Dual alternator kit for the Ram Promaster announced

[avanti]

Originally Posted by booster

The system that had the issue was the 270 amp alternator, Balmar regulator, 300ah of AGM and tied to a Xantrex 100/2000 inverter/charger, for reference.

Do you happen to know if he was using the Balmar MC-614 specifically? I have read the manual for that unit and it seems pretty sophisticated, so it is kind of surprising. Worth a phone call though. Thanks again.

[booster]

Originally Posted by avanti

Do you happen to know if he was using the Balmar MC-614 specifically? I have read the manual for that unit and it seems pretty sophisticated, so it is kind of surprising. Worth a phone call though. Thanks again.

Nope, don't know the model number, unfortunately., but the install was fairly high end, so not cheap stuff. To get the system fixed and working took a high end marine tech (read expensive) to figure it out (he didn't do the install) with help from the Balmar tech line. Definitely worth a call, I would think. Symptoms were that it would not transition to float and held 15ish voltage continuously.

[Nomad32]

Originally Posted by markopolo

Nations Starter & Alternator has put a photo of their dual alternator kit for the Ram Promaster on their Facebook page: https://www.facebook.com/permalink.p...d=147260728552





Nations Starter & High Amp Alternator- Best Quality Starter & Alternator Supply!

So this is the engine generator on the Roadtrek Zion. Interesting.

[avanti]

OK, I called the nice folks at Balmar. Here's what happens:

--The charger is in absorption mode and decides it is time to go to float.
--The charger gently ramps down the excite voltage to the alternator, in an effort to get to the float voltage.
--BUT, if there is no load at all, it continues to see the battery's surface charge and it is unable to ever get down to the targeted float voltage.
--Eventually, it turns the alternator completely off, and stays there as long as the surface charge survives.

This is why absent a load you continue to see the higher absorption voltage even though the inverter is in float mode. In the marine world, this bothers people, because with the alternator turned completely off, it stops sending it's tachometer signal even though the engine is still running. Clearly, this will make no difference at all in a typical RV scenario, except perhaps a slightly confusing Trimetric display.

So, apparently all is well. Thanks for the heads up.

[gerrym51]

Originally Posted by avanti

OK, I called the nice folks at Balmar. Here's what happens:

--The charger is in absorption mode and decides it is time to go to float.
--The charger gently ramps down the excite voltage to the alternator, in an effort to get to the float voltage.
--BUT, if there is no load at all, it continues to see the battery's surface charge and it is unable to ever get down to the targeted float voltage.
--Eventually, it turns the alternator completely off, and stays there as long as the surface charge survives.

This is why absent a load you continue to see the higher absorption voltage even though the inverter is in float mode. In the marine world, this bothers people, because with the alternator turned completely off, it stops sending it's tachometer signal even though the engine is still running. Clearly, this will make no difference at all in a typical RV scenario, except perhaps a slightly confusing Trimetric display.

So, apparently all is well. Thanks for the heads up.

finally- i never understood roadtrek when they explained it to me. they said that even if alternator was spinning from the engine that it was not always charging but the alternator would decide. you have now clarified it for me and it makes sense.

[gerrym51]

Originally Posted by Nomad32

So this is the engine generator on the Roadtrek Zion. Interesting.

i am not sure-i believe they use the nations mounting kit but i am not sure which alternator.

the one they have been using is not the xp270

[booster]

Originally Posted by avanti

OK, I called the nice folks at Balmar. Here's what happens:

--The charger is in absorption mode and decides it is time to go to float.
--The charger gently ramps down the excite voltage to the alternator, in an effort to get to the float voltage.
--BUT, if there is no load at all, it continues to see the battery's surface charge and it is unable to ever get down to the targeted float voltage.
--Eventually, it turns the alternator completely off, and stays there as long as the surface charge survives.

This is why absent a load you continue to see the higher absorption voltage even though the inverter is in float mode. In the marine world, this bothers people, because with the alternator turned completely off, it stops sending it's tachometer signal even though the engine is still running. Clearly, this will make no difference at all in a typical RV scenario, except perhaps a slightly confusing Trimetric display.

So, apparently all is well. Thanks for the heads up.

That is very interesting to say the least. I will forward your information to the guy that had the problem. Right now they have him running a resistor pack to get the 4 amp load, and the way it was explained to me, it sounded like that recommendation had come from Balmar.

I will let you know what I hear back.

[avanti]

Originally Posted by booster

Right now they have him running a resistor pack to get the 4 amp load, and the way it was explained to me, it sounded like that recommendation had come from Balmar.

The tech guy said that the above is the standard advice they give to boaters who complain about their tach not working (either that or "leave a light on"). I suspect that whomever your friend spoke to simply overgeneralized.

Thanks again.

[booster]

The explanation you got has me wondering one thing, and not being an alternator expert doesn't help.

As far as I know, the excitation voltage is always lower than the output voltage, as it has to be to be able to get a voltage higher than battery voltage. If that is the case, and the Balmar is not able to go low enough because of the surface charge on the battery (13.1 volts tops, maybe), which is the excitation voltage, does that mean it is also holding its output voltage up that high, or higher probably, also? How else would it hold the voltage above the 14 volts that they said they say the saw?

I think the shutoff that Balmar talks about would be when it hit maximum absorption time, maybe.

Did the guy you talked to say what voltage you would expect to see at the batteries when the situation occurred?

[avanti]

Originally Posted by booster

The explanation you got has me wondering one thing, and not being an alternator expert doesn't help.

As far as I know, the excitation voltage is always lower than the output voltage, as it has to be to be able to get a voltage higher than battery voltage. If that is the case, and the Balmar is not able to go low enough because of the surface charge on the battery (13.1 volts tops, maybe), which is the excitation voltage, does that mean it is also holding its output voltage up that high, or higher probably, also? How else would it hold the voltage above the 14 volts that they said they say the saw?

I think the shutoff that Balmar talks about would be when it hit maximum absorption time, maybe.

Did the guy you talked to say what voltage you would expect to see at the batteries when the situation occurred?

Well, I'm no expert either. But, with modern charge pump ICs, a device as fancy as the Balmar regulator can clearly change any voltage to any other, so I am not sure that the rules-of-thumb that you cite are necessarily true any more.

My understanding of what the tech told me is that the charge output gets turned off entirely. The voltage that you see is apparently coming totally from the battery, which as I understand it could be nearly as high as the absorption voltage before it was shut off. The device is highly programmable, so exactly what that voltage is depends on the configuration. The installation manual says that it can be programmed in the range 13.9 to 14.7 volts.

[booster]

I thought that is what you were saying, just wanted to be certain. I just don't understand how they could still have been seeing absorption level voltages, I will have to confirm all that.

On my testing of the Lifelines on the bench from the Magnum charger, when it switches to float, the voltage drops quickly, just a matter of a couple of minutes. If I disconnect them and check they will be in 13.1-13.2v range which is lower than the float voltage.

[avanti]

Originally Posted by booster

On my testing of the Lifelines on the bench from the Magnum charger, when it switches to float, the voltage drops quickly, just a matter of a couple of minutes. If I disconnect them and check they will be in 13.1-13.2v range which is lower than the float voltage.

I think that this behavior would depend on the output impedance of the charger. I wouldn't be surprised if that varied by model. If the impedance were infinite, the battery would behave as if it were disconnected. In that case, the surface charge can allegedly last for hours. I imagine that a high impedance would be a design goal, since otherwise an inactive charger would represent a vampire load.

As I understand it, the "surface charge" is pretty much the battery acting as a capacitor, in which case it would "remember" whatever voltage it last saw.

I repeat, though, I am no expert.

[booster]

I still have it so I can easily setup the Lifelines again, so I think tomorrow I will hook them up and do a full charge, put it back into absorption for a few minutes after it autos to float, and then disconnect the batteries before they see any lower float voltage. That way I will be able to see how high a voltage they actually will sit at, and for how long.

As you say about the sophisticated newer electronics, it is surprising that the Balmar can't just set it's output to float, and if the battery is higher, no current flows.

[avanti]

Originally Posted by booster

I still have it so I can easily setup the Lifelines again, so I think tomorrow I will hook them up and do a full charge, put it back into absorption for a few minutes after it autos to float, and then disconnect the batteries before they see any lower float voltage. That way I will be able to see how high a voltage they actually will sit at, and for how long.

Cool. That will be interesting. Be sure to disconnect the battery while the absorption current is still present--I could imagine the discharge happening very rapidly.

As you say about the sophisticated newer electronics, it is surprising that the Balmar can't just set it's output to float, and if the battery is higher, no current flows.

I suspect that that could be done (or they could reduce the impedance to kill the surface charge). The impression I got from them was that they didn't consider it a very important problem. He said that they sell mostly to boaters and implied that a zero-load situation is rare. Didn't get the impression that they cared much about RVers.

[booster]

Originally Posted by avanti

Cool. That will be interesting. Be sure to disconnect the battery while the absorption current is still present--I could imagine the discharge happening very rapidly.

I suspect that that could be done (or they could reduce the impedance to kill the surface charge). The impression I got from them was that they didn't consider it a very important problem. He said that they sell mostly to boaters and implied that a zero-load situation is rare. Didn't get the impression that they cared much about RVers.

From the previous testing, the return amps will be very low at about 1.7 amps when the batteries get full, so if I just set the Magnum transition to 1 amp, it won't go to float by itself, but I will know when it is done by the amps on the meter. That should assure disconnecting with maximum surface charge.

I think a lot of the builders of the really cool stuff base them for boats, it is where the money, I would think. I know when I have talked to Magnum, Sterling, Outback, Victron, etc, I got the same impression you did.

[avanti]

Well, I just placed my order, so we'll see how it goes.

[booster]

Originally Posted by avanti

Well, I just placed my order, so we'll see how it goes.

No doubt that is the best way to find out how it really works in the real world--I have found out many times, things don't always happen the way they tell you they will.

Looking forward to what you find out once up and running.

[booster]

I have the test up and running right now. Batteries had been sitting for about 3 weeks, I think, and were still at 13.0 volts. They were separated into two 12v pairs, so I was surprised they were both exactly the same voltage. They did pull slightly different charge current, though, by about .4 amp out of the only 8 amps they started out at in 13.4v absorption. Down to 3.8v after 30 minutes and still running. Should be down to under 2 amps in a couple of hours, and be totally full. It is set to not go into float, so I will be able to disconnect and see what the surface charge is. I will also be able to put a small load on with the inverter to see how long it takes to remove that charge, as we, and Avanti I think, will have some loads on like a compressor frig.

I have not looked at a Balmar manual, but one question would be if it does the same as many of the chargers do (including the Magnum) at charge initiation. That process would be to look at the battery voltage and determine from that voltage whether or not to do a full charge or directly to float. If they do that process, you could easily wind up in float when you don't want to because of surface charge (less likely) or the solar holding the voltage up.

[booster]

OK, test done. Batteries at total full based on return amps so positively full to maximum.

Absorption voltage at 14.3v, return amps at end at 1.8 amps

Shutoff charger and unplugged, disconnected charger leads from batteries and separated the pairs (about 30 seconds). Voltage of each pair at 13.48 volts. Nowhere near absorption voltage.

I reconnected the charger and turned on the inverter with no output and it showed the same 13.4 volts and was using about 2 amps. In 15 minutes the voltage dropped to 13.2 volts.

I took a look at the Balmar site and they are big on not using shunts to calculate full batteries. Even their battery monitor does it with an algorithm and no shunt. They also add a "smart bulk" and "smart absorption" time to the charge cycle that they say is based on the battery and bunch of other conditions. They sense charge current by checking the field current or voltage at the various conditions.

My guess, and this is only a guess because we will never get told how they run their algorithm, is that the load current is messing up probably a couple things in their control logic. It makes a bit of sense in that these units were probably designed to control engine alternators, so they would always have a load on them.

"Normal" chargers go to float whenever they meet their absorption transition parameters, be them time, amps, whatever. It appears that the Balmar looks at what is going on when the absorption timer runs out, and then tries to figure out what is needed, going into float or staying in absorption or bulk based on what it sees. With no load on the system, and some surface charge or solar holding up the voltage, the unit sees low amps compared to running an engine, and above full charge battery voltage, so it thinks the batteries are full when it does the check. It would then probably get confused and shut off the charging, but is what Avanti was told, but my acquaintance didn't see that and was said to be staying in absorption, so that is a question for sure.

Perhaps the 4 amps is the minimum the unit will allow without going into a "keep checking" mode to determine what is going on, staying in absorption in process.

The two amp load that I had on would take quite a while to drop the voltage to what most charger folks indicate a full battery-12.7 volts, so even the 4 amp load might have trouble getting to that level in the time that the unit is checking the system before float, so the current is probably the major factor, voltage to a lesser degree.

I am becoming more and more convinced over time that the manufacturers who are trying to build algorithms to get around using shunts are up against a nearly impossible task because of varying loads and other charge sources like solar.

It is going to be extremely interesting to see what Avanti comes up with when he gets his system up and going, as it should help fill in the blanks.

[avanti]

Originally Posted by booster

I have not looked at a Balmar manual, but one question would be if it does the same as many of the chargers do (including the Magnum) at charge initiation. That process would be to look at the battery voltage and determine from that voltage whether or not to do a full charge or directly to float. If they do that process, you could easily wind up in float when you don't want to because of surface charge (less likely) or the solar holding the voltage up.

Here is the section of the Balmar manual that describes the alleged behavior:

Regulator Operation
The MC-614 regulator’s microprocessor controlled charging system uses a sophisticated, multi-stage profile to deliver maximum charging output, while protecting the batteries from overcharging damage. When the regulator is first turned on, the processor performs a quick one-second self diagnostic assessment. Following that diagnostic, the MC-614 initiates a charge program as follows:
1. Start Delay - Factory set at one second. Can be user-adjusted to a maximum of 999 seconds in the regulator’s ad- vanced programming mode. See Advanced Programming section for adjustment instructions.
2. Soft Ramp - Gently increases voltage to bulk preset levels based on battery program selected.
3. Bulk Charge - The most aggressive of the charging stages. Voltage is held at a pre-set level, specified by battery program selected, for a set time period. Factory-set bulk time is 18 minutes. Adjustable in 6-minute increments.
4. Calculated Bulk Charge - Holds voltage at bulk level for six minutes, then calculates battery condition by comparing existing voltage, time at voltage, and field percentage to target values. If values are met, the regulator advances to the next stage. If values are not met, the regulator continues to bulk charge and compares real-time to target values. This will re-occur until all values are met.
5. Ramps down to Absorption voltage.
6. Absorption Charge - Regulator continues to control the alternator’s output voltage for an additional 18 minutes at approximately 2/10’s of a volt below bulk charging voltage. Adjustable in 6-minute increments.
7. Calculated Absorption Charge - Holds voltage at absorption level for six minutes, then calculates battery condition bycomparing existing voltage, time at voltage, and field percentage to target values. If values are met, the regulator advances to the next stage. If values are not met, the regulator extends the absorption charge and compares real- time to target values. This will re-occur until all values are met.
8. Ramp down to Float.
9. Float Charge - Regulator continues to control the alternator’s output voltage for an additional 18 minutes, typically at a volt less than bulk voltage (based on battery program presets). After that initial fixed time period, the regulator can respond to increased charging demand by cycling to absorption voltage. After 12 hours of continuous operation, the regulator will automatically revert to absorption voltage through calculated absorption and back to float charging stage.

So, taken at face value, #4 seems to imply that it will ALWAYS go into bulk charge for a settable period of time, every time the regulator is "first turned on", which I assume means every time the engine is started. You can set the time of this "guaranteed bulk" charge, with a minimum of 6 minutes. Moreover, #9 seems to say that you can never get back to bulk mode except by stopping and restarting the engine, which I guess makes sense since you have presumably been subsisting on the generator output since the original bulk charge. Complicated.

I have always been kind of confused by the multiple charger thing. Seems too good to be true that one could connect two or (in this case) three chargers all together and have the right thing happen. I guess the right thing to do is to carefully tweak the thresholds of all the chargers to try to coax the right behavior out of the system.