How long can I go after Alternator stops working w/four 12v batts? and diagnising/fixing 200amp hummer alt on LMTV

[GeneralDisorder]

Does your voltage regulator have LED's?

 

[coachgeo]

Does your voltage regulator have LED's?

no. its a 200amp dual volt unit off a Hummer

 

[coachgeo]

Cabs up....
a review of a video that showed which terminal is what on regulator. It appears that the one closest to corner on side of the regulator is IGN and the AC terminal is the one more central. Was questioning myself about if the IGN and the Excite is the same thing. Further reading clarified it was.

So with that, did some testing- Sadly.. have full 24v at excite/ign with engine running.... but still no reading at at alt terminals with engine running beyond a reading of 12v at the 14v lug on the regulator and what I assume to be the 28v lug on the alternator. which I assume means no alternator output at all and just seeing battery voltage.

Any the assumptions above wrong? Suggestions for further testing?

 

[Ronmar]

Sounds about right. If its a Neihoff you can get the troubleshooting guide from their military section. It should have a procedure for determining wether it is an alternator chassis or regulator fault.

Depending on how available the humvee alts are,this sounds like a great time to swap to a straight 24v alt and a 24-12 converter...

 

[coachgeo]

Sounds about right. If its a Neihoff you can get the troubleshooting guide from their military section. It should have a procedure for determining wether it is an alternator chassis or regulator fault.

Depending on how available the humvee alts are,this sounds like a great time to swap to a straight 24v alt and a 24-12 converter...

Have picked up several 12/24 bussman convertors when saw them on sale for inevitable issue to arise like this. one to just balance batteries and other incase this alt goes out.

will check .... about converting.... it is a price game of cost of neihoff regulator, alt., or both (if it is one or both) compared to high output 24v alt PLUS cost of having fabrication done to mount it.

 

[coachgeo]

Sounds about right. If its a Neihoff you can get the troubleshooting guide from their military section. It should have a procedure for determining wether it is an alternator chassis or regulator fault.

Depending on how available the humvee alts are,this sounds like a great time to swap to a straight 24v alt and a 24-12 converter...

the docs for this alt

https://www.steelsoldiers.com/attachments/200a-troubleshooting-pdf.900392/

 

[Ronmar]

@24, You don't really need a very high output alt. 100A @ 28V is 2.8KW of power. A 100A alt would easily feed the OEM 240AH 4 battery bank In standard lead-acid. In fact it would just barely be past full load(108A) to feed that same bank if they were AGMs. A 125-150A alt would be great…

Where they went wrong was trying to pull 12 out of the middle of 24 and using that dam dual volt alt. Because the alt output is limited by amps thru the windings, pulling 12 out of the middle of the 24 limits the overall alt output by ~1/3(~1900W), and doesn’t leave enough of either to feed the monster bank Properly.

if they would have just used a straight 100A@24v alt and a converter/equalizer, and perhaps a solar float charger, these trucks would have been fine electrically until AGMs came along, then a 150A would have kept up their good reputation

a 50 or 75A alt would feed a pair of group 31s which is what should be in there anyway…

 

[coachgeo]

@24, You don't really need a very high output alt. 100A @ 28V is 2.8KW of power. A 100A alt would easily feed the OEM 240AH 4 battery bank In standard lead-acid. In fact it would just barely be past full load(108A) to feed that same bank if they were AGMs. A 125-150A alt would be great…

Where they went wrong was trying to pull 12 out of the middle of 24 and using that dam dual volt alt. Because the alt output is limited by amps thru the windings, pulling 12 out of the middle of the 24 limits the overall alt output by ~1/3(~1900W), and doesn’t leave enough of either to feed the monster bank Properly.

if they would have just used a straight 100A@24v alt and a converter/equalizer, and perhaps a solar float charger, these trucks would have been fine electrically until AGMs came along, then a 150A would have kept up their good reputation

a 50 or 75A alt would feed a pair of group 31s which is what should be in there anyway…

how much of 28v output though is indirectly lost though when you send some juice away thru a converter to create some 12-14v out of the 24-28v bank (with LMTV in mind). Alternator still has to produce enough power to full fill all needs. Such as the dual volt 200amp is think you guessed at max times it was about 140amp used for 24v side and 60amp for 12v side?? (may be remembering numbers wrong.)

 

[Ronmar]

how much of 28v output though is indirectly lost though when you send some juice away thru a converter to create some 12-14v out of the 24-28v bank (with LMTV in mind). Alternator still has to produce enough power to full fill all needs. Such as the dual volt 200amp is think you guessed at max times it was about 140amp used for 24v side and 60amp for 12v side?? (may be remembering numbers wrong.)

Yea I think you are remembering the numbers wrong. I think those are what that alt was capable of, 140A@24 and 60A@12. You don’t need a lot to make 12v from,24. The lighting load on a lmtv is 26A(33 on a 1079). thats only 13A@24v plus a little for converter efficiency. With standard lead acids a 240AH bank wants 60, so a lot left over. That 200A humvee alt should have been what the LMTV was delivered with initially, but you can do the same thing with a 100A single volt as it is way more efficient to not pull half of your alt amp capacity out of your alt at 12v, and instead convert your 12 from 24 at a 2x rate…60A for the batteries worst case, 40 left over to run the truck and make 12v, so not ever over 100% load@100A.

in my analysis of the 100A dual volt, On the 12v side you only typically have 40A available. Minus 29 for lights and that is not a lot left for the thirsty battery. With 60A left available on the 24v side, a depleted battery will draw all of that, a depleted AGM, nearly double that. Add in what is needed for the truck, and you have a grossly overloaded generator, and unless you run long enough to reach full charge, consistently undercharged batteries…

no wonder they had to develop the LBCD, i bet the alt failure rates in service were horrific once they fielded AGM batteries.

The sad part is this is not rocket science, and is fairly easily obtainable information. With a hundred amps, once my pair of 100AH group 31 service batteries are topped off, if I am not running the lights(and even maybe if I am as I shifted to LEDs) i will be able to charge 6 more of them(300AH@24V house bank), while driving. 75AH for the batts and 25 left to run the truck…

 

[coachgeo]

Possible solution fell in my lap. little more than wanted to spend but solves couple problems. Two Balamar 24v 140amp alternators with regulators. Price was so good got second one as spare. Pull outs from a military boat apparently. Already have some Bussman converter/balancers I can use to pull 12v out.

After pulling plug hit me that "maybe" could use George Leonard's new dual alt. bracket he made and is selling. Might give me option to maybe put both under the hood. second one dedicated to house batteries. Eliminates need for isolation switch. Gives me ability to shut down alt. charge to house batteries (switch off power to the excite wire? Will that work?) If that would work this would put house batt charging it into solar charge only. (Wiith alt. always excited..... alt otput to house would over power solar output to house thus solar controllers would stop outputting power "according to solar guru's".)

With dual alt. set up.. and depower trigger wire that I hope does like I think it would...... then I could de-power the Excite wire with dash switch.... alt would go off... reduce drag on engine and let solar keep charge up. From then forward; to compensate for any draws on the house bank while driving only solar wold charge. This is an advantage in my case. Have a device to be powered off house batts that while driving I want to run on solar only. Been struggling with how to make that happen yet have Alt. too. An alt. dedicated to house batts solves this if the Exicte wire depower idea works. Wan to run an HHO production system that came off a European diesel bus of solar only. HHO offer's no value beyond engine cleaning if alternator is what is providing the electricity. So shutting down house bank alt. charging thusly putting it in solar charge mode.. fits this plan great. Battery isolators wont do that. Dc to Dc would I think but they are really limited in amp output compared to an alternator. Old school solenoid could but its hard on components and can create charge reduction and parasite drains too.

 

[Ronmar]

Possible solution fell in my lap. little more than wanted to spend but solves couple problems. Two Balamar 24v 140amp alternators with regulators. Price was so good got second one as spare. Pull outs from a military boat apparently. Already have some Bussman converter/balancers I can use to pull 12v out.

After pulling plug hit me that "maybe" could use George Leonard's new dual alt. bracket he made and is selling. Might give me option to maybe put both under the hood. second one dedicated to house batteries. Eliminates need for isolation switch. Gives me ability to shut down alt. charge to house batteries (switch off power to the excite wire? Will that work?) If that would work this would put house batt charging it into solar charge only. (Wiith alt. always excited..... alt otput to house would over power solar output to house thus solar controllers would stop outputting power "according to solar guru's".)

With dual alt. set up.. and depower trigger wire that I hope does like I think it would...... then I could de-power the Excite wire with dash switch.... alt would go off... reduce drag on engine and let solar keep charge up. From then forward; to compensate for any draws on the house bank while driving only solar wold charge. This is an advantage in my case. Have a device to be powered off house batts that while driving I want to run on solar only. Been struggling with how to make that happen yet have Alt. too. An alt. dedicated to house batts solves this if the Exicte wire depower idea works. Wan to run an HHO production system that came off a European diesel bus of solar only. HHO offer's no value beyond engine cleaning if alternator is what is providing the electricity. So shutting down house bank alt. charging thusly putting it in solar charge mode.. fits this plan great. Battery isolators wont do that. Dc to Dc would I think but they are really limited in amp output compared to an alternator. Old school solenoid could but its hard on components and can create charge reduction and parasite drains too.

They may not be capable of remote conttol, depends on the alt. Got a model number?

The LMTV is unusual in that regard as remote generator control is usually an aviation thing. Most automotive alts do not have it, if they're turnin, they're burnin

140A@24v is a lot of power. How large are your house batts going to be?

I would bet you only need one, then a voltage controlled bi-dir charge relay(BIRD RELAY) or a simple contactor which you could control remotely would take care of house charging. If you use a large contactor solenoid(500A?) You could then have house power available for start assist.

The cool thing about using a Bird relay is that they can be setup to work both ways. If either system goes over a preset voltage, say 13.5v, indicating a power source(solar or alt) has charged/is charging one bank, the bird will close to charge the secobd bank. So when running, the alt can charge service and house, or if setting, the solar can charge house then service... when neither source is available the relay opens isolating the systems.

Georges mount looks intrigueing. I dont know about how his use of two different voltage, independently regulated alts into a series battery string will work. He hasnt answered any of my tech questions on how he plans on balancing the batteries and allowing the 12-24batt to fully charge so...

Technically speaking it is far simpler and probably more reliable and easier on the batts to generate straight 24, and use a converter to derive your 12v...

 

[coachgeo]

They may not be capable of remote conttol, depends on the alt. Got a model number?

Balmar 94-140-24-IG w/external regulator MC 624.. likely not the newer version that has lithium charge parameter choice built in.
house .... I can match batts to alternator. Was thinking two large 24v AGM or four 12v. BUT........ my lithium is in the mix..... A dc to dc(ish) device is connected to the house bank. Thus Alternator charging flows thru this lead house bank and on to the lithium. This adds additional 400ah total at 24v (two 200AH 24v rack batts)

 

[Ronmar]

that reg has an ign input so can be easily remote controlled

How big is your service battery?

ok Lithium changes the game for house charging. Must have a dc-dc charge controller, and you can tailor that to whatever excess your alternator will support. You could have 2000AH back there, but the alt is only ever going to see that the charge controller draws…

 

[coachgeo]

that reg has an ign input so can be easily remote controlled

How big is your service battery?

ok Lithium changes the game for house charging. Must have a dc-dc charge controller, and you can tailor that to whatever excess your alternator will support. You could have 2000AH back there, but the alt is only ever going to see that the charge controller draws…

Service/Start. so the 140 wont back down when it senses what ever is there is full? was going to go to just two 12v agm. I have a small 100amp 24v.... but was hoping to put that on my APU

 

[Ronmar]

Charging is based on voltage output, and alternators typically dont care about state of charge, they only know output voltage. So battery is low and you give it enough voltage it draws current this causes alt voltage to drop, its reg builds the field and makes more output trying to get back to its set voltage. Thats where the alt rated current figure comes into play. That is the ammount of current the alternator can give without overheating, and still maintain an acceptable charge voltage.

As the battery charges it draws less current, the alt voltage rises and the reg reduces field to maintain its set voltage(Same voltage less current output). When the battery fully charges, it stops drawing any real current but the reg keeps the alt at its set voltage Using minimal field to do so.

thats the problem with too large a battery/too small an alt, it will take all the alt can produce and more. Thats the problem with LI and an alt, their internal resistance is so low, it is like trying to power a short if y0u connect an alt directly to them. Victron has a good video describing this. The dc-dc charge controller buffers this load on the alt to keep it within the limits of the source alt.

A pair of 100AH AGM service batts should work great. Worst case, stone dead they will be looking for around 45A out of the alternator for the bulk of their charge. But they should charge fairly quickly because they are not oversized, and once charged, like any other battery will draw 0 from the alt, freeing up the majority of your alt to do other work…

 

[coachgeo]

,,,,

thats the problem with too large a battery/too small an alt, it will take all the alt can produce and more. Thats the problem with LI and an alt, their internal resistance is so low, it is like trying to power a short if y0u connect an alt directly to them. ....

by your description of how alt. regulator....... regulates... Too large an alt. for amount of batts is not really an issue in that no potential damage is happening anywhere. It is a waste. YES, . but won't slowly or quickly brick anything alt. or battery related....... where opposite as you describe above does brick things. Do I read that correct?

one thing I liked about Balmar alternators and regulators.. but figured I could never have ability to take advantage of is because they are astronomically expensive..... is they have a temp sensor on alt that regulator actually uses to dial down alt. output to keep alt. from overheating. Being Balmar's main customer's were Marine where engine is stuck inside an engine bay that gets hotter than under a vehicle hood...... they likely found their customers ran into atl heat more often. Thuse why they are ahead of the game on this.

Anyway; just recent discovered that on brushed alternators (unlike our brushless Neihoff.. but it has similar built in already though) you can create this dial back output if over heating of alt is occurring yourself for many common type alts. Below video explains how to do it and what components the alt has to have, to use a temp sensing mod.

 

[Ronmar]

Yes, thats correct. The batteries set the tune and draw energy based on relative voltage difference and their internal resistance. Thats why AGMs want more, and can deliver more current. Tgey have a lower internal resistance. That is why you cannot just hook up any old alt to a LI battery. Their resistancw is so low it would be like trying to arc weld with the alt

So you could have a 100A alt or a 1000A alt and as long as their output/regulated voltages are the same, the lead-acid batteries could care less...

Thermal derating is common on automotive alts i cant think of any alt that doesnt have a thermistor in its regulator circuit to dial back the output with increasing temps to prorect the alt.

The cool thing about that Balmar reg is it has remote temp sensor inputs to monitor battery temps(for two banks i think), as lead acid batteries absorb energy differently at different temps. This allows the regulator to taylor the output for changing battery conditions. Most all new smart chargers at the least have a temp sensor in their box to adjust the charge for ambient temp. Some even put a sensor in the battery alligator clip to sample temp directly at the battery terminal. Every battery backup power
System I have worked with in the past 15 years has temp compensated charging.

Also looks like the Balmar can support a 3 stage charging regime(more efficient/faster).

Thats a nice alt...

 

[coachgeo]

Update about two batts use with no working alternator.

If it gets much below 40f.... and your batts are not brand new..... you need all four to make it 60 miles. Seems ever 5 to 10 degrees it goes colder you loose a lot of voltage. On 20f days with two batts.... the 30 mile drive home in the 60 mile trip I do... with headlights on and heater fan., the 12v batt hitsc 40% state of charge results are; can not back into my own parking space (takes several forward-n-backward off dead end to get turned into my spot) cause it pops into Neutral. If I turn off headlights.... it works fine..... so it for sure is a voltage thing.. thank god it is litterally @ my parking spot that this comes about. Granted Ive risked driving with headlights off in a few spots to get me that extra distance.

soooooo seems like ..... if you are in cold weather.. 4 batts is needed to have best chance at emergency No Alt. chargeing drive ability (approx 60 miles) . In the warm.... 50+.... your fine for 60 miles. 60f+.... probably good for 80 miles.

Wish me luck...... I dont want to drive this truck this much "yet.".. It$ breaking me. If times dont change soon I will have to abandon this whole dream, retirement living in LMTV camper, career change plans and give up- sell it all / come up with some other plan jLIKE SOON (Thanks Brandon.. can't afford both you and Murphy )

 

[Ronmar]

yep, lead acid capacity drops off steeply with temp, but not as steeply as lithium

At 20F a lead/acid only has ~75% of its rated capacity, and that is its current rated capacity IF fully charged. An older battery will have a lower capacity to begin with. if you were going to make a habit of this, you could run a pipe loop thru the battery box and apply some engine coolant heat to the battery bank... ~80F should yield 100% capacity.

Its the 25A of lighting load and the increased Peukert losses that are killing you. You could throw about any 12v alt in there and make up for the lighting loads which would greatly extend your range.

in the end batts are not power sources, but storage tanks that get smaller with age (and temperature drop)

I really should measure the 24v loads on my truck, have been meaning to simply for info, but never seem to get around to it... since i am pulling 12 out of my 24 with a converter this should be easy to measure on mine now, I just need to put my shunt on the 24v line to the cab and shutoff the converter feed...

 

[GeneralDisorder]

C7 engine computer only draws 1.1 amp at 24v. Like Ronmar said - it's the lighting that's killing the batteries. I figure if you ran during the day with only stop lights you could likely go the full range of a stock fuel tank - at least I'm positive I could on my four Hawker 6TAGM's. Recharge them from my 1600 watt solar array while driving. Might be late but I'll get there eventually. I carry a spare VR but the math says it's not worth carrying a spare alternator.