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What battery do I put the diode on?


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#1 Colin Donahue

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Posted 08 January 2013 - 06:08 PM

I am rewiring my Archer and I want to wire two AB plates in parallel. I have purchased a couple of diodes but I am not sure If I need to put them on both battery plates or just one.
If it is just one, do I put it on the battery plate at the end of the power run or the one in between? I have researched quite a few posts by guys who have done this, but can't seem to get this straight. Any help would be appreciated.

Colin Donahue
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#2 William Demeritt

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Posted 08 January 2013 - 07:36 PM

By my reasoning, you'll need diodes on the + line from each battery. In parallel, the load draws from both batteries, so the two batteries are directly connected (the + on each battery is connected and supplying power to the load, and - on each battery is functioning as neutral). Since both + are connected, both must be protected from power flowing back to charge the other battery.

For example, if battery A has a diode on the +, it only allows power to flow out. However, if battery B doesn't have a diode on the +, then it can still accept power from A. If you diode only B, then vice versa. So you need a diode on the + of both batteries A and B.
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#3 Colin Donahue

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Posted 08 January 2013 - 08:26 PM

William,
Thank you.
Colin
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#4 Lukas Franz

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Posted 09 January 2013 - 10:17 AM

Will is right with the functionality of the diodes and how they should be set correct. But actually I wouldn't recommend to use diodes for the batteries. Because you will lose 0.7V on each battery with a regular diode and you will reduce the possible amperage. That all depends on the type of diode you use but you will lose power anyway. And given that you probably like to have more power with two batteries parallel I would leave the diodes out. Your batteries don't suffer as long as you always take two fresh ones together and two of the same type. My 2 cents.

Best.
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#5 Eric Fletcher S.O.C.

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Posted 09 January 2013 - 10:40 AM

Will is right with the functionality of the diodes and how they should be set correct. But actually I wouldn't recommend to use diodes for the batteries. Because you will lose 0.7V on each battery with a regular diode and you will reduce the possible amperage. That all depends on the type of diode you use but you will lose power anyway. And given that you probably like to have more power with two batteries parallel I would leave the diodes out. Your batteries don't suffer as long as you always take two fresh ones together and two of the same type. My 2 cents.


except the lower voltage of the two AB's will go into protection mode if you don't run the diodes.

1 diode on each V+ lead on the battery plates and you will be fine. Diodes don't reduce amperage either
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#6 chris bangma

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Posted 09 January 2013 - 10:59 AM

Be careful running Nimh batteries in parallel without a diode. Most battery chemistries will load balance between the 2 of them, Nimh will not. You will want the diodes, if they are Nimh otherwise you risk damaging the battery.
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#7 Lukas Franz

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Posted 09 January 2013 - 11:06 AM

Eric, yes you're right, diodes don't reduce amperage. But every diode has a current rating and with regular diodes you don't have the high strength of current anymore you want when shooting with a very power hungry camera, focus motor and wireless transmitter.

And as I said: always use two batteries of the same type and same voltage! Then there shouldn't be a problem with protection mode of a battery.

It is just my opinion (as an electronic engineer).

Peace.
Lukas
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#8 Lukas Franz

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Posted 09 January 2013 - 11:08 AM

Yes that's actually true, Chris! With liion there shouldn't be a problem.
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#9 Ken Nguyen

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Posted 10 January 2013 - 02:32 AM

Lukas,
What if your batteries won't hold the same charge dues to age and cycle of use?
What if one of the battery is not fully charge?

Better have the diode installed for peace of mind and extra protection.
You can mix different charge and capacity battery without frying the circuit and damaging the battery.
The 0.7v drop is not a big deal.
I used Dual Schottky Diode 80A/45V. It can handle all kind of power or current hungry equipment.

Cheers,

Ken Nguyen.
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#10 Jens Piotrowski SOC

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Posted 10 January 2013 - 11:54 AM

http://www.mouser.co...xKEkEDEfs9dBHE=

this what Gregg Bubb uses in his sled's
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#11 Matthew Hutchens

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Posted 01 July 2013 - 11:48 PM

By my reasoning, you'll need diodes on the + line from each battery. In parallel, the load draws from both batteries, so the two batteries are directly connected (the + on each battery is connected and supplying power to the load, and - on each battery is functioning as neutral). Since both + are connected, both must be protected from power flowing back to charge the other battery.

For example, if battery A has a diode on the +, it only allows power to flow out. However, if battery B doesn't have a diode on the +, then it can still accept power from A. If you diode only B, then vice versa. So you need a diode on the + of both batteries A and B.

 

I'm adding a second battery to my rig and was looking into wiring to prevent backcharge so this thread is of interest to me.  I am however concerned over it's acuracy as electrons are negatively charged particles and therefore attracted to the positive terminal so the electrons flow from negative to postive and not from the postive to the negative.  It's been a while since I've studied electronics so I can't say anything more than that or what should work with diodes but thought someone who know more than I do might explain in more detail how the diodes function in this circuit to protect form backcharge.


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#12 Alan Rencher

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Posted 02 July 2013 - 11:25 AM


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#13 Matthew Hutchens

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Posted 02 July 2013 - 09:48 PM

Apparently I did remember correctly.  It seems though electrons flow from Negative to Positive through some quirk in history we have come to define Current flow as being from positive to negative.  I didn't find out exactly how this came to be but did find a few places that referenced it.

 

urgent_mission.png


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#14 Devindra Sooknanan

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Posted 10 January 2016 - 03:03 AM

Lukas,
What if your batteries won't hold the same charge dues to age and cycle of use?
What if one of the battery is not fully charge?

Better have the diode installed for peace of mind and extra protection.
You can mix different charge and capacity battery without frying the circuit and damaging the battery.
The 0.7v drop is not a big deal.
I used Dual Schottky Diode 80A/45V. It can handle all kind of power or current hungry equipment.

Cheers,

Ken Nguyen.

Hi Ken, did you just splice the a diode into both positive wires?


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#15 Jess Haas SOC

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Posted 11 January 2016 - 12:41 PM

Without the diodes its easy to trip the protection circuit in Dionics.

As long as you orient the diode in the right direction it will oppose reverse current flow regardless of which terminal you put it on. Also we are trying to prevent reverse current flow so that would be electrons moving from the positive to negative terminal ;-)
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