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RE: Redarc 40 amp DC to DC Charger issue
Forgot to mention this previously. Something that needs to considered when electing to turn on a dc to dc charger based on ignition voltage (vs. alternator output voltage) is potentially reduced current to the starter while starting the engine. As soon as the ignition is turned on, a 40a dc to dc charger could be drawing as much as 60a from the battery. On some vehicles that 60a reduction could impact starter performance---especially in extreme cold/hot weather conditions.
As I recall there is a delay from when the ignition is activated to when the charger passes current.
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Teleman
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01/22/22 11:05am |
Tech Issues
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RE: Redarc 40 amp DC to DC Charger issue
Using the battery isolator didn't work. It didn't shut down so we connected the ignition wire and now it turns off with the ignition. Don't worry, even if there wasn't a warning beep when the ignition is on until starting the motor it's not something I'd forget.Did you happen to check voltage at the battery isolator with the engine not running? If the BI didn't shutdown the dc to dc charger that suggests your BI was defective or it was receiving >13.3v when the alternator was off-line. A fully charged automotive, lead-cell battery can only produce a max voltage of 12.7v-12.8v when the alternator is off-line (even with the ignition on). In any event, if you're ok having your dc to dc charger active with the ignition on and the engine not running, that's certainly your call. Good luck with everything.
I don't leave the ignition on with the engine not running. Like I said it was just an experiment.
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Teleman
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01/21/22 05:12pm |
Tech Issues
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RE: Redarc 40 amp DC to DC Charger issue
I would disconnect your blue trigger wire and see if it will work sensing the alternator voltage, less chance of drawing down your starting battery.
Again that was the original configuration and it didn't work. The charger stayed active.
I'm constantly monitoring my battery shunt and I have power pack to jump start the battery, generator, erc. It's fine.
Ok no problem, I would check again. On mine it takes 30 sec to 60sec to turn off after the ignition is shut off. It freaked me out at first because I thought it was not turning off. I I think takes a little bit for it to sense the voltage drop.
It's in the shop now but I'll do some more experimenting when I get it home.
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Teleman
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01/21/22 11:37am |
Tech Issues
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RE: Redarc 40 amp DC to DC Charger issue
I would disconnect your blue trigger wire and see if it will work sensing the alternator voltage, less chance of drawing down your starting battery.
Again that was the original configuration and it didn't work. The charger stayed active.
I'm constantly monitoring my battery shunt and I have power pack to jump start the battery, generator, erc. It's fine.
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Teleman
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01/21/22 10:59am |
Tech Issues
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RE: Redarc 40 amp DC to DC Charger issue
I only turned the ignition on to measure the current briefly out of curiosity before I started the motor. The charger activates with a signal from the ignition. The output current is about 43A at higher rpms and 48 at idle like I said.I prefer using a battery isolator because it requires >13.3v to activate the dc to dc charger. Zero chance of inadvertently discharging the starter/TV battery—ignition on or off.
I was hoping it was your input current fluctuating. Very unusual for charge current to fluctuate like that based on alternator rpm/output. The whole purpose of a dc to dc charger is to stabilize the charge process.
Using the battery isolator didn't work. It didn't shut down so we connected the ignition wire and now it turns off with the ignition. Don't worry, even if there wasn't a warning beep when the ignition is on until starting the motor it's not something I'd forget.
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Teleman
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01/21/22 10:46am |
Tech Issues
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RE: Redarc 40 amp DC to DC Charger issue
. . . Input current to the Redarc gets as high as 54 amps with the ignition on without starting the motor . . . Any particular reason you would allow your dc to dc charger to be on-line when the alternator is off-line? Most use a battery isolator or trigger wire (found on most dc to dc chargers) to prevent the dc to dc charger from inadvertently discharging the starter/TV battery when the alternator is off-line for any reason.
Output current stays about 43 amps when driving and climbs to about 48-49 at idle.Are you saying the output or input current climbs to 48-49a at idle?
If the output/charge current climbs to 48-49a at idle, I'd have to agree, it's definitely out-of-spec. How high did the input current go?
If you're referencing input current to the dc to dc charger, then 48-49a would seem perfectly normal with the alternator operating less efficiently at idle (higher voltage drop forces higher current).
I only turned the ignition on to measure the current briefly out of curiosity before I started the motor. The charger activates with a signal from the ignition. The output current is about 43A at higher rpms and 48 at idle like I said.
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Teleman
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01/20/22 07:55pm |
Tech Issues
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RE: Redarc 40 amp DC to DC Charger issue
Ok DC/DC chargers are voltage converters. they work one of two ways (Buck only or Buck/Boost) if boosting the amps in go up as the volts out go up.
And they also draw "overhead" power.
How to limit the current so the breaker does not pop I do not know other than a longer wire.. I'd not recommend a smaller wire, between the unit and the battery Make sure the wire can haul the full 40 (in fact 50 to be safe) amps but lengthen it so the resistance limits the current DO NOT COIL IT
Replacing the cheap breaker with a quality Blue Sea unit did the trick.
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Teleman
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01/20/22 03:33pm |
Tech Issues
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RE: Redarc 40 amp DC to DC Charger issue
Oh ok mine is not triggered by the ignition, it is sensing voltage to trigger it on and then after about 30 seconds slowly ramps up the amps. I wonder if you got a mislabeled 50 amp unit?
Maybe? That works for me.
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Teleman
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01/20/22 01:57pm |
Tech Issues
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RE: Redarc 40 amp DC to DC Charger issue
All cabling is well within spec. The starting and house batteries are within two feet of each other and the charger is next to the house battery. Replacing the tripping breaker with a Blue Sea unit solved the problem. Input current to the Redarc gets as high as 54 amps with the ignition on without starting the motor. Settles to around 45 with the motor running. Output current stays about 43 amps when driving and climbs to about 48-49 at idle. This seems somewhat out of spec but it's certainly acceptable to me in terms of performance.
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Teleman
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01/20/22 12:21pm |
Tech Issues
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RE: Redarc 40 amp DC to DC Charger issue
After about 15 seconds or so when I start the engine my shunt reads up to almost 49 amps and then the 60 amp input breaker pops. Whats going on here? Isn't the charger supposed to limit the output current to 40A?
what side are you reading on? its 40a on output, breaker shouldn't be tripping at 50 amps either.
Looking at the house battery shunt. Seems to have stabilized at about 43 amps. Breaker trips at about two minutes making me think it's a **** breaker. I'll check with a clamp on ammeter tonight.
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Teleman
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01/18/22 03:37pm |
Tech Issues
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RE: Redarc 40 amp DC to DC Charger issue
dead short?
I don't see how. It would trip immediately.
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Teleman
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01/18/22 11:47am |
Tech Issues
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Redarc 40 amp DC to DC Charger issue
After about 15 seconds or so when I start the engine my shunt reads up to almost 49 amps and then the 60 amp input breaker pops. Whats going on here? Isn't the charger supposed to limit the output current to 40A?
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Teleman
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01/18/22 11:28am |
Tech Issues
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RE: Alternator and LiFePo battery question
The Redarc also has an MPPT controller. I'm planning to add 600 watts of solar. I upgraded to LiFePo to charge the big batteries on our E-mtbs. Between the driving and solar I think we'll be fine.
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Teleman
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01/09/22 10:37am |
Tech Issues
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RE: Alternator and LiFePo battery question
The wire from the alternator to the batteries and from the house battery to the inverter is all 1/0 ga. The very short wires from the batteries to the DC to DC charger are 6 ga as specified by Redarc. The problem is the alternator is tied directly to the house battery. This is so it can be used as a boost if the starting battery is too weak to start the engine. I need to disconnect the alternator from the house battery so it only feeds the starting battery, then passes through the DC to DC charger to the house battery
I will miss the super fast 80-100 amp charging lol, but I don't want to risk burning out the alternator.
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Teleman
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01/08/22 01:30pm |
Tech Issues
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RE: Alternator and LiFePo battery question
I have a Redarc 40 amp DC to DC charger but apparently there is a solenoid that sends current from my alternator to the house battery when the ignition is on. I was unaware of this when my mechanic installed the charger. I just finished a 1500 mile road trip and was seeing a lot more than 40 amps on my shunt while driving. Fortunately I have a very robust alternator. I just found out about this solenoid so I will try and straighten it out so only the DC to DC charger is charging the battery.
Not clear how it was done from that. If part of the plan was to isolate the LFP from the alternator in case of way high draw from low SOC LFP (which is in dispute how much of a threat that is, but let's say it is valid for now) then leaving the OEM charging in place was wrong.
Next, the DC-DC itself will draw more than its 40 amps output as its input. Depending on the wiring from engine batt to DC-DC, if long and thin, could be 60 amps. If short and fat could be 45 amps.
So you need to pick the DC-DC output amps size to go with what your alternator can do, which depends on the input amps that you can only guess at.
If the amps are too high you could perhaps fatten that wiring to bring it within spec, or else before buying the DC-DC just assume 50% higher input over the output amps and match that to the alternator amps
It was an oversight. I was unaware of the solenoid that connected the alternator to the house battery. Obviously my alternator survived the high current draw which topped 100 amps at one point. The DC to DC charger is very close to both batteries with 6 ga cables recommended by Redarc for their length so that is not a problem.
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Teleman
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12/31/21 10:46am |
Tech Issues
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RE: Alternator and LiFePo battery question
I have a Redarc 40 amp DC to DC charger but apparently there is a solenoid that sends current from my alternator to the house battery when the ignition is on. I was unaware of this when my mechanic installed the charger. I just finished a 1500 mile road trip and was seeing a lot more than 40 amps on my shunt while driving. Fortunately I have a very robust alternator. I just found out about this solenoid so I will try and straighten it out so only the DC to DC charger is charging the battery.
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Teleman
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12/30/21 08:33pm |
Tech Issues
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Alternator and LiFePo battery question
What percentage of an alternator's rated output is it safe to run at a steady charge rate? 50%?
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Teleman
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12/30/21 02:54pm |
Tech Issues
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RE: Tank treatment that can restore sensor accuracy?
I have a feeling anything that would make your sensors work would be something you'd have to do on a consistent basis. Spend enough time in your coach and you won't need them. You'll get a pretty good idea of how long you can go.
Yes I have been able to go by feel pretty much. I'd like to have them work if possible. I'll try the Commando product mentioned above.
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Teleman
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12/18/21 12:02pm |
Tech Issues
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RE: Tank treatment that can restore sensor accuracy?
I use a toss in packet called commando from Amazon or Walmart. Last day of camping I toss one in and add water to the tank to get it close to full , then drive home. When I dump the tanks the following day the sensors are nice and clean
Thanks I'll try this. Looking at the product description it only mentions black water. Do you use it in the Grey water tank too?
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Teleman
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12/18/21 09:41am |
Tech Issues
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Tank treatment that can restore sensor accuracy?
Both my black and grey water tank sensors read full or partly full even when empty. Has anyone found a product to truly clean the tanks to restore them to proper functionality?
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Teleman
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12/18/21 09:29am |
Tech Issues
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