Yes, exactly. This is not a trivial current, but it is for only a momentary period. We actually plotted the field current verses output of our Nations 280amp alternator . . . so have some targets available if someone wants to try it.
It is interesting that you have a current plot for the field. We have an Ample Power regulator that has two settable, near full range, field settings that can be switch activated, which we have done. The adjusting pots are probably for output voltage as that is what I was told to check and note for the future. I also had an ammeter on it, so I actually set by the current because I knew what I wanted but also noted the voltage as that is an easy way also. They tracked similarly, but I didn't do a full range or anything.
If you also have field voltage to relate to the current, that would be very handy for those that don't have a big ammeter on the alternator output.
It becomes more and more complicated to use the Voltstart with lithium. When I ordered the RV I ordered Voltstart and UHG. There were stickers on the kitchen backsplash that said Eco Trek inside or something like that. It only had one AGM, I added a 2nd battery and 280W of Solar a couple weeks after I got it. I found after a few trips that the Voltstart worked but the starting voltage was wrong. I found and checked the module nd found it was for Lithium and I had AGM. I called RT and found that I was right. By now RT was in the midst of self destruction. the one that shorted and started the mess.
Originally I had other ideas how to accomplish what I wanted. 1. was to junk the 150A BMS but found all the 300Amp ones only were good for 150A charging. 2. I could temp short the C- and B- together until the current got below 150A, hoping not the overheat the Alternator. 3. Was to buy and parallel another 150A BMS, this was the cheapest. Again hoping not to overheat the alternator. I was posting on 2 other forums and they kept telling me I need a DC2DC, lots of bad info out there. However nobody mentioned that the Renogy needed a battery to start. I thought about using large relay (selonide) to short the C- to B- but got talked out of that, However I could use the same method to parallel the AGM for the DC2DC but now I only have 60A (measured closer to 50 Amps with my meter.
As far as running the Air-condition, Its not as bad as one might think. The Air uses 106Amps OLY with the compressor running, If the Volts start came on it should keep the Air on and charge the battery untill the compressor cycled then all the current would be available for the battery. Although Im kind of giving up on this idea even though the Higher up RT models say it can be done with Eco Trek, which I don't understand.
markopolo: it would be easy to provide the 12v to start the alternator BUT that battery would be out of use due to its before the DC2DC. I could use a small 5A backup battery, the downside is I will only have 50 to 60 amps out of the DC2DC to charge batteries which makes the UHG kind of redundant.
BTW: 280A Lifepo4 battery cost $475 shipped. 150A BMS $100, then I bought a used Renogy 60A for $160 shipped, and a couple of 4 gauge wires. Everything including the new inverter, battery, AC switch for shore power, and small charger and DC2DC fit inside the original inverter cabinet under the back side cousin box.
Will Prouse tested 2 BMS 60A I believe in parallel and said it would work but some other members on his forum chimed it that its would not, but provided no proof or references. For me that would be the cheapest and best solution.
As I read, I am getting happier and happier that our forthcoming dual-alternator Transit will gladly give me pretty much as much current as I want, no questions asked. Let the Ford engineers think about all this stuff.
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Now: 2022 Fully-custom buildout (Ford Transit EcoBoost AWD)
Formerly: 2005 Airstream Interstate (Sprinter 2500 T1N)
2014 Great West Vans Legend SE (Sprinter 3500 NCV3 I4)
Nations 280XP-SE info attached. I think SE means self exciting. Attachment 12270
Yes, that is a single wire alternator so it has to, but it does confirm voltage as stated and very likely also uses the battery line for initial field but not for long. After that it is self exciting itself through the internal regulator.
I think what the are comparing to is that many factory setups have a wire that does the initial power for starting the output, usually tied to the run side and often with a timer so the alternator doesn't start immediately before the engine settles after starting. Many confusing terms with this stuff.
I asked nations about that and if I remember correct you cant remove the 12v or the alternator will stop. If that would work a simple timer relay circuit would work to short around the dc2dc to get things going. I also know at least 1 guy that uses 2 BattleBorn batteries and the UHG and says it works good for 1 year. But BB told me don't do it.
It is probably more accurate to say the a REGULATED alternator needs a reference voltage and some amperage capacity to run
Yes. Just to be clear, there are two completely different things going on:
1) No electrically-excited alternator will generate any power whatsoever unless it is initially connected to an external power source. The reason for this is the need to generate the magnetic field needed for the generator to work.
2) Most regulators require a "reference voltage" to do their job. The reason for this is that regulators are cybernetic devices that use a feedback loop using the measured voltage to adjust the generated voltage. If there is nothing to measure, the feedback loop can't work.
#1 would be true even if you didn't have a regulator.
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Now: 2022 Fully-custom buildout (Ford Transit EcoBoost AWD)
Formerly: 2005 Airstream Interstate (Sprinter 2500 T1N)
2014 Great West Vans Legend SE (Sprinter 3500 NCV3 I4)
It is interesting that you have a current plot for the field . . . If you also have field voltage to relate to the current, that would be very handy for those that don't have a big ammeter on the alternator output.
Here is our data on field voltage/current verses output current. Unfortunately we have no notes on the test setup including 2nd alternator output voltage or, even, what load we had on the alternator during these tests.
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2016 159" High Top DIY ProMaster with 500ah Starlight Solar/Elite LiFePo4, 930 watts Hyundai Solar w/MidNite Solar Classic MPPT, Magnum 2812/MMP250-60S Charger/PSW w/remote, Nations 280amp 2nd Alternator with DIY [formerly, Balmar] regulator, NovaCool R4500 12/120v frig, 2 burner TruInduction cookstop, SMEV 8005 sink, FloJet R4426143 pump. No A/C or indoor washroom.
I'm back. Arm better, cold weather gave me a break so I was back at it. I checked my hookup today and I hooked the AGM before the DC2DC it wasn't connected to anything, and started the engine and no output from the dc2dc. I found that the AGM was reading 2.2v. It wasn't even hooked up so no current drain. I tried to charge it with a battery charger and its bad. Very weird.
So I disconnected it.
I then started the engine and temporary shorted the output of the dc2dc to the input and it started and the Lifepo4 is charging at 59 amps.
So for me the simple solution is a temporary short from the output to the input.
Maybe a wire from the STARTER switch. Now to find a place to get it.
I wonder if a small 12v Battery would work instead and how long would it last? Push button last choice.
Linear Mode
