M916A1 battery alternative configuratons

zebedee

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6TL's are hard to come by and silly money. What are the viable options for 12/24 series/parallel ?
Battery layout.png
Factory layout. Cables are very specific lengths so would have to recable if going with 4 "civi" batteries.


alt battery.png
24V only as in M809 series.
 

Tow4

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I put a couple of the 1140 CCA Super Start AGM batteries from Walmart in my M915A1. They were $150 each, have a 5 year replacement, 7 year pro-rated warranty. You have to make a hold down bracket because of the size.
 

zebedee

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I put a couple.....
... but do you need 12V and if so, how did you get it? The 916A1 needs both. Pilling 12V off of one battery will then unbalance the loading of the pair - pressumably.
 

Tow4

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... but do you need 12V and if so, how did you get it? The 916A1 needs both. Pilling 12V off of one battery will then unbalance the loading of the pair - pressumably.
The M915A1 is all 12 volts except for the starter and provision to power 24 volt trailer lights. Mine also has air conditioning and that is 12 volts too. The 12 volt circuit is powered from the first battery in the series pair. The second battery is only used for starting and powering 24 volt trailer lights. The alternator is dual voltage, 12 and 24 volts. Each battery in the series pair has it's own charging circuit, there can be no imbalance because each battery is charged individually.

How does the M916A1 power the 12 volt circuit?
 

Tow4

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Here is a picture of my M915A1 battery installation. I was looking at a picture of my M929 batteries and got the type of battery wrong in my first post. You can read the battery type from the picture. The left battery is number one (B- at the top left) and is the 12 volt source, the right battery is number 2 (B+ at the top right) and is the 24 volt source. The wire with the blue tape is the 12 volt supply being pulled from the jumper between the two batteries.


M915A1 Batteries.jpg
 

Mullaney

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Here is a picture of my M915A1 battery installation. I was looking at a picture of my M929 batteries and got the type of battery wrong in my first post. You can read the battery type from the picture. The left battery is number one (B- at the top left) and is the 12 volt source, the right battery is number 2 (B+ at the top right) and is the 24 volt source. The wire with the blue tape is the 12 volt supply being pulled from the jumper between the two batteries.


View attachment 844827
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Well, that isn't exactly a Mil-Spec battery hold down...
But on the other hand, that configuration would cause the crackheads and thieves to possibly "just walk on by..."

I like it. Definitely sturdy and nothing will get jostled around going down the road or trail!
 

Floridianson

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My 916, 920 and 915 had that same blue wire for 12 volts. I never did understand why there was never a fuse on that line. My 920 I installed a fuse inline right after the battery close to the terminal.
Bit off topic but the coolant to fuel line heat exchanger needs to be bypassed.
 
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Tow4

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.
Well, that isn't exactly a Mil-Spec battery hold down...
But on the other hand, that configuration would cause the crackheads and thieves to possibly "just walk on by..."

I like it. Definitely sturdy and nothing will get jostled around going down the road or trail!
Thanks, the battery hold down is repurposed from the radio rack that was in my S-250 shelter, so it is made from mil-spec parts!

You can't see it in the picture, but there is a relay and circuit breaker between the batteries on the 12 volt supply wire. I turn off the 12 volt supply when the truck is not in use because the tachograph clock will kill the 12 volt supply battery in a few weeks.
 

Floridianson

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Well at least you have a fuse. Myself battery fuse then wire not battery some extra wire then fuse. Dang squirrels, rats and mice chew always want to chew up the sheathing. That is why I feed my squirrels. Rats and mice I leave to the cat.
 
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zebedee

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..... I turn off the 12 volt supply when the truck is not in use because the tachograph clock will kill the 12 volt supply battery in a few weeks.
Does you truck have the large red isolator/battery cutoff knob next to the battery box - if so, doesn't that not kill power to EVERYTHING?
 

Tow4

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Does you truck have the large red isolator/battery cutoff knob next to the battery box - if so, doesn't that not kill power to EVERYTHING?
No it doesn't. I don't have to turn off the 24 volt power. There is nothing on the truck that is 24 volts except the starter and it's only on when I push the start button.

... Pilling 12V off of one battery will then unbalance the loading of the pair...
I'm still waiting for you to tell me how the batteries become imbalanced. I was under the impression that the M916A1 is the same electrically as the M915A1. since I don't have that problem with my truck, what is different about your truck?
 

Floridianson

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.Yea my 915A2 has the 24 volt red kill switch / button to stop any major short in that big line. They do / can start a nice fire. My computer is wired just to 12 volt side and it always has a small draw. I just keep all batteries charged 24 volt or disconnect my two grounds and charge the batteries separate.
 

Floridianson

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Yea agree why. Ray said he has 12-24 volt charging without converter. My 915A2 has the step down converter 24 to 12 The only thing if he wanted he could install the emergency cut of switch for that 24 volt starter line or just be sure it is not rubbing metal or it is supported correct.
 
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Tow4

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If someone is worried about imbalance and only had a 24v charging system-then pulling 12 off of one would eventually cause an inbalance. By using a DC-DC converter to feed your 12v you eliminate the inbalance
That would be true for that situation. However, this thread is about a M916A1, and since a M915A1 which I have, is the same electrically, I answered OP questions based on his truck, which is a dual voltage design.
 

wheelspinner

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That would be true for that situation. However, this thread is about a M916A1, and since a M915A1 which I have, is the same electrically, I answered OP questions based on his truck, which is a dual voltage design.
Well since Howard asked specifically about inbalance I offered an alternative. That’s all.
 

Tow4

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Well since Howard asked specifically about inbalance I offered an alternative. That’s all.
I understand that, however the OP doesn't know how the electrical system in his truck works and suggesting a solution to a problem he doesn't have is confusing. It's better to explain how the electrical system in his truck works so he can see for himself. Maybe he will take the time and read through the TM and become familiar with how the electrical system works.
 

zebedee

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I follow'ish how the factory set up is - I was looking for the right way to use type 31 batteries as an alternative to 4 x 6TL's - do I squeeze 4 in there and get new cables so I can wire the posts the same as factory (posts will be in different physical locations) or is there a way to use just 2 and still have the 12 V supply too. A pic like I drew in post 1 would help!
 
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