 / ft
I think Don (Acousticart) has used the tinned marine cable, maybe he will chime in...
Yeah, but now they both say four hours. :D
Trent
I used 4/0 marine cable and I "fondled" some 4/0 welding cable. I wasn't able to compare them side by side, but my feeling was that the welding cable was a bit more supple than the tinned marine cable. However, I found the marine cable quite workable and though more money (Bay Marine Supply's price at the time with a slight discount for frequent buying was $8.90 per foot), I just liked the idea of the tinned cable being basically corrosion proof in the RV application. There was apparently some high resistance in the interconnecting link between the original two chassis batteries. Replacing that short piece (actually doing away with it because I replaced the 2 red tops with one 8DAGM O'reilly battery), made all the difference in starting without boost. All of the other original cabling was still functioning just fine. But since the inverter upgrade (Magnum MSH3012M) called for 4/0 cabling, I felt obliged to replace all of the house battery cable and so opted for the more expensive marine cable because that is what made me happy :)) .
Don
Alan Ferber at Bay Marine Supply is a Forum Commercial Member and will give forum members 10% off just for asking. Nice guy to talk to on the phone as well.
Amazon has Ancor marine 4/0 tinned cable for about $10.75/ft including shipping. For some reason Black is more expensive than red.
Amazon.com : Ancor Marine Grade Electrical Tinned Copper Battery Cable :... (http://amazon.com/Ancor-119502-Electrical-Battery-0-Gauge/dp/B000NI3BOQ/ref=sr_1_1?ie=UTF8&qid=1448159244&sr=8-1&keywords=Ancor+4%2F0+cable)
Bay Marine has 4/0 Marine cable for about $8.10 /ft. Looks like HD ends are reasonable too. Assembing the cable is $4.00. Not sure about shipping but it is $8.95 on most orders.
Custom 4/0 gauge marine battery cable (http://baymarinesupply.com/store/electrical/wiring/custom-battery-cables/custom-0000-gauge-marine-battery-cable.html)
WireNCable has 4/0 welding cable for $4.31/ft. 100 ft appears to ship free. Not sure what Class K means. EPDM cover. 90°C (194° F)
4/0 Welding Cable Class K (http://wirencable.com/4-0-welding-cable-class-k/?gclid=CPvs0P6Do8kCFQasaQodqzkGAA)
Yes, I called Bay Marine Supply a while back to check on something. Alan asked "what are you working on?"... We talked for about a half hour...
I wasn't sure either, here is a good explanation (http://www.iewc.com/resources/technical-guide/stranding-classes). Has to do with the stranding. Class K is next to the finest wire used.
Here is another source that has both tinned marine cable and welding cable. Welding cable has 2007 strands. Both are rated to 105°C
4/0 AWG UL Approved Marine Grade Tinned Copper Boat Battery Cable Rated 600... (http://ewcswire.com/4-0-awg-ul-approved-marine-grade-tinned-copper-boat-battery-cable-rated-600-volts/)
Welding cable is about $5/ft. Marine cable about $10. Maybe marine cable in the engine bay and battery connections in there. In the bays maybe welding cable, more flexibility, less external environmental issues.
Roger
be sure to check this place for wire too...I've heard good things Marine Wiring, Boat Cable and Electrical Genuinedealz.com (http://www.genuinedealz.com/)