The Once And For All On Batteries...

[JD4044M]

Nice Charger but big bucks to at $400.00 each on sale.

 

[Awesomeness]

Nice Charger but big bucks to at $400.00 each on sale.

They have sales and stuff. I think I got mine <$300, like 4-5 years ago. I assume it pays for itself over time, by maintaining the batteries better and prolonging replacement. I don't know how old the batteries in the truck were when I got it (or how many times soldiers had mistreated them and run them dead), but one finally failed last year, and two this year. So I'm satisfied with it.

 

[Ronmar]

The 6TL’s I have are 120AH(says it right on the lable).. AH capacity is only additive in parallel, just like voltage is only additive in series, so the 4 battery bank on the LMTV is 240AH... a pair in series would be 120AH...

The limiting factor for charging a battery, is the same as for discharging one, which is the ammount of time it takes to draw or push the sulfur ions out of or into the electrolyte solution, and this requires that the electrolyte move into close contact with the plates. Thats why batteries are usually rated at 20 hour AH rates, as that is the most efficient time frame with the least loss to circulate the electrolyte and draw out the batteries full capacity. As mentioned the faster you try to push or pull, the more heat is made and heat = loss...

The mat in the AGM’s are way more efficient at distributing electrolyte(like the wick in a oil lamp)so they can deliver more current and also draw more current during a charge. Since the plates or grids are supported and surrounded by mat, they are more resistant to vibration, but In my experience they are no more tollerant of mistreatment and undercharge than any other lead acid(maybe less so) and I have experience with a couple different platforms to base that opinion on.

I wouldn’t use AGM’s for a house battery or deep cycle application for a couple reasons. They do have a slight edge on charge efficiency, and they can charge faster(if you have the energy source), but in deep cyclic use, they typically have a significantly shorter lifespan, and cost significantly more. IE: a good wet cell will typically last 1.5 times as many cycles before dropping to the 50% capacity point as an AGM...

Off-road race car, motorcycle, ATV, go-fast boat or airplane, or even a slow moving wheeler that operates at extreme angles, and where weight and vibration resistance are important, AGM is the ticket. The added cost and shorter life just don’t make sense to me for an RV house battery... And unless you are fitting out one of these trucks to race in Dakar, they don’t make a lot of sense as a service battery either...

 

[Awesomeness]

The 6TL’s I have are 120AH(says it right on the lable).. AH capacity is only additive in parallel, just like voltage is only additive in series, so the 4 battery bank on the LMTV is 240AH... a pair in series would be 120AH...

The CCA/charge current only adds in parallel, but the AH capacity adds both in series and in parallel. So adding 4 batteries @120AH/each equals 480AH.

(The AH capacity is basically "how big of an energy bucket" they are. So adding more "buckets" literally adds more energy volume to drain from. Or think of it like gas tanks. Putting two gas tanks in series, one after the other, doesn't let you drain it any faster, because it's still just going through one hose. But you do get twice as much volume to drain. And putting two gas tanks in parallel, side by side, lets you both drain the extra capacity of two, plus drain from two hoses at once.)

 

[doghead]

Don’t forget to factor in the size of the hoses.

And the hose connections as well.

 

[Ronmar]

The CCA/charge current only adds in parallel, but the AH capacity adds both in series and in parallel. So adding 4 batteries @120AH/each equals 480AH.

(The AH capacity is basically "how big of an energy bucket" they are. So adding more "buckets" literally adds more energy volume to drain from. Or think of it like gas tanks. Putting two gas tanks in series, one after the other, doesn't let you drain it any faster, because it's still just going through one hose. But you do get twice as much volume to drain. And putting two gas tanks in parallel, side by side, lets you both drain the extra capacity of two, plus drain from two hoses at once.)

No, Amp hours is the wrong term to express the amount of energy storage gained in series... IE: A 12V 100AH battery would support a 12V@10A load for 10 hours. Two 12V 100AH batteries in series to make a 24V battery, would support a 24V@10A load for the SAME 10 HOURS... It is twice the amount of work being performed, but it is still the same application to the amp hour rating... the 24V unit takes the same amount of time to charge as the 12V unit given the same charge current at the two different voltages. The difference from 12V to 24V doubles or halvs the energy in play, but has no bearing on an amp hours rating. Now if you parallel another set of batteries, you have now added to the amp hour capacity while maintaining the same voltage.

The correct term for capacity added by adding in the series dimension would be watt hours, which is not as often used... It is twice as much energy(watt hour capacity), when you add two batteries in series, but you are also drawing from it at twice the energy rate(24V vis 12) so it is still the same draw on the amp hour capacity...

 

[Mullaney]

Hoses / Cables (similar enough?)

Strangely enough, the M1088 with 4 batteries that were replaced (after the thief stole mine) had a charging problem. I went to the local parts store months ago. Bought 4 twelve inch "lugged ended cables". I attached them to the batteries with lots of help on here. Struggled but finally connected the wires to the right place - again with help here.

Everything was fine for about a month. And then one day I went to to crank the truck. The normal sounds where relays clicked, after-cooler fans came on, and dash lights came one - except they didn't happen (turn on). All the 12v stuff was down around 9v. Measured with a volt meter to confirm.

ANYWAY,

I charged all four batteries one by one. Charged to about 13v +/- and while everything was disconnected I figured out that the small "jumper" wires were just too small. When I replaced them from McMaster Carr 2/0 wire, my problems disappeared.

So, size definitely does matter. In battery cables anyhow...

.

 

[Awesomeness]

No, Amp hours is the wrong term to express the amount of energy storage gained in series... IE: A 12V 100AH battery would support a 12V@10A load for 10 hours. Two 12V 100AH batteries in series to make a 24V battery, would support a 24V@10A load for the SAME 10 HOURS... It is twice the amount of work being performed, but it is still the same application to the amp hour rating... the 24V unit takes the same amount of time to charge as the 12V unit given the same charge current at the two different voltages. The difference from 12V to 24V doubles or halvs the energy in play, but has no bearing on an amp hours rating. Now if you parallel another set of batteries, you have now added to the amp hour capacity while maintaining the same voltage.

The correct term for capacity added by adding in the series dimension would be watt hours, which is not as often used... It is twice as much energy(watt hour capacity), when you add two batteries in series, but you are also drawing from it at twice the energy rate(24V vis 12) so it is still the same draw on the amp hour capacity...

You're right. The AH rating stays the same, but the "two gas tanks" analogy is still meaningful. In series you now have 2x the voltage, you'll be drawing 1/2 the amps for a given work (Watts), and thus run 2x as long with two batteries. So it is a capacity improvement, and still takes 2x as long to recharge too.

 

[Third From Texas]

I was watching the 4 New Batteries I just put in. Found that one 12 volt was dropping and not the other? It was not tied into the other 12 v. Charged all 4 at 24 volts they did not charge equal for me. To get them all floated even I had to do one at a time at 12v. The 12 v part is going down slowly over a few days? It did the same thing with the 4 Red Tops that were in it. Pulled them out and found only one was bad out of the group. I still have them. Going to put a amp meter on the cable to see where it is bleeding off to. The Cold Temps I was talking about was me freezing my butt off. I did not have gloves. It is blowing 23+MPH and 39 MPH Gusts at 19 degrees. Did not take long unhooking my batteries to get my fingers froze! Will be dropping down to 1 degree real soon here.

12v vampiric drain?

Add a balancer and all will charge evenly.

 

[Ronmar]

You're right. The AH rating stays the same, but the "two gas tanks" analogy is still meaningful. In series you now have 2x the voltage, you'll be drawing 1/2 the amps for a given work (Watts), and thus run 2x as long with two batteries. So it is a capacity improvement, and still takes 2x as long to recharge too.

Correct, except the 2x as long to charge part. That would only be true if you are charging at the same wattage input for both voltages. IE: A 12V@100Amp alt is 1200W. A 24V@ 100A alt is 2400W. Now if your 24V alt is only 50A/1200W, then yes, the 24V will take twice as long to charge the 100AH battery, because your alt has half the amp output at the higher voltage...

If your two different systems, 12V @ 100AH and 24V@ 100AH Both use 100A alternators in their respective voltages, they will both recharge in the same amount of time...

AC systems typically deal in watts, but I think DC systems, particularly those with batteries usually stay in amps so it is a little easier to design and eval just looking at labels, because for a given voltage everything is already in like terms...

 

[Superthermal]

Lithium Cranking Amps and LiFePO4 CCA Guide - Power Sonic

Power Sonic's guide to lithium cranking amps and LiFePO4 CCA. We explain what cold cranking amps are on a lithium starter battery. Learn more

www.power-sonic.com

I was looking into making my own Lithium battery set that would be mounted under the seats in the cab (For several reasons I will not go into here), but when I came across this from a Lithium battery manufacturer I decided Lithium is not "Military Grade" since it will never satisfy a cold start in crazy cold weather. Bummer. I was wanting to have it integrated with a set of solar panels but if they will not charge when chilled what good would they be? NO GOOD LOL.

 

[Third From Texas]

View attachment 854155

Lithium Cranking Amps and LiFePO4 CCA Guide - Power Sonic

Power Sonic's guide to lithium cranking amps and LiFePO4 CCA. We explain what cold cranking amps are on a lithium starter battery. Learn more

www.power-sonic.com

I was looking into making my own Lithium battery set that would be mounted under the seats in the cab (For several reasons I will not go into here), but when I came across this from a Lithium battery manufacturer I decided Lithium is not "Military Grade" since it will never satisfy a cold start in crazy cold weather. Bummer. I was wanting to have it integrated with a set of solar panels but if they will not charge when chilled what good would they be? NO GOOD LOL.

Lithium are best suited for house batteries (ie: RV where they are tucked away indoors). The benefits there are valid if you can afford to go with them.

But I'd never considered lithium for "truck" batteries.

 

[chucky]

while were on the subject ive had all 4 of my 6tl hawkers out of the truck individualy charging them and at rest 3 of them are 12.98 on the meter and 1 is 10.78 at rest so i put them back in truck today the 24 spins it over no start i meter the 12v batt side reads 10.81 and 13,8 on 24 side so i flip the switch to tie 12 house batteries to the 12v side of truck batts fires rite up so it looks like i need 2 12v batteries for truck side do they have to be agm or can i put 2 31s beside the 2 agm 6tl 24v and the 31s be the 12v side

 

[chucky]

Dual 6TLs on all my trucks.

Mostly because I like the OEM tie down system and didn't want to hack up the top in case I reverted back to four (never know when we *all* may be at war or have to bug out to nasty cold places, etc). But I've seen people retrofit all sorts of sizes. There are a size or two that will fit in the OEM holder, but be advised that one company may add different handles or strap slots that suddenly make their battery not fit. So if you can, see one fit before purchasing two (or four).

There are several threads here and on the LMTV FaceBook page (FB blows goats with their censorship, fyi). Look for ideas. Decide if you want to chop your box lid or make a custom tie down, etc. If you are willing to be a bit creative, it opens more options (and some guys have made some slick battery box solutions). Or if you want to stay OEM. Then work from there.

And AGM's (or gels) are awesome especially if you are hammering around off road and don't want to risk banging the plates around. I don't have that kind of money to spend at the moment (I'd love to try big-arse Optimas or something). But I'm poor, so NAPA/Interstate 6TL's for me.

How much are u giving for the napa/interstate 6tls

 

[Ronmar]

Why dont you just take the two best of the three 6TL’s that have 12.98 at rest and install just them? A pair of 6tl’s is way more than the engine/starter needs… They will charge faster and maintain a higher state of charge and your alternator will not be working as hard…

 

[chucky]

In my mind the 2 back batts are my 24v stuff the 2 not so good are in the 12v positions im feeding the 2 12v 8d agm with 1000 watts of solar every day to my house agms in the camper then on to my 2 12v truck batteries and im feeding the 12v winch off of the 2 12v truck batteries so i comfortable with 4 batteries in the truck to be backing up the house batteries if the need arose ! just wanting to keep redundancy in either direction for total silent power over night without running any gens or engine till sun up or whatever the case

 

[chucky]

I guess what im really saying im spoiled to all the agm power back up to the house if i ran all 6 agms down to nothing over night my diesel generator is on its own battery to start it then it charges all the batteries back up to full if theres no sunlite to feed solar or atleast enough to charge truck batteries enough to start truck motor then it can recharge all the 6 agms by itself i just dont know if i can mix 2 31s for the time being with the 2 6tls or will that mess something up between lead acid and agm mixing

 

[Superthermal]

It seems that the 6T-AGM is the stock battery for the M809/939 series... Correct? But I see in the 5 TON parts list that 8D batteries are listed and the 31 series.. From the sizes listed below the 8D batteries are virtually two 6T batteries put together.
So I am a bit confused on that... I see talk that just two batteries are fine for the 24 Volt system for civilian use. But 4 is stock Military style.

Question: If your running a dual voltage alternator are you running three batteries? Two for the 24 Volt system and a third for the 12 Volt add on items? Or ???

https://www.steelsoldiers.com/threads/dual-12-24-volt-alternator-on-m932a2.115742/
https://www.ceniehoff.com/Documents/Ctrl_Hyperlink/II0030A_uid121020091141311.pdf

Question#2 If you are going to run only two batteries, would running the 8D batteries give a bit more oomph in the CCA department and the overall Amp hours? These were some examples that I was looking over below.


Group 31- AGM Batteries
Example Battery:
https://www.batteriesplus.com/productdetails/battery/sli/bci-group-31/sli31agm
L= ±13
W=±6.5
H= ± 9.5
± 100 Amp hour
±925CCA
Cost ± 275 USD
Weight: 67


The 6T-AGM Batteries
https://replacementbatterystore.com/fiamm-6t-agm-military-ordnance-replacement-battery/
Sizes seem to vary on these...
L= ±10.47 / 11.26
W= ±11.02 / 10.59
H= ±9.05 / 9.17
± 120 Amp hour
± 1225 CCA
Cost ± 640 USD
Weight = 86


The 8D-AGM Batteries
https://www.renogy.com/deep-cycle-a...4GjOHtSwnCT85zxodfZn5uDk3O0PYAXRoCmzYQAvD_BwE
L= ±20.75
W= ±11
H= ±10
± 200 Amp hour
± 1425 CCA
Cost ±400 USD and up
Weight = 127lbs

 

[chucky]

It seems that the 6T-AGM is the stock battery for the M809/939 series... Correct? But I see in the 5 TON parts list that 8D batteries are listed and the 31 series.. From the sizes listed below the 8D batteries are virtually two 6T batteries put together.View attachment 854230
So I am a bit confused on that... I see talk that just two batteries are fine for the 24 Volt system for civilian use. But 4 is stock Military style.

Question: If your running a dual voltage alternator are you running three batteries? Two for the 24 Volt system and a third for the 12 Volt add on items? Or ???

https://www.steelsoldiers.com/threads/dual-12-24-volt-alternator-on-m932a2.115742/
https://www.ceniehoff.com/Documents/Ctrl_Hyperlink/II0030A_uid121020091141311.pdf

Question#2 If you are going to run only two batteries, would running the 8D batteries give a bit more oomph in the CCA department and the overall Amp hours? These were some examples that I was looking over below.


Group 31- AGM Batteries
Example Battery:
https://www.batteriesplus.com/productdetails/battery/sli/bci-group-31/sli31agm
L= ±13
W=±6.5
H= ± 9.5
± 100 Amp hour
±925CCA
Cost ± 275 USD
Weight: 67


The 6T-AGM Batteries
https://replacementbatterystore.com/fiamm-6t-agm-military-ordnance-replacement-battery/
Sizes seem to vary on these...
L= ±10.47 / 11.26
W= ±11.02 / 10.59
H= ±9.05 / 9.17
± 120 Amp hour
± 1225 CCA
Cost ± 640 USD
Weight = 86


The 8D-AGM Batteries
https://www.renogy.com/deep-cycle-a...4GjOHtSwnCT85zxodfZn5uDk3O0PYAXRoCmzYQAvD_BwE
L= ±20.75
W= ±11
H= ±10
± 200 Amp hour
± 1425 CCA
Cost ±400 USD and up
Weight = 127lbs

Great info butt some where it seem i read something about not mixing batteries together with amp hr differences. When we would have a 8d agm go down on the road in the house batteries they would replace both agms at the same time even though just 1 battery went down so they were a matched set is why im hesitent to put reg batteries in with agms with loads of amp hrs compared to not so much

 

[Ronmar]

It seems that the 6T-AGM is the stock battery for the M809/939 series... Correct? But I see in the 5 TON parts list that 8D batteries are listed and the 31 series.. From the sizes listed below the 8D batteries are virtually two 6T batteries put together.View attachment 854230
So I am a bit confused on that... I see talk that just two batteries are fine for the 24 Volt system for civilian use. But 4 is stock Military style.

Question: If your running a dual voltage alternator are you running three batteries? Two for the 24 Volt system and a third for the 12 Volt add on items? Or ???

Question#2 If you are going to run only two batteries, would running the 8D batteries give a bit more oomph in the CCA department and the overall Amp hours? These were some examples that I was looking over below.

4 batteries were chosen to meet a particular milspec requirement like being able to set for a month on the Siberian step in wintertime and still be able to crank the engine long enough to start it with no supplemental heat. Un fortunately the person designing the electrical system wasn’t in on this plan and didn’t put an alternator in large enough to comfortably handle this situation. This is the kind of error that recalls and class action law suits are made of out in the real world you can very comfortably drop to two batteries in series for 24 and take the 12v out of the middle to feed the 12v circuits. To answer your questions:

1. Only 2 or 4 batteries are used. The alternator is designed to operate as a simple battery balancer and is looking to supply 2 batteries of equal size placed in series.

2. Yes, two 8D’s would be more capacity than two of anything else. Keep in mind that the alt is strained keeping large batteries fully charged. Cat specs a pair of group 31 lead acid wet batts(100AH) for the power equipment that uses these engines. A pair of group 31’s is also a good match for the alternator. A pair of group 31 AGM’s will push the alt over 100% load. As for cranking capacity, my 3116 pulls a brief peak to about 290A when starting to crank, but averages just over 150A when cranking… If I was worried about being able to start when cold, I would take steps to mitigate that instead of oversizing the bank as there are other disadvantages besides alt overload.

No you do not want to mix battery capacities. One will top off faster than the other and then start to overcharge, while the other larger battery may have trouble reaching a full state of charge. AGMs are still lead acid, it is just their internal design gives them a lower internal resistance so they can feed more current and can accept/demand more current(nearly twice as much) when charging for a given size battery compared to a normal wet plate cell design.

You certainly don’t want to mix those different types. This same thing can happen when you have a failing battery in parallel with a good one. The failing battery gets overcharged and gets progressively worse, and the good battery never gets fully charged and quickly joins the other bad one…

Unless you have a 260A A1R alt, 4 discharged wet cells is an overload for the alt, 4 discharged AGM’s is an extreme overload for the standard 100A alt. The oversized bank and its associated problems are where the LBCD came from, to disconnect a dead or damaged battery bank from the alt to keep from cooking it…

What kills lead acid batteries is time spent below a full state of charge. The deeper the discharge below full the faster their life clock ticks away as the sulfation builds up robbing them of plate surface area/capacity. Unless you run these trucks for hours at a time, frequently, or keep a maintenance float charge on them when parked, it is more than likely that the batteries rarely if ever reach a full state of charge. The 12v side also has more electrical load so there is less available power from the alt on that side. The 12v side also has a small vampire load… the combination of oversized batt, undersized alt and low run hours is probably why these trucks have so many battery/alt problems. They changed the charging system design twice, so at least they realized something was wrong. They added the LBCD(monitors alt load and disconnects the batts when it becomes overloaded) on the A1, and finally fitting a 260A alt on the A1R. That alt was pretty-much a necessity as the military introduced the AGM batteries…

if I was wanting more house battery, I would have more house battery and not rely on regularly mixing house and service… But maybe that’s just me…