Dashboard Alternator light

[eric1514]

Hi all,

The MPPT controller on my coach will deliver 14.6 volts in bulk mode which is fine. In fact it’s exactly what the specs on my GC2 house batteries call for. But when I turn on the engine and the system connects the coach and starter batteries together, the dashboard alternator light will illuminate, presumably because Ford thinks 14.6v is to high.

Couple of questions. Do I care? As far as I know, 14.6v is not excessive and the condition should only last a couple of hours until the charger drops to absorbtion mode and a lower voltage. Or, is there an easy way to reprogram the light or turn it off completely? I’m monitoring all the batteries while I travel with an app constantly running on an old cell phone so I know what’s going on without an idiot light. I can change the profile of the charger to a different battery type and lower the voltage to 14.2v but I don’t wanna if I don’t have to.

TIA,
Eric

[BFL13]

eric1514 wrote:

MrWizard wrote:
Eric1514..Ok , I'm on page 5 of 7,
Find the heavy battery cable that goes from the Intellitec to the house batteries, find the most convenient spot in that cable run to cut it and in insert a 200 amp DC circuit breaker, the marine style have push button that opens the breaker contacts so it acts like a switch, and a lever reset that closes them, this will be manually operated by you the driver when travelling, these are very reliable and can removed or replaced easily if there is ever a need to do so

Or I could put a switch on one of the two small leads running to the isolation solenoid as Pianotuna suggested. But either way, I would be losing the alternator's contribution to charging the house batteries while traveling and amps is amps.

Your alternator amps are lamed by any higher voltage charger also on the house batts, so you are not getting so many alternator amps anyway.

You can test for that with low house batts. Have the monitor on the house set to amps. See the solar amps engine off, see the alternator amps solar off, engine on AND warmed up, then see the total amps solar on, engine on warmed up.

See the amps reading on the solar controller's display, subtract from total seen on the monitor, and that is your alternator amps.
---------

You have four 6s and say, " The only issue was it took forever to replenish the batteries if I boondocked and used 150 Ah up"

You could use 120 amps on that in Bulk, but how many amps do you need to be at say 90% SOC on arrival? How long is the drive? 150/450 is 67% SOC, so it is a "67-90".

You could do that in under two hours starting at 120 amps but if the drive is four hours you don't need so many amps. You don't halve the amps and double the time--it is not linear. But at 70 amps it would only take maybe half an hour longer. Whatever, call it three hours and you have an hour left. what if it is a five hour drive?

You can drive all day and night trying to do the 90-100 so forget that.

If you shoot for 70 amps total starting at 67% SOC, and you get 55 amps from the converter off gen, you need 15 more amps. Solar might average 5 amps or whatever for the time of day and conditions, so all you need now is 10 more amps. Is a Dc-Dc going to be worth it? How many amps of a DC is needed limited by what it will pull from 1/3 the alternator spec amps?

So IMO do some math like that before spending million$ on improving the charging set-up. You might be ok even with what you have installed now doing solar and the PD.

[eric1514]

BFL13 wrote:

This only happens when the batts are nearly full. If they are low when starting out, you can set the controller to 14.6 and unless they get nearly full while driving, no light. Unless there is still some sun or if gen is allowed on arrival that's as high as it gets that day.

You real problem is getting them full while driving when starting low. Your alternator charging will be lamed by the solar's higher voltage, but it has low amps. You need lots of amps to get them up before arrival at the next site.

Your best amps would be from gen charging with a high amp converter. But high amps gets you to Vabs sooner at a lower SOC so the light comes on, and stays on during the Absorption the rest of the way there.

You could isolate the engine batt, and go with a high amp converter off the gen with solar added by setting solar and converter to the same high voltage. With a DC-DC you could have three chargers adding their amps and no light.

Your only limit is the gen watts as to how big an amp converter it can run, and to have the converter voltage adjustable. So toss the PD unless it is as high amp as the gen can run, and get an adjusatble voltage PowerMax LK model with as high amps as the gen can do. Set it to 14.6, the solar to 14.6, and any Dc-Dc to 14.6.

Note that a PowerMax 75 amper pulls 1700VA set to 14.6v doing 75 amps on a low battery. If your built -in gen is one of those non-inverter types it will likely not run as high an amp converter as an inverter-gen of the same |"watts" (acting more like it is MSW -it is not but it acts in a similar way for this exercise), so it can get tricky picking how big an amp converter you can run. The PowerMax 100 amper is PF corrected so it can be run by almost the same inverter-gen as the 75 amper which is not PF corrected. A Honda 2200 portable does 1800VA but my B&S 2200 does 1700VA. Gotta watch out when running things to the max you can get away with.

Of course it is no good having a converter with too high an amps that you can't run it at home on an extension cord, but only off your RV gen. BTDT. Have to have a lower amp portable charger to do the RV at home. Keeps you busy making sure you are using the right charger for where you are.

Or just accept a lower amp charging rate while driving and get by somehow with however full the batts get on arrival.

I think I'll give up RVing and take up something simpler like rocket science.

I've learned a lot since I started this and I think the ultimate solution is to install B2B charger like Pianotuna suggested many posts ago.

What I once saw as a daunting task, is really simple. If I were to buy the non-isolated version of Victron's charger I would only need to remove my isolation solenoid and add one wire, a wire from a good chassis ground up to the unit. I could probably wire in a Trik-L-Start like you would if you had a iso. solenoid. I would probably wire in a switch instead of relying on auto voltage sensing so I could turn the thing off if I though my alternator needed a rest.

Thanks all for your contributions in this thread. It's been an education.

[eric1514]

MrWizard wrote:
Eric1514..Ok , I'm on page 5 of 7,
Find the heavy battery cable that goes from the Intellitec to the house batteries, find the most convenient spot in that cable run to cut it and in insert a 200 amp DC circuit breaker, the marine style have push button that opens the breaker contacts so it acts like a switch, and a lever reset that closes them, this will be manually operated by you the driver when travelling, these are very reliable and can removed or replaced easily if there is ever a need to do so

Or I could put a switch on one of the two small leads running to the isolation solenoid as Pianotuna suggested. But either way, I would be losing the alternator's contribution to charging the house batteries while traveling and amps is amps.

[MrWizard]

Eric1514..Ok , I'm on page 5 of 7,
Find the heavy battery cable that goes from the Intellitec to the house batteries, find the most convenient spot in that cable run to cut it and in insert a 200 amp DC circuit breaker, the marine style have push button that opens the breaker contacts so it acts like a switch, and a lever reset that closes them, this will be manually operated by you the driver when travelling, these are very reliable and can removed or replaced easily if there is ever a need to do so

[BFL13]

eric1514 wrote:

BFL13 wrote:
So set the controller to LFP 14.4 and head down the road. When you get there, you can do whatever works as required.

Yup. That's looking more and more like the plan. I'm not sure 14.4 won't light the lamp. That's the next test. I learned today 14.2, won't.

This only happens when the batts are nearly full. If they are low when starting out, you can set the controller to 14.6 and unless they get nearly full while driving, no light. Unless there is still some sun or if gen is allowed on arrival that's as high as it gets that day.

You real problem is getting them full while driving when starting low. Your alternator charging will be lamed by the solar's higher voltage, but it has low amps. You need lots of amps to get them up before arrival at the next site.

Your best amps would be from gen charging with a high amp converter. But high amps gets you to Vabs sooner at a lower SOC so the light comes on, and stays on during the Absorption the rest of the way there.

You could isolate the engine batt, and go with a high amp converter off the gen with solar added by setting solar and converter to the same high voltage. With a DC-DC you could have three chargers adding their amps and no light.

Your only limit is the gen watts as to how big an amp converter it can run, and to have the converter voltage adjustable. So toss the PD unless it is as high amp as the gen can run, and get an adjusatble voltage PowerMax LK model with as high amps as the gen can do. Set it to 14.6, the solar to 14.6, and any Dc-Dc to 14.6.

Note that a PowerMax 75 amper pulls 1700VA set to 14.6v doing 75 amps on a low battery. If your built -in gen is one of those non-inverter types it will likely not run as high an amp converter as an inverter-gen of the same |"watts" (acting more like it is MSW -it is not but it acts in a similar way for this exercise), so it can get tricky picking how big an amp converter you can run. The PowerMax 100 amper is PF corrected so it can be run by almost the same inverter-gen as the 75 amper which is not PF corrected. A Honda 2200 portable does 1800VA but my B&S 2200 does 1700VA. Gotta watch out when running things to the max you can get away with.

Of course it is no good having a converter with too high an amps that you can't run it at home on an extension cord, but only off your RV gen. BTDT. Have to have a lower amp portable charger to do the RV at home. Keeps you busy making sure you are using the right charger for where you are.

Or just accept a lower amp charging rate while driving and get by somehow with however full the batts get on arrival.

[eric1514]

wguss wrote:
I ran into that exact situation on our last trip out earlier this year. I haven't changed my solar system for years but for the first time my battery light came on when I started the engine. I had the rig plugged in all night so the batteries were topped off and didn't require much charging. I glanced at the volt meter and it was pushing 15 volts! I turned off the engine then thought to look at the voltage coming out of the solar controller and it was 15 volts. I disconnected the current coming from the solar controller and restarted the engine, no light.

I shut down the engine, re-connected the solar and waited a few minutes and the voltage from the controller dropped to 14.6 volts. (What's recommended for my AGMS) I re-started the engine (2005 Ford F-53 chassis with V-10) the light stayed off. My first thought was that the controller will equalize the batteries automatically once a month and that was the cause of the high voltage coming out of the controller so I am going with that, but I could be all wet!

You might be right.

[eric1514]

BFL13 wrote:
So set the controller to LFP 14.4 and head down the road. When you get there, you can do whatever works as required.

Yup. That's looking more and more like the plan. I'm not sure 14.4 won't light the lamp. That's the next test. I learned today 14.2, won't.

[wguss]

I ran into that exact situation on our last trip out earlier this year. I haven't changed my solar system for years but for the first time my battery light came on when I started the engine. I had the rig plugged in all night so the batteries were topped off and didn't require much charging. I glanced at the volt meter and it was pushing 15 volts! I turned off the engine then thought to look at the voltage coming out of the solar controller and it was 15 volts. I disconnected the current coming from the solar controller and restarted the engine, no light.

I shut down the engine, re-connected the solar and waited a few minutes and the voltage from the controller dropped to 14.6 volts. (What's recommended for my AGMS) I re-started the engine (2005 Ford F-53 chassis with V-10) the light stayed off. My first thought was that the controller will equalize the batteries automatically once a month and that was the cause of the high voltage coming out of the controller so I am going with that, but I could be all wet!

[BFL13]

So set the controller to LFP 14.4 and head down the road. When you get there, you can do whatever works as required.

[eric1514]

BFL13 wrote:

I think you have it backwards. If you idled for a while the alternator voltage would taper to 13.8ish. meanwhile the PD set to 14.4 might eventually get the batts to near that. with voltage drop on the PD wiring you might never see 14.4 at the battery even with the low amps at the high SOC meaning almost no voltage drop.

Solar's low amps means little voltage drop unless thin wiring, so you could set that to 14.5 and get 14.4 which might ot set off the light.

You have to test for how high you can set the solar without the light coming on when the house batts are full. If they are full you don't need to be doing that at all, so if you did have a way to turn off the solar when the house is full while driving, you could get to the campground with the house full, no red light, and alternator charging looking after the starter batt.

BTW, do you have the charge wizard or pendant to make the PD do 14.4? If not, it will only do 13.6. What are you doing with that for testing?

When I started the RV, the voltage at the starter battery dropped from 14.3v to 14.25v. What I meant was that if I was more patient, I could have idled the engine until the PD brought it up to 14.4v to see if 14.4 would set off the light. I've seen 14.4v at the starter battery on the monitor but not with the MH engine running at the same time. The highest I got today was around 14.25v at the starter battery with both the converter and the alternator running. The current was about 6 amps.

I'm not sure what you mean by low amps from solar. Granted, it's not converter amperage but the potential is there for almost 25 amps.

My cheap controller doesn't give me much choice is to how high I can set voltage. Tops is 14.6 (Flooded profile) 14.4 (Lithium profile, no float) and 14.2 (gel profile). This test was just to see if lowering the voltage from 14.6 would keep the alt light from illuminating and it seems to. Setting the profile before traveling is not tough. Turning the panels off while drive requires pulling off the road. I didn't anticipate this issue. Now when I first noticed this problem, my batteries were full. The light might have gone out shortly anyway if I hadn't pulled off and shut the solar down or as Doug suggested, the voltage output from the controller would have dropped to 13.something in 2 hours.

My PD converter has the Charge Wizard.

[eric1514]

pianotuna wrote:
That will work for the alternator--but the six volt batteries may prefer 14.8 from time to time. (once a week?)

The specs for the Interstate batteries I have say 14.6. I can get there with solar when I'm parked by changing the profile back.

[BFL13]

eric1514 wrote:
First test.

I ran the batteries down a bit and then plugged in the coach to shore. I have a PD converter and I let it bring the batteries back. When the starter battery was at 14.3v started the engine. That brought the voltage down to about 14.25. I couldn’t get the voltage back up. I suppose if I idled for a while I might have been able to raise it. The current was at about 6 amps. The dash alternator light didn’t come on.

It’s still too hot here to uncover the RV, so I was using the converter/charger to simulate the solar panels. What I think I learned is that the PCM is tolerant of voltage above 14.2. So right now I think if I change the profile in the controller so that it never goes above 14.2v I should not see a light.

I think you have it backwards. If you idled for a while the alternator voltage would taper to 13.8ish. meanwhile the PD set to 14.4 might eventually get the batts to near that. with voltage drop on the PD wiring you might never see 14.4 at the battery even with the low amps at the high SOC meaning almost no voltage drop.

Solar's low amps means little voltage drop unless thin wiring, so you could set that to 14.5 and get 14.4 which might ot set off the light.

You have to test for how high you can set the solar without the light coming on when the house batts are full. If they are full you don't need to be doing that at all, so if you did have a way to turn off the solar when the house is full while driving, you could get to the campground with the house full, no red light, and alternator charging looking after the starter batt.

BTW, do you have the charge wizard or pendant to make the PD do 14.4? If not, it will only do 13.6. What are you doing with that for testing?

[pianotuna]

That will work for the alternator--but the six volt batteries may prefer 14.8 from time to time. (once a week?)

[eric1514]

First test.

I ran the batteries down a bit and then plugged in the coach to shore. I have a PD converter and I let it bring the batteries back. When the starter battery was at 14.3v started the engine. That brought the voltage down to about 14.25. I couldn’t get the voltage back up. I suppose if I idled for a while I might have been able to raise it. The current was at about 6 amps. The dash alternator light didn’t come on.

It’s still too hot here to uncover the RV, so I was using the converter/charger to simulate the solar panels. What I think I learned is that the PCM is tolerant of voltage above 14.2. So right now I think if I change the profile in the controller so that it never goes above 14.2v I should not see a light.