1Quik7 Posted August 25, 2017 Report Share Posted August 25, 2017 So I recently picked up a Powerstroke for a good deal and today decided to upgrade the sound system. Well, when I was hooking my power wire up to the driver side battery, I noticed when I unhooked the positive lead...I lost power? Should I ever lose power with just 1 battery disconnected? I thought they were parrallel and acted like just a big battery... The main reason I ask is I've recently been having crank no start issues, fuel/oil pressure good, yada yada....but a jump fires it right up. Quote Link to comment Share on other sites More sharing options...
STEVE-O Posted August 25, 2017 Report Share Posted August 25, 2017 That could be the stronger battery and the other is weak, I would get them both tested Quote Link to comment Share on other sites More sharing options...
1Quik7 Posted August 26, 2017 Author Report Share Posted August 26, 2017 Well I went to AutoZone and they tested good, which means literally nothing since they've told me that before and a brand new battery fixed a previous issue. But I asked them if I needed to isolate the battery...of course they said no. Quote Link to comment Share on other sites More sharing options...
STEVE-O Posted August 26, 2017 Report Share Posted August 26, 2017 Did they dis connect them and test each separate or leave them connected as Factory and try and test them? Quote Link to comment Share on other sites More sharing options...
1Quik7 Posted August 26, 2017 Author Report Share Posted August 26, 2017 Nah..he just hooked it up to the other battery...which I questioned. Quote Link to comment Share on other sites More sharing options...
unfunnyryan Posted August 26, 2017 Report Share Posted August 26, 2017 Is it hooked up in parallel? is there two wires going to positive and negative? Is the drivers side the main battery or secondary battery? Quote Link to comment Share on other sites More sharing options...
SPL_Josh Posted August 26, 2017 Report Share Posted August 26, 2017 Yes with one disconnected you still should have power. Check your grounds and positive cables for a bad connection. Quote Link to comment Share on other sites More sharing options...
99StockGT Posted August 28, 2017 Report Share Posted August 28, 2017 Welcome to the Powerstroke world! And yes you should have power with just one battery connected, how old are the batteries in there? Are they matched or no? Often times people will cheap out on buying batteries and just toss 1 good one in while the other limps along... until it doesn't. Quote Link to comment Share on other sites More sharing options...
xlr8tn Posted August 28, 2017 Report Share Posted August 28, 2017 same way on my duramax....you get the dual batteries in parallel to provide starting amps and glow plug amps but only one powers the other electronics. If memory serves me correctly it's reverse on my truck.....I can unhook drivers side and not lose power to radio and things but will if I uhook passenger side. Quote Link to comment Share on other sites More sharing options...
1Quik7 Posted August 28, 2017 Author Report Share Posted August 28, 2017 Welcome to the Powerstroke world! And yes you should have power with just one battery connected, how old are the batteries in there? Are they matched or no? Often times people will cheap out on buying batteries and just toss 1 good one in while the other limps along... until it doesn't. Batteries are fairly new, I believe from this year, and they match. It has not been driven much; if the oil change info is correct it got about 3k miles since last July. I only drive about a mile to work, so that may be the issue of why they are low. Quote Link to comment Share on other sites More sharing options...
Red Beard Posted August 28, 2017 Report Share Posted August 28, 2017 Depending on the year of the truck, that may be causing your hard start issues. Short trips less than 10 min are hard on older diesels (not sure about the newer ones). Doesn't give them enough time to warm up and burn off nasties that build up over time. I would suggest running some Diesel clean through the tank to clean things up a bit. Might help with getting some easier starts. This will also help if you are getting some algae growth in the fuel tanks. It is common in older diesel that has been sitting to start growing unwanted stuff lol. Also some power strokes require you to hold the gas on at start (half pedal in warm weather/ floored in cold). This again applies more to the older ones than new, but may help. Quote Link to comment Share on other sites More sharing options...
supldys Posted August 30, 2017 Report Share Posted August 30, 2017 So I recently picked up a Powerstroke for a good deal and today decided to upgrade the sound system. Well, when I was hooking my power wire up to the driver side battery, I noticed when I unhooked the positive lead...I lost power? Should I ever lose power with just 1 battery disconnected? I thought they were parrallel and acted like just a big battery... The main reason I ask is I've recently been having crank no start issues, fuel/oil pressure good, yada yada....but a jump fires it right up. What year? 6.0 or 7.3? I'm fairly certain on mine (2006) if I unhook the passenger side I will lose all power, but the driver side I won't. I believe the driver side is only hooked to the passenger battery and not to any of the fuse blocks. So not sure depending on what year you have if its the same or reverse. So that means if the passenger battery is bad, then only the driver side is powering it and when you unhook it, everything will lose power. Basically test them individually, never does any good to test the batteries together. If you drive short trips, maybe invest in a trickle charger to keep a charge on them. Quote Link to comment Share on other sites More sharing options...
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