2 chargers connected to one battery bank?

[WilliamKorn]

Has anyone used two chargers connected to one battery bank? I have four (4) six volt GC batteries with 464 amp hrs. at 12 volts. The onboard "dumb" one stage charger is a 55 amp. unit. I just ordered a POWERMAX PM3-100 12 VOLT DC 100 AMP POWER CONVERTER CHARGER WITH 3 STAGE AUTOMATIC SMART BATTERY CHARGER. When using the generator I would like to charge the batteries as quickly as possible. Is it possible (and safe)to connect both chargers simultaneously to obtain a charge rate of 155 amps per hour?

[mena661]

Wow MEX, that's a monster. Does it come in 48V?

[MEXICOWANDERER]

Here ya go. It's a 450 ampere 24 volt alternator. Equivalent to 900 amperes (equal wattage) at 12 volts. This otter top off those batteries. no sweat.

[ktmrfs]

I have a PD60A in the pass through and a PD55A in the converter panel. When I have enough generator (both honda 2000's) I use both. It gives 100A+ initially and with both on holds the 100A for quite a while before tapering.

battey bank is 4 T-125's. How well different brands will work, don't know, but you can try.

[McKenziek]

pianotuna wrote:
Hi McK,

I would simply put the new converter "in line" and as close to the battery bank as is possible. If the old wire is too small for the new higher amperage then run thicker wire from the converter to the bank--and use an appropriately sized automatic circuit breaker on on the wire going to the distribution panel.

I've completed the build of my charging system using RoyB's schmeatic but I have an issue that I think I have the answer to but want to run it by the forum.

I've blown the 125amp ANL fuse twice now, both times on battery power while raising the auto-levelers which I assume must use a lot of juice.

I believe the 20' run from the batteries to the 12 volt distribution panel using the stock 6ga wire is too long for the wire size. The converter can accept up to 2ga.

Just want to see if replacing the run with 2ga will fix my problem before I drop the coin.

[BFL13]

Four chargers on one battery bank . Approx 130a total. No sweat. The higher voltage 40 amper stayed at 40 till the other three were all done then it started to taper in its turn.

The only limitation is gen power VA to run all the chargers. Honda 3000 limit is 130 amps worth of Vectors with whatever their PF is.

[MEXICOWANDERER]

Woowee I love some of these answers. I have had FIVE chargers working on one RV battery bank at the same time. Just don't let the voltage exceed 14.8 volts. And you do need to keep an eye on this.

Some chargers have a steeper charge curve than others. More voltage higher potential. What happens then, is the worker will keep digging while the less aggressive charger leans on its shovel.

Again, when it is costing a few dollars an hour to generator charge batteries, keep the voltage at 14.8 or less. Don't let it climb higher.

I remember one day on a beach in Mexico a know-it-all RV'er neighbor wandered over. He lusted for my diesel generator. "Say isn't that a lot of generator to be running just to charge the batteries?"

"Not really" I replied. "The last time I checked the charge rate was 310 amperes"

"Not possible!" he declared "No way are you charging 300 amps!"

I took him inside and introduced him to my 6" Triplett wall meter and the base for my kitchen table - A 300 lb adjustable ferroresonant charger. The meter on the charger was registering 200+ amps.

"The other chargers are adding another hundred amps" I declared.

He stared at the TRACE monitor. More than 300 amperes is big red numerals stared back. He staggered outside.

"Then I let the solar panels take over" I offered. I was using a Patton Whole House Ventilator 24/7.

[WilliamKorn]

mena661 wrote:
You can have multiple chargers connected. No damage will occur at all. I've done this myself a number of times. Hopefully the charging king, BFL13, will chime in. You won't gain much by having the dumb charger connected though. They typically have very low charge rates anyways. Just use the Powermax.

Kudos for the positive reinforcement........

[WilliamKorn]

RoyB wrote:
I upgraded my real old single mode converter/charger to a WFCO 45AMP smart mode converter/charger only to find out I could never get my WFCO unit to go into smart mode charging.

Then I purchased a PD9260C 60AMP smart mode converter/charger but I mounted it stand alone closer to the battery bank. I decided to leave the WF8945 unit in its location in the bottom compartment of the WF series Power Distribution Panel.

I ran a 120VAC connection to the PD9260C from another circuit breaker in my panel.

I most of the time use the PD9260C by just flipping the circuit breaker for this unit and have the WF8945 converter turned off by flipping its circuit breaker.

I only have the brand new WF8945 converter around for back-up purpose. I only have one converter turned ON at a time however I don't think it would harm anything having both of them on. It just didn't seem like having two converter units ON at the same would be a good idea.

You can see where my two converters are installed in this floor plan drawing of my trailer...


This is a schematic diagram of my how my two converters are wired in my setup...


There is some posts on here where a B&D VEC1093DBD smart mode portable battery charger was being used along with the on-board trailer converter/charger to get to full 100% charge state on the batteries quicker.

Roy Ken

Super, That's the type of info that I was looking for 🙂
Do I need to pay a royalty or is this "freeware" material ?! 🙂

[WilliamKorn]

da.bees wrote:
You can connect similar chargers in paralell but it sounds like the new charge is more advanced so it's probibly not a good idea. Your batterys might be in series-paralell , in which case you can charge each pair with each charger. The problem with that is that banks will not reach full charge at same time which is ok if you wait until both pair are at full charge. Otherwise the lesser charged pair will be unduely stressed under load. You should read for yourself what battery and charger manufactures say about quick charging depleted batteries. Throughing a 100 amp charge on a battery for secounds to replinish the power consumed by say starting an engine has a far different effect than throwing 100amps on a heavyly discharged battery. Esp repeatedly doing it.

Hi, and thanks for the input.

My S.O.P. is to charge the batteries when they are discharged to 60% as that greatly extends the life. (last battery bank replaced at almost nine years) The intended 155 amp charge would be from a 60% base and be for 70 - 75 minutes with the generator. So the dumb charger can stay dumb!
I'll only use the smart charger for extended plug-in charging.

[McKenziek]

So basically intercept the wire coming from the other converter and connect it to the new converter. Then run a heavier gauge wire from the other positive post of the new converter to the batteries?

[pianotuna]

Hi McK,

I would simply put the new converter "in line" and as close to the battery bank as is possible. If the old wire is too small for the new higher amperage then run thicker wire from the converter to the bank--and use an appropriately sized automatic circuit breaker on on the wire going to the distribution panel.

[McKenziek]

pianotuna wrote:
Hi McKenziek,

I don't understand the advantage of doing that.

.

The current converter and fuse panel is quite a distance from the battery bank, like +20'. I want to locate the new converter close to the batteries so I plan to run a 120 volt line on a new 20 amp breaker to power the new converter charger. I also thought keeping the 2nd converter as a backup and make it easier to remove the 9280 in case of future sale would be a good idea.

[pianotuna]

Hi McKenziek,

I don't understand the advantage of doing that.

[McKenziek]

I have a similar situation and I'm thinking of it a little different. I'm thinking of using my new "smarter" PD9280 to perform just the charging duties and the existing "dumb" converter to perform just the converting duties.

Any comments on this setup?