B&D VEC1093DBD vs Mega Watt S-350-12

[sjturbo]

As some of you know I have a bank of four CR235's in series parallel. And you also know that I have a Mega Watt S-350-12 that I have to top charge them. And that it takes a long time for the batteries to reach even 14.8V, (about 10-12 hrs). My important question is I have found a B&D VEC1093DBD and wondered if I would be better served with it's 40a and higher voltage capabilities than with the Mega Watt? I realize that monitoring the charging is important so I would not intend to set it and forget it initially until I knew it's charging characteristics.

[Empty_Nest__Soo]

Niner - Yes, I understand. A proper hydrometer is at the top of my shopping list. It seems I need to visit a real auto parts store to find one. Maybe tomorrow.

BFL - Hmmm, temperature compensation is another factor I never thought of. Air temperature was about 38* yesterday, and the batteries were probably colder than that starting out. Maybe this VEC1093 is smarter than I thought?

Wayne

[BFL13]

The VEC has temperature compensation so that 14.8v is only for whatever they picked as the "nominal temp." Mine reads about 15.2 when ambient is just above freezing out. In summer it only gets to 14.6 or whatever.

You could take a battery inside where it is warm and try the VEC there (wait till it warms up to ambient)and see what voltage it does then.

The Paramode converter with TempAssure has its temp comp "nominal" at 60F ISTR. Some things use 77F/25C as the "nominal" temp for their ratings.

[NinerBikes]

Empty Nest, Soon wrote:
I’m still getting to know the B&D VEC1093-BDB that I bought recently. If others are getting 14.8 or so volts maximum, I wonder whether there may be differences in different editions of the same model charger.

After charging the batteries with the on-board Heart inverter/charger recently, I took advantage of a good weather day yesterday to top-charge with the VEC1093.

On the house batteries, I set it at the 40-amp rate and it wasn’t long before it started tapering the amps input. I can’t recall that I checked the voltage with the initial charging. When it had tapered to the point where I was sure it was in Absorption mode, I found it was feeding the batteries 15.3-something volts. I got the same result with 2 different digital voltmeters. After 2.5 hours it had finished with top-charging 4 Deka Group 27 dual-purpose batteries.

I switched it to the chassis batteries. It immediately tapered the amps to a very small rate. Voltage was again 15.3-something. It declared the chassis batteries FUL within 10 minutes.

I did not run the Recondition or Equalize mode on either set of batteries.

Wayne

Wayne, now go measure the specific gravity of every cell on every battery, write it down, and post it up here, on your fully top charged Deka batteries off.

You are looking for all cells to be 1.275 or slightly better. Specific Gravity always trumps what voltage the batteries are taking when you shut the BD off.

[Empty_Nest__Soo]

I’m still getting to know the B&D VEC1093-BDB that I bought recently. If others are getting 14.8 or so volts maximum, I wonder whether there may be differences in different editions of the same model charger.

After charging the batteries with the on-board Heart inverter/charger recently, I took advantage of a good weather day yesterday to top-charge with the VEC1093.

On the house batteries, I set it at the 40-amp rate and it wasn’t long before it started tapering the amps input. I can’t recall that I checked the voltage with the initial charging. When it had tapered to the point where I was sure it was in Absorption mode, I found it was feeding the batteries 15.3-something volts. I got the same result with 2 different digital voltmeters. After 2.5 hours it had finished with top-charging 4 Deka Group 27 dual-purpose batteries.

I switched it to the chassis batteries. It immediately tapered the amps to a very small rate. Voltage was again 15.3-something. It declared the chassis batteries FUL within 10 minutes.

I did not run the Recondition or Equalize mode on either set of batteries.

Wayne

[jrnymn7]

I was thinking along the same lines, but I don't know what the OP has available for gen power? And I'm not under the impression he already has a VEC? But it would certainly help with bulk and EQ charging.

With its lower voltage setting, I imagine the VEC could be removed around the 30a mark, and let the (more permanently installed) MW finish things up. It would likely require some fiddling with the voltages to max out overall amp contribution.

[MEXICOWANDERER]

What's the harm in letting the Dack & Blecker play pattycake with the power supply? BFL has a veritable symphony of chargers humming away and I must agree that he has arrived at "The Logical Answer". Sorta like the philosophy of when you're engaged in a pitched battle you shouldn't withdraw half your soldiers to keep them from getting shot.

[NinerBikes]

Maybe he should unparallel those 4 batteries, and run them as two separate 12v battery systems instead for discharge and charging?

SJ, how many amp hours daily, are you sucking down and consuming? Have you done an energy audit yet to determine your daily 24 hr amps usage? Perhaps you should.

[jrnymn7]

sjturbo,

You may recall our discussion about voltages in your other thread. I just spent a few weeks trying to get my two 215Ah banks wired back to 430Ah's. It was a bit of a chore to get the voltages of the two 215's to balance out in parallel. But now they are resting at identical voltages throughout.

What I have noticed consistently is, my 6's react to higher voltages somewhat like a reverse peukert effect. After a good top charge at 15+ volts, their resting voltages drop significantly, and become unequal. And the voltages are unequal during the charge. But then if I follow up with another (gentler 14.8v) top charge, resting voltages come back up, and equal out; and voltages across each individual 6v are all equal during the charge, as well. So, just something to watch for.

That bank will easily handle a 100a charger during cc and cv. That's a C/4.7 rate... pretty much the same as my 45 amper on my 215Ah bank. At 14.8v, I see amps begin to taper at a little over 80%. This means a 100 amper would stay maxed out to over 80% soc on your bank.

[jrnymn7]

Yep, that cannot be top charging. That 30 amper on a 470Ah bank (less than a C/15 charge rate), at 14.8v, will stay maxed out well into the charge; past 90% soc, in fact. A 50-90 will take about 6 1/4 hrs. A ~97-100% top charge should not take long at all; a few hours at best.

[landyacht318]

You need a higher amp charger, the megawatt does 30 amps reliably, the B&D will do upto 40, and your batteries if they are taking 12 hours to get to 14.6v, well sounds like they could easily handle an 80 amp charger. What can your genny handle powering?

My single 130 Amp hour group 31 takes 41 amps easily from my Meanwell rsp-500-15. if it is 51 amp hours from full, and I set it to 15V, it takes nearly an hour before amps begin to taper.

[BFL13]

I have the time the 40a Vector takes to do a 50-90 on your bank of 470a. ( 6 hours) The charging profile of the VEC is not the same as other current- limited chargers, in that the voltage keeps rising during Absorption so that by the time it gets to 90% SOC the voltage will be about 14.5-14.6. It will reach 14.8 by the time it gets to 97% SOC and shuts off, saying FUL.

However that 50-90 time will be the same or shorter than another charger that does the classic rise to Vabs of 14.8 and then holds at 14.8 for the entire absorption stage. (ugly graph of VEC vs adjustable PowerMax)

So your comparison measurement has to be in battery SOC vs time, not by when each gets the batts to 14.8v. Other 40 amp cc/cv chargers should take about the same time as the VEC

That 6 hours is why, with a 458AH bank, I use 150 amps of chargers and try to get the 50-90 done in 2 hours. Of course you need enough generator to run the 150a and it helps if that is PF corrected so you don't need so much of a generator.

The VEC can be left alone to do it all including its Equalizing, because it shuts off when it is done. You don't need to babysit it. It has the amps read-out so you can tell when you are down to 5 amps per battery at 90% so you know you are done and can shut off the generator.

[time2roll]

That is not a top charge if it takes 10 hours to get to 14.8 volts. That is called a bulk charge.

Use the converter 24 hours. Then the MW should be just doing a top charge the next day.

[MEXICOWANDERER]

You need BOTH. You're trying to feed a coal-fired locomotive boiler with a teaspoon.

Hence the reason for my monster BORG charger. When I twist the Intermatic timer dial the sucker goes to work. Ignore the brownout it may cause, the batteries are charging!

I feed my (on the ground) bank, almost 600 amperes @ 28 volts at times. The same wattage (energy) as 1,200 amperes @ 12 volts.

Put a TIMER on the Megawatt, so you don't forget. A shut-off timer, not a ding-ding timer.