DC to DC Charger October 28, 2023, 11:18:45 am I'm getting ready to install a 60 amp (adjustable to 30) Renogy DC to DC charger. The thing is pretty large. Where have you guys mounted it? Also, looking for some tips on the installation. Thanks.jor
Re: DC to DC Charger Reply #1 – October 28, 2023, 11:27:55 am Quote from: jor - October 28, 2023, 11:18:45 amI'm getting ready to install a 60 amp (adjustable to 30) DC to DC. The thing is pretty large. Where have you guys mounted it? Also, looking for some tips on the installation. Thanks.jorI installed 30amp behind the driver seat close to floor. This position helped me getting the input from existing batteries (indirectly from alternator) to new batteries which I installed bellow the dinnet seat behind the passenger seat. I think I posted few pictures here ,,60 amp !!!! do you have dual alternator? if not, will it put too much load on alternator?
Re: DC to DC Charger Reply #2 – October 28, 2023, 11:35:26 am Quoteo you have dual alternator? Yea, I'm wondering if I should have gone with 30. Stock alternator. This one is adjustable to 30. I'll wait for more comments. Thanks.jor
Re: DC to DC Charger Reply #3 – October 28, 2023, 12:44:07 pm I'm not sure what size alternator your 2009 LD has, 130, 140, 155-amp or ?Alternator overheating may be a problem as lithium batteries pull high charge rates until nearly full.On hot days with the A/C on, a large DC-to-DC converter may overload the alternator and its output will drop. The alternator's voltage regulator is built-in, it monitors the alternator temperature and reduces output when it gets too hot. Too bad the amp-gauges seen in old trucks and cars are not commonly used today, it would show the actual alternator output while on the road.Watching the voltage level on a Scagauge or Ultragauge would show lower voltage when too hot, also the battery monitor (assuming one is present) would show reduced amperage flow into the battery when the alternator is too hot.The good news is many DC-to-DC converters have two charge rates, if the high rate is too much, the lower rate should be fine.The problem is knowing how high a charge rate is too much.Larry
Re: DC to DC Charger Reply #4 – October 28, 2023, 12:57:14 pm So do our house batteries get a charge from the alternator stock from the mothership? Karen~Liam 98 ~ MB NinA
Re: DC to DC Charger Reply #5 – October 28, 2023, 01:02:00 pm Thanks, guys. I am going to go with Muhammad's suggested location. And as both Muhammad and Larry pointed out, 60a is too much so I will set the charger to 30 amps. Should be good. Re the OEM setup, yes, the house batteries charge when driving. Just need to change to a DC to DC because of the requirements of lithium batteries.jor
Re: DC to DC Charger Reply #6 – October 28, 2023, 02:18:49 pm One more question. Did you guys use the existing wiring from the solenoid under the hood (LD refers to it as a power contactor) for the charger input? I believe the stock wiring is 6 awg. I see in my Renogy manual, that a run of over 10 feet requires 4 awg. for the input (start battery to charger). * I have the 60 amp charger but I will be configuring it to charge at a 30 amp rate.Thanks.jor
Re: DC to DC Charger Reply #7 – October 28, 2023, 02:32:50 pm Quote from: Karen & Liam - October 28, 2023, 12:57:14 pmSo do our house batteries get a charge from the alternator stock from the mothership? year If your LD still has a diode isolator, the type that came stock in your year LD, it will charge lithium batteries at a low rate, I see about 20 amps maximum through the isolator. Someday, a DC-to-DC charger may be installed, but so far I have not seen a need. The solar and isolator have been adequate to keep the battery charged 95% of the time. Only three hours of battery charging generator time have been needed during the last 18 months, all while camped in deep shade for many days, situations where a DC-to-DC wouldn't have been helpful.Larry
Re: DC to DC Charger Reply #8 – October 28, 2023, 03:22:18 pm QuoteIf your LD still has a diode isolatorLarry, I don't have a diode isolator. Just a solenoid that LD calls a power contactor. Here's a photo. I've been reading threads on the DC to DC charger issue and I see there is disagreement if one even needs to replace this solenoid at all. My worry was that the lithiums could demand enough current to burn up my alternator. So now I'm wondering if I should:1. Just go with the factory solenoid isolator and its 6 gauge wire;2. Install the Renogy charger at 30 amps and use the 6 gauge factory wiring from the start battery to the house batteries;3. Install the Renogy charger at 30 amps and rewire with 4 awg. I believe my alternator is 155 amps.Head is spinning but having a great time!!!jor
Re: DC to DC Charger Reply #9 – October 28, 2023, 03:30:06 pm Hi JOR; I have the Renogy 60-60A DC charger. Set up for 60A or 'LC' (low current?) at 30A. Switchable from the dash. If I am driving with headlights, air conditioner clutch and high temperatures I use the 30A charge rate. If it is just to charge the LiF batteries faster than the generator, it's cool, and the rig isn't in motion, then the 60A charge rate can be used. I haven't needed to use either yet. The solar keeps them at near full. (400 AH capacity) After 4 days of rain in Morro Bay in '23, cloudy with little sun, running the heater a Lot, lights, cooking, etc. the batteries got down to 73%. Just driving to Lompoc (Jalama Beach) on a sunny day, about 100 miles and the batteries were back to 100% SOC. I wasn't using the toaster oven though. I did go through 6 gallons of propane in a week, and the first propane place was flooded out. Second propane place was in business. (that was in Morro Bay) RonB
Re: DC to DC Charger Reply #10 – October 28, 2023, 03:38:28 pm OK. Here's what I'm going to do. I'll set the Renogy for 30 amps, use the factory 6 gauge wiring, install an ANL fuse in place of the solenoid isolator and call it a day. Should be good.jor
Re: DC to DC Charger Reply #11 – October 28, 2023, 05:47:37 pm Hi Jor; Instead of the ANL fuse, use this: Blue Sea Systems Surface Mount Breaker - 285-Series I would use the 100 A. More usually used in car systems, weather resistant, 12VDC, and all. Fuses to be avoided unless you plan to carry spares around. You should already have a 100A or 150A breaker in your battery box on the wire coming from the battery isolator, at the house batteries. My rig had #4 wire from the 120A diode isolator to the battery box. I have a 100A breaker feeding the LIF's. That is just to protect the wire in case of an accident. RonB
Re: DC to DC Charger Reply #12 – October 28, 2023, 05:59:38 pm I don't know squat about all of these installation parameters and precautions, but I have not seen anyone mention that lithium batteries have a problem with recharging below 32°. What I have read is that they can be USED below freezing but not charged.If this is true, then care must be taken that there is available some disconnect apparatus for freezing weather.I don't have lithium batteries, so have not run into the problem. Please correct me if this is not really a worry. Virtual hugs, Judie
Re: DC to DC Charger Reply #13 – October 28, 2023, 06:26:48 pm Quote from: Judie Ashford - October 28, 2023, 05:59:38 pmI don't know squat about all of these installation parameters and precautions, but I have not seen anyone mention that lithium batteries have a problem with recharging below 32°. What I have read is that they can be USED below freezing but not charged.If this is true, then care must be taken that there is available some disconnect apparatus for freezing weather.I don't have lithium batteries, so have not run into the problem. Please correct me if this is not really a worry. Virtual hugs, Judie Unlike other batteries, the current LFP replacement batteries are 'smart' - they have their own battery charge management built-in. So, MOST have temperature sensors to protect the batteries if it gets too cold. Some also have built-in heaters, but this is just to extend their operating temperature range without the need for an external heat source to do that.Steve 1 Likes
Re: DC to DC Charger Reply #14 – October 28, 2023, 06:30:31 pm Quote from: jor - October 28, 2023, 03:22:18 pmLarry, I don't have a diode isolator. Just a solenoid that LD calls a power contactor. Here's a photo. I've been reading threads on the DC to DC charger issue and I see there is disagreement if one even needs to replace this solenoid at all. My worry was that the lithiums could demand enough current to burn up my alternator. So now I'm wondering if I should:1. Just go with the factory solenoid isolator and its 6 gauge wire;2. Install the Renogy charger at 30 amps and use the 6 gauge factory wiring from the start battery to the house batteries;3. Install the Renogy charger at 30 amps and rewire with 4 awg. I believe my alternator is 155 amps.I think some sort of current regulator or current limiter is needed, the old diode isolator's inherent voltage drop seems to limit current flow, from 2007 on, LD used the contactor that allows as much current flow as the wires can handle.Using the 60/30 amp DC-to-DC converter along with Ron's selectable charge rate switch is a practical option.Upgrading to 4-gauge wire, for no more than a 3% voltage drop when using the 60-amp setting, is suggested.If you are feeling highly motivated, running 2-gauge cable from the starting battery to the coach battery and adding a 3-way marine battery switch would provide power for the DC-DC converter and jump-starting at the twist of a switch. It can provide emergency engine power too. Our alternator failed last summer, returning from Canada. The coach battery and solar provide enough power to keep things running for the last 1-1/2 days, plugging in to power the one night and charging with the converter. It is much easier to repair things at home on my own schedule and not to do it on the side of the road.Larry
Re: DC to DC Charger Reply #15 – October 28, 2023, 06:51:53 pm "install an ANL fuse in place of the solenoid isolator"If I understand your proposed setup correctly, this would open the possibility of draining your start battery if you run your house batteries too low. That scenario may seem unlikely, but it's what an isolator (diode or contactor type) is there to protect against.
Re: DC to DC Charger Reply #16 – October 28, 2023, 07:46:44 pm Man, I thought this was going to be a plug and play. I figured a few of you guys would have done this long ago and I'd just knock off your plan! Isolator: According to the documentation, the charger is also a battery isolator so that would seem to cover Andy's concern. Wiring: I intend to set the charger at the 30 amp limit so I'm thinking the 6 gauge OEM wiring should be fine. I should have bought a 20 or 40 amp unit but it's too late to return this one. I bought it early on in my solar project. Breakers/Fuses: I used those nifty breakers in my solar install. I mentioned ANLs because the manufacturer suggests them. For example, for a 40 amp unit they suggest a 60 amp fuse on the input side (start battery to charger) and 50 amp on the output side (unit to house batteries). Nice to see all this action on this thread. Thanks to all and keep em' comin'! jor 1 Likes
Re: DC to DC Charger Reply #17 – October 29, 2023, 03:05:41 am Mentioned before but we kept the FLA batteries, put the lithiums inside for temperature control, and installed a marine battery switch to choose which one would run the coach. Works very well. We never hooked the lithiums to the alternator with a DC to DC converter and sometimes miss that. We charge at 100+ amps by generator.
Re: DC to DC Charger Reply #18 – October 29, 2023, 04:20:22 am Hi Jor; As Andy said, the DC-DC converter charger will take power out of the chassis battery to charge the Lithium batteries unless you inhibit that charger when the engine is not running. The wire that turns on that contactor(relay) will also provide the D+ signal that the DC-DC charger needs to turn on. The grounds are connected on the Renogy charger. The input 12v dc. comes from the alternator, the output of the charger goes to the plus leads of the LiF batterie(s).Judie; My SOK batteries have a low temperature shut off, so they won't try to charge below 28 degrees. They also will shut off output below zero degrees. I do have a 12vdc. (meant to be a water tank) heater between the batteries and the outside wall. That will keep the batteries warm at 40 degrees or so, using the batteries or solar or whatever is available. Space heating the insides of the coach should keep the batteries comfortable also. RonB
Re: DC to DC Charger Reply #19 – October 29, 2023, 12:45:33 pm With Renergy's DC-to-DC charger having an ignition terminal, the contactor can be removed if desired, it is not needed.Just checking, Renergy is having a real sale with significant markdowns on chargers.12V 40A DC-DC On-Board Battery Charger | in-vehicle dual battery chargers |...Larry 1 Likes
Re: DC to DC Charger Reply #20 – October 29, 2023, 01:59:28 pm Hi Larry; That is a good sale price for that charger. I have the old contactor (leftover from another persons AM Solar install), and I'm considering using it to connect the #4 wire that goes back to the LiF batteries (installed by LD) under the hood as an emergency start relay to assist the chassis battery if need be. For chassis that came from LD with that heavy duty contactor, that wire is already there and connected in the right location to do exactly that. Only that energizing wire needs to have a push button switch on the dash added in series to use it as an emergency start switch. Sounded like a good idea. For me I can connect to that wire at my battery box location, locate the relay there (it is sealed and spark proof) and I just need an energizing wire to turn it on momentarily from a dash push button. RonB 1 Likes
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