Dual Rx battery/Switch Set-up?
12-01-2014, 08:54 PM
#26
Thread Starter
Before starting this thread I did find another discussion and it was pretty much the same debate: Just plug the dual batteries into the RX vs. use some "fancy" addition. Nevertheless, I do appreciate all of the posts and comments.
On the issue of A123 packs, I have a Hyperion AC/DC EOS0606iAD-C (Gad! What a string of gobbledygook!) charger which stated that it can be used for 1-6 LiFe packs (3.3V/cell types, including A123 brand cells). Will this charger do the job for those 6.6V 2300mAh A123 packs? I really can't afford to be buying a new charger every time I change to a new type of battery.
On the issue of A123 packs, I have a Hyperion AC/DC EOS0606iAD-C (Gad! What a string of gobbledygook!) charger which stated that it can be used for 1-6 LiFe packs (3.3V/cell types, including A123 brand cells). Will this charger do the job for those 6.6V 2300mAh A123 packs? I really can't afford to be buying a new charger every time I change to a new type of battery.
12-01-2014, 09:03 PM
#28
I do not need google, as I have been using these batteries for years. I think you maybe getting chemistries confused.
http://www.valleyviewrc.com/estore/a...v-battery.html
http://www.valleyviewrc.com/estore/a...v-battery.html
12-01-2014, 09:05 PM
#29
Before starting this thread I did find another discussion and it was pretty much the same debate: Just plug the dual batteries into the RX vs. use some "fancy" addition. Nevertheless, I do appreciate all of the posts and comments.
On the issue of A123 packs, I have a Hyperion AC/DC EOS0606iAD-C (Gad! What a string of gobbledygook!) charger which stated that it can be used for 1-6 LiFe packs (3.3V/cell types, including A123 brand cells). Will this charger do the job for those 6.6V 2300mAh A123 packs? I really can't afford to be buying a new charger every time I change to a new type of battery.
On the issue of A123 packs, I have a Hyperion AC/DC EOS0606iAD-C (Gad! What a string of gobbledygook!) charger which stated that it can be used for 1-6 LiFe packs (3.3V/cell types, including A123 brand cells). Will this charger do the job for those 6.6V 2300mAh A123 packs? I really can't afford to be buying a new charger every time I change to a new type of battery.
Yes, you want to charge on the 3.3 volt mode. If charging LiPos, you need to switch it to 3.7 v per cell.
12-01-2014, 09:11 PM
#30
I do not need google, as I have been using these batteries for years. I think you maybe getting chemistries confused.
http://www.valleyviewrc.com/estore/a...v-battery.html
http://www.valleyviewrc.com/estore/a...v-battery.html
Remember, Google is your best friend.
12-01-2014, 09:22 PM
#32
We are all winners if we can learn something from these discussions.
I've always thought that A123 batteries are Li Ion and have 3.6 volts per cell. It's interesting that your LiFe batteries which are 3.3 volts per cell, are also designated as A123"s. This is the sort of thing that makes it confusing.
I've always thought that A123 batteries are Li Ion and have 3.6 volts per cell. It's interesting that your LiFe batteries which are 3.3 volts per cell, are also designated as A123"s. This is the sort of thing that makes it confusing.
12-02-2014, 12:16 AM
#41
Of all the subjects related to RC models batteries seem to attract the most BS!
Some facts:
Two batteries feeding two switches to the receiver is good.
The switches can be plugged into any channel on the receiver as receivers have a common circuit for positive & negative, only the signal circuits are separate.
Batteries fail in only two ways, a cell can go open circuit (no voltage from the battery) or a cell can short circuit (voltage only reduced by the voltage of the shorted cell).
With two batteries if a cell goes open circuit the remaining good battery will provide full voltage to the receiver but the total mAh capacity of the two batteries will be halved.
Now, this is the big one!
If one of the two batteries has a shorted cell the good battery WILL try to charge the bad battery.
BUT, the current flowing from the good battery to the bad battery is very low, it will take a long time,
and the COMBINED voltage of the two batteries will drop very little for quite a while giving the average
modeller more than enough time to notice something wrong.
No, that's not the case. As I said above, first scenario (open circuit cell) the good battery will get you home.
Second scenario (shorted cell) the voltage of the two, combined batteries will drop very slowly so you will still get home.
That's exactly what you will get.
Your Futaba 3305 servos will be fine, the less powerful servo on the throttle fine also.
Your 2000 mAh Ni-Mh batteries will be fine (of course providing they are in good shape.)
No, you will not need a regulator.
There's been lots of advances in battery technology lately but the type batteries that have served you well for years & years
will still serve you well as will your charger & other accessories.
And at what point does redundancy end? An extra transmitter in case that dies in flight & a spare Abu in case you keel over?
For me two batteries (2000 mAh Ni-Mh by coincidence!), two switches & two servos on the main flight controls (ailerons & elevators) are the
best you can reasonably do. Like Vertical Grimace said everything else is more complication & more potential failure points.
Hope that helps. - John.
Some facts:
Two batteries feeding two switches to the receiver is good.
The switches can be plugged into any channel on the receiver as receivers have a common circuit for positive & negative, only the signal circuits are separate.
Batteries fail in only two ways, a cell can go open circuit (no voltage from the battery) or a cell can short circuit (voltage only reduced by the voltage of the shorted cell).
With two batteries if a cell goes open circuit the remaining good battery will provide full voltage to the receiver but the total mAh capacity of the two batteries will be halved.
Now, this is the big one!
If one of the two batteries has a shorted cell the good battery WILL try to charge the bad battery.
BUT, the current flowing from the good battery to the bad battery is very low, it will take a long time,
and the COMBINED voltage of the two batteries will drop very little for quite a while giving the average
modeller more than enough time to notice something wrong.
You're saying that with this set-up, if ONE battery fails, they will BOTH fail? If so, then I don't see the point of doing it at all.
Second scenario (shorted cell) the voltage of the two, combined batteries will drop very slowly so you will still get home.
Dumb question: Does the dual battery/switch system (as described above) draw on both batteries equally during the flight (at least in principle)? So would it be equivalent to flying with one 6.0V 4000mAh battery...but with greater protection again single battery or switch failure?
Your Futaba 3305 servos will be fine, the less powerful servo on the throttle fine also.
Your 2000 mAh Ni-Mh batteries will be fine (of course providing they are in good shape.)
No, you will not need a regulator.
There's been lots of advances in battery technology lately but the type batteries that have served you well for years & years
will still serve you well as will your charger & other accessories.
And at what point does redundancy end? An extra transmitter in case that dies in flight & a spare Abu in case you keel over?
For me two batteries (2000 mAh Ni-Mh by coincidence!), two switches & two servos on the main flight controls (ailerons & elevators) are the
best you can reasonably do. Like Vertical Grimace said everything else is more complication & more potential failure points.
Hope that helps. - John.
Last edited by Boomerang1; 12-02-2014 at 12:22 AM.
12-02-2014, 02:45 AM
#43
Thread Starter
At least for now. But I've learned a lot from this "can of worms" and I imagine I'll be picking up some A123 packs and maybe a regulator at some point in the future. And I'm definitely going to be ordering the twisted wire servo lead extensions. In fact, a clubmate has already pointed me to a Japanese online RC shop where I can get a 90cm heavy-duty JR-connector version for about $2).
12-02-2014, 03:25 AM
#44
Of all the subjects related to RC models batteries seem to attract the most BS!
Some facts:
Two batteries feeding two switches to the receiver is good.
The switches can be plugged into any channel on the receiver as receivers have a common circuit for positive & negative, only the signal circuits are separate.
Batteries fail in only two ways, a cell can go open circuit (no voltage from the battery) or a cell can short circuit (voltage only reduced by the voltage of the shorted cell).
With two batteries if a cell goes open circuit the remaining good battery will provide full voltage to the receiver but the total mAh capacity of the two batteries will be halved.
Now, this is the big one!
If one of the two batteries has a shorted cell the good battery WILL try to charge the bad battery.
BUT, the current flowing from the good battery to the bad battery is very low, it will take a long time,
and the COMBINED voltage of the two batteries will drop very little for quite a while giving the average
modeller more than enough time to notice something wrong.
No, that's not the case. As I said above, first scenario (open circuit cell) the good battery will get you home.
Second scenario (shorted cell) the voltage of the two, combined batteries will drop very slowly so you will still get home.
That's exactly what you will get.
Your Futaba 3305 servos will be fine, the less powerful servo on the throttle fine also.
Your 2000 mAh Ni-Mh batteries will be fine (of course providing they are in good shape.)
No, you will not need a regulator.
There's been lots of advances in battery technology lately but the type batteries that have served you well for years & years
will still serve you well as will your charger & other accessories.
And at what point does redundancy end? An extra transmitter in case that dies in flight & a spare Abu in case you keel over?
For me two batteries (2000 mAh Ni-Mh by coincidence!), two switches & two servos on the main flight controls (ailerons & elevators) are the
best you can reasonably do. Like Vertical Grimace said everything else is more complication & more potential failure points.
Hope that helps. - John.
Some facts:
Two batteries feeding two switches to the receiver is good.
The switches can be plugged into any channel on the receiver as receivers have a common circuit for positive & negative, only the signal circuits are separate.
Batteries fail in only two ways, a cell can go open circuit (no voltage from the battery) or a cell can short circuit (voltage only reduced by the voltage of the shorted cell).
With two batteries if a cell goes open circuit the remaining good battery will provide full voltage to the receiver but the total mAh capacity of the two batteries will be halved.
Now, this is the big one!
If one of the two batteries has a shorted cell the good battery WILL try to charge the bad battery.
BUT, the current flowing from the good battery to the bad battery is very low, it will take a long time,
and the COMBINED voltage of the two batteries will drop very little for quite a while giving the average
modeller more than enough time to notice something wrong.
No, that's not the case. As I said above, first scenario (open circuit cell) the good battery will get you home.
Second scenario (shorted cell) the voltage of the two, combined batteries will drop very slowly so you will still get home.
That's exactly what you will get.
Your Futaba 3305 servos will be fine, the less powerful servo on the throttle fine also.
Your 2000 mAh Ni-Mh batteries will be fine (of course providing they are in good shape.)
No, you will not need a regulator.
There's been lots of advances in battery technology lately but the type batteries that have served you well for years & years
will still serve you well as will your charger & other accessories.
And at what point does redundancy end? An extra transmitter in case that dies in flight & a spare Abu in case you keel over?
For me two batteries (2000 mAh Ni-Mh by coincidence!), two switches & two servos on the main flight controls (ailerons & elevators) are the
best you can reasonably do. Like Vertical Grimace said everything else is more complication & more potential failure points.
Hope that helps. - John.
12-02-2014, 04:57 AM
#45
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No. If this is your concern then a product such as the Smartfly Batshare device is a inexpensive and reliable solution. A batshare device will isolate both batteries from each other and in the smartfly's case it will equally draw from both batteries. I had 2 packs in my 60cc and each pack went into it's own swtich and each output of the switch went into the smartfly batshare. Then the outputs of that went into the RX. The batshare also has 2 LED's to indicate that both packs are healthy. I have to disagree with some of the other posts. I have seen a dual NIMH setup where one pack shorted and it brought the plane down.
12-02-2014, 05:31 AM
#46
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Of all the subjects related to RC models batteries seem to attract the most BS!
Some facts:
Two batteries feeding two switches to the receiver is good.
The switches can be plugged into any channel on the receiver as receivers have a common circuit for positive & negative, only the signal circuits are separate.
Batteries fail in only two ways, a cell can go open circuit (no voltage from the battery) or a cell can short circuit (voltage only reduced by the voltage of the shorted cell).
With two batteries if a cell goes open circuit the remaining good battery will provide full voltage to the receiver but the total mAh capacity of the two batteries will be halved.
Now, this is the big one!
If one of the two batteries has a shorted cell the good battery WILL try to charge the bad battery.
BUT, the current flowing from the good battery to the bad battery is very low, it will take a long time,
and the COMBINED voltage of the two batteries will drop very little for quite a while giving the average
modeller more than enough time to notice something wrong.
No, that's not the case. As I said above, first scenario (open circuit cell) the good battery will get you home.
Second scenario (shorted cell) the voltage of the two, combined batteries will drop very slowly so you will still get home.
That's exactly what you will get.
Your Futaba 3305 servos will be fine, the less powerful servo on the throttle fine also.
Your 2000 mAh Ni-Mh batteries will be fine (of course providing they are in good shape.)
No, you will not need a regulator.
There's been lots of advances in battery technology lately but the type batteries that have served you well for years & years
will still serve you well as will your charger & other accessories.
And at what point does redundancy end? An extra transmitter in case that dies in flight & a spare Abu in case you keel over?
For me two batteries (2000 mAh Ni-Mh by coincidence!), two switches & two servos on the main flight controls (ailerons & elevators) are the
best you can reasonably do. Like Vertical Grimace said everything else is more complication & more potential failure points.
Hope that helps. - John.
Some facts:
Two batteries feeding two switches to the receiver is good.
The switches can be plugged into any channel on the receiver as receivers have a common circuit for positive & negative, only the signal circuits are separate.
Batteries fail in only two ways, a cell can go open circuit (no voltage from the battery) or a cell can short circuit (voltage only reduced by the voltage of the shorted cell).
With two batteries if a cell goes open circuit the remaining good battery will provide full voltage to the receiver but the total mAh capacity of the two batteries will be halved.
Now, this is the big one!
If one of the two batteries has a shorted cell the good battery WILL try to charge the bad battery.
BUT, the current flowing from the good battery to the bad battery is very low, it will take a long time,
and the COMBINED voltage of the two batteries will drop very little for quite a while giving the average
modeller more than enough time to notice something wrong.
No, that's not the case. As I said above, first scenario (open circuit cell) the good battery will get you home.
Second scenario (shorted cell) the voltage of the two, combined batteries will drop very slowly so you will still get home.
That's exactly what you will get.
Your Futaba 3305 servos will be fine, the less powerful servo on the throttle fine also.
Your 2000 mAh Ni-Mh batteries will be fine (of course providing they are in good shape.)
No, you will not need a regulator.
There's been lots of advances in battery technology lately but the type batteries that have served you well for years & years
will still serve you well as will your charger & other accessories.
And at what point does redundancy end? An extra transmitter in case that dies in flight & a spare Abu in case you keel over?
For me two batteries (2000 mAh Ni-Mh by coincidence!), two switches & two servos on the main flight controls (ailerons & elevators) are the
best you can reasonably do. Like Vertical Grimace said everything else is more complication & more potential failure points.
Hope that helps. - John.
1. Only early JR servos are affected by greater than 6 volts.
2. Because the power buses are connected in the receiver, you can only charge one battery at a time.
12-02-2014, 05:58 AM
#47
Join Date: Sep 2006
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One issue "all" seem to be leaving out of the equation is the batteries fully charged voltage. All batteries will be well above the given rated volt when fully charged and this is where the volts can possibly hurt electronics. Why is it such an issue with most to follow mfg's recommendations, sure some things will work just fine, according to some for years, but where are these folks wallets when something fries and is in need of replacement, exactly.
Another thing, two batteries running into the Rx whether through the Rx or a Y is not redundant it is just more power. Redundant has to have a means of isolating one battery and that can not happen without a device, such as a Smart-Fly power board.
And why is it that many don't see these larger, some extremely larger, birds not needing of such added security and control. Is it not smart to add the protection of redundancy, extra electronic power?
If adding these things are in vain then why not remove them from your vehicle, place of work, or home.
How about going home and removing all the smoke alarms and fire extinguishers, after all they are not a necessity and could give a false sense of security.
Another thing, two batteries running into the Rx whether through the Rx or a Y is not redundant it is just more power. Redundant has to have a means of isolating one battery and that can not happen without a device, such as a Smart-Fly power board.
And why is it that many don't see these larger, some extremely larger, birds not needing of such added security and control. Is it not smart to add the protection of redundancy, extra electronic power?
If adding these things are in vain then why not remove them from your vehicle, place of work, or home.
How about going home and removing all the smoke alarms and fire extinguishers, after all they are not a necessity and could give a false sense of security.
Last edited by acerc; 12-02-2014 at 06:07 AM.
12-02-2014, 06:28 AM
#48
Thread Starter
The BatShare does look like a reasonable safety measure for a reasonable price (around $30).
From what I'm reading here there seem to be three levels of safety: 1) Single battery/single switch = no protection, 2) Double batteries/double switches directly into the Rx = partial protection against a failed switch or bad battery, and 3) Double batteries/double switches run through a regulator such as the BatShare = maximum (redundant system) protection.
From what I'm reading here there seem to be three levels of safety: 1) Single battery/single switch = no protection, 2) Double batteries/double switches directly into the Rx = partial protection against a failed switch or bad battery, and 3) Double batteries/double switches run through a regulator such as the BatShare = maximum (redundant system) protection.
12-02-2014, 06:43 AM
#49
vertical: The JR 791 high torque retract servo is limited to 4 cell Nixx (See Horizon Hobby spec sheet). It will burn out quickly using 6v or more. Folks may use this single JR servo as an example for many (all?) JRs. I am using two of these retract servos with regulators in Hangtimes Hobby A123 LiFe battery systems.
Brian
Brian
Last edited by aghost; 12-02-2014 at 06:57 AM.
12-02-2014, 07:02 AM
#50
Here is an excellent article on dual battery/switch setups: http://www.hangtimes.com/parallel_packs.html
It debunks the "theories" of what happens if a battery fails.
My opinion is that adding diodes, regulators, isolators, etc adds more points of failure into your system.
It debunks the "theories" of what happens if a battery fails.
My opinion is that adding diodes, regulators, isolators, etc adds more points of failure into your system.