T1N 200amp alternator

Donphillipe

Active member
What difference would it make if I put the positive lead from the dc/dc charger onto the alternator whether it's the 90 AMP or the 200 amp?
Best I can describe it, is people here pointed out all potential permanent loads you have on that alternator, someone then said that a 30A DC2DC requires 40A and they also said you did not have 40A left coming from the alternator, or the charger wouldn't work if there weren't enough amps.. If you then touch the DC2DC to a 90A alternator, sorry all the amps are taken. If you instead touch the DC2DC to a 200A instead, it's like an oil gusher of amps and everyone bellies up to the bar and feasts on whatever they want. With 90A, all the seats and the kitchen's overlaoded; with 200A, there's plenty for everyone to eat and drink (from the AMP keg that is) :)

Just count the amps up you need vs. what amps you can have. When you start the engine, that's 45A drawn from the alternator automatically with the lights on, if your chassis battery had been parked somewhere for 3 weeks it would have been nearly dead, so as soon as you start the motor, the 45A are taken by the dash electronics, so at the same time the chassis battery calls to "feed me!!!!" and it will only rest when it can have a a 110A firehose of power funneling into it where it will stop when it's full. But what the Chassis battery wants and what it gets are 2 different things. The 90A alternator with now a 110A potential load from the chassis battery added to the 45A verified dash load which presents a potential load of 155A on an alternator that simply doesn't have it. So the poor 90A alternator chokes and everything begins pulling it down to the floor.

The alternator if it could talk, it would shout back up to everything demanding more power from it, saying, "sorry here's my 90A, you guys just have to fight over it". So the chassis battery charging dips down to about half or 50A and the cab computer, dash electronics and lamps along with a high speed heater will drop down to maybe 40A. Of course this overload will dim the lights and slow the fan speed a little bit as well as add a whole lot of time to how long it will take to charge the chassi battery. Now at this early-on point let's say you walk up and slap another 40A load from that DC2DC converter on the alternator or the chassis battery attached to the alternator. As this point the other instuments see that you want even more from a resource which has already reduced their outputs, so that additional load of yours is really bad news.

Everyone settles it out but while they go down further in amp flow and at the time early-on that you walk up, there's nothing really to share with you but there will be enough to power your DC2DC to the point of failure indication. What's left for your add-on device can be half or less of what your device asked for as well. So this shows up as your device in effect saying "no dice without my demanded full 40A so the DC2DC starts to click and shuts down or whatever. Now in 10-30 minutes your chassis battery says "all full, I'm done, you guys battle for the rest". So there's no more 110 wannabe that ends up cramping your style so - 45A for the dash lights and heater fan. You now have 45A on the 90A alternator to spare and enough when you attached your DC2DC to the alternator so it now comes alive. Or maybe something else is wrong, but this is what happens when it is working perfectly with the exception that you don't have enough amps or current.

So you fix that issue by upping your amp resource hopefully to provide what it's asking for. In this case we'll add a 200A alternator. At this point you attach that red wire to the alternator and there's almostt 110A for the almost dead chassis battery, there's 45A for the dash and with the heater on high and there's 40A that new DC2DC is askign for. So you are still actually very close to being overloaded with the potential of 110A + 45A + 40A = 195A but you escaped it. YOU ARE JUST UNDER THE WIRE!!! And of course no shutting down of the DC2DC converter any longer and assuming it was not defective of course. (Time passes). Now you see how charging at 30A is like not charging at all, so you either load all your equipment and send it to me with a good luck statement (only kidding) or you may want to experiment with sucking a little bit more from the alternator into the house large lithium battery bank by various methods of direct charging.
 
Last edited:

vincelif

Active member
Best I can describe it, is people here pointed out all potential permanent loads you have on that alternator, someone then said that a 30A DC2DC requires 40A and they also said you did not have 40A left coming from the alternator, or the charger wouldn't work if there weren't enough amps.. If you then touch the DC2DC to a 90A alternator, sorry all the amps are taken. If you instead touch the DC2DC to a 200A instead, it's like an oil gusher of amps and everyone bellies up to the bar and feasts on whatever they want. With 90A, all the seats and the kitchen's overlaoded; with 200A, there's plenty for everyone to eat and drink (from the AMP keg that is) :)

Just count the amps up you need vs. what amps you can have. When you start the engine, that's 45A drawn from the alternator automatically with the lights on, if your chassis battery had been parked somewhere for 3 weeks it would have been nearly dead, so as soon as you start the motor, the 45A are taken by the dash electronics, so at the same time the chassis battery calls to "feed me!!!!" and it will only rest when it can have a a 110A firehose of power funneling into it where it will stop when it's full. But what the Chassis battery wants and what it gets are 2 different things. The 90A alternator with now a 110A potential load from the chassis battery added to the 45A verified dash load which presents a potential load of 155A on an alternator that simply doesn't have it. So the poor 90A alternator chokes and everything begins pulling it down to the floor.

The alternator if it could talk, it would shout back up to everything demanding more power from it, saying, "sorry here's my 90A, you guys just have to fight over it". So the chassis battery charging dips down to about half or 50A and the cab computer, dash electronics and lamps along with a high speed heater will drop down to maybe 40A. Of course this overload will dim the lights and slow the fan speed a little bit as well as add a whole lot of time to how long it will take to charge the chassi battery. Now at this early-on point let's say you walk up and slap another 40A load from that DC2DC converter on the alternator or the chassis battery attached to the alternator. As this point the other instuments see that you want even more from a resource which has already reduced their outputs, so that additional load of yours is really bad news.

Everyone settles it out but while they go down further in amp flow and at the time early-on that you walk up, there's nothing really to share with you but there will be enough to power your DC2DC to the point of failure indication. What's left for your add-on device can be half or less of what your device asked for as well. So this shows up as your device in effect saying "no dice without my demanded full 40A so the DC2DC starts to click and shuts down or whatever. Now in 10-30 minutes your chassis battery says "all full, I'm done, you guys battle for the rest". So there's no more 110 wannabe that ends up cramping your style so - 45A for the dash lights and heater fan. You now have 45A on the 90A alternator to spare and enough when you attached your DC2DC to the alternator so it now comes alive. Or maybe something else is wrong, but this is what happens when it is working perfectly with the exception that you don't have enough amps or current.

So you fix that issue by upping your amp resource hopefully to provide what it's asking for. In this case we'll add a 200A alternator. At this point you attach that red wire to the alternator and there's almostt 110A for the almost dead chassis battery, there's 45A for the dash and with the heater on high and there's 40A that new DC2DC is askign for. So you are still actually very close to being overloaded with the potential of 110A + 45A + 40A = 195A but you escaped it. YOU ARE JUST UNDER THE WIRE!!! And of course no shutting down of the DC2DC converter any longer and assuming it was not defective of course. (Time passes). Now you see how charging at 30A is like not charging at all, so you either load all your equipment and send it to me with a good luck statement (only kidding) or you may want to experiment with sucking a little bit more from the alternator into the house large lithium battery bank by various methods of direct charging.
Simply the Best that was amazing thank you
 

Donphillipe

Active member
It's the one I just bought and I'm taking the opportunity to flush my radiator, replace the thermostat, water pump, belt, rollers and headlamps while I have everything torn off the front. Wish me luck, I will need it..
 

vincelif

Active member
May good luck be by your side. The Florida van man found himself under his T1N, and with some effort and a bit of cursing, managed to replace the alternator from underneath. Just wanted to let you know.

 

vincelif

Active member
I plan to install a 200 amp alternator, and I'm looking for information on the recommended length and gauge (AWG) of the positive cable from the alternator to the battery. Additionally, is there a recommended battery terminal lug for this setup? I'm not with my vehicle currently and want to gather all the necessary information for a successful installation. Thank you.
 

Donphillipe

Active member
Wire charts say 2/0. Not sure what is on there now. Also can't find an online calculator to add over 0 gauge. So if you look at the square mm of the cross sectional area, it looks like 2/0 is 67mm and plain 2 is 33mm so perhaps doubling a 2 if that is what is currently in use and assuming the same length of wire would be adequate? I don't normally calculate wires sizes per amp carrying capacity but hopefully that comes close.
 

Midwestdrifter

Engineer In Residence
1AWG for a longer run is fine, and fuse for 100A. I would personally go with 2/0 if you have a 200A alternator, and fuse for 175 or 200A. If you connect directly to the alternator you don't need a second fuse (just one at the aux battery). Otherwise you need 2 fuses, one at each end of the run.

A 200A alternator isn't strictly necessary, a 150A unit will still make plenty of charge at idle.

I wouldn't bother with a DCDC on a T1N. They just add additional bottlenecks and losses. A simple constant duty relay tied to the D+ terminal works just fine. That also eliminates the issue with 90A alternators dropping below 13.5V at idle, and causing DCDCs to drop out.
 

vincelif

Active member
1AWG for a longer run is fine, and fuse for 100A. I would personally go with 2/0 if you have a 200A alternator, and fuse for 175 or 200A. If you connect directly to the alternator you don't need a second fuse (just one at the aux battery). Otherwise you need 2 fuses, one at each end of the run.

A 200A alternator isn't strictly necessary, a 150A unit will still make plenty of charge at idle.

I wouldn't bother with a DCDC on a T1N. They just add additional bottlenecks and losses. A simple constant duty relay tied to the D+ terminal works just fine. That also eliminates the issue with 90A alternators dropping below 13.5V at idle, and causing DCDCs to drop out.
Thank you so much for your valuable advice; it's excellent. I wish I had known about it a few weeks ago, as I had already gone with the DC to DC method I found. However, now that you've mentioned the D+ method, can I use both the DC to DC and D+ methods simultaneously? I'm a bit disappointed, as I thought I was making the right choice.
 

vincelif

Active member
Although it is a great point I did come across these issues that could be challenges using a constant voltage relay for charging expensive battery Banks.


Challenges of Using a Constant Duty Relay for Auxiliary Battery Charging in a T1N Vehicle:

- Voltage Regulation: Alternator voltage fluctuations based on RPM may cause inconsistent charging.

- Battery Health: Risk of overcharging the auxiliary battery, potentially reducing battery lifespan.

- Compatibility: Success may vary depending on your T1N's electrical system; ensure compatibility.

- Idle Issues: 90A alternators can lead to inadequate charging at idle.
 

marklg

Well-known member
Thank you so much for your valuable advice; it's excellent. I wish I had known about it a few weeks ago, as I had already gone with the DC to DC method I found. However, now that you've mentioned the D+ method, can I use both the DC to DC and D+ methods simultaneously? I'm a bit disappointed, as I thought I was making the right choice.
D+ is an extra connection to the DC to DC converter. Without it, the converter will measure the starter battery voltage / alternator voltage and try to determine if the engine is running and if it should pull current to charge the house batteries.

With D+ connected to an enable input, the DC to DC converter can be set to run only if D+ is 12V, which means the engine is running. Many can be programmed to wait a minute or two after D+ shows the engine is running. That way it waits for the glow plugs to finish. It makes things easier on the alternator and eliminates the chance it could run when the engine is off, such as if you are trying to jump start the vehicle.

Regards,

Mark
 

Donphillipe

Active member
MWD has the question to answer but he once told me that the Sprinter has some safeguards in the circuitry that something like a Ford wouldn't have. I put what he said through a lot of tests and he was right. As far as why everyone told you to buy something you can get around and not need to buy and with more power out, that is a marketing thing. It's also when you see me I'll be driving a car 20 years older than everyone else. We don't always get what we need but we often get what we don't need. It's called "America" (by some or the USA by those who know better :) ) Anyway sound like you have some fun experiments coming up. Use a $12 hall effect meter or two and you'll be a good amp chaser soon.
 

Midwestdrifter

Engineer In Residence
Although it is a great point I did come across these issues that could be challenges using a constant voltage relay for charging expensive battery Banks.


Challenges of Using a Constant Duty Relay for Auxiliary Battery Charging in a T1N Vehicle:

1:- Voltage Regulation: Alternator voltage fluctuations based on RPM may cause inconsistent charging.

2:- Battery Health: Risk of overcharging the auxiliary battery, potentially reducing battery lifespan.

3:- Compatibility: Success may vary depending on your T1N's electrical system; ensure compatibility.

4: Idle Issues: 90A alternators can lead to inadequate charging at idle.
1. Does not matter for the T1N, voltage regulation is 14.4 to 13.5V or so and is fine for charging LFP.
2. Pure nonsense. LFP won't overcharge at the voltages listed above.
3. You obviously need to design appropriately, which is no different than for a DCDC.
4: As you have discovered its the exact opposite. While a direct connection to a 90A alternator would still allow some charging at idle, a moderately sized DCDC faults out in the same situation, resulting in intermittent or no charging.
 

vincelif

Active member
D+ is an extra connection to the DC to DC converter. Without it, the converter will measure the starter battery voltage / alternator voltage and try to determine if the engine is running and if it should pull current to charge the house batteries.

With D+ connected to an enable input, the DC to DC converter can be set to run only if D+ is 12V, which means the engine is running. Many can be programmed to wait a minute or two after D+ shows the engine is running. That way it waits for the glow plugs to finish. It makes things easier on the alternator and eliminates the chance it could run when the engine is off, such as if you are trying to jump start the vehicle.

Regards,

Mark
That makes a lot of sense. I will look into it some more, in the meantime I've just had my 200 amp alternator installed and the charger is charging at idle albeit through the starter battery where I have both of the cables running to the DcDC.
 

marklg

Well-known member
That makes a lot of sense. I will look into it some more, in the meantime I've just had my 200 amp alternator installed and the charger is charging at idle albeit through the starter battery where I have both of the cables running to the DcDC.
Most connect the cables to the battery. Especially in the US where there is a power distribution box, it's easier there. It makes little difference if there is a good cable between the alternator and battery.

Regards,

Mark
 

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