Dual Battery - Smart Alternator

[Black Betty DXB]

Hey,

 

Iv seen a bunch of posts about setting up a dual battery system and what to use, and i understand all that.

Problem is i keep seeing articles about standard relay style isolators and smart isolators (VSR) not working if you have a "smart alternator" because of the fluctuations from the alternator based on driving conditions, and therefore have to go and spend a load on a DC-DC charger. $50 vs $300

 

Anyone have any issues with their standard relay style or smart isolators on their dual battery setup?

 

Articles below,

https://www.12voltplanet.co.uk/auxiliary-battery-charging-in-vehicles-with-smart-alternators.html

https://www.redarc.com.au/faq-tech-tips/new-vehicles-technology-can-affect-dual-battery-systems-charging-performanc

[Snowcamo]

Not sure many here have donethe dual battery upgrade or even have it from factory. I've been contemplating it tho.just can't see taxing the factory system.

[1SLOW1500]

I have dual batteries and a isolator. It is wired with a small switch and a small relay. I have it so on a normal day the factory acc wire powers it and two batteries start truck. When truck is of it is disconnected. The switch is if I try to start truck and factory battery is dead then the acc wire is dead. So small wire from the 2nd battery powers isolator and starts truck. 

I have used this one day all day. Every time I stopped the truck it wouldn't start. Push button and truck starts right up. After that day the truck charged the factory batter enough to be ok. But I said screw it and ordered a yellow top. 

Issue us the smart alternator and more importantly the bcm program only sees the factory battery till the the key is turned then it tries to play catch up. Real issue I hear most is if one battery dies it will take out the other or the alternator will be in higher amp output to play catch up. 

[aseibel]

I had dual batteries on an old truck, that I just wired up in parallel. No real issues, but that tech was much different than the current one, so I can't give you any current info. I have not installed a second battery on my new truck as my plow doesn't strain the electrical system too much.

 

I would recommend you check out this forum for plow guys, there are several threads about installing dual batteries on there. Caution, the forum is full of a bunch of grumpy old-timers!

 

https://www.plowsite.com/forums/chevy-trucks.6/

 

Edited April 24, 2019 by aseibel

[kickass audio]

I had 2 batteries left over from my old truck with a sound system so I threw it under my hood just for the hell of it. I put a 200a fuse between the positive line and ran it along the positive line that comes across the firewall at the top. For ground I ran it on the same path back to the OEM battery on the passenger side. I just had to buy the battery wedge and bolt from ebay as I have a 14 with the battery tray already installed it just doesn't come with the hold down bolt or wedge. I used 4ga OFC stranded wire, the same you would use for amplifiers. I also ran the positive wire through the OEM hall effect sensor so it didn't mess with the charging system by bypassing it. You can only fit at most a 2ga wire through the sensor with the OEM wires in there as well so be advised of that.