# Controller Range Loss



## GizmoEV (Nov 28, 2009)

Just a guess here but have you tried setting the limits on the NetGain to exactly match your old controller to be sure you aren't pulling more current out of your batteries? A relatively small change in the battery current translates to a larger change to range.


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## Tesseract (Sep 27, 2008)

Yes, we see that happen all the time... one of our beta testers had an early 500A version of our controller and when the internal hardware was swapped out for the full 1000A stuff they noticed their range dropped almost in half. Same switching frequency, same battery pack, but one day they could go 21 miles and the next it was like 11 or 12. The only difference is that once you have more power on tap you tend to use it.

Now, it is true that switching losses go up with frequency, especially for big IGBT modules, but those losses are still a small fraction of the pack power. Maybe you lose 1% of your range going from performance mode (8kHz) to quiet mode (14kHz) with the Soliton1, but it's really hard to prove such a tiny change in range is caused by the switching frequency among all the other variables that can affect it at the same time.

Do you know for sure how much current your homemade controller could pull from the battery pack? Maybe set the NetGain to limit to the same amount (I'm assuming it can do that... don't know for sure as I've never played with one).


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## GerhardRP (Nov 17, 2009)

Has this happened only with PbA packs where Peukert's Law prevails?
Any Lithium packs?
Gerhard


Inframan said:


> Has anyone ever switched over to another controller and found that they had less range? I recently switched over to a Netgain 1000 amp and I notice that I am getting significantly less range than with my homemade controller. Sure there is a bit more power but I am getting like 18 miles as opposed to the 27 miles I was getting. I have not changed the flooded lead acid battery pack, nothing has changed but the controller. Could it be the frequency I was at about 1 k with the frequency of my pic controller and I had two of these transistors toshiba MG600Q1US41 compared to the 15 k + of the unknown transistor in the warpdrive? Is there a way with the interface to lower the frequency b/c I have not purchased it yet?


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## Inframan (Jan 30, 2011)

I will try to set it to similar settings when the interface comes in b/c I have just ordered it. I also had no motor voltage limit so I had about 180 volts going to a warp 9 motor could that be a factor in using a greater amount of amperage b/c I have heard that Netgain controllers come preset to 160 motor volts? Do you see a big drop in performance when going down to a 500 amp version? I was never really measuring motor amps but battery amps are a bit higher on take off I wonder if I could program in some sort of soft start?


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## DJBecker (Nov 3, 2010)

This is almost off-topic, but I'm going to ask anyway.

With a slower IGBT I can understand using a low PWM frequency. And especially if using a slow 8 bit PIC as a controller. But doesn't a 1KHz PWM frequency result in a horrible motor whine?


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## Inframan (Jan 30, 2011)

Yes there is a motor whine but I guess I was just under the erroneous assumption that the motor controller would be more efficient so it didn't matter after all. Besides it let the smoke out pretty bad about a month back so I decided to quit jacking around and put a professionally done unit in.


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## ngcontrols (Nov 4, 2009)

Inframan said:


> Is there a way with the interface to lower the frequency b/c I have not purchased it yet?


Be careful with those floodies! They don't tolerate as much current as AGMs (or Lithium cells). I guess the answer to your question depends on if you've been driving it differently than with your other controller. Also, how long did the batteries sit? They might just have to get "exercised" back into shape.

The WarP-Drive can't be set for anything other than super-silent 15.7kHz mode.


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## Inframan (Jan 30, 2011)

Do golf cart batteries fall prey to the whole over current plate buckling thing like marine batteries? btw what is the lead time on your interface modules every dealer I talked to said they were out. The batteries did sit for a while how long does it take for them to shape up? Do you have any plans to give your customers the option of selecting frequencies? What new expansion devices for the canbus are in the works right now?


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## bumblebee (Jan 29, 2011)

I added a capacitor bank to my controller and I gained quite a bit of range with my flooded cells... I think I gained almost 20%. Maybe you had a bigger cap bank on your old controller???

I used an EPC 50,000 microfarad 150V capacitor bank. The acceleration is a lot better too...





Inframan said:


> Has anyone ever switched over to another controller and found that they had less range? I recently switched over to a Netgain 1000 amp and I notice that I am getting significantly less range than with my homemade controller. Sure there is a bit more power but I am getting like 18 miles as opposed to the 27 miles I was getting. I have not changed the flooded lead acid battery pack, nothing has changed but the controller. Could it be the frequency I was at about 1 k with the frequency of my pic controller and I had two of these transistors toshiba MG600Q1US41 compared to the 15 k + of the unknown transistor in the warpdrive? Is there a way with the interface to lower the frequency b/c I have not purchased it yet?


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## Tesseract (Sep 27, 2008)

bumblebee said:


> I added a capacitor bank to my controller and I gained quite a bit of range with my flooded cells.
> ...
> I used an EPC 50,000 microfarad 150V capacitor bank.


Sorry, bumble, but this sort of thing is squarely in the snake oil category, along with HHO generators and magnets on the fuel lines.

Capacitors don't increase range, they just reduce the reflected ripple seen by the batteries (assuming they aren't hampered by more than a few nanohenries of inductance).

The amount of energy in watt-seconds (Joules) stored in a capacitor is 0.5CV² or, in this case, 1125J. Since you can't drain the capacitor completely if it is feeding a controller that feeds a motor and still do useful work, this gives you enough energy to power the average conversion for about 1-2 seconds. And it has to be recharged by the battery.

However, adding this much capacitance could help smooth over - literally - excessive ripple caused by batteries with way too much internal resistance. Like, say, crappy starting batteries or gel cells or other types which are singularly unsuitable for use in EVs.


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## ngcontrols (Nov 4, 2009)

Inframan said:


> Do golf cart batteries fall prey to the whole over current plate buckling thing like marine batteries?


I'll have to let someone else comment on this one. "Golf cart" batteries tend to have higher internal resistance than AGMs or LiFePO4 though.




Inframan said:


> btw what is the lead time on your interface modules every dealer I talked to said they were out.


Unfortunately, we're dealing with a lead time on one of the components. It's a first for long lead times with the particular manufacturer. We'll try to plan accordingly for future builds. I apologize for the wait.



Inframan said:


> The batteries did sit for a while how long does it take for them to shape up?


From my experience, it seems to only take a couple of cycles. Cooler temperatures will certainly make a difference as well. It might be colder than when you last drove it.




Inframan said:


> Do you have any plans to give your customers the option of selecting frequencies?


While this seems like a cool feature, I haven't had anyone in years (lots of exposure to people doing conversions in these years) ever request it. The only request has been for silence. Consequently, adjustable PWM frequency is not in our plans.



Inframan said:


> What new expansion devices for the canbus are in the works right now?


There are a handful, but I'm not going to let the cat out of the bag yet. I'd prefer to have semi-solid release dates before getting anyone excited


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## Inframan (Jan 30, 2011)

YES! I did have a big cap bank almost what you had 40,000 uf? Because I do have flooded marine batteries w/ high internal resistance? Maybe there something to it what did you have on your controller before you were getting less range bumblebee? Hey NG controls what is the spec on your cap bank? Can anyone else attest to this phenomenon?


> Tesseract said-However, adding this much capacitance could help smooth over - literally - excessive ripple caused by batteries with way too much internal resistance. Like, say, crappy starting batteries or gel cells or other types which are singularly unsuitable for use in EVs.


I didn't think gel cells had that high of resistance how much do they have as opposed to golf cars or marines?


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## ngcontrols (Nov 4, 2009)

Inframan said:


> Hey NG controls what is the spec on your cap bank?


Depends if you have the earlier electrolytic version or the current film cap design. The electrolytic bank was in the 5000uF range. The film cap version has a much lower capacitance (but substantially lower ESR and consequently higher ripple current rating).


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## bumblebee (Jan 29, 2011)

I don't think the range has anything to do with the energy stored in the cap bank... I think the range increases because with a large cap bank, you're not beating the crap out of your flooded cells..... it's a much smoother draw, with less initial surge.

I would re-install your old cap bank... I don't think the warp controller will have a problem with it...



Inframan said:


> YES! I did have a big cap bank almost what you had 40,000 uf? Because I do have flooded marine batteries w/ high internal resistance? Maybe there something to it what did you have on your controller before you were getting less range bumblebee? Hey NG controls what is the spec on your cap bank? Can anyone else attest to this phenomenon?


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## Inframan (Jan 30, 2011)

Hey Ngcontrols how would the precharge time and circuitry be affected by a larger outside cap bank? I wonder if I could just have the capacitor bank charged all the time hooked to the batteries direct to not really "add" to the warpdrives cap bank so it wouldn't affect the precharge of the controller? Would there be any draw backs to having the outside caps charged all the time?


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## ngcontrols (Nov 4, 2009)

Inframan said:


> Hey Ngcontrols how would the precharge time and circuitry be affected by a larger outside cap bank?


It would increase the time it takes to precharge. However, the maximum allowed capacitance for the current precharge circuitry is about 7000uF.



Inframan said:


> I wonder if I could just have the capacitor bank charged all the time hooked to the batteries direct to not really "add" to the warpdrives cap bank so it wouldn't affect the precharge of the controller? Would there be any draw backs to having the outside caps charged all the time?


Just be careful when you connect them!

The drawback for leaving electrolytics connected is it eats into their lifetime. But since they would be at ambient temperature for most of that connected time, it probably wouldn't affect the life that drastically. Someone else with more experience with electrolytics might be able to give more insight on that.


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## Inframan (Jan 30, 2011)

I have this version I think it is the film cap version what capacitance is it?


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## ngcontrols (Nov 4, 2009)

Inframan said:


> I have this version I think it is the film cap version what capacitance is it?


Yes, film, and less than 1000uF.


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