Convert 24v alternator to 12v?

[justinm001]

Thank you for posting those curves.

The voltage spikes shown are more than enough to trip the BMS of at least some LiFe batteries. What WS suggests is to have a delay built into the system to prevent the BMS from tripping faster than the WS can shut down and the field coil de-energize. Easier said than done but possible sometimes.

If you look at the curves, the out is spiking when the rpm is high - maybe during an acceleration?

Try cutting your power output to 50 % while you fine tune things - it will not solve all issues but it helps to soften it a bit.

The engine rpm is off I had to enter the size of the pulleys but was complicated and couldn't get it to match but the alternator rpm has to be right.

Today I should get the Orion so tomorrow I'll rewire and see if I can get 24v out of the alt. The old regulator doesn't have anything written on it so can't tell the voltage or model. If it really is 24v then maybe the wakespeed was trying to control the voltage using the field and couldn't keep it under 14v so it spikes. If not then the Orion will tell me it's too low of voltage to run. Also if it's 24v that means I can parallel 5 Orions and get 3500w in the front bumper as I only have 2/0 cable the 40ft up there.

I think the voltage spike was absorbed by my 12v firefly and thermostat blowing it before it blew the bms. While the alt shut down

 

[justinm001]

So I wired up the original external regulator and it's outputting 15.2v. Has an adjustment knob which was turned up but I could turn it down to around 9.7v.

Setup the wakespeed to 24v but it won't turn on without battery so connected my 24v chassis batteries to the alternator but couldn't seem to get it to turn on the field. It's like it won't allow me to switch to 24v.

So I figured I'd setup the 24/12 Orion. Made sure I was getting 26v up front and plugged into input then plugged my 12 into output and the ground into ground. Started back up and plugged in my 24v jumper cables then went to measure the voltages and the Orion was smoking. Verified all voltages were right and all wired up so no idea what happened there.

Now I'm at a complete loss on what to do. I can't trust my alternator not to spike on 12v and no clue how to get it to pump out 24v. Also seems the victron dc chargers aren't the best because no app or anything for the 70a

 

[HarryN]

There isn't any need for an application to run a DC - DC converter IMHO but some people like apps. I don't. Just something to go wrong and have someone play with settings when you aren't looking.

It would be nice if WS were to provide you some settings to use with that controller vs leaving you high and dry like that.

I wonder if you approached the original alternator company and asked them for a suggestion for a new alternator and related settings for a WS if they would have any info for you?

 

[justinm001]

There isn't any need for an application to run a DC - DC converter IMHO but some people like apps. I don't. Just something to go wrong and have someone play with settings when you aren't looking.

It would be nice if WS were to provide you some settings to use with that controller vs leaving you high and dry like that.

I wonder if you approached the original alternator company and asked them for a suggestion for a new alternator and related settings for a WS if they would have any info for you?

I'm not sure if I can use the Orion dc converter as I can't put a lithium profile on it, but I guess I can just pump a voltage in and be fine. The plan was to run 5 of these in parallel and pump 3500w into the batteries. That'll be 175a of 24v and right at the 2/0 wire limit and we'll below the 275a alternator limit. This would be enough to run 2 ACs while driving and not use battery.

I think I just need something to absorb any voltage spikes or some way to prevent those spikes from hitting my system. I'm wondering if I coul attach my 12v generator optima bluetop battery to my lithium setup and it'll absorb the loads. Even have it wired up so it's between the alternator and the lithium.

I did order a 24v 50dn external regulator just to so see what happens. I'm betting they put a 12v regulator on the 24v alternator and it works, but me putting the wakespeed on works most of the time but not perfect.

Another thought is the wakespeed needed 2 pairs of wire and i used 14gauge which runs 40ft to the front of the coach. One pair connects to the shunt to measure amperage (don't think that does anything) but the other measures voltage and I'm assuming provides power to the ws. They said it needs to be at the battery but maybe I need to put at the alternator.

I have a day trip tomorrow so I'm going to program it back to 12v and connect it just to my generator battery alone (with the voltage wire) and I'll see if I get the spikes.

I have a big trip next Friday where we're taking the whole family on a road trip for 6+ hours to Pigeon Forge and the alt would be great to have powering the ACs

 

[Partsjockey]

I'm not sure if I can use the Orion dc converter as I can't put a lithium profile on it, but I guess I can just pump a voltage in and be fine. The plan was to run 5 of these in parallel and pump 3500w into the batteries. That'll be 175a of 24v and right at the 2/0 wire limit and we'll below the 275a alternator limit. This would be enough to run 2 ACs while driving and not use battery.

I think I just need something to absorb any voltage spikes or some way to prevent those spikes from hitting my system. I'm wondering if I coul attach my 12v generator optima bluetop battery to my lithium setup and it'll absorb the loads. Even have it wired up so it's between the alternator and the lithium.

I did order a 24v 50dn external regulator just to so see what happens. I'm betting they put a 12v regulator on the 24v alternator and it works, but me putting the wakespeed on works most of the time but not perfect.

Another thought is the wakespeed needed 2 pairs of wire and i used 14gauge which runs 40ft to the front of the coach. One pair connects to the shunt to measure amperage (don't think that does anything) but the other measures voltage and I'm assuming provides power to the ws. They said it needs to be at the battery but maybe I need to put at the alternator.

I have a day trip tomorrow so I'm going to program it back to 12v and connect it just to my generator battery alone (with the voltage wire) and I'll see if I get the spikes.

I have a big trip next Friday where we're taking the whole family on a road trip for 6+ hours to Pigeon Forge and the alt would be great to have powering the ACs

You have a picture of your setup in the engine bay?

 

[justinm001]

You have a picture of your setup in the engine bay?

Here it is. Maybe I'm missing something. The yellow stator wire seems to be the only thing not 100% also ill double check the red alt positive and black neg are actually on the alternator.

On the wall has my oem external regulator (left) which is disconnected. Wiring isn't the best as I haven't got it actually working reliable yet.

From the alt goes the 2/0 wire 40ft to my front bumper where it was connected to my Lynx distributor along with the red stripe. The yellow/black was on the lynx and the purple and grey are on my shunt which is reporting properly on the wakespeed software.

 

[Partsjockey]

Here it is. Maybe I'm missing something. The yellow stator wire seems to be the only thing not 100% also ill double check the red alt positive and black neg are actually on the alternator.

On the wall has my oem external regulator (left) which is disconnected. Wiring isn't the best as I haven't got it actually working reliable yet.

From the alt goes the 2/0 wire 40ft to my front bumper where it was connected to my Lynx distributor along with the red stripe. The yellow/black was on the lynx and the purple and grey are on my shunt which is reporting properly on the wakespeed software.

So lets just do the basics. If you disconnect your Lithium does the alternator go wacky?

 

[justinm001]

So lets just do the basics. If you disconnect your Lithium does the alternator go wacky?

It won't turn on without power since the wakespeed needs power to turn on. When I wired it up to the 24v chassis the ws wouldn't turn the field on at all.

The alternator works fine for a good 10 minutes then just spikes which causes the ws to shut it down. Before I've turned the bus on and off at lights and it would keep working for 10+ minutes until it happens. The alt works great and the spike happens regardless if it's pulling a huge load or just floating the battery

 

[Partsjockey]

It won't turn on without power since the wakespeed needs power to turn on. When I wired it up to the 24v chassis the ws wouldn't turn the field on at all.

The alternator works fine for a good 10 minutes then just spikes which causes the ws to shut it down. Before I've turned the bus on and off at lights and it would keep working for 10+ minutes until it happens. The alt works great and the spike happens regardless if it's pulling a huge load or just floating the battery

ok

 

[HarryN]

Having a load is good.

I will just tell you a little bit about what I remember about what we did and see if any of it clicks for you.

In the application that I had with the WS , it was 48 volt and the alternator was at the front of the sprinter. The WS was located approx 3 ft away under the hood.

The shunt and battery pack were located approx 25 wire feet away and that was the absolute max that the alternator supplier was willing to support. Their preference was 10 ft long wire lengths no matter what WS says.

We put the shunt on the negative wire and we did initially make a mistake that the sense was wired backwards so the current measurement was reversed but swapped it.

Our goal was 60 amps @ nominal 48 volts ( so 56 volts charging ) and we ran 2 awg wire.

While there is ground through through the alternator to engine body and back to the battery pack, we ran a full size, dedicated negative wire along with the positive current carrying wire as well.

All of this power from the alternator has a lot of RF noise, so stranded / braided wires and braided ground straps all over the place are critical.

The signals were all done with twisted pairs to reduce RF interference as that can be an issue with these. I cannot remember if we ran this in shielded wire or wrapped it in aluminum or not.

The battery pack was rated to be able to absorb 100 amps continuous and 200 amp spikes at 56 volts, so ~ 2 - 4X the goal output of the alternator.

The supplier had us feed power to the WS and field current from the battery pack instead of from the alternator so that it would be more stable.

Even with this it was not perfect until my buddy played with settings and got revised settings from their engineer a few times.

They wanted us to add an additional lead acid "keeper battery" right next to the alternator for stability and to prevent spikes but we haven't done it yet and so far so good.

For your application - with those kinds of currents - it makes sense to see if you can make it work with a very close coupled arrangement with a significant number of lead batteries first if at all possible and then look at longer distances. You don't necessarily need a lot of capacity but you need a lot of dampening and that comes from multiple batteries that can charge / discharge quickly.

It was not a 1 month project - it took months to get it all to work. Now that we did it we can replicate it exactly very well but not sure about in 1 week. Given that you have a vacation in one week and all of the stress that goes along with that - I would be tempted to just run the generator this time.

As I think of other things that we did for the application I will add them here with an "edit / added" note to the end.

Added / edit

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60 amps might not sound like much, but we are getting ( 40 amps ) x ( 56 volts) ~ 2 000 watts at idle / stop light and 3 000 watts at anything above idle. The single a/c is pulling ~ 1 000 watts during the compressor on cycle.

So just driving around town he can charge at least 1 - 1.5 kW in stop and go traffic while driving on a hot day in a dessert city and that is massive for a sprinter.

We had a higher power alternator in there and we just could not tame it. It was fine most of the time but we would have big spikes during acceleration.

Works great now but what an expensive learning exercise and WS isn't all that supportive. The alternator company provided reasonably good tech support in terms of helping but nothing in terms of some of the hard lessons that came with the process.


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[justinm001]

Thanks for this Harry, I left the 24v settings on and hooked it up to my 12v genny battery and it kicked on the field pumping 22.7v which I quickly shut off.

I'm convinced they just swapped a 24v regulator with a 12v and it works fine for leadacid.

I'm also convinced I got a bad Orion (got off Amazon and it didn't seem to have the bubble wrap I'm used to with others so likely returned.

I have the 24v regulator and another 24/12 Orion coming so can test. My chassis is 24v using 4 large 12v batteries so I could pump both alternators into the chassis batteries then use that to draw from. It's only a couple feet from alt (under the packout mount). I also have a couple like 24ah 12v lithium batteries I could run in series next to the alternator.

But if the new stock 24v regulator pumps out constant voltage and I run 5 70a orions which are pumping out constant voltage then the wakespeed is kinda pointless. The orions will limit the alternator draw.

 

[HarryN]

Another approach would be to just hook an inverter up to the battery and run 120 vac from there to the other end of the coach.

Feed that to the input of your main coach power setup and run the coach loads that way.

People do this in the conversion van world - but it does require good quality inverters to pull off.

 

[justinm001]

Another approach would be to just hook an inverter up to the battery and run 120 vac from there to the other end of the coach.

Feed that to the input of your main coach power setup and run the coach loads that way.

People do this in the conversion van world - but it does require good quality inverters to pull off.

This is what I do now and have 12v lithium battery bank. The point of the alternator is so I can charge these batteries and also power 1 or 2 ACs/heaters while driving.

I'm building some logic so I can use my 12v system as the main while driving then let the 12v loads eat the battery up until 20% or so and then it'll charge from my 48v main inverter system. This way the 12v has the important loads (like lights and comms) so will get low then drain my 48v to 5% (over AC) then drain the last 20%

 

[justinm001]

Hooked up a 24/12 Orion to my alternator with the regulator disabled and used jumper cables to connect my 24v chassis to the alt and it worked fine. So new Orion is good and the wiring doesn't have anything weird going on.

Then plugged in my wakespeed and it ramped up the field while still running fine. But couldn't tell if it was generating power or not since both alternators are hooked up.

Then plugged in just the new 24v OEM regulator and disconnected the jumper cable but wasn't outputting any power since no battery. I had the idea to connect the battery wire on the regulator to the chassis battery which fried my Orion and actually set on fire. I'm assuming it ramped up the voltage of the alternator over the 35v limit of the Orion. I think I saw 63v on my voltmeter but was hard to hold everything and see the screen.

This confirms my suspicion that the external regulator can use the field to control voltage. Either that OR my alternator is fried... or both. I don't trust the alternator so going to just replace it down the road. Might pickup a basic 12v car alternator just to get 100a or so for now then replace the big one with a balmar 48v 100a