Neihoff seem to be Temp sensing/compensating alternators... where is the sensor?

[coachgeo]

If I recall right both the 100amp FMTV and the 200amp Hummer alts folk have used are temperature compensating alternators? Where is the temp sensor? Is it in the regulator and it just senses it by the temp via contact to the alt body it bolts too orrr?

 

[coachgeo]

side question.... how do these cool?? does the rear? fan push air thru the alt.... or does it suck cool air from front and blow the heated air out thru the fan at back of alt. ? Granted Im assuming that is a fan at the rear that shroud is protecting from... . for all I know its just a heat sink.

I assume it pulls cool air thru the alt and blows the now heated air at the turbo behind it. Would not make since to suck air from hot exhaust into the alt.

but you know what they say about assuming.... and ..... it is military who does at times do things ass-backward

 

[Ronmar]

Pretty sure the sensor is in the regulator as there are no wiring shown for a temp sensor between reg and alt chassis on any of the diagrams.

The air blower is on the rear. It creates suction and draws air thru the alternator chassis front to rear…

 

[coachgeo]

Pretty sure the sensor is in the regulator as there are no wiring shown for a temp sensor between reg and alt chassis on any of the diagrams.

The air blower is on the rear. It creates suction and draws air thru the alternator chassis front to rear…

thanks... was curious about sensor. I didn't remember a sensor wire. Few folk who used the 200amp hummer alt have put the regulator off on a bracket because their orientation on the body hits a bracket or the block... I forget which.... thought that mayyy be an issue with temp sensing but wanted to verify.

 

[Ronmar]

Most alternators have some form of temp compensation built into their regulator circuit. It is not so much about the alt getting too warm as it is about the batteries being overcharged when warm. Most auto applications have the batteries in the engine compartment, so putting the thermal control in the regulator is a simple/lazy way to add some compensation. Truly advanced alts, like advanced charging controllers have remote sensors attached to the battery to more closely tailor the charge control to the battery conditions…

 

[coachgeo]

Most alternators have some form of temp compensation built into their regulator circuit. It is not so much about the alt getting too warm as it is about the batteries being overcharged when warm. Most auto applications have the batteries in the engine compartment, so putting the thermal control in the regulator is a simple/lazy way to add some compensation. Truly advanced alts, like advanced charging controllers have remote sensors attached to the battery to more closely tailor the charge control to the battery conditions…

would that be the design intent on our Neihoff's alts though? Neihoff's are used in large rigs (military, coaches etc.) and none of them keep the battery in same compartment as the alt.

 

[coachgeo]

Most alternators have some form of temp compensation built into their regulator circuit. It is not so much about the alt getting too warm as it is about the batteries being overcharged when warm. Most auto applications have the batteries in the engine compartment, so putting the thermal control in the regulator is a simple/lazy way to add some compensation. Truly advanced alts, like advanced charging controllers have remote sensors attached to the battery to more closely tailor the charge control to the battery conditions…

hmmm.... interesting... looks like it is not alt. temperature like your pointing out.. but ambiant. Here is the temp compensation description on the 100amp dual volt from PDF on that model

"..N3135* regulator used with these units also is negative temperature compensated. Setpoints are 28.0 ± 0.2 V and 14.0 ± 0.2 V at 75° F..."

honestly not exactly sure what the above means though... example is that ambient temp or temp of alternator body measured thru the back of the regulator. Likely ambient as Ron Suggest. It also does not seem to tell me what it does when temp is NOT 75f but hotter or colder?

pretty sure this is the regulator on the 200amp 14/28v alt.


@Ronmar- interestingly the pdf does say the regulator allows for running in 24v only if chose.... granted it does not say or not say it allows it at a degraded amp output "running" as you have found it to be.

 

[Ronmar]

Well the alt really is not in an engine compartment on an LMTV... so even with the batteries remotely located they still see similar ambient temperatures and temp compensation from a regulator sensor is still relevant in a warm climate To help protect the batteries.

Thats not an LMTV alternator. It has the switching power supply elements in the regulator, so appears to be able to be setup for single voltage… my 100Amp 1506 will not run at rated 28V output unless it sees the 12v from the middle of the 24v series batteries…

Ours can provide single 28v, you just need a different single voltage regulator. One could probably be adapted from an off the shelf delco or leece alternator…

if someone wants to donate a 100A alt, I am sure I can cook something up

 

[coachgeo]

...Thats not an LMTV alternator. It has the switching power supply elements in the regulator, so appears to be able to be setup for single voltage… my 100Amp 1506 will not run at rated 28V output unless it sees the 12v from the middle of the 24v series batteries…...

updated the attachments above.

 

[Ronmar]

Negative compensation means it lowers output as temp increases. Hot lead acid batteries absorb energy differently than cold ones. So above 75F it starts to reduce output voltage so as not to overload/overwhelm the batteries and evap electrolyte.

Even the cheap smart chargers you buy do this. The fancy ones have the temp sensor in the cliplead and read temp at the battery terminal...

 

[Third From Texas]

Negative compensation means it lowers output as temp increases. Hot lead acid batteries absorb energy differently than cold ones. So above 75F it starts to reduce output voltage so as not to overload/overwhelm the batteries and evap electrolyte.

Even the cheap smart chargers you buy do this. The fancy ones have the temp sensor in the cliplead and read temp at the battery terminal...

Unrelated question, but as good a place as any to ask:

So, I have a little 24v equalizer on my truck (dual 6TL batteries). I have a little 5a NOCO pulse maintainer (that I move between the two batteries and run periodically).

I've wondered how well these two will play together.....charger and balancer.

 

[Ronmar]

I am not sure how a pulse maintainer will play with the equalizer. I havebeen using a small equalizer and a simple buck converter supply on a solar panel for a few years now and it worked great. I no longer have a 12v vampire load

 

[coachgeo]

Unrelated question, but as good a place as any to ask:

So, I have a little 24v equalizer on my truck (dual 6TL batteries). I have a little 5a NOCO pulse maintainer (that I move between the two batteries and run periodically).

I've wondered how well these two will play together.....charger and balancer.

yeah have had same wonder.... yet then again the spendier versions of Solar Pulse Tech units I believe also had a balancer in them. And the more spendier also were Solar "charge" controllers and not just enough solar to run the pulse system

 

[Ronmar]

if it is pulsing one battery, it may be raising and lowering the one battery in relation to the other. The equalizer would see this and might try and equalize to the ever changing conditions. This might stress the equalizer and would most likely blunt/negate any benefit the pulsing might provide…

 

[coachgeo]

if it is pulsing one battery, it may be raising and lowering the one battery in relation to the other. The equalizer would see this and might try and equalize to the ever changing conditions. This might stress the equalizer and would most likely blunt/negate any benefit the pulsing might provide…

sounds like adding a timer into the circuit might be a way around that..... or just a 2 pole toggle (and solenoids) to turn off equalizer and on pulser?