# Anyone use Dual pro Onboard multibank 12V charger? Bad idea?



## major (Apr 4, 2008)

Thaniel said:


> For my charging system I'm considering a onboard multi bank 12V chargers. This way the batteries will always be balanced between each other and not over/undercharged.
> 
> Was looking at this product
> http://www.dualpro.com/products/sportsman/
> ...


Hi Thaniel,

Personally I think it is a good idea, but wrong product choice. I had good luck with the Minn Kota 2 and 4 bank chargers on up to about 140 Ahr Pb-Acid batteries, 4 in series, 48 volt systems. Always seemed enough to get them charged overnight.

Had a charger salesman after me to use the Dual Pro. He either sampled us a 4 way, 10 amp model or got my boss to buy one. I didn't like it near as much as the Minn Kotas. Did some testing and found the Dual Pro didn't put out advertised current and I thought the charge algorithm sucked. Also, I thought the product quality was far less than the Minn Kotas.

If you choose to use modular charging, go with Minn Kota. They even have models which do 15 amps per battery. Made for marine use, so h2o tight. I liked them, or can you tell 

And I have no interest in the company. Just a happy customer.

Regards,

major


----------



## Thaniel (May 25, 2008)

major said:


> Hi Thaniel,
> 
> Personally I think it is a good idea, but wrong product choice. I had good luck with the Minn Kota 2 and 4 bank chargers on up to about 140 Ahr Pb-Acid batteries, 4 in series, 48 volt systems. Always seemed enough to get them charged overnight.
> 
> ...


Major, Thank you for your feedback. This is exactly the type of feedback I was looking for. Good vs bad experiences etc. What model are you using if you don't mind sharing? Are you using it on an EV?

Yah the charge Algorithm on the Dual Pro is not good. They did say they could put on a customer specified Algorithm. I would have to just to get it to work right with an AGM. That's when I started thinking wonder if there is something else.

I will check out the Minn Kotas's website and info. 

Thaniel

Edit: THought I'd add the charge profile that Dual Pro provided and the info incase someone else was interested or searched for the answer.

"Absorption is at 2.42 VPC at 21C/70F, max finishing voltage allowable is at 2.66 VPC at 21C/70 F and Float voltage is 2.235 VPC at 21C/70F. The temperature compensation works out to .004V/degC/cell except that finishing voltage is not ever adjusted higher than 2.66VPC, even in extreme cold conditions. This algorithm utilizes a combination of time, DV/DT calculations, and max voltage readings to terminate the Finish stage. Float maintenance is a "Green" approach whereas charge current is off for 60 minutes and on for 5 minutes instead of steady on. If the charger is attached to AC power for 30 days continuously, an automatic equalization is initiated at the 30 day point

Charge profiles are not selectable except for the Eagle Performance Series, but the chargers may be ordered with specific charge algorithms set to up to customer specs.

All multibank chargers contain individual, isolated chargers which allows the user to use only the amount of banks desired. If charge cables are not attached to a battery, there is no output and no sparking will occur if the leads are shorted together. 

Any combination of units may be used to charge batteries in series."


----------



## major (Apr 4, 2008)

Thaniel said:


> What model are you using if you don't mind sharing? Are you using it on an EV?


Hi Than,

We started evaluating a MK440. Worked well. But was too long to fit our battery tray. So we went with 2 of the MK220 models for 4 twelve volt batteries. 

It was an EV. An IUV (Industrial Utility Vehicle) to be exact. 48 volt traction system. Had a 12 volt need pulled from #1 battery in the string. Didn't want the cost and such of a converter or extra 12V battery, so this worked great. No worry about unequal discharge because each battery was charged separately. No need to equalize the string. Worked well. A number of units in the field with no complaints.

Our 12 volt load wasn't too large. But with this modular charging, if it was, we could have increased the A-hr on battery #1. Meaning when you have modular charging like this, you can actually use batteries in your series string which are not all equal in capacity, or even types, or brands. Now granted, on your discharge, you're only as good as the weakest one in the string. And have to somehow be able to watch for that or you'll boil that weak sucker to death.

Regards,

major


----------



## Thaniel (May 25, 2008)

I checked out the Minn Kotas's and they look promising. For one thing it looks like they can be picked up cheaper. That's aways good. Thermal compensation and no "balance" mode. All good things. And of course a good recomendation  I still need to compare their charge profiles to my battery MFG recommendation. The graphs on their website are difficult to read. I'll see if I can get more detail.



major said:


> We started evaluating a MK440. Worked well. But was too long to fit our battery tray. So we went with 2 of the MK220 models for 4 twelve volt batteries.


If I understand correctly you are using 2 to charge one pack. This is good news as I'd like to use 4 to charge my pack (14 batteries total so, 2 MK440's and 2 MK330's). Some of the multibank chargers I looked at actually had a common ground for the batteries.



major said:


> Our 12 volt load wasn't too large. But with this modular charging, if it was, we could have increased the A-hr on battery #1. Meaning when you have modular charging like this, you can actually use batteries in your series string which are not all equal in capacity, or even types, or brands. Now granted, on your discharge, you're only as good as the weakest one in the string. And have to somehow be able to watch for that or you'll boil that weak sucker to death.


I love this aspect of using this method of charging. Seems safer for the batteries than bulk charging with a high voltage charger.

Thaniel


----------



## Thaniel (May 25, 2008)

I'm still looking into the charger thing. I've convinced myself if the car isn't moving then it doesn't need a charger. So the car has yet to move and therefore this research has slid to the back burner. However I expect to move the car in the next few days so I'll be back in the hunt. Anyway.

Was looking for detail on the charge profile for the MK chargers. Called the company and the person I spoke to didn't seem to understand my question. Perhaps I'll try again after the holidays. I did get copies of the owners manual from them. But it didn't have the information needed. Best I can tell it looks as these chargers will work but Can't get the tech specs.

I've attached the owners manuals as they were not available on the website and perhaps maybe of interest to someone.

Thaniel


----------



## EV-propulsion.com (Jun 1, 2009)

We have a multibank charger made by quickcharge (usa made) that has 12 of the 10 amp outputs. Not sure how the pricing would compare, the quickcharge is about 1100.00 with different algorithms available. (FLA, Gel, AGM) here's a link, http://www.ev-propulsion.com/chargers.html
It makes for neat packaging if you go this way.
Mike
EV-propulsion.com


----------



## Thaniel (May 25, 2008)

EV-propulsion.com said:


> We have a multibank charger made by quickcharge (usa made) that has 12 of the 10 amp outputs. Not sure how the pricing would compare, the quickcharge is about 1100.00 with different algorithms available. (FLA, Gel, AGM) here's a link, http://www.ev-propulsion.com/chargers.html
> It makes for neat packaging if you go this way.
> Mike
> EV-propulsion.com


Can you send me some specs on the charge profile? I've found a number of chargers that are for AGM but have a profile that goes against what the MFG of my battery states. Also does it have temperature compesnation and any details on that. So many things to look at with chargers. Ugh.


----------



## EV-propulsion.com (Jun 1, 2009)

Below is a description and link to their standard algorithm for AGM batteries. Basically, a constant current stage, then a constant voltage stage that never exceeds 14.7 volts per battery (the standard maximum), then a float charge. The multibank charger does not have a temp compensation, since technically it would need 12 of them.
Quickcharge will make just about charger you need, with special algorithms and most likely would add a temp compensator to a multibank (or 12 of them) if required.
Note the attached link shows multiple battery styles (fla, agm,etc) for a 25ah charger, so scroll down to the agm. and also the ah output is 10amps per bank. The multibank graph would be similar to this, except for the ah.
 There is also a discrepancy of max charge- 2.4 or 2.45 volts per cell between the graph and written discription-which one as standard we will have to find out.
 BTW, Qiuckcharge themselves will answer any questions directly rather quickly if you wish to e-mail them or call them directly- they are very customer satifaction orientated, and located in the USA too.


*F4 - AGM: *Batteries bulk charge to 2.3vpc, and enter (a timed) absorption cycle where voltage is allowed to climb to a maximum 2.45vpc before dropping into indefinite float of 2.26vpc. 

*http://www.quickcharge.com/Images and PDF's/charge curves all.pdf*

*mike*
*www.EV-propulsion.com
*


----------



## EV-propulsion.com (Jun 1, 2009)

"_I've found a number of chargers that are for AGM but have a profile that goes against what the MFG of my battery states."_

What are you specific specs? We have been using three step chargers on AGMs for years and they work great. Here is a basic style algorithm for the 3 step. We never charge over 2.45 volts per cell, and float at 2.23 vpc. Never had an AGM battery problem related to charging with these numbers.










Mike,
www.EV-propulsion.com


----------



## Thaniel (May 25, 2008)

EV-propulsion.com said:


> What are you specific specs?
> 
> Mike,
> www.EV-propulsion.com


Hi Mike. Thank you for the information. 

My battery instructions state "Do not exceed 14.6 volts at 68 degrees F". I have been suprised how many battery chargers that stated AGM had charge profiles that exceeded the 14.6 volts (including the Dual pro chargers I had been looking at" 

The instructions also stated "Always use and automatic temperature sensing charger" And went on to explain that needs to be at the battery and not at the charger. Few chargers meet this spec too but looks like a few do. 


Thaniel


----------



## Thaniel (May 25, 2008)

Looks like I'lll be going with the Minn-Kota chargers. Major was kind enough to take some real world measurements on a unit he had as it charged (thank you again) and comparing to their advertized specs it appears to meet the specs required.

Hopefully it turns out well. Time will tell.

Thaniel


----------

