Modify an airplane lvc for car use? - RC-Monster Forums

DrKnow65 · **Modify an airplane lvc for car use? -** 10.24.2007, 01:33 AM

Anyone here feel confident they could help me mod a cellshield lvc
http://http://www.dimensionengineeri...CellShield.htm
that is intended for airplane use (i.e. backs the throttle signal to 0% or 1ms in servo signal terms), which sounds like it will throw the car into full reverse if it has the option---bad.

What I have gathered is that this lvc delinks the throttle signal from the receiver and substitutes the 1ms squarewave.

Would it be possible to open one of these up, find the timer circuit, and modify it (the timer control resistors) to put out 1.5ms (neutral) or an adjustable time?

Who's up for it? we'd get a lvc that monitors individual cells, has an adjustable cutoff, and is rated for 6s.

jhautz · 10.24.2007, 02:00 AM

Just use this. Its already made for Car LVC. Much simpler.

http://www.rc-monster.com/proddetail...rod=lisavercar

DrKnow65 · 10.24.2007, 02:10 AM

Does it monitor each cell on my 2s2p 8000hv lipo?
I have read that the two series/2 parallel have a higher potential of having a single cell get low while the overall pack voltage is acceptable.
I want somthing to monitor each cell and shut the esc down.

jhautz · 10.24.2007, 02:21 AM

The dimension enginering one wont monitor all 4 cells in your 2s2p pack either. It will only read the voltage of each parallel set. The way I understand it is, in paralell the cells tend to seek a level with each other which is why lipos that are 2p or more are only wired to balance the voltage of each parallel set of cells vs the other parallel sets.

If you balance your packs regularly using a standard cell balancer when you charge them you wont have any problem using a cut off that just goes by the total pack voltage.

DrKnow65 · 10.24.2007, 02:27 AM

Hmmmm didn't know about the way it monitors the cells that are parallel, I have the Mamba Max esc that had a custom setable lvc built in and I have a balance charger to. Just want to ensure this $140 battery as well as I can... Thanks much for the insight. Still monitoring each set can't be a bad thing, I've got some time to work this out so I'll play it by ear for a bit.

DrKnow65 · 10.26.2007, 10:09 AM

I've had another thought about modding this failsafe, if I just "opened" the signal generating circuit so it didn't put out any signal when it goes into bypass wouldn't the failsafe on my esc kick in and the car go to neutral?

I still think I will persue this mod for a bit, the more I think about it the more I like the idea of having a failsafe for voltage and temperature (even if it does onlt monitor the paralleled cells).

Finnster · 10.26.2007, 05:21 PM

You don't need to monitor Par'd cells as its not possible for them to be out of balance to ea other as long is there is a connected circuit.

Think of two standing buckets of water. Now connect them at the bottom w/ a hose. They can then only be at the same level. There is no way to keep one more filled than the other. Ie they act as a single bucket.

DrKnow65 · 11.04.2007, 12:47 AM

Called Castle Creations today and while they don't call it a "fail safe" they do say the "default" on the controller, should it lose a signal, is neutral position. So I could just kill the substitute signal in the LVC to get it to work. I would be able to guard both paralelled cells and the motor temps. And I can keep the same LVC unit for when I go up in series. Will get the unit, do the mod and post pic's and how-to's for anyone else interested...