M818 batteries

[Thomas_G]

What size or model battery are being used if not using 6TL.

I have to get new batteries for my M818.

Text at me pics. 832.674.5792

 

[simp5782]

Group 31 from Oreillys Part # 31-5 use 2 of them or You can use 4 of the 24Fs from walmart @ $50 each that are smaller. Or You can use 2 big ole 8D's that are around $160 each from Batteries plus for Duracells.

 

[Thomas_G]

You have picture of cable connection for the two set up?

 

[73m819]

I uses two 8Ds in my m819, new blems that cost $80 each the last time I replaced the set, that was three or four years ago.

 

[simp5782]

You have picture of cable connection for the two set up?

For two batteries. + to the + on the starter on one battery. - to - starter on the other battery then hook + on one battery to the other battery -

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[Thomas_G]

With the two 585cca how does it start? Not too slow?

 

[simp5782]

With the two 585cca how does it start? Not too slow?

Those are just throw ins for a wrecker i am working on to operate. It only runs the fuel solenoid for power. Nothing else. No lights or anything else. just around the yard. I would suggest 4 of them or two group 31s or two 8Ds for anything needing to go on the road. if you had a starting issue those two 24s i don't think will spin it over long. especially without a gear reduction starter.

 

[MyothersanM1]

Two Interstate group 31's in a custom installed M915 battery box. One of the best mods I have ever done.

 

[tobyS]

(2) 8D 1450 cca

 

[swbradley1]

With the gear reduction starter in my 813 two Group 31s spin it like a top at freezing and I'm sure it would work great at lower temps I'm just not going out to try.

 

[74M35A2]

I have one more of those gear reduction starters left if anybody is Jonesing for one... Can package deal with a 24v 100A brushless 33Si alternator if you really want to update your ride to modern spec.

 

[sandcobra164]

Good batteries are important. I'm sure 74M35A2 can explain better than I can. I had a set of old group 31's in my truck that were probably well past their get rid of date. On a warm day they would start the M923 as long as it started on the 6th or 8th rotation of the engine. Worst day I had was when the truck failed to start on the 10th rotation of the engine. Somehow the starter stayed engaged after I turned both switches on the dash off. Next thing I know, the passenger seat was smoking. I quickly disconnected the negative cable and heard the starter solenoid clunk indicating it disengaged. Cleaned connections, installed new Exide 6TAGM 1550 CCA batteries and no more issues. Truck starts much easier and can even handle extended cranking when changing the fuel filter. I've never understood why weak batteries would cause wires or connections to smoke. In my mind if they are too weak to turn the starter over, they are too weak to cause damage. I'll turn it over to the experts to chime in. I guess if you have strong batteries, they have enough current to "bridge the gap" of a weak connection.

 

[74M35A2]

The load of the starter is fixed. Example, 7.0kW (actual number for 24v modern gear reduction). So, at 24v, this would be 292 amps (7000/24), well below what a battery can deliver, rightfully so. As the battery is discharging during cranking, the voltage is dropping, but the load stays the same, so the current draw increases. Let’s say the cranking voltage drops down to 15v quickly because the batteries are old/weak, for the fixed 7.0kW starter load, you are now pushing 467 amps (7000/15). So as voltage drops, current increases, to the limit of the battery. Volts x amps = watts. Weak connections are exposed as the current is nearly doubling, etc...

Fresh batteries (less than 5 years old) which hold a high level of cranking voltage will keep the current draw down.

Seperately, the faster a starter can spin, the cooler it will run, and longer it will last, because less time is spent heating each commutator segment as the brushes pass on the armature.

 

[Thomas_G]

Very nice setup

 

[MKD73]

Thanks for your help! The wind and rain finally let up long enough to get it installed.. It works great!

 

[74M35A2]

Glad you like it. Apology they sound modern, because, they are.

 

[MKD73]

I am ok with sounding modern since it actually makes noise now! haha

 

[simp5782]

Cummins dealers actually sell their 8Ds for $180 exchange. Which isnt too bad.

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[Iceman3005]

Those 8D's batteries are pretty sweet.