can i add a third or even forth battery ?

[Thatoneguy]

My van spends a lot of time running accessories without the engine running. So I added four batteries with a 200A relay in between. The two original batteries run only the engine. Accessories, including head lights run off the secondary batteries. The secondary batteries can be run dead and there are still two full batteries to start the engine. A single 3G alternator charges all six.

Would you happen to have a write-up???

 

[raydav]

Would you happen to have a write-up???

Give me a list of questions. I'll provide answers, and that will be the write-up.

 

[triverrat]

Check ALL of your cables, both ground and positive. Make sure they ALL are clean with NO CORROSION. Clean all posts and joints. There are grounds running form the engine to the chassis. You will be amazed how well they work after the cleaning.

Ya i cleaned all conections and changed a cable it does start better. but from time to time after driving 20 miles or more i turn it off and try to restart it and it will barely turn over.but if its been sitting an hour or so it turns over and starts.any idea what could cause that?

 

[triverrat]

it isnt just a cold start problem,it turns over the worst after driving for awhile.it starts first thing in the morning best!all conections are clean and tight.I could probably use new battery just cant realy afford it. it is like the baterys are weak when its warm but i dont think thats it or it wouldnt help to wait till it cools down to restart it?im confused!:***:

 

[chillman88]

Sounds like starter heat soak but I didn't think our trucks were prone to that....

How old is your starter?

 

[IDIoit]

hard starts when warm sounds like a bad IP to me.

but I have plans on running another set of batteries and a inverter for AC use.

DC coffee pots just suck.

dual alternators, and one of those motorhome bypass switches if the main charging system has an issue.

 

[chillman88]

hard starts when warm sounds like a bad IP to me.

I would too but he didn't say it starts hard, he said turns over hard.

isnt just a cold start problem,it turns over the worst after driving for awhile

 

[DaveBen]

Ya i cleaned all conections and changed a cable it does start better. but from time to time after driving 20 miles or more i turn it off and try to restart it and it will barely turn over.but if its been sitting an hour or so it turns over and starts.any idea what could cause that?

Did you clean the ground cables? They need to be just as clean as the positive cables. They are the other half of the electrical system.

 

[mblaney]

Ya i cleaned all conections and changed a cable it does start better. but from time to time after driving 20 miles or more i turn it off and try to restart it and it will barely turn over.but if its been sitting an hour or so it turns over and starts.any idea what could cause that?

You need to get a meter on that and measure voltages. I would suspect you have a bad ground between engine and chassis. I suggest this for hot condition and for cold, and check at both batteries:

1. measure voltage in the center of battery posts (not on the cable clamps).
2. measure voltage in the center of battery posts (not on the cable clamps) while cranking.
3. measure voltage at the starter terminal (on the starter side, not the + going to the solenoid) while cranking. Measure to a battery negative (might need to use a booster cable to bring the connection under the truck).
4. You probably can't easily measure the continuity between the engine and chassis (ground) but you can easily replace it. Put a booster cable between an engine stud and a negative battery terminal. Try your hot start again.
5. Hot start, try boosting it off another vehicle. I doubt you could have a bad battery (but only when hot) but this is an easy way to isolate the issue.

If you have a clamp meter you can do some additional checks measuring the current draw at the starter.

 

[79jasper]

Sounds like starter heat soak but I didn't think our trucks were prone to that....

How old is your starter?

But.... what do all engines have in common? Starter, cables, etc.
So if any other engine can do it, why couldn't it happen to a IDI starter?
What it is, is the starter gets hot and builds resistance. Which can happen with bad cables also.

Sent from my SM-G892A using Tapatalk

 

[MIDNIGHT RIDER]

I have a f 350 super duty 4x4 1987 will adding another battery or 2 increase my cold cranking power? and i use extra lights on the back alot to see while loading and unloading! ive got a switch that has three settings on it.battery A,B and both , i was going to use that to run my lights and to back up my original batterys for cold starts or dead battery.is there any spiecal way that they need to be wired or is this too much for my altinator?sugestions and advise welcome ,thanks

You have the right idea and a good start to implementing it; more batteries are always better.

This is how I did my multiple battery setups in some of our trucks:
To maintain 12-volts, and not 24 or 36 or even more, always put the HOT cables on the +/positive posts and the GROUND cables on the -/negative posts and you will only ever have 12-volts, regardless of how many batteries you connect.

All of my batteries are Group 31s stud terminal.

I have two dedicated starting batteries that are only ever used when starting the engine; I have these tied together via a four position Cole-Hersee switch as you already described; I can turn ON both batteries, turn OFF both, or turn ON only a single battery should one or the other ever have a dead cell or internal short or such; I can also turn OFF the batteries as an anti-theft measure.

The alternator is always connected to these batteries.

The remaining batteries power ALL other accessories and are isolated from the starting batteries whenever the engine is not running by an oil-pressure switch controlled HUGE constant-duty solenoid.

When oil pressure reaches 5-psi, the solenoid engages and thus connects the accessory batteries to the alternator and starting batteries; when the oil pressure drops below 5-psi (engine OFF), the solenoid dis-engages and breaks the connection between the starting batteries and accessory batteries.

I have a big battery ON/OFF switch that can connect the accessory batteries to the starting battery circuit should I ever need to "self jump-start" the engine in the event that something should be amiss with the starting batteries. (or should the big solenoid ever fail)

I can leave lights and accessories ON for days and it not affect the starting batteries; they will remain fully charged and ready for action, regardless of how low the accessory batteries may become.

This constant duty solenoid set-up is way better than the more commonly used isolaters as I have a lot more control over what is going on with the batteries and a lot more options as to the what and when.

I hope this helps.

 

[MIDNIGHT RIDER]

As for the easy cranking when cold and sluggish cranking when hot: things expand when hot and contract when cold; the first place I would look is the main cable connection at the starter and also the main HOT terminals connection INSIDE the starter.
I have had experience with this on large over-the-road trucks and in all cases the problem has been at the main cable connection of the starter.
The engine heat causes the starter housing to expand and any loose connection to open up enough for poor connectivity; when the engine is not running, the starter cools off and contracts, and the questionable connection comes together enough to provide cranking power.
At least that has been my experience.

 

[sgallaty]

I strongly prefer marine connections on batteries. I got into the habit on my RV, and have never looked back. For regular batteries you can crimp marine ends onto your cables, and then make a good clean snug connection with a marine terminal adapter using dielectric grease (think vaseline) on clean connectors and never remove it.

 

[MIDNIGHT RIDER]

I strongly prefer marine connections on batteries. I got into the habit on my RV, and have never looked back. For regular batteries you can crimp marine ends onto your cables, and then make a good clean snug connection with a marine terminal adapter using dielectric grease (think vaseline) on clean connectors and never remove it.

If by "marine connections" you are meaning copper "ring" terminals, that is definitely the way to go.

On the few odd things I own that I cannot fit a stud terminal Group-31s, and have to settle for a lead post battery, I use marine terminal adapters as you describe; and, as you state, once I install the marine adapter, it remains unmolested until the day the battery dies; a good dose of Vaseline and it will remain clean as a whistle with no need to ever be removed.

Also, I am a firm believer in Vaseline in electrical connections and slathered over battery connections.

On any wire or cable that I cannot solder for whatever reason, I force as much Vaseline as I can up into the strands and fill the terminal cavity with Vaseline before inserting the cable, then I firmly crimp the connection.

I have inspected some of my Vaseline battery cable connections ten or more years later and the inside of the terminal and the wire strands are always cleaner and shinier than they were on the day the connection was made.

In fact, on anything bigger than 8-AWG, I prefer and trust my Vaseline/crimp connections over a crimp/solder connection.

 

[sgallaty]

If by "marine connections" you are meaning copper "ring" terminals, that is definitely the way to go.

...

Yes. When I finally pull off my RV batteries, there is zero rust and corrosion on any of the wire terminals so long as I've maintained a good coating. I don't slather it, but I make sure everything has a good film on it.

Also in response to the OP - borrow an amp tester from autozone if you don't have one and see what your CCA are. That way you can adjust and test.

Yes you can add batteries but don't tap off of the end battery. Tap your positive from the first in the parallel and the negative from the last so that you don't overload the last parallel wires in the set. From experience.