Can you have two converters?

[quicky06]

Originally Posted by Larry-NC

Instead of two converters, why not just go with a bigger one. The Progressive Dynamics PD9280A delivers 80 amps. Is that enough?

Larry

I was trying for redundancy.

[quicky06]

Originally Posted by UT_Grandpa

Whenever you have more than one source charging a battery problems can happen. The voltage regulators on multiple sources if not set exactly and have exactly the same foldback will create what is called hysteresis or a bouncing back and forth with the charging current.

This is the same reason you should not have solar AND a converter trying to charge the same battery bank at the same time.

As was said earlier you would have to split your DC load between the two chargers and you can bet there isn't enough spare wire to reach another panel and adding a foot of wire in with a splice is never a good idea. So I would stay with a single converter, one panel, and one source for power.

I would like to know why you believe a splice is a bad idea. A good solder splice is no different than a solid wire

[quicky06]

Originally Posted by Splitshaft

Supplying safe DC voltage to power RV 12V devices without damage and charging batteries are two very different things. Ether can be done alone well, yet both can not be done as well together. Lead acid batteries are best charged at 14.8V bulk to include current high enough to create a temperature rise of the battery. Voltage that high or higher may damage some 12V devices (think about the control board in the frig or the 12V flat screen TV). And no battery is going to accept more current than it pushes back against the charger supplying it. Even a 1,000-amp battery charger if well made may only supply 2-amps to change batteries if that is all the batteries will accept. Lead acid batteries are best charged at no more than 35-percent of their amp-hour rating during bulk charge and beyond that, charged at much lower current to reach full charge which may take up to eight hours depending on how well the battery charger is programmed and the condition of the batteries being recharged. For my money, hybrid charging systems are best. Bulk charge is supplied by a three stage charger powered by a generator and then, solar panels supply the lower current need for several hours to top the batteries off when dry camping.

All of my components are rated at max input voltages above 18 volts. I have never seen a 12v compnet rated less than 16 volts. Modern cars will fluctuate charging voltage between 12.4 ( no load) and 15.5 volts at full load. Hell a oem Honda alternator testor will no fail an alternator until it
Barges over 16 volts.

[MR.M]

honestly it's a waste of money to buy 2 . if a 50 amp powered all your stuff doubling it won't make a difference . you'd be better off if wanting more charging power to go with one larger amp model . also i've replaced more progressive converters then i have wafco's even though i come across more wafco. . if you want to just have a back up that's one thing but to wire two together is a waste and will accomplish nothing

[JLeising]

Hooking two converters to one battery bank - I would want to bench test with meters, but I would guess it would work. The batteries would “smooth out” the voltage. One or the other converter would see the battery voltage as “high” relative to its “target voltage” and would ramp down. The other converter would supply.
I guess some sort of a feedback loop between the converters may be possible - but I doubt it. These things have to be compatible with lots of varying loads (resistive, capacitive, inductive) and still behave.
Again, I would bench test first - but I suspect no issue.

[WolfWhistle]

Go to one large Progressive converter 80 or even 90 amps... or another option is a nice inverter / charger like Magnum MS-2012 (100 amp charger) which lets you match whatever the battery maker recommends are and not settle for a converter that takes 34 hours before going into float all the while not reaching the voltage needed to fully charge your batteries. That #1/0 you think it overkill really isn't. 60 amps nets you a little under the ideal maximum of 3% voltage drop for a charging source at 30 feet run. Why reinvent the wheel that is rolling along just fine... folks with tank heaters have one converter and it works. Maximize what you have and darn sure ditch that WFCO.

[quicky06]

Originally Posted by WolfWhistle

Go to one large Progressive converter 80 or even 90 amps... or another option is a nice inverter / charger like Magnum MS-2012 (100 amp charger) which lets you match whatever the battery maker recommends are and not settle for a converter that takes 34 hours before going into float all the while not reaching the voltage needed to fully charge your batteries. That #1/0 you think it overkill really isn't. 60 amps nets you a little under the ideal maximum of 3% voltage drop for a charging source at 30 feet run. Why reinvent the wheel that is rolling along just fine... folks with tank heaters have one converter and it works. Maximize what you have and darn sure ditch that WFCO.

I know it’s not overkill. It’s the biggest I had in the shop so it was free. It’s better than the 8 gauge that coachman ran. And the positive was a 12 gauge wire.

I was just curious if two was possible. Thanks for the other option I’ll look into that

Redundancy is a nice feature for me. I’m an hour from a gas station when I deer hunt so 2 is one and 1 is none.

[Bluepill]

Have you calculated the maximum allowable charge rate for your battery bank? For example, the popular Trojan T105 batteries have a recommended charging current of 23 to 30 amps. per pair in series connection.

https://www.trojanbattery.com/tech-s...y-maintenance/

[Bluepill]

A possible way to use a pair of converters might be with a solar controller that allows 2 different inputs (e.g. solar panel and charger) to be combined. I am NOT any kind of expert in this area, but a reputable sales outlet should be able to tell you if it would work.

[camaraderie]

Originally Posted by quicky06

I would like to run both at the same time.

2 50 amp converters give me more power than a 80 amp converter.


I just don’t know if this would cause issues or not.

The IOTA DLS90/IQ4 might be a better solution. And Iota makes fine equipment. https://www.iotaengineering.com/12vdc.htm



Note that you will need an IQ4 smart charging module to suit your needs as well,,,nice thing is you can swap IQ modules as your needs or batteries change. https://www.iotaengineering.com/pplib/iq4spec.pdf

If you prefer TWO units or THREE or FOUR...the entire DLS series ALL have the capability for simple parallel connection to provide additive amp output (or series connection for additive voltage output), This would simplify your wiring & switching
https://www.iotaengineering.com/pplib/dlsparallel.pdf

[TitanMike]

Originally Posted by quicky06

I was trying for redundancy.

You may just end up with twice the chance of a failure.

[clr]

You should not connect two converters to the same battery. So this would force you to separate the loads or secure a larger single converter. A converter needs to be able to sense the battery voltage in order to determine the proper voltage or charge state to apply to the battery. With two converters connected to the battery and both powered up they would see the output of the other converter and not the actual state of the battery and would not charge properly if at all.

[camaraderie]

Originally Posted by clr

You should not connect two converters to the same battery. So this would force you to separate the loads or secure a larger single converter. A converter needs to be able to sense the battery voltage in order to determine the proper voltage or charge state to apply to the battery. With two converters connected to the battery and both powered up they would see the output of the other converter and not the actual state of the battery and would not charge properly if at all.

Chuck...see the Iota website. You CAN parallel multiple charges quite safely and use the external IQ control to drive all outputs at the same state and at additive amps thought the use of a single smart controller feeding multiple charger inputs.
https://www.iotaengineering.com/ppli...l_Charging.pdf

[clr]

You are correct you Can parallel multiple chargers if you have some type of external control that is used to sense the battery and also control the output of the converters. But that was not my understanding of what the OP was asking. So I stand by my statement that two converters from different mfr. should not be connected to the same battery as the OP asked.

[camaraderie]

Originally Posted by clr

You are correct you Can parallel multiple chargers if you have some type of external control that is used to sense the battery and also control the output of the converters. But that was not my understanding of what the OP was asking. So I stand by my statement that two converters from different mfr. should not be connected to the same battery as the OP asked.

Absolutely. The only way is paralleling with an external controller and as far as I know...only IOTA has converters that can be governed externally and run in series or parallel.
(FYI they have about six different external IQ devices for different chemistries and situations.)

[ScottBrownstein]

Totally agree and the IOTA specs pretty much prove that connecting converters in parallel is not advisable...without special voltage sense circuitry (like IOTA) that allows it. Most converters do not offer this feature, heck, most converters do not even offer remote voltage sense or battery temperature compensation.

[MR.M]

Originally Posted by quicky06

I was trying for redundancy.

if you want redundancy then just buy 2 converters store one and use the other . then if one goes switch them out . or wire them both in and have the switched so you can use one or the other

[MadDog2020]

You can’t tie the outputs of two converters directly. There may be ones designed for that so you would need to check. You would need to connect the outputs through diodes but they would need to be very big to handle the current. You also would lose voltage across the diodes so the converter may be able to compensate. I know something of power supplies but am not that familiar with RV converts. I would check with the experts.

[pgandw]

Redundancy improves overall reliability ONLY IF the redundant components are totally independent. Tying 2 converters to the same battery bank and the same power input provides next to nothing in improving electrical reliability. You still have single point failures in the battery bank and the power supply to the converters.

There is a reason twin engine airplanes give each engine its own fuel tank, fuel pump, ignition system, and propeller.

As others have pointed out, to gain the increased reliability from 2 converters each would have to have its own battery bank that can be switched in if/when the other converter and battery bank fails.

FWIW, I am one of the few that had one of a pair of parallel 12V batteries fail. And as some could have predicted, the good battery was dragged down to 10.5V (completely discharged) before I even realized I had a failure. If you are going to run 12V batteries in parallel, wire up one of the marine dual battery switches so that in the event of a failure, you can switch the bad battery out, and recharge the good one by itself (still somewhat useable after recharging despite the complete discharge). I went to dual 6V batteries as a cheaper and simpler solution.

In the OP's case, replacing the WFCO converter with a Progressive Industries (or similar) converter will do a lot more to improve system reliability than trying to parallel unreliable components. Also, getting a converter rated for more than 25% of the battery bank AH capacity is a waste of money. The batteries will not accept more current than that, and that amount of current will only flow for maybe 30 minutes. By then, the charge current will drop to about 10-15% of AH capacity until 90% SOC, at which point current will drop to trickle levels.

Fred W

[SCClockDr]

Originally Posted by quicky06

Looking ino replacing my 50 amp wfco POS with a progressive dynamics converter that will actually go into bulk mode and was wondering if I could put two 50 amp converters in instead of a single 80 amp.

We plan on winter camping a lot. Half of which will be boondocking so all my pipe and tank heaters are 12v to the tune of 65 amps of specified amperage ( I haven’t installed everything yet). I understand everything will be cylicing on and off and not everything will be cycled on at the same time.

I would like to have faster battery charging and redundancy with two separate converters.

Wire size is not an issue. Between the converter/ fuse box to the batteries is 1/0 welding cable and my 6v batteries are all wired togeather with the same cable. ( it’s a 30foot run)



D

I'm not understanding your reasoning.

1. Boondocking
2. Winter
3. 65 amp draw for all heaters.
4. Seeking advice re 1 or 2 AC/DC converters.

Boondocking & 2 converters seem to be at odds. 65 amp DC draw would require huge battery capacity with a good sized generator to keep them charged.
What power source do you expect to use while boondocking?
How large is your battery capacity & what type?
1/0 over 30 feet is a bit light for 100 amp dual converter charging & supplying the loads. (I'm assuming you are meaning 15' times 2 for pos & neg.)
I'd invest in underbelly insulation & closing it up. Set up fresh hose & fill then take down & stow. And do the same with the waste. I'd run on the tanks between times. Ensure the furnace routes heated air to the tank area.
What am I missing?