Allfat

My Feedback: (1)

I have been thinking about switching to a lipo receiver pack for my glow planes. I looked up the specs on Spektrum's website and it says that it can take voltages up to 9.5 volts. Does this mean that I can simply plug in a 2S lipo as a direct replacement for the receiver battery, or do I need a voltage regulator? Also, where are voltage regulators purchased, I have looked around a little but can't find much. Thank you.

Jetdesign

My Feedback: (8)

[link=http://www.tech-aero.net/]Here are some nice regulators.[/link] They are made with heavy duty wires and heavy duty switches, and have the option of coming with charge jacks and stuff. They are adjustable, or you can have Ed adjust them for you.

Even if your receiver can handle higher voltages, some servos can not run at such high voltage. Ed likes to set the regulators at 6.2 volts which is fine with most JR servos, but you can have it set to 6 or 5.x if you want. Some servos are not meant to be run over 4.8 volts.

Tech-aero regulators are widely used in pattern, where guys are flying thousand dollar airframes and have thousands more wrapped up inside. These are made by very meticulous people only concerned about making the best product.

It is nice to have the switch and regulator built together as it is one less connection point you have to make, and you are assured to have high quality wires and such. Not having the proper gauge wire can lead to a loss of current running through the system which could be problematic, so you will want heavy duty wires.

Jetdesign

My Feedback: (8)

BTW there is an email link on that webpage. Send them an email. I put my phone number on my email and got a nice phone call back, and talked to them for over an hour about how to set things up, how to get the most out of my system without causing damage, etc. Very, very first rate service

ChuckW

My question is why?

Are good old NiCads or NiMH failing you for some reason?

In my opinion, NiCad provides a lot of bang for the buck. They are extremely reliable, light enough for most glow sport planes, inexpensive, and provide plenty of current on demand. Same goes for the newer NiMH cells with lower internal resistance than those in the past.

I've never had a Nicad or NiMH pack fail but I have had lipos fail in my electric planes.

Take a look at the FAQ's here: http://www.hangtimes.com/rcbattery_faq.html

Also keep in mind that the regulator now becomes a potential failure point. A guy at the field yesterday was telling me how he had an on-board battery monitor short and killed his receiver battery. Luckily he caught it on the ground. More gadgets mean more potential failures. If it were me, I'd run parallel Nicad or NiMH batteries with separate switches. That will give you more available mAh (i.e. flight time), double the reliability and make the batteries act like they have less than half the internal impedance they would individually. It is an easy thing to do.

Don't get me wrong, lipo receiver batteries do have their place. I just don't think they may be necessary for many applications though.

opjose

I'll go the opposite route on this one....

LiPo's ( with a regulator ) are robust and problem free and pose no big point of failure.

The Voltage regulators put almost no strain on the packs.

Using LiPo's means that I can swap out the packs at the field quite easily, so I can continue to fly my glow and gasser planes all day long without worrying about the state of NiCD's or NiMH packs that tend to be affixed in ( because of their weight ) and thereby more difficult to remove.

LiPo's even with the regulator weight less than NiCD/NiMH packs.

I can charge LiPo packs in one hour w/o problems.

By wiring in the Regulator like this:



I can easily transfer the entire setup to another plane.

Allfat

My Feedback: (1)

The reason I am looking into this is because I am on a collegiate team designing a heavy lift RC aircraft. In this application, we are trying to make the airframe as light as possible so we will be able to squeeze as much payload weight as we can. The less the airplane weighs, the more dead weight payload we will be able to achieve. We want to do a lipo because of the considerably lower weight that they have vs. nicad or nimh.

Thanks for the link gardfield, I will check it out and contact them.

ChuckW

There ya go... you have a need where it makes sense.

MinnFlyer

My Feedback: (4)

I have seen people use these, and have seen good, expensive regulators fail - ending their day of flying. And by adding the weight of a regulator, you're re-gaining any weight you may have lost by using LiPos.

I just see this as turning something simple into something complicated, and adding one more thing that can go wrong.

CGRetired

My Feedback: (1)

This is sort of what I've been trying to say now for quite a while, in several different posts.

I was originally taught that simple is best. Even the pattern flyers I fly with, three of which are very prominent in the Pattern Community, say the same thing. Simple is best. And these guys have been doing this, in one case, for over 35 years, and one of which is at the international level and is well known througout the pattern community.

One switch, one battery. In my case, i've added one voltwatch, but that's not per battery, that's per plane. If I have a pair of batteries, there is matching pair of switches for each one. And the switch is not a complicated mess of gadgets, just a plain ordinary double pole, single throw switch. Simple. (this openes or closes both the hot (+) and ground (-) paths with a single movement of the switch actuator). It could be done with a single pole single throw, by opening or closing just the hot side of the supply leaving the ground or negative side always connected. Of course, there are other simple switch designs, those that when open (or powered off) will allow a path for the charger to charge the battery, or for an ESV to be connected to check the battery under load. Either way, this is the basic simple switch without all the gadgets that can be a point of failure that could cause serious problems.

Everything you add to the power path adds one layer of point of failure. Any one of which can be devastating, including a regulator.

Now, it goes without saying that very complicated setup's, like some of the gasoline aircraft I've seen, have some serious power requirements, including some serious setups using multiple high-torque digital servos. These are not the normal for most of us, although some will argue that point... These systems have a much higher current draw than most "four channel" RC aircraft out there. Four channel in quotes just to say that, yeah, I know.. you guys with 12 servos, one on each control surface, plus a throttle, landing gear, bomb drops, door openers, pilot waving to you as it passes by you.. have a "much higher" current draw than most others.. but even at that, one switch for the power supply will do the trick, without all the fancy gimics and gizmos that you may wish to add to your Four Star 40 or even your Tiger 120! (whatever).

You can do what you like, but I'll stick with simple. I've already experienced a power failure on one of my aircraft, and, was blessed enough to be saved by the dual battery pack setup I was using. Again, one battery, one switch.. in this case, two batteries, two switches, both on, and when one (battery) failed, I never even knew it until I safely landed it and did my routine check after the flight and discovered that one battery had indeed failed.

CGr.

opjose

I disagree.

The Regulator weights less than 1/3 oz and the savings by going lipo is in the 3-5oz range if not higher for a typical plane even with the regulator.
If I'm using a set of 2800mAh or greater batteries such as in giant scale planes the weight savings can be quite significant.

There is a higher likelyhood of having a NiCD/NiMH pack run down during multiple flights, than there is if I change out the LiPo packs and charge them at the field. This alone gives the LiPo's and advantage, as their lighter weight means I can set them up for easy removal, versus having to bind down NiCD/NiMh packs. Also while I'm flying with one pack I recharge another...something that takes longer to do with NiCD/NiMH packs.

Regulators fail while NiCD/NiMH packs can develop a bad cell, break a solder joint, etc, with about the same frequency. This is pretty much a wash in terms of failure rates.

I can throw on much larger capacity LiPo packs while still retaining less or the same weight as the NiCD/NiMh packs, while the LiPo's end up with a higher reserve capacity, with very little load on the packs thanks in part to the buffering capability of the regulator.

A regulator adds no more "complexity" than a switch if that.

ChuckW

Yep, you gotta always keep the KISS principle in mind. The best solution to a problem is once that achieves the goals & meets the necessary parameters but is as simple and reliable as possible.

I suppose this is a hobby though and most of us are tinkerers by nature. People will always experiment with different stuff whether it is to try and improve something or just for the cool factor.

As for receiver batteries... I'm putting together a 1/4 scale Sukhoi and I'm orderimg two high capacity NiMh packs. No need to complicate it in my opinion.

CGRetired

My Feedback: (1)

opjose: Do you charge that LiPo in the aircraft?

CGr