Does a Schulze 18.97kw have a lvc? - RC-Monster Forums

lincpimp · **Does a Schulze 18.97kw have a lvc? -** 09.02.2009, 11:55 AM

Just wondering if they have a lvc or not? My smaller schulze escs did not have lvcs and the online instructions do not mention lvc at all for any of the models.

Thanks guys!

MetalMan · 09.02.2009, 12:22 PM

Nope! The technology is too old. The software was made well before the days of lipo, and we know how Schultze is...

lincpimp · 09.02.2009, 12:55 PM

Good to know Travis. I am dealing with another member that bought a pack from me, ran it and now claims that it will not charge correctly. Looking at his pics and specs he may have an external lvc wired it, but I am not sure what brand/spec it is.

Since you also know about the astro 109 charger, how does it determine cell count? I am guessing it reads the at rest voltage before charging and determines the cell count that way?

Thanks for the help buddy!

MetalMan · 09.02.2009, 02:22 PM

The 109 uses a total of three stages to charge the battery.

1. Charges at half the rate selected (so if you set it at 5.0amps it will actually be charging at 2.5amps). This goes on for two minutes, at which point it determines the cell count by the voltage it reads from the battery. This is a crucial point because it is the only point where the cell count could wrongly be selected. However, anything less than 7s should not pose an issue to cell count selection unless it was discharged excessively prior to charging.

2. CC phase, charges at the selected rate. Cell count is locked in.

3. This is where it gets weird - instead of a CV phase, the 109 pulses the selected current to keep the voltage as close to 4.20v/cell as possible. The pulses become shorter and shorter as the pack nears 100% charge.

lincpimp · 09.02.2009, 09:25 PM

Interesting, so there is room for some error in determining the cell count. Thanks for that info dude!

BrianG · 09.02.2009, 09:51 PM

Quote:

Originally Posted by MetalMan

...3. This is where it gets weird - instead of a CV phase, the 109 pulses the selected current to keep the voltage as close to 4.20v/cell as possible. The pulses become shorter and shorter as the pack nears 100% charge.

Wow, sounds like a cheap/easy way to achieve a sort of CV. Really, how much more CPU would it have taken to do a true CV (or at least an adaptive CV)? Besides, even though the pulses are short, I'm sure there are still some hefty instantaneous currents before the circuit "realizes" the voltage is too high.

On a related note, don't some battery manufacturers specifically not allow pulse chargers?

lincpimp · 09.02.2009, 10:32 PM

Quote:

Originally Posted by BrianG

Wow, sounds like a cheap/easy way to achieve a sort of CV. Really, how much more CPU would it have taken to do a true CV (or at least an adaptive CV)? Besides, even though the pulses are short, I'm sure there are still some hefty instantaneous currents before the circuit "realizes" the voltage is too high.

On a related note, don't some battery manufacturers specifically not allow pulse chargers?

Sounds like astro were not running on all 8 when they designed this charger...

BrianG · 09.02.2009, 10:37 PM

Maybe it's because it was a simple matter to adjust the NiMH firmware the way they did?

lincpimp · 09.02.2009, 10:47 PM

Quote:

Originally Posted by BrianG

Maybe it's because it was a simple matter to adjust the NiMH firmware the way they did?

Likely. I just cannot understand why someone would want to run an expensive truck, with a 1527, good lipos and then use an outdated, featureless charger... Blinky balancer too, so that will not do anything to protect the pack if the charger messes up.

He also runs a schultze esc and some off brand lvc. I can see why he is having lipo issues, bet the pack ran down below 3v per cell, then he tried to charge it and it saw the low voltage as a 5s pack, and charged it as that. Plus that esc is only rated to 5s by the mfg, not 6s. Like pushing water up a wall...

MetalMan · 09.03.2009, 03:22 AM

Quote:

Originally Posted by lincpimp

Interesting, so there is room for some error in determining the cell count. Thanks for that info dude!

Any time

Quote:

Originally Posted by BrianG

Wow, sounds like a cheap/easy way to achieve a sort of CV. Really, how much more CPU would it have taken to do a true CV (or at least an adaptive CV)? Besides, even though the pulses are short, I'm sure there are still some hefty instantaneous currents before the circuit "realizes" the voltage is too high.

On a related note, don't some battery manufacturers specifically not allow pulse chargers?

The circuit is really good at cutting the pulse right when 4.20v/cell is reached, but you're right, it is a really cheesy way to complete a Lipo charge. In fact, I often perform a manual CV phase when I charge with my 109.

Quote:

Originally Posted by BrianG

Maybe it's because it was a simple matter to adjust the NiMH firmware the way they did?

This would be my guess. The AF109 is a pretty old charger, and aside from a SMD conversion (used to be thru-hole) and new software chips (single item with the charging algorithm store on it) it's likely the same charger as one of AF's old NiCd chargers.

Quote:

Originally Posted by lincpimp

Likely. I just cannot understand why someone would want to run an expensive truck, with a 1527, good lipos and then use an outdated, featureless charger... Blinky balancer too, so that will not do anything to protect the pack if the charger messes up.

He also runs a schultze esc and some off brand lvc. I can see why he is having lipo issues, bet the pack ran down below 3v per cell, then he tried to charge it and it saw the low voltage as a 5s pack, and charged it as that. Plus that esc is only rated to 5s by the mfg, not 6s. Like pushing water up a wall...

Tell him to invest in some new technology... IE drop the Schulze and AF109.

lincpimp · 09.03.2009, 10:21 AM

Quote:

Originally Posted by MetalMan

Tell him to invest in some new technology... IE drop the Schulze and AF109.

Yeah right... Would be like trying to push water up a wall. That is his best bet though. Just annoying that I have to fool with a pack that was most likely damaged by incorrect use. Oh well, just how it is.

swiftneed · 10.08.2009, 10:14 PM

hey guys dont be so rough on the guy, sometimes our wallets or our knowledge is not as quick to comprehend the basics as you guys see it and we look for help even after we read the instructions, we try to get the help of the rcm pros who really know, sometimes the instructions are not as black and white as they seem or someone wants to come back, Hey maybe in some way we will be able to help on a different subject, I apologize and dont mean to say you guys dont help thanks you guys are full of knowledge