Normal resistance between battery connections?

[Westo]

The resistance between the outer connections of my truck (1114 if it matters) is 85 ohms when on, and 30k ohms when off. Are these figures normal? the relatively low resistance when off seems wrong to me.

Background: I recently put my batteries in again and tried to start it but had some issues. I've started and run the truck before without trouble, although since then I installed headlights and a fuel cutoff. This time there were no problems when I connected the batteries and none when I turned on the truck, but when I started the engine I got smoke from the inner negative terminal and it partially melted. I think it was just a bad connection since the terminal was pretty beat up and deformed, but I've been checking some other stuff since then.

 

[Coug]

smoke from a battery connection IS a bad connection. there isn't good contact between the battery post and the terminal clamp. Even though you have power flowing, when you try to crank the small amount of connection you have at the battery terminal isn't enough for the load, and so it heats up really fast, causing smoke at first, and will melt the lead of the terminals/posts quite quickly if not corrected. You need to disconnect everything and thoroughly clean everything. My recommendation is to get a 4 way post cleaner/scraper that scrapes the surfaces evenly into a relatively even circle, as opposed to a brush type that just only cleans the surface but doesn't fix irregularities.
Example

Amazon.com

However, you can't use a meter for resistance in high power circuits because you can have low resistance to a meter, but the circuit might not have a good enough connection to handle the amount of power the starter is drawing.

I'm not sure what you mean by "outer connections" or "inner connection"on your truck.

If what you mean by outer and inner connections is measuring resistance from the positive battery terminal to the negative one STOP! What you are doing there is measuring resistance through the battery, which is in essence turning your meter into an electrical load. The meter is NOT designed to test resistance in this manner, and you can destroy it.

My guess is the 85 ohm reading you got was through the truck's electrical system and run switch. The reading you got with it off was through the batteries themselves.

 

[Westo]

smoke from a battery connection IS a bad connection. there isn't good contact between the battery post and the terminal clamp. Even though you have power flowing, when you try to crank the small amount of connection you have at the battery terminal isn't enough for the load, and so it heats up really fast, causing smoke at first, and will melt the lead of the terminals/posts quite quickly if not corrected. You need to disconnect everything and thoroughly clean everything. My recommendation is to get a 4 way post cleaner/scraper that scrapes the surfaces evenly into a relatively even circle, as opposed to a brush type that just only cleans the surface but doesn't fix irregularities.
Example

Amazon.com

However, you can't use a meter for resistance in high power circuits because you can have low resistance to a meter, but the circuit might not have a good enough connection to handle the amount of power the starter is drawing.

I'm not sure what you mean by "outer connections" or "inner connection"on your truck.

If what you mean by outer and inner connections is measuring resistance from the positive battery terminal to the negative one STOP! What you are doing there is measuring resistance through the battery, which is in essence turning your meter into an electrical load. The meter is NOT designed to test resistance in this manner, and you can destroy it.

My guess is the 85 ohm reading you got was through the truck's electrical system and run switch. The reading you got with it off was through the batteries themselves.

Thanks for confirming the bad connection idea. I cleaned the other terminals that didn't have problems and since the one that did was so messed up I just ordered a new one. The testing I did was through the electrical system of the truck without the batteries in. By inner connections I mean the ones connected by the bridge cable that goes between the batteries, and the outer the other ones. I'm not familiar with this stuff so I don't know what those are normally called.

 

[Mogman]

If you are talking about replacing one of the batteries you should always replace them in pairs, and yes on a 24V system you can burn off a terminal in just a couple seconds due to a loose or dirty terminal.

 

[Westo]

Just got the new one, and it looks like aside from the old one being in overall bad shape my truck may have also come with a positive connector. The markings on it are gone but it looks a lot bigger than the new one.
Here's the old vs new

 

[Mogman]

turn the 5/16 nut around on the new one.

 

[juanprado]

Positive terminal is a different size than negative on oe mil spec terminals.
I don't see a + or - negative on terminal.
You might have chinacom knockoff.

 

[Westo]

Positive terminal is a different size than negative on oe mil spec terminals.
I don't see a + or - negative on terminal.
You might have chinacom knockoff.

the old one was damaged so I couldn't tell what it was, but the new one is marked negative on the other side

 

[Coug]

There is no way that old terminal could make a good connection.
Hopefully it didn't do any damage to the battery post when it let out the smoke.

Personally (and there is debate on this) I like to use a little Noalox grease on the posts before attaching the terminals, and apply it liberally to the bolts and all exposed surfaces. The difference between this grease and dielectric grease is the dielectric doesn't conduct electricity, where the Noalox has zinc in it specifically to aid the electrical connection (but it does NOT replace starting with 2 clean and properly shaped connection points like the post and terminal clamp).
That's just me. I deal with standby generators and occasionally off grid battery banks and inverter systems, so I've seen my fair share of battery terminals, and after cleaning them up and greasing them, I've never had issues with any of them for years afterwards.