more powerful alternator

bodger · Post by **bodger** » Tue Jan 06, 2009 2:42 pm

i'm thinking of fitting a more powerful alternator , i have a 75amp one at the moment
but with engine battery / leisure battery / electric fans / spot lights and an invertor ... etc etc it could do with some more help on charging ..
i'm looking at maybe 100 amp or even 120 amp
what else do it need to change / do ??

thanks
keith

ChrisJC · Post by **ChrisJC** » Tue Jan 06, 2009 2:48 pm

Nothing. Assuming the wires are large enough to take the juice and that the V-belt can transfer the power into it in the first place.

Why not fit 2 alternators like I did? (if you want to make lots of work for yourself!!)

Chris.

bodger · Post by **bodger** » Tue Jan 06, 2009 3:00 pm

thankyou Chris , i did think about fitting 2 i even bought a second one then couldn't work out where to put it ??

if fitting just the one how high would you go ??

there are loads on ebay ...100 120 or even 150 ..the 100amp vauxhall zafira looks possible or the astra 120amp is quite cheap too

Post by **katanaman** » Tue Jan 06, 2009 4:59 pm

As Chris said you will have to rewire your main wiring to take the extra load. I havent seen an alternator over 75 amps that isnt a serp belt so you might have problems driving it at full load if you go above that. The shafts are usually different to take the serp pulley as well.

bodger · Post by **bodger** » Tue Jan 06, 2009 9:22 pm

the highest they go is 100amp on V belt so i'll have a look round for one of those
ambulances had them fitted on v8 ldv's ...but i'm sure with a little bodging i can fit a v pulley to a serp alternator

pictures to follow ..lol

topcatcustom · Post by **topcatcustom** » Tue Jan 06, 2009 10:08 pm

I think I have a 100amp one on my 90, and the guys in motor factors exchanged my old 45amp one for it

That is on a V belt, where there's will there's a way bodger you know that! Not much to bodging pulleys anyway

ChrisJC · Post by **ChrisJC** » Wed Jan 07, 2009 8:27 am

I drove mine from the spare pulley on the air-con pump, and mounted it to the air-con bracket.

I'll see if I can find a picture.

Chris.

bodger · Post by **bodger** » Wed Jan 07, 2009 4:04 pm

thankyou for your suggestions guys ..
one vauxhall astra 100amp with V pulley fitted and working well no point in hanging about
£25 from the local breakers ..just need to sort out the tension bracket but it's getting dark now

topcatcustom · Post by **topcatcustom** » Wed Jan 07, 2009 5:56 pm

nope, no hanging about!!! Hope it works ok!!!

ChrisJC · Post by **ChrisJC** » Wed Jan 07, 2009 8:43 pm

Impressive stuff!

bodger · Post by **bodger** » Thu Jan 08, 2009 5:42 pm

all tested and working , it's reading 14.4 volts on both batteries on tickover ..
so that'll do ..

i was just pondering is there any reason why the main battery cable can't be run like this ????????????

the split chage relay is now a 100amp jobby

Post by **katanaman** » Thu Jan 08, 2009 5:54 pm

I take it the split charge unit only cuts the supply to the aux battery? Only ask because the ones I have seen divert to the different batteries depending on condition. What your showing is basically a big relay. Also be careful if it is as it will drain the main battery if it is higher charge possibly resulting in a lot more than 100 amps flowing. Course if its an actual unit it will have flow protection built in so it isn't a problem. Might be an idea to put another relay or isolator on the main battery if it isn't. you can isolate it then with the added bonus of not flattening the main battery so the motor will always start.

bodger · Post by **bodger** » Thu Jan 08, 2009 7:44 pm

basicly thats all it is yes , it's trigger by the alternator sense wire when the charge light go's out the relay closes then charges both batteries , the aux battery feeds a ZIG unit in the back of the van

what i was wondering if there any reason that starter runs to the battery / then the alternator has a seperate wire to the battery / then the spilt charge has another wire to the main battery from the relay ie:STD

i was wondering if it could be done like the picture to save running 3 seperate cable from onwe side of the engine to the other and just have the one cable

topcatcustom · Post by **topcatcustom** » Fri Jan 09, 2009 10:18 am

Why not use a rubber exhaust bobbin as a stud near the alternator and use it as a base to join wires instead of on the back of the alternator?

I have done this on my landy to move some of the wires away from the battery to clean it all up a bit and it works a treat!

Just drill a hole in the bulkhead and bolt on the bobbin, then use the other as a + stud. You can get a good connection on an 8mm thread as well.

bodger · Post by **bodger** » Fri Jan 09, 2009 10:58 am

Exceelent thankyou TCP , have you done as per picture with all the wires ?
i have done it so far with just the split charge wire and i want to change all to as the picture ..
what sort of size wire would i need to run from the battery ?