Converter and Charger at the same time

Your batteries, while charging, won't get warm unless there is something wrong with them. 14.6 is fine, 14.8 is fine, even 15V is fine.

If you are charging at 40 amps with a 5 amp load running then you are actually charging at 35 amps. Takes longer.

Charging with a converter has this problem in any rig, but with the VEC you can avoid it by charging disconnected batts and let the converter run the rig. You might have a minute there with no 12v in the rig while you switch over. Nothing bad happens, the fridge comes back on by itself, eg.

You can leave the solar on for more amps too. With the controller set to 14.8 same as the VEC it works all the way up. Temperature matters with the VEC which has temp comp. If it is hot out that 14.8 might be 14.6 so if you have 14.8 on another charger, at some point the VEC will drop out first. Amps will have tapered by then so no problem. The lower voltage charger does not suddenly stop, it tapers amps first as the voltage spread shrinks.

The VEC charging profile is to get the batts to 14v and then let amps taper. Do not be alarmed! :) The voltage continues to rise which keeps the amps from tapering as fast as if the voltage were held constant. Result is it comes out the same as if voltage rose to 14.8 and then was held there while amps tapered rapidly.

Love VEC charging. Only thing better is two VECs- now you get 80 amps (perfect for a bank of about 220AH--say two 6s or two 27s)
but you need a gen that can run 1600w. Ignore those who say fast charging at high amps is bad for the batteries. The batts have a "natural acceptance rate" and they won't take any more amps than they can safely take at 14.x volts.

All you get by *****-footing (the stupid editor just blanked out my word for a small cat) around with lower amps is longer gen times.

Golden_HVAC wrote:

The problem with charging a battery at 14.6 volts means that the battery will get warm and boil a lot more than normal amount of water out of the battery. If you do this frequently, plan on adding water every month or so. Also if the battery plates get to warm, they can warp. This can cause the plates to touch each other, shorting out that cell, and require battery replacement.

So far, the batteries don't seem to get warm when charging at 14.6 volts. With the current mounting location I can only feel the plastic box they are mounted in. So getting a good feel for temp is harder.

I don't plan on doing the 40A charge often and will get the water monthly or more when we are drawing down and charging the batteries like that.

BFL13 wrote:
Sometimes you have to get the VEC running and then turn on the converter. Depends. No problem just find out how your converter and VEC like to do things.

I'll play around with this to see how they work together. I thought the VEC would always start in bulk mode so it would deliver amps even if the battery was at 13.6 volts.

BFL13 wrote:

So what to do with the WFCO? Use it to run the rig 12v while you charge the batts with the VEC with the batts disconnected from the rig (battery disconnect switch open) That is, put the shore power cable into the gen and also plug in the VEC. Open the disconnect Now the VEC can put all 40 amps in while the rig is not drawing some amps at the same time, reducing net amps in, and so increasing gen time.

I assume the reason for disconnecting the battery is because the WFCO won't supply any DC current if the voltage is above 13.6 volts. I don't have a disconnect yet, it's on "the list". I would have to remove the cable at the breaker near the battery. I don't think the DC load will be that high when charging. Maybe 2-6 amps for fans and LED lights.

I guess I can play it by ear. As long as the VEC is at 40 amps, I know that disconnecting the batteries and running the WFCO can help some. If the VEC is running at below 40 amps then I know it's servicing the DC loads and the batteries and disconnecting won't help.

Hi,

If both are plugged in at the same time, then the factory converter will see the 14.6 volts, and then stop charging.

The problem with charging a battery at 14.6 volts means that the battery will get warm and boil a lot more than normal amount of water out of the battery. If you do this frequently, plan on adding water every month or so. Also if the battery plates get to warm, they can warp. This can cause the plates to touch each other, shorting out that cell, and require battery replacement.

So Yes you can charge at 14.6 volts. No, not my battery, but yours - go ahead. If you are running from a generator, you can recharge much faster with the portable 40 amp charger. If I really wanted to save generator run time, then I would set my inverter/charger for 70 amps and let the generator run about 1 hour, charging from 60 to about 40 amps (tapers as the 4 golf cart batteries fill). Then shut off the generator, and let the sun keep filling my batteries via my 415 watt solar system. This will very slowly fill the battery - at 8 - 25 amps per hour, just they way batteries like it. The battery will not warm up, water loss will be minimal.

SunElec.com

Fred.

No worries, no blowouts. WFCO will basically shut itself off as the B&D pushes above 13.6 volts.
VEC1093DBD is an excellent charger BTW.

The WFCO charging at 13.6 and the VEC charging at 14.8 will not add their amps very long. As soon as the battery voltage is above 13.6 the WFCO can't do anything (no voltage spread between it and the battery) It won't do much before then either since the spread is so small.

That leaves the VEC to do it all. BTW excellent battery charger--use that and to heck with the WFCO.

The WFCO did not go into bulk because when on it did not see 13.2 or less. The resting voltage of a 50% battery is about 12.1 (varies by brand) BUT as soon as you apply a charger, there is a voltage spike into the 13s. What the WFCO wants to see is the spike not going over 13.2. If it stays below 13.2, then the battery is about half full.

BUT that also depends on the amps of the WFCO and the AH capacity of the battery how big a spike you will get. Small battery, high amps, big spike. So still no Bulk--battery too small.

If you had a PD that you could force to 14.4 then you could run it and the VEC to add their amps till the battery reaches 14.4 and the PD drops out and the VEC keeps going. By then amps will be tapering so no big deal. Sometimes you have to get the VEC running and then turn on the converter. Depends. No problem just find out how your converter and VEC like to do things.

So what to do with the WFCO? Use it to run the rig 12v while you charge the batts with the VEC with the batts disconnected from the rig (battery disconnect switch open) That is, put the shore power cable into the gen and also plug in the VEC. Open the disconnect Now the VEC can put all 40 amps in while the rig is not drawing some amps at the same time, reducing net amps in, and so increasing gen time.

Might not charge any faster but won't do any harm.

Charger is a VEC1093DBD. Battery bank is 210 AH. The converter will be trying get the battery to 13.6 volts. The charger will be trying to get it to 14.8 volts.

I guess I could also turn off the converter breaker so the charger and the converter don't confuse each other.

I'm more concerned about blowing something out with them both competing with each other.

If the other charger is a smart charger, it will see the 14.x the WFCO is putting out and it will not charge because it looks like the battery is already at a high SOC.
So smart chargers don't always play nice with other chargers.