Renogy 60A DC-DC charger in 2016 Pleasureway

[reilym]

I am taking steps to better manage charging the two 100 Ah LiFePO4 batteries that came in my 2016 Lexor. I got a good deal on a new Renogy 60 amp DC-DC unit on eBay. Not my first choice, but could not pass up the deal. The biggest problem with it is the requirement of having an ignition signal to turn it on and no start delay to allow the alternator to warm up. For now, I am using the stock SurePower solenoid as the power input and to provide the "on" signal and this seems to work fine delivering a full 60 amps to the batteries and drawing about 75 off the alternator. I am working on a voltage sensing circuit with built in delay that will mimic the SurePower logic. Once that is working, I can bypass the SurePower and reserve it as a back-up charging system. With the stock system, it was not unusual to have well over 140 amps going back to the batteries through dual 2 gauge cables running the length of the RV. Hard on the alternator and possibly the batteries too. The unit fits nicely under the left rear ottoman seat, near the existing power distribution. Once I have this all worked out, I'll post an update, but in the meantime, I welcome any comments or suggestions.

[rowiebowie]

I have a similar Renogy DC to DC charger but the smaller 40A model and only a 160A alternator.

I installed an on/off switch on the ignition wire. If I need to charge while driving, I leave the switch off initially to allow time for the alternator to top off the engine battery. Then, when I'm ready to hit the highway, I switch it on.

On a few rare occassions when idling at stop and with dash ac on high, I've seen the voltage on the engine battery drop momentarily under 12 volts as if the 40A DC to DC charger was drawing more power than the alternator was providing. As soon as the engine was off idle, the engine battery voltage returned to normal. Never a problem when at speed.

[reilym]

I noticed an intermittent drop in voltage similar to the one you described until the alternator warmed up. I like the idea of a voltage sensing circuit that will turn on the DC-DC at > 13.2 volts after a 1 minute delay and off below 12.8 volts. Your switch is a simpler solution, but my DC-DC is located in the back of the coach and I see no easy to get a wire from the dash back to it. Is your unit close to the cab or how did you route the wiring?

[rowiebowie]

Originally Posted by reilym

I noticed an intermittent drop in voltage similar to the one you described until the alternator warmed up. I like the idea of a voltage sensing circuit that will turn on the DC-DC at > 13.2 volts after a 1 minute delay and off below 12.8 volts. Your switch is a simpler solution, but my DC-DC is located in the back of the coach and I see no easy to get a wire from the dash back to it. Is your unit close to the cab or how did you route the wiring?

I probably could have intercepted the ignition wire and placed my switch on the dash (which would be ideal). Instead, I did the easy (lazy) thing and put the switch in the rear of the coach near my electical components. So I have to remember to pull over and turn it on before we're headed on the highway.

The switch is lighted so I know when it is on.

[markopolo]

Originally Posted by reilym

........... I am working on a voltage sensing circuit with built in delay ...........

I've considered doing the same but without the delay. - https://www.classbforum.com/forums/f...tml#post118519 - I like your idea of implementing a delay though.

DVB01-Digital-Led-Voltage-Comparator.jpg

The DVB01 comparator ($5 to $15) has 5 functions to choose from:

1. voltmeter
2. charge controller
3. discharge controller
4. within voltage range
5. outside of voltage range

Function 4 seems ideally suited for this.


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[markopolo]

Originally Posted by reilym

............... delivering a full 60 amps to the batteries and drawing about 75 off the alternator.............

Good ventilation would be needed. Up to 200W heat at full output maybe ...?

[reilym]

Originally Posted by markopolo

Good ventilation would be needed. Up to 200W heat at full output maybe ...?

That is another concern I had. That compartment is relatively large, and not well sealed, but after a 15 mile drive, the DC-DC was definitely warm to the touch. I need to monitor the compartment temperature and decide if I need to add some passive or active ventilation.

[reilym]

Originally Posted by markopolo

I've considered doing the same but without the delay. - https://www.classbforum.com/forums/f...tml#post118519 - I like your idea of implementing a delay though.
----------

Along the lines of the above thread, below is a schematic that will make use of the current limiting function (LC+) of the DC-DC charger that should remediate the situation where the alternator voltage drops when cold or at idle under heavy load. When the alternator output voltage starts to drop, LC+ gets voltage and the DC-DC charger would limit the current to 50%. When the alternator voltage recovers, it would go back to 100%. Currently, I am using the SurePower to do the switching that the voltage sensitive switch (VSS) would take on. I need to see if the comparator that markopolo posted can accomplish this. This schematic does not show a delay circuit yet.

[booster]

As I have done often, I caution everyone who is using the single alternator setups to check the alternator temps when charging hard. In ability to hold full voltage is a sign that they may be getting hot, it can also be an indication of the alternator doing a self turn down from temperature. The temp control built in to the alternators can be highly variable, I think, even in the high output versions as I know people that have measured over 250* on stock alternators that were still trying to put out full power. A $20 Harbor freight infrared thermometer works well enough for this so not a bit investment and you can also use it for tire temps, etc. Where the alternator sits in the engine compartment is also a big issue. If it is in an area that uses radiator air, like the Chevies do, you can be trying to cool the alternator with air that is over 150*F so you lose a lot of usable output of the alternator if you want to keep in it a safer range. We have 530amp of rated alternator output in our Chevy and if we want to keep the alternators under 225* we can only take about 180 amps for the coach batteries before we get above that in some conditions like idling or going up steep grades where the radiator air get much hotter. We can actually see the alternator temps climb with the radiator temps. The van itself appears to take between about 15 and 40 amps depending on speed, load, and what else is on like the AC, so we would be running in the low 200s amps many times if charging the batteries as quickly as we can for a longer period. That is only about 40% of the rated output of the alternators



The aftermarket high output alternator builders I have contacted say that their alternators can run at up to 250- 270* without self destructing, but pretty much agreed that lifespan starts to drop somewhere in the 220-230* range. With a single alternator if it dies, so does the van, so having a spare and knowing how to change it might be a choice if possible, or good road service/towing plan. I have no idea how any of the OEMs would handle warranty claims on a van that was pulling a lot of power off the alternator, but we know MB does not want you to.



If the B to B in this discussion is pulling the mentioned 75 amps, and you put 40 amps possible to chassis, you would be using 115 amps, which is quite a bit. If you have electric cooling fans, as is getting more common all the time, you could add another 30-40 amps easily from what I have seen. Even at 115 amps, you would need a 230 amp alternator to stay at 50% output or less.


As a point of reference, based on a data log that a poster put up on the forum a while ago, the 280amp high output Nations aftermarket standalone alternator netted out at about 165amp average output by the time it heat cycled up and down on command from a standalone Balmar regulator which turns it down at about 225* IIRC. That alternator did get pretty good fresh air, I think, as it was on a Sprinter so hanging low in the front. No radiator air can be a big deal, I think.


Best thing to do, IMO, is not guess if you are OK. Just take the temp and see for sure as it is normally very easy to do.

[reilym]

Booster,
Alternator temperature is a legit issue. I have not measured mine yet, but I do have an IR thermometer and will do so next time I get on the road for a decent stint. I am seeing the same sort of chassis load on the alternator as you reported. The chassis does draw as much as 40 amps, but usually not for long. The alternator in my Promaster is 220 amps, so 75 amps + 40 puts me at 52%. I figure this has to be better than the 190 amps combined I was pulling without the DC-DC charger. Maybe I need to consider markopolo's idea of a switch to manually actuate the current limiting function on the DC-DC when there is high demand on the alternator from the chassis. The RV has 25000 miles on it with the formerly unregulated charging set up, so my alternator may not be as healthy as it could be. Having a spare along is probably prudent.

[booster]

Originally Posted by reilym

Booster,
Alternator temperature is a legit issue. I have not measured mine yet, but I do have an IR thermometer and will do so next time I get on the road for a decent stint. I am seeing the same sort of chassis load on the alternator as you reported. The chassis does draw as much as 40 amps, but usually not for long. The alternator in my Promaster is 220 amps, so 75 amps + 40 puts me at 52%. I figure this has to be better than the 190 amps combined I was pulling without the DC-DC charger. Maybe I need to consider markopolo's idea of a switch to manually actuate the current limiting function on the DC-DC when there is high demand on the alternator from the chassis. The RV has 25000 miles on it with the formerly unregulated charging set up, so my alternator may not be as healthy as it could be. Having a spare along is probably prudent.

Does the Promaster have electric fans? If so you probably would see more than 40 amps with them running and the engine working hard as the injectors, ignition, fuel pump also us more power under heavy load. Fans in my Buick stock are rated at 480 watts total so they are just about there. This is with a 260hp 5.7l GM engine. I have heard of references to 707hp Chrysler Challengers using nearly 100 amps under full load.

[reilym]

Originally Posted by booster

Does the Promaster have electric fans? If so you probably would see more than 40 amps with them running and the engine working hard as the injectors, ignition, fuel pump also us more power under heavy load. Fans in my Buick stock are rated at 480 watts total so they are just about there. This is with a 260hp 5.7l GM engine. I have heard of references to 707hp Chrysler Challengers using nearly 100 amps under full load.

Yes, it has dual electric fans with 2 60 amp fuses, so it's a pretty heavy load. I can't really get to the fan wiring harness easily, so was not able to measure the current draw. For grins, I backed the RV out and started it. Ambient temperature was 45F and within 30 minutes the alternator body was reading almost 200F I had the AC on and the fans cycled on several times. My coach batteries were close to full, so I was only pushing 40 amps back to them through the DC-DC. The reading on the input side of the DC-DC was about 45 amps.
Sounds like you have a Roadmaster? I have a '96 Impala SS with the same engine and probably the same fans.

[booster]

Originally Posted by reilym

Yes, it has dual electric fans with 2 60 amp fuses, so it's a pretty heavy load. I can't really get to the fan wiring harness easily, so was not able to measure the current draw. For grins, I backed the RV out and started it. Ambient temperature was 45F and within 30 minutes the alternator body was reading almost 200F I had the AC on and the fans cycled on several times. My coach batteries were close to full, so I was only pushing 40 amps back to them through the DC-DC. The reading on the input side of the DC-DC was about 45 amps.
Sounds like you have a Roadmaster? I have a '96 Impala SS with the same engine and probably the same fans.

IIRC, the Roadmaster has two 40 amp fuses so yours may pull even more. I have changed the stock L/H fan to the towing version with the stock fan on the right. Yes, 1996 Roadmaster wagon that I am in the process of building a "smiled on" stock torque curve, hopefully higher output and efficiency engine for. Lots of work on the car to get the handling as good as I can and it is now quite good. Your SS has a definite head start on that part. I will be doing the SS similar 3.08 gears and ditching the 2.53 that is in it also. The voltage on the RMW drops very quickly when the fans are on, but it rarely if ever runs both. I have override on switches as the factory settings are way too high. I have a tuner for it now, so I will be able to change those temps, along with some other stuff like the speedo with the gears, egr, air pump, tank vent stuff.


Hood down, chugging up a long climb, I think I would definitely shut off as much extra alternator load as possible as it is likely you will have both fans running which will be a very quite big number, it appears.



I think you would be able to check the amps to the fans pretty easily if you have a clamp on meter on the alternator output when the fans come on as you will be able to see the increase.


Pix after last winters paint and bodywork project.


https://www.classbforum.com/forums/f...ulk-10352.html

[reilym]

Originally Posted by markopolo

I've considered doing the same but without the delay. - https://www.classbforum.com/forums/f...tml#post118519 - I like your idea of implementing a delay though.

Attachment 10898

The DVB01 comparator ($5 to $15) has 5 functions to choose from:

1. voltmeter
2. charge controller
3. discharge controller
4. within voltage range
5. outside of voltage range

Function 4 seems ideally suited for this.

----------

I have just ordered two of these things - one I'll use one to feed D+ for turning on the DC-DC above 13.2 V and off below 12.8 and one to feed LC+ to limit current to 50% when in between. I see in the manual (poorly translated from Chinese) that these also allow a time delay of 1-99 seconds to be programmed, so I think this will fit my needs. I will let you know how it works out. Thank you for the nice find!

[markopolo]

It would be great if it works. The translated manual is a difficult read. This guy's video is very thorough & very helpful:

https://www.youtube.com/watch?v=Yvoa1sThnMI

[reilym]

Originally Posted by markopolo

It would be great if it works. The translated manual is a difficult read. This guy's video is very thorough & very helpful:

Excellent, thanks. I just watched this and re-translated the published documentation. Once I get mine and go though my edited instructions (which include a link to this tutorial), I will make them available.

[markopolo]

It would be fantastic if you make new instructions available. Thanks for pointing out the additional new feature of being able to add a delay up to 99 seconds. That is not in the manual I found but it is in the video. At the very least, that would smooth things out a bit so that brief under or over voltage occurrences don't cause excess relay activity and/or excess internal switching in the Renogy unit.

[markopolo]

Just thinking about what voltages to set on the DVB01, Renogy DC-DC, & with lithium batteries ....

For the Renogy D+ connection:

DVB01 Function 4 (within a range)
30 second delay upper voltage 15V
90 second delay lower voltage 12.9V
Renogy on at 12.9V, off at 15V.

For the LC connection: (second DVB01 unit)
Note: The LC connection is described as needing signal input just like the D+. Also, LC is likely only needed with the 60A Renogy units because of 50% LC versus 12.5% for 40A & 20A units.

DVB01 Function 2 (charge controller) or Function 4 (within a range)
90 second delay upper voltage 13.3V
1 second delay lower voltage 12.9V
On at 12.9V, off at 13.3V - Reduced amperage from 12.9V to 13.3V

For the Renogy lithium profile:
S5 - off
S3 & S4 - both On (no float)
S1 & S2 - both Off for my preference of 14.00V charging lithium

I'm definitely looking for input/discussion here so all comments welcomed.


Edit: Just adding: With the LED displays turned off (power saving) & relays open, it looks like two DVB01 units would only consume around 4Ah per month if the listed specifications and my calculations are correct.

[reilym]

Originally Posted by markopolo

Just thinking about what voltages to set on the DVB01, Renogy DC-DC, & with lithium batteries ....

For the Renogy D+ connection:

DVB01 Function 4 (within a range)
30 second delay upper voltage 15V
90 second delay lower voltage 12.9V
Renogy on at 12.9V, off at 15V.

For the LC connection: (second DVB01 unit)
Note: The LC connection is described as needing signal input just like the D+. Also, LC is likely only needed with the 60A Renogy units because of 50% LC versus 12.5% for 40A & 20A units.

DVB01 Function 2 (charge controller) or Function 4 (within a range)
90 second delay upper voltage 13.3V
1 second delay lower voltage 12.9V
On at 12.9V, off at 13.3V - Reduced amperage from 12.9V to 13.3V

For the Renogy lithium profile:
S5 - off
S3 & S4 - both On (no float)
S1 & S2 - both Off for my preference of 14.00V charging lithium

I'm definitely looking for input/discussion here so all comments welcomed.

Here is my thinking on this, also very open to the group wisdom.

For D+: Function 4 might work, but I am looking at Function 3 for this signal. I want the unit to turn on above 13.2 V (indicating that the alternator is running) and stay on until the voltage drops below 12.8 (indicating that the alternator is not running). These are the voltage setpoints for the SurePower battery separator that came with the PW. The Surepower has a few seconds delay before connecting the battery, I agree that at least 30 seconds delay before turning the DC-DC on would allow the alternator to warm up and stabilize. I had not thought about a shut-off delay. Disconnecting the batteries when the engine is off seems like something that should happen immediately to avoid any drain on the chassis battery.

For LC+: Here I think function 4 will work. I have to experiment with the limits here, but think I will start with with upper and lower limits of 13.1 and 12.8. This should kick the DC-DC down to 30 amps if the alternator is struggling under load, before it has a chance to drop low enough to turn the DC-DC off. Delays will be zero for this, since I would want to drop the current draw immediately if the alternator voltage drops below 13.1. Like D+, the relay will be off when the engine is not running.

Charging profiles: Pleasureway got back with me regarding charging profiles and they like 14.2 for their batteries. Thus, their suggested dip switch settings, which were also the ones Renogy provided me with are:

S5: OFF
S1: ON
S2: OFF
S3: ON
S4: ON

Same as yours, with the exception of 14.2 vs. 14.0 V.

Once I figure out how to get wires from the cab back to the DC-DC, I also like the idea of a switch(es) on the dash that allow me to manually disconnect the DC-DC and limit current when necessary or desired.

P.S. I got the DVB01s yesterday and hope to do some test then out along with my instructions today.

[markopolo]

I hadn't thought of using Function 3 for D+. I like the idea - turn on at 13.2V and stay on until 12.8V is breached. That would work.

Function 4 differs by providing an upper voltage limit. In the unlikely occurrence of an alternator extreme over-voltage event that limit might protect the Renogy unit and maybe downstream stuff. Renogy unit upper limit input is 16V.

I see shut-off & turn-on delays as being useful to prevent relay chatter due to short duration out of range voltage fluctuations. That would apply to D+ & LC.

I'm wondering if one of the lead acid profiles would be better than the lithium profiles. Example:

Lead Acid
S5 - On
S1 - Off
S2 - On
S3 - Off
S4 - On
14.1V Absorption, 13.5V Float

The 13.5V Float would maintain the lithiums when running the fridge for example while driving. Most sources indicate that not much charging of LiFePO4 batteries happens at less than 13.6V. If No Float is used then there's the potential of several hours lithium battery use powering the fridge and other house loads if the voltage trigger to No Float is reached very early during the day's drive as it would if starting the driving day with near full batteries. My assumption is that the Renogy would restart the charge process only after having been first turned off because I haven't found anything in the manual that indicates otherwise. With No Float, the potential to arrive at a destination with batteries at a lower SOC than when the drive started exists.