Renogy DC DC Charger w/ MPPT

[RandyP]

My 'works perfectly' subjective choice would be a redarc bcdc1250 charge controller.

 

[powerwagon]

redarc manager 30

 

[RandyP]

redarc manager 30

agreed. AC, DC and Solar Control all in one unit !

 

[Remy1927]

Congratulations on the free exchange, I'm sure that solved your problems including the broken stud.

I'll see if my unit falls in the recall group and consider exchanging it. At this point it works as advertised and I am happy with it.

It did. It's all installed now and is working perfectly.

 

[RandyP]

Guys recently some comments have appeared on Wills original review video suggesting the unit reduces alternator charging from 50A to 25A if any Solar input is detected!
This sounds crazy to me and absolutely not what I would expect to happen as it would be counter productive
Has anybody validated the claims or seen it documented by Renogy?

Thanks

Perhaps some may want to ALWAYS use ALL the solar energy available. Buy reducing the start battery to 25A input when solar is available every amp of solar available can be used in low solar energy (25A solat or less available) conditions instead of filling the aux battery with energy from the start battery/alternator. If you want 50A of power to be taken from the start batt alternator, open the switch on the solar power source and go 100% start/alt battery power. Or open the switch from the start/alt source and go 100% solar charge up to 50A.

If there is ample solar energy available you will get 50% solay (25a) and 50% (25A) start/alt power max charging the aux battery.

 

[chevymike]

You could put a relay in the feed line from the solar panels, that would open (normally closed relay) when you turn on the ignition. This way with the engine running, you would get max charge from alts but with engine off, it would revert back to solar.

 

[Bob B]

I am thinking about using this Rengy controller in my RV in conjunction with a Samlex inverter charger. I like the Samlex becasue it can handle AC input from both grid power and generator power. It also has independent remote start stop for charge and inverter .... and it can control battery charging from both AC and from other charge controllers,

What I am wondering is if I could use the renogy to combine solar and alternator charging and then bring the output of the Renogy into the Samlex external charger input. That way, I could essentially use the Samlex settings to control everything. I would be able to control charge and load cutoff with low current remote control ..... I would only need a higher current relay to control other misc 12V loads.

Any thoughts about a better way to accomplish this are welcome.... or is it a really bad idea? The 1 thing I don't like is the limitation of the solar voltage input to the Renogy.

 

[RandyP]

solar input circuit to the renogy should be opened before device output to aux battery circuit is opened.

 

[RandyP]

You could put a relay in the feed line from the solar panels, that would open (normally closed relay) when you turn on the ignition. This way with the engine running, you would get max charge from alts but with engine off, it would revert back to solar.

And you would loose max harvest of 'free' solar energy.

 

[chevymike]

And you would loose max harvest of 'free' solar energy.

I would rather have the full 50 amps from alt power then 25 amps alt power and whatever you get from the panels while driving, which will likely never reach 25 amps on the move. Once engine is off, all solar that that point.

 

[RandyP]

FOUND THE TROUBLE MAKER.
The Victron BM-712 had a aux battery voltage circuit 100ma FUSE that measured 69 ohm of resistance. This was messing all the BM voltage indications up. Has been doing this for some time. Now the voltage at the BM is identical to the voltage on the battery measured with a DVM at the battery end. This is a great relief for me, to find and fix this problem.

Original message:

"Installed the Renogy DCC50S battery charger. Input is from two 180 w Grape solar 12v panels in parallel. Alt input is from vehicle alt/batt (usually switched off). Charges three BB LiFePO4 100AH 12v batteries wired in parallel.
The BCDC50S charges the batteries up to 14.4 v, 100% SOC as monitored by a victron 712 monitor. Then it maintains a charge voltage of 14.15 v dc, 0 amps, 0 watts. Normally the camper it lives in draws about 0.2 A dc to keep the smoke/carbon monoxide monitors going and the refer and heater control devices active (not on, just ready). I call this the camper burden. So it appears to be supplying the parasite load, maintaining 14.15v on the battery but not charging it (no need, its at 100 % SOC). I looked at the Tech Spec page of the installation & operation manual. It stated for battery type Li Boost charge voltage is 14.4 v, float charge voltage is listed as --, Equalize voltage is listed as --, Boost Return voltage is listed as 13.2v.
Is the Renogy DCC50S battery charger performing IAW the specs ?"

Because of the incorrect voltage readings at the BM device, the voltages noted above were not accurate. In reality the DCC50S goes thru Bulk charge mode and enters Boost charge mode, as indicated by the slow flashing solar charge indicator red light. It just stays in that mode with 0.00 A charge to battery. If I use a clamp-on meter, I see that it is still charging 0.005 A to battery. There is a burden load (parasite load) on the battery caused by an under voltage device that must pull some current at all times. If I turn on the dc power to the inverter/charger there is a 2A burden (parasitic load) caused by the inverter, even if it is not charging or inverting. So I think the DCC50S is staying in boost charge mode (about 14.3v) to supply power to the parasitic loads and finish up a full charge on the Li battery (very slowly).

I think its working per specs.

 

[RandyP]

I would rather have the full 50 amps from alt power then 25 amps alt power and whatever you get from the panels while driving, which will likely never reach 25 amps on the move. Once engine is off, all solar that that point.

My '05 Ford F250 SD 6.0 L crew cab draws 100A from the alternator going down the road. Stock alternator is not rated much more than that hot. SO I have a 275 A (alternator cold rating) replacement alternator.
But pulling an additional real 50A or more off the stock alternator going down the road is a serious load. As stock auto alternators heat up during use, they usually have built in protection to limit their output amps so they do not burn up. Voltage drops, DC-DC charger drops out because the 13.2v 'charging' level is not there.
How many amp hours do use between charging cycles ?
If its 50-100 AH, a 25A charge for 2-4 hours would bring it back up to 100% SOC. A 2-4 hour drive between boon docking sites is not unusual.
Do you need the 50A starter batt/alt charge, or do you just want it?

 

[Sgt Raven]

My '05 Ford F250 SD 6.0 L crew cab draws 100A from the alternator going down the road. Stock alternator is not rated much more than that hot. SO I have a 275 A replacement alternator.
But pulling an additional real 50A or more off the stock alternator going down the road is a serious load. As alternators heat up during use, they usually have built in protection to limit their output amps so they do not burn up. Voltage drops, DC-DC charger drops out because the 13.2v 'charging' level is not there.
How many amp hours do use between charging cycles ?
If its 50-100 AH, a 25A charge for 2-4 hours would bring it back up to 100% SOC. A 2-4 hour drive between boon docking sites is not unusual.
Do you need the 50A started batt/alt charge, or do you just want it?

Jeeze, what is drawing 100A after the starting batteries are recharged from starting the engine? I guess I need to get a clamp meter and see what my 2005 Ram 2500 4x4 CTD is pulling from the alternator, after it tops off the batteries from starting the engine. Oh well I was planing on buying a clamp meter anyways.

 

[RandyP]

My current draw is with headlights on hi, AC on high, traveling 80 MPH on cruise control across the desert at night in 100 deg f ambient temps pulling a 23' car hauler tag along trailer with a 6K # jeep and a 2.5K# jeep trailer on the car hauler (Virgin River to Vegas, I15). I actually watched the volt meter drop with time, the alt could not keep up with the load. Dropped to below 13v.

If you measure yours with a clamp on meter, measure the alternator output, not the battery output.

 

[RandyP]

Jeeze, what is drawing 100A after the starting batteries are recharged from starting the engine? I guess I need to get a clamp meter and see what my 2005 Ram 2500 4x4 CTD is pulling from the alternator, after it tops off the batteries from starting the engine. Oh well I was planing on buying a clamp meter anyways.

There's the headlights, air conditioning clutch and blower motors, Radio, FICM if a fuel injected ford diesel, ECM, PCM, TCM, cruise control, tail and running lights, including those on a trailer if towing and who knows what else.

 

[Mike M]

I really want to use this charger for my LFP bank keeping lead acid for the starter battery to secure the alternator. But I don't want to charge the LFP batteries to more than 13.8 V and stop charging when they reach that level. I don't want any float charging for the LFP's.
Can I do that with this charger?

Wouldn't that be controlled by the bms in your battery bank?

 

[RandyP]

Wouldn't that be controlled by the bms in your battery bank?

NO, unless you programmed the BMS yourself. Not a typical max charging voltage set point.

 

[RandyP]

I really want to use this charger for my LFP bank keeping lead acid for the starter battery to secure the alternator. But I don't want to charge the LFP batteries to more than 13.8 V and stop charging when they reach that level. I don't want any float charging for the LFP's.
Can I do that with this charger?

NO.

 

[Bob B]

@toverb .....This is a common port BMS .... so, if you shut of the charge you also shut off the load.

Check out the Chargery BMS for that capability .... There are external devices that will switch based on voltage, but i am not familiar with them.

 

[RandyP]

@toverb .....This is a common port BMS .... so, if you shut of the charge you also shut off the load.

Check out the Chargery BMS for that capability .... There are external devices that will switch based on voltage, but i am not familiar with them.

Victron BP (battery protect).