HO alternator and dual battery charging
I also put this in the technical 12 volt section but don't think there is much traffic there and I am thinking of finishing this up tomorrow.
I am working out the best way to install my new DC Power engineering 180 amp HO alternator to replace the factory 100 amp. I already have dual batteries, 1 DHP group 31m for added circuits and 1 DHP group 65 as the starting battery and for OEM circuits. I have everything wired through a Blue Sea ACR.
Tacozord provided some good information in his build thread
http://www.expeditionportal.com/forum/threads/139692-Boden-Build-2015-Tacoma-DCLB-4wd?p=1845558#post1845558
and I ended up reading all of the
"Alternator Bible" based on his recommendation. It is full of a lot of good information.
So it turns out that a lot of vehicles have the alternator directly feed the battery and then all circuits feed off of the battery. Essentially even when the battery is topped off after startup, you are still running all of your alternator power through the battery then back out to the vehicle circuits. The Alternator Bible says it is ideal to have the alternator and battery running to a distribution block and the alternator sense wire run to the distribution block. All circuits will feed from this centralized power distribution block.
I believe that Toyota already covered this with their system. The 100 series already has this type of system from the factory. The alternator/charge cable is on the left and the alternator sense wire is in this distribution/fuse block.
I will be upgrading my battery ground wires to the chassis to 2 awg and also running a dedicated 2 awg ground wire from the battery to the the new alternator along with the new 2 awg alternator/charge cable. From the factory there is no ground direct to the alternator, it is grounded to the engine.
I will get to my questions soon.
Right now my understanding of the system is as follows, I hope this is all clear.
Starter draws power from the starting battery.
Once the vehicle is running the alternator will top off the starting battery then continue to provide enough power to run the vehicle circuits. Power produced is based on the alternator sense wire in the OEM distribution block.
When the Blue Sea ACR senses that the starter battery is charged back to ~13.4 volts it connects the batteries so that the house battery will also be charged from the alternator.
I believe in this system even after the the starter battery is charged, when the two batteries are connected, the power being drawn from the alternator to charge the house battery is still running through the starter battery first. Is this true?
I already know that it is not ideal to run two different brand, type, or size batteries in the manner I am. Running two of the same is not an option so I want to make the system as good as I can with what I have.
I am thinking that when I run my new alternator 2 awg wire I will connect it to the starter battery post on the Blue Sea ACR. My thought is that this will allow for a more direct feed to the house battery. If power goes the route of least resistance, this method would allow power to go direct to the house battery for charging when the ACR is connecting the two and the starter battery is already topped off. How does this sound?
Of course I will have an appropriately sized fuse in my new alternator charge cable. If this is all a good idea, where is the ideal spot for my alternator sense wire?
Thanks in advance.