Members here have succesfully run 160 (I'm one of them, but I upgraded my cable to the battery from the Alt) and 200 amp alternators from www.mralternator.com

I strongly suggest going with one of those two known successful upgrades, and upgrade your cables, as well as installing another battery behind an isolator. Do NOT use a deep-cycle battery unless you want to fry the investment in your alternator. Use two automotive batteries, with one of them behind an isolator. A link to a good isolator price was just posted in the last couple days.

Do a search of the Forum for the word 'isolator' and you'll find it.

Didn't you have a couple failures?

I had a nut come loose on the casing 3 years ago, and it was replaced under warranty. Shipping both ways was also covered. I wouldn't call that a failure in the terms you're talking about.

(caused an uneven torque on the case halves and made the alternator make squeaky noises as the bearing preload became uneven).

Here is another link to check out. I have only skimmed through the information here, but they touch on many topics including additional batteries, isolators and second alternators. willwren spoke of a second battery and isolator. This is definitely a good idea.

http://www.zena.net/htdocs/alternators/AutoSound.shtml

http://www.zena.net/htdocs/alternators/alt_inf.shtml

We run dual alternators and two banks of two batteries separated with an isolator in all our ambulances. This nets us a current producing capability of 240 - 260A. We would not likely have the space to install a second alternator in our cars, but it'* a really good idea for high current applications. Ambulances obviously do this because of the redundancy and preferred engineering to power all the electrics.

wow, i really am going to have to disagree with that statement there.

a deep cycle battery is just another battery technology, which has low memory. the whole purpose of the battery is to start the car,and act as a reserve until the alternator can catch up with the load, which is usually a matter of milliseconds. after that the alternator takes over and supplies the current and voltage to the electrical system. i really dont see how a battery could fry an alternator, would you like to elaborate on that?

i also dont need more than one battery, as i dont use the system whilst the car is not running.
i am curious as to your reasoning behind your thoughts, so please dont assume im bashing or calling you out or anything of the nature.

willwren will likely have some additional thoughts on this, but I know that deep cycle RV batteries do have different charging characteristics. The inverter/chargers we have in all our ambulances have different settings based on whether they are used to charge regular or deep cycle batteries. I can dig up some additional info for you in the next few days if you'd like.

i love learning, if you dont mind i would like all the information i can get.

If you want to get a deep cycle battery, get a marine/rv alternator. You will fry an automotive alternator before it'* time due to the charging load demanded by a deep cycle battery.

The reason I suggested dual batteries seperated by an isolator was so that you would charge your 'reserve' when you weren't under max load, leaving it so supply demand when you were. This is called duty cycle.

The wrong (or bad) alternator can kill a battery. The opposite is also true. The wrong (or bad) battery can kill an alternator.


The 'Yellow Top Myth' is widely circulated amongst auto audio enthusiasts. It'* not really a myth, and has some truth. A deep cycle battery will supply current for longer and 'deeper' into the battery reserves than a typical automotive 'starting' battery can, but what isn't widely discussed is the negative effect it will have on your alternator.