Dual Battery Help

jonny72888 · April 14, 2011

So today I added second battery to my truck. I made a mount for it and put in in the opposite corner of the factory battery. I ran a 1/0 cable from on + to the other + and then grounded the second battery with a 0 gauge cable to the engine block. I also replaced the alternator wire from a #8 to a #1 wire.

So now my question is how come when I turn the truck on the second battery starts to bubble out acid. I have tried 2 other batteries. If I take the second battery and put it on the ground and then hook up jumper cables from one battery to the other it will do the same thing. both batteries are cool to the touch and all of the cables are cool. Im puzzled. I have done this to many other trucks will good results.

Both batteries are brand new and the same kind. 850cca 1000cc. Made on the same day.

Truck specs... 2007 silverado 1500 classic. z71. 5.3l 100% stock. 145amp alternator

I didnt not want to use a battery isolator but unless I can get this to work I guess Ill have to.

crankman · April 14, 2011

okay i run dual batteries i have always just ran postive post from one battery to postive post of the second battery and negative post to negative post of second battery. I didnt go to the block. Can you back up and check your charging voltage at the original battery without the other connected and verify its around 14volts?

jonny72888 · April 14, 2011

okay i run dual batteries i have always just ran postive post from one battery to postive post of the second battery and negative post to negative post of second battery. I didnt go to the block. Can you back up and check your charging voltage at the original battery without the other connected and verify its around 14volts?

yes, sorry I forgot to add that.

charging voltage with one or both batteries is 14.3 and when the truck is not running the voltage is 13.1

I also tried with the negatives hooked up together.

I started thinking and is the alternator wire small for a reason?

jmacca · April 15, 2011

okay i run dual batteries i have always just ran postive post from one battery to postive post of the second battery and negative post to negative post of second battery. I didnt go to the block. Can you back up and check your charging voltage at the original battery without the other connected and verify its around 14volts?

yes, sorry I forgot to add that.

charging voltage with one or both batteries is 14.3 and when the truck is not running the voltage is 13.1

I also tried with the negatives hooked up together.

I started thinking and is the alternator wire small for a reason?

hmm...I can't think of any reason why your setup is doing that.

If nothing is hot, then you don't have a strange current problem.

I have just received my isolator, and was just about to pull the trigger on a dual setup myself.

I plan on connecting the positives at the original battery, fusing the second battery, and running the ground to the block or frame.

I wish I could help, but it sounds as though all is proper.

John

old-chevy-dude · April 15, 2011

Both batteries are brand new and the same kind. 850cca 1000cc. Made on the same day

defective batteries.. coming from the same lot series I would suspect it is very possible both are bad.. might try a different brand and return those.... just a thought

jonny72888 · April 15, 2011

Both batteries are brand new and the same kind. 850cca 1000cc. Made on the same day

defective batteries.. coming from the same lot series I would suspect it is very possible both are bad.. might try a different brand and return those.... just a thought

At first I had a 770cca and the 850cca battery then the 770 started to spill so I returned it to get another 850 so that both batteries would be the same. So I do not think that would be the problem. I have tried other batteries but never without one of the 850s in the mix. Ill give that a try tomorrow.

Anyone else have any thoughts on it?

Wires · April 15, 2011

Both batteries are brand new and the same kind. 850cca 1000cc. Made on the same day

defective batteries.. coming from the same lot series I would suspect it is very possible both are bad.. might try a different brand and return those.... just a thought

At first I had a 770cca and the 850cca battery then the 770 started to spill so I returned it to get another 850 so that both batteries would be the same. So I do not think that would be the problem. I have tried other batteries but never without one of the 850s in the mix. Ill give that a try tomorrow.

Anyone else have any thoughts on it?

What happens if you unhook the first battery? Does it still leak? Sounds like a bad battery issue.

jonny72888 · April 15, 2011

Both batteries are brand new and the same kind. 850cca 1000cc. Made on the same day

defective batteries.. coming from the same lot series I would suspect it is very possible both are bad.. might try a different brand and return those.... just a thought

At first I had a 770cca and the 850cca battery then the 770 started to spill so I returned it to get another 850 so that both batteries would be the same. So I do not think that would be the problem. I have tried other batteries but never without one of the 850s in the mix. Ill give that a try tomorrow.

Anyone else have any thoughts on it?

What happens if you unhook the first battery? Does it still leak? Sounds like a bad battery issue.

well right now I have have battery 1 hooked up and im driving the truck. Its going just like it should. tomorrow Ill try switching the batteries around more and Ill try to get 2 more to use in place of the 2 that I have now,

jandersinc · April 15, 2011

Just out of curiosity, why do you need 2 batteries?

jonny72888 · April 15, 2011

Because of the various things I run with my truck.

Plow

10000lbs warn winch

3000watt inverter

Those take their toll on the battery. The inverter and the radio can be running for hours at a time so it would be nice to have that extra power. I did not want to use a isolator because I wanted all the current I could get for the winch and plow.

jrrod2004 · April 15, 2011

Because of the various things I run with my truck.
Plow

10000lbs warn winch

3000watt inverter

Those take their toll on the battery. The inverter and the radio can be running for hours at a time so it would be nice to have that extra power. I did not want to use a isolator because I wanted all the current I could get for the winch and plow.

Several questions:

1) are all the battery connections fused?

2) are these cables that you installed low resistance? (dont automatically assume so, test if possible)

3) Only recommendation for an isolator (my experience and money thrown away at my setup): Perfect Switch Single Rectifier Isolator

http://www.perfectswitch.com/power-gate/ba...ifier-isolator/

Painless Wiring and others have all these extra wires, drilling the firewall for the control switch, cooling, huge power drops, etc....too damn much to deal with at the end of the day

(Stupid easy to install) - to buy directly from site, click order and type in "buy" for password.

redsled2007 · April 15, 2011

Are you using the inverter and running the engine at the same time? On my RV, if I'm driving and turn on the inverter, in a couple of minutes the over temp alarm will sound. The instrument panel shows that I'm discharging at about 100 amps and charging at 160 amps. (If I turn on the coffee pot, it will go up to 300 amps) If I ignore the alarm in a few minutes the batteries start to boil and I can smell the acid.

So do you have the inverter on all the time or can you turn it off? A 3000 watt inverter will draw a HUGE amount of amps. mine is only a 2000 watt.

Sir Dan · April 15, 2011

I installed the Painless system recently. Fairly easy to install and yeah, there is some wiring involved such as grounding the device and an indicator light (optional) but so far, it works great. Never have to worry about a dead battery, which was my main reason for buying it. If you're looking for more continuous amperage, you may want something else since Painless only ties the aux. battery in when a large load is placed on the main or if it senses voltage below a set point.

jonny72888 · April 15, 2011

Are you using the inverter and running the engine at the same time? On my RV, if I'm driving and turn on the inverter, in a couple of minutes the over temp alarm will sound. The instrument panel shows that I'm discharging at about 100 amps and charging at 160 amps. (If I turn on the coffee pot, it will go up to 300 amps) If I ignore the alarm in a few minutes the batteries start to boil and I can smell the acid.
So do you have the inverter on all the time or can you turn it off? A 3000 watt inverter will draw a HUGE amount of amps. mine is only a 2000 watt.

No, the inverter was not on while this was going on. It does draw alot when I have alot of tools running.

I installed the Painless system recently. Fairly easy to install and yeah, there is some wiring involved such as grounding the device and an indicator light (optional) but so far, it works great. Never have to worry about a dead battery, which was my main reason for buying it. If you're looking for more continuous amperage, you may want something else since Painless only ties the aux. battery in when a large load is placed on the main or if it senses voltage below a set point.

Thats why I didnt go with the painless. I needed to have more current. If I used the isolator I would still only have the power from one battery. Im not worried about the battery going dead as much as the winch and plow. every time I used the winch I woould shut the lights off because they would dim some much that it was pointless to have them on.