stuck Posted February 3, 2012 Share Posted February 3, 2012 Gents, I'm sure mounting a second alternator on a Gems 4.6 has done before but I can't find any info on here or via Google. Any chance of a pic of how it's done, bracket details & what belt you have used? At the moment I'm not running an air con pump as a compressor but would like to if it's possible with the additional alternator. Thanks in advance, Mick. Quote Link to comment Share on other sites More sharing options...
mickeyw Posted February 3, 2012 Share Posted February 3, 2012 That will be interesting to see - like a V8 engine bay isn't tight enough already No doubt it'd be much easier without the A/C pump there Quote Link to comment Share on other sites More sharing options...
zardos Posted February 3, 2012 Share Posted February 3, 2012 Talk to Gwyn Lewis as he does a kit for a second alternator not sure if anything needs to be different for a GEMS 4.6 but it works fine on a 3.9 Quote Link to comment Share on other sites More sharing options...
stuck Posted February 3, 2012 Author Share Posted February 3, 2012 It will be tight I admit, must have been done already surely? If not I'll cue the music & make an arse of it probably! Quote Link to comment Share on other sites More sharing options...
stuck Posted February 3, 2012 Author Share Posted February 3, 2012 Cheers Zardos, Will give him a call on monday. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted February 3, 2012 Share Posted February 3, 2012 It's very easy on a Tdi Mo ... waddya mean, the door is this way Quote Link to comment Share on other sites More sharing options...
stuck Posted February 3, 2012 Author Share Posted February 3, 2012 Take a walk Mo :-) Quote Link to comment Share on other sites More sharing options...
zim Posted February 3, 2012 Share Posted February 3, 2012 Why do you want another one ? Would a single 200A alt be an easier option. Quote Link to comment Share on other sites More sharing options...
stuck Posted February 3, 2012 Author Share Posted February 3, 2012 Yes it would but the biggest I can find is 120A Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted February 4, 2012 Share Posted February 4, 2012 Zena make 200 amp alternators that can be used for welding or normal use. Not sure if there is a UK importer though.... http://www.zena.net/ I've not used them though .... there were some for sale on here last year Quote Link to comment Share on other sites More sharing options...
jbs Posted February 4, 2012 Share Posted February 4, 2012 Have a look here: http://www.ebay.co.uk/itm/MERCEDES-SPRINTER-2-1-2-2-CDI-200AMP-NEW-BOSCH-ALTERNATOR-06on-/280733091714?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item415cff0782#ht_500wt_1140 Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted February 4, 2012 Share Posted February 4, 2012 Why do you want another one ? Would a single 200A alt be an easier option. thats gonna take a hell of a belt to drive it.. Batterys only accept about 25amps maximum charge so unless your powering a small town off the landy a alt that size is pointless. The joy of 2 alts is you get 2 self maintaining, independant electrical systems, if you want to then pull big current, you join the battery possitves through an isolator and off you go. I run 2 65 amp alts and they keep up with anything i throw at them. Quote Link to comment Share on other sites More sharing options...
zim Posted February 4, 2012 Share Posted February 4, 2012 thats gonna take a hell of a belt to drive it.. Batterys only accept about 25amps maximum charge so unless your powering a small town off the landy a alt that size is pointless. The joy of 2 alts is you get 2 self maintaining, independant electrical systems, if you want to then pull big current, you join the battery possitves through an isolator and off you go. I run 2 65 amp alts and they keep up with anything i throw at them. Hi, Belt - a normal serpentine belt as found on a v8 p38 will be perfectly fine. The same theory applies if you're running 2 x 100A alts on the same belt. We've done this many a time. I honestly don't see the point in running 2 x 12v battery systems. May as well make one big system that powers everything. Use a split relay if you wish to save one of the batteries for if you were using it and the engine was not running. Batterys only accept about 25amps maximum charge so unless your powering a small town off the landy a alt that size is pointless. Agree, to a degree, but why not have a couple batteries with a nice big alt and you're onto a winner. Take for example if you're operating a winch that is drawing 200A - your truck will draw for example another 30A max ? (My p38 draws about 30A under normal conditions).... Your alt will be producing max at this point (say 100A), the remainder will be coming from the battery. When you let off the winch motor the alt will produce as much as the battery(s) can take to recharge it. If you had in this instance 2 seperate systems (2 x small alts)...Then you'll effictively have less power on the winching side, although the engine side will be as normal. I guess it all comes down to how you'd sperate the 2 systems. What components would be run off what ? Winches on one, lights on the other / with engine ?? But how often do you winch in the grand scale of things, how often are your lights on etc ? This is probably the main reason i prefer to stick to a KISS method. A vehicle itself does not need much power to keep running. If you want to know about silly current draw, my F250 today which isn't starting for some reason was drawing 680A max peak. These come as standard with 2 bat's wired without split relay. G Quote Link to comment Share on other sites More sharing options...
zardos Posted February 4, 2012 Share Posted February 4, 2012 Belt - a normal serpentine belt as found on a v8 p38 will be perfectly fine. The same theory applies if you're running 2 x 100A alts on the same belt. We've done this many a time. 1 x 200A alternator does not have the same properties as 2 x 100A, the 2 x 100A will have more than twice the wrap angle for belt contact area (looking at mine it's more like 3 times the wrap angle) and therefore less likely for the belt to slip. Quote Link to comment Share on other sites More sharing options...
zim Posted February 4, 2012 Share Posted February 4, 2012 Doh...ok, on that part yes 2 x alts are better. I was meaning in energy required. i.e 100 x 2 = 200 x 1 I still say that a single serp belt does work. Personally i've run 2 x 200A @ 18v+ (variable reg) as well as a basic 80A @ 12v. One a little peugeot 1.6. Quote Link to comment Share on other sites More sharing options...
Daan Posted February 5, 2012 Share Posted February 5, 2012 One thing I have found is that at tickover, a smaller alternator pushes out more than a bigger one. They basically need more revs to work. So the above is basically not true when winching. Daan Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted February 5, 2012 Share Posted February 5, 2012 One thing i missed in my previous post is that when your all singing all dancing expensive 200 amp packs up, your all singing all dancing split charge relay is of no use, the car comes to a halt... On a 2 alt system, if one packs up you close the isolator between the 2 possitives and the car and its accessories will keep on going... Another reason I always recommend 2 alts instead of a split charge. Quote Link to comment Share on other sites More sharing options...
zim Posted February 5, 2012 Share Posted February 5, 2012 Daan. Can i ask how you've tested this ? We used to have a limit of 2,000rpm and we had our alternators producing as much as possible at this point. I'd put it more down to different makes / models / types of alternators and the amount that they put out at idle. G Quote Link to comment Share on other sites More sharing options...
zim Posted February 5, 2012 Share Posted February 5, 2012 One thing i missed in my previous post is that when your all singing all dancing expensive 200 amp packs up, your all singing all dancing split charge relay is of no use, the car comes to a halt... On a 2 alt system, if one packs up you close the isolator between the 2 possitives and the car and its accessories will keep on going... Another reason I always recommend 2 alts instead of a split charge. I can't disagree. If it freaks out then well ya, a second would definately help. The latest price i had for a 210 A alt was c. £130 - £150. Grove Auto Parts Quote Link to comment Share on other sites More sharing options...
Daan Posted February 9, 2012 Share Posted February 9, 2012 Daan. Can i ask how you've tested this ? We used to have a limit of 2,000rpm and we had our alternators producing as much as possible at this point. I'd put it more down to different makes / models / types of alternators and the amount that they put out at idle. G I did not physically test this, but I was involved with a sandwhich van at some stage in my career, which stood stationary for hours on time with the engine running at 1000 rpm. This did suffer from flattened batterys, and one of the solutions to try and combat this problem was to fit a larger alternator (24 V iskra from memory). This made things worse. We then got the charging curves of both the alternators and the result was that at 1000 rpm (about 1500 rpm on the alternator), the larger alternator was worse. Daan Quote Link to comment Share on other sites More sharing options...
Daan Posted February 9, 2012 Share Posted February 9, 2012 like this basically: http://www.newindo.com/delcoremy/images/delco%20remy%20alternator%2033SI-28V_pc_sm.jpg Daan Quote Link to comment Share on other sites More sharing options...
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