More power

[Gusgusa1]

I put some lights and am putting on a warn 10,000lb winch on my truck as I work in the bush in the winter 🇨🇦 

My headlights before the additions would drop my volt metre dangerously low but with out them it always reads full charge.
 
I'm thinking I need a high capacity alternator does anyone have any suggestions?

Next summer I'll be putting in dual batteries as well. At least that's the plan.

1987 k10 350TBI,

[zieg85]

Put a relay kit on your headlights, something like this

https://www.ebay.com/itm/For-Headlight-H4-9003-Ceramic-Controller-Harness-Relay-Wire-Adapter-Kit/171559005371?epid=17018523471&hash=item27f1b6acbb:g:GdMAAOSw88RbAapV&vxp=mtr

[bd]

X2 on the headlamp relay kit regardless of whether you upgrade the charging system.

For alternator upgrades, take a look at...

Stupid-simple alternator upgrade -- 55A to 94A

AND

Powermaster 57294 150A alternator or similar products.

You will need to install larger gauge charge leads with a charging system upgrade to enjoy full benefit.  Depending on your circumstances, you should also consider a battery isolation system when installing a second battery.  The type of system will be dependent on your specific purposes.

[Gusgusa1]

Are you saying a relay will draw less power? How does that work?

[Gusgusa1]

Would I need 2 harnesses I have quad lights.

[zieg85]

Look for one for the 4 headlight system.  The relays take the load off of the headlight switch

[75gmck25]

The original alternator in our trucks was a 10si, which came in versions up to a 63 amp.  The cheapest budget choice is to directly replace it with a V-belt 12si that puts out 94 amps. 

All you need to do is buy a rebuilt Delco 12si with the right clocking and a V-belt, bolt it in, and upgrade your charge wire to an 8 gauge wire.  This site has info on the stock systems and how they differ. http://www.madelectrical.com/electricaltech/delcoremy.shtml ,  If you are interested I can look up the lester number (parts exchange catalog) of the 12si I used on my '75.

The other common choice is to upgrade to a newer CS130.  Its also a good upgrade, and the alternators put out more, but it gets a little more complicated than a simple swap to a 12si.

I did both the 12si swap and the headlight relay upgrade on my truck.  I also added a junction on the passenger fenderwall to connect it all together, and use that for the new charge wire connection.

Bruce

[VileZambonie]

The relay allows you to deliver a high current load with a low current control. The factory design provided current to the headlights directly through the switch. The unwanted voltage drops result in reduced performance however this will not improve your charging system output. Tackle that upgrade first and go from there if you are in need of getting better lighting.