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Quick question about batteryminder


bradp

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Hi All,

If I were to hook up a battery minder to a three prong external power plug (the Cessna / NATO style plug) - will the battery minder be able to open the battery circuit relay (and keep it open during it's cycling or desulfation cycles)?

 

Any disadvantages to using this method to charge (via the relayed circuit) versus direct connection to the battery terminals?  I see a lot of "interface kits".  
 

Thanks,

 

Brad

11-03158.jpg 

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It will not. The ground power port goes through a really requiring power to activate it. The battery minder does not provide enough power to both activate relay and charge the battery.

I have my battery minder wiring permanently attached to the battery and ran to baggage compartment. It’s secured down and terminates to a plug into which the bm plugs to. I have the bm wired in series to a remote gsm switch and out to power from an extension cord through pilot window. Airplane is locked with a wire hanging out the pilot window and I have instant notification of status on my iphone. This setup has served my Concorde battery well going on 10 years now. I considered adding a little access door on the avionics bay panel but decided it wasn’t necessary.

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16 minutes ago, PTK said:

It will not. The ground power port goes through a really requiring power to activate it. The battery minder does not provide enough power to both activate relay and charge the battery.

 

It's not a question of the battery minder not being able to power the relay. The relay requires very little current to operate. The way the battery minder works, is that it tries to sense the battery condition before applying power to the battery. Without the relay closed, it won't sense any battery voltage and will shut down. 

I use a separate ordinary 12V supply to close the relay and apply the battery minder once the relay is closed. Then it will do what it has to do - charge/condition the battery.

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10 minutes ago, bradp said:

Does battery minder logic ever drop voltage enough dip to below the closing voltage for the relay? 

I could see wiring the three prong to have a separate 12 VDC input for just the relay... 

You really can't use the Batteryminder as a DC source to close the relay. In battery re-conditioning mode, the batteryminder puts out a pulsed signal possibly with no DC level (I should probably put that on a oscilloscope and see what the signal actually looks like!). Without the DC output, the relay would open. Hence, we need a basic DC supply to keep that relay closed (it can be pretty crappy), even a wall wart with a few 100mA of current output might work. The grounds for the batteryminder and the relay supply can be shorted together.

Edited by wishboneash
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4 minutes ago, bradp said:

Thinking wire the second (relay) positive to a  12V rail from a cheapo old computer power supply lying around and then common ground between a minder and the computer power supply.  

Nah, just install  one of the fused cables Battery Minder sells  on the battery and route the connector to some place you can connect it to after flying. I used my O2 door portal, some people stick it through the baggage shelf like Peter described above which is a great solution for J's. You don't need to use their big connectors on the aviation approved cables, I used the older cable intended for cars because the connectors were to big to fit behind my O2 portal door, but its still fused.  Very easy minor mod for simple battery minder connection.

The external power plug isn't intended for anything more than intermittent use. 

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Clearly the better way... is to use the solution supplied by the Battery Minder people...

They have all sorts of options to wire multiple batteries, and have nice receptacles...

Going through the ground power plug with the safety relay is just too counter productive... :)

Finding the best place to mount the receptacle... now that’s the question..!

In the hat shelf area is nice if you hangar the plane...

External, in the area of the ground power plug has some opportunity...

Best regards,

-a-

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I have the BatteryMINDer® 28252-AA and use the GPU function to close the relay while plugged in using the Cessna style three prong plug to the aircraft. Then, switch to the charge/maintain mode to condition the battery. No issues.

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Batteryminders must have a great history, but I can’t get over my apprehension over a full time battery charger. This stems from having the 12v car battery on my Generac standby home generator explode. It’s on a built in trickle charger and the battery is/was a sealed one about 3 years old. One would think a company like Generac would incorporate whatever would preclude such from happening, but an online search shows it is not all that rare. The battery sits adjacent to the gas line and regulator. What could go wrong?

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1 hour ago, BDPetersen said:

Batteryminders must have a great history, but I can’t get over my apprehension over a full time battery charger. This stems from having the 12v car battery on my Generac standby home generator explode. It’s on a built in trickle charger and the battery is/was a sealed one about 3 years old. One would think a company like Generac would incorporate whatever would preclude such from happening, but an online search shows it is not all that rare. The battery sits adjacent to the gas line and regulator. What could go wrong?

There are many differences between a trickle charger and a battery tender (minder).   A tender/minder is supposed to be smart enough and monitor the battery to specifically prevent such things.   A tender/miner also applies conditioning (e.g., desulfating) to extend battery life, and chargers don't do that.

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@Bryan is this what you are using?

https://www.batteryminders.com/28-volt-aviation-power-supply-charger-maintainer-desulfator-world-wide-usage/

Looks amazing as it takes care of two the two main functions we’d be looking for in our singles.  Wish there was a similar unit as a 12V.

What I might do is a ham switching power supply separately (reasonably priced of course) to run avionics / test electrical systems.  Heck gear swing could be done with one of those units.    Then run a battery minder separately.  

Aren’t there separate temperature curves for trickle and or thermal safety circuits built into the latest generation of battery minders? 

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Check again, Brad...?

The BatteryMinder is available in more specific version for the Concorde 24V Battery... at a slightly lower price...

Also available for the 12V Concorde...

The Battery Tender is also a brand name for a different company and product... not as advanced technology... from what I see...

 

The more expensive model of the BatteryMinder can be selected to match the battery in any plane that arrives at the FBO... and can change inputs, in the event the FBO moves to Europe...  :)

 

It is easy to go to the BatteryMinder website to select the proper model... expect to match voltage, battery type, and manufacturer... then a few options for types of connectors and receptacles you want... 

Best regards,

-a-

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2 hours ago, bradp said:

@Bryan is this what you are using?

https://www.batteryminders.com/28-volt-aviation-power-supply-charger-maintainer-desulfator-world-wide-usage/

Looks amazing as it takes care of two the two main functions we’d be looking for in our singles.  Wish there was a similar unit as a 12V.

What I might do is a ham switching power supply separately (reasonably priced of course) to run avionics / test electrical systems.  Heck gear swing could be done with one of those units.    Then run a battery minder separately.  

Aren’t there separate temperature curves for trickle and or thermal safety circuits built into the latest generation of battery minders? 

Yes sir - it is great.  I use it for Ground Power Unit (GPU) for updating databases or anytime I need to power on the aircraft bus without the engine running.  It also, as I said, manages my battery.  It has specific settings for Concorde, Gill, and other types of avaition batteries.  Built-in is thermal sensor, as well as polarity and other protections.  I use the Anderson SB-50 to Cessna-style aircraft interface.  I had bought the Airframe Interface Kit but after talking with their tech support, figured out I did not need it; only the Cessna-style plug listed above.

You'd think they would have a function built-in to select 24volt or 12volt but it appears it is made only for the 24v systems :(

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That thing is $800!  I've got dual batteries so there is no way to do that even by that method.  I just got done installing the fused connector kit.  The SB50 connectors are big, but I like that they are well insulated.  This is a direct to battery connection.  If it gets wet or something, bad things can happen before the fuse blows.  I put them in the TKS door so that I can access them from the outside while the plane is locked and without getting a screwdriver out.

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I looked the waveforms from the battery minder while connected to an almost fully charged Concorde battery. The blue and yellow waveforms are two signals across a 2.4 ohm resistor and the pink is the difference between the two. From this one can determine the current going in and out of the battery. Since the battery was almost fully charged the charging pulse was quite narrow (about 10V, 10us wide swing in the positive direction) and probably net zero charge going on based on the current profile (Fig. 2). The pulses are spaced about 9.5ms as in the Fig. 1 picture. During maintenance mode, the pulses are at around 50kHz with a roughly 5V peak-peak pulse amplitude (Fig. 3). The charger is AC coupled to the battery so there is no charging going on. There is very little chance any battery damage will occur (in terms of overcharging the battery) during maintenance mode and therefore the charger can kept be left connected indefinitely to the battery.

charging_pulse_zoom_out.jpg

charging_pulse.jpg

maintenance_mode.jpg

Edited by wishboneash
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  • 1 month later...
On 8/3/2019 at 9:56 PM, kortopates said:

Nah, just install  one of the fused cables Battery Minder sells  on the battery and route the connector to some place you can connect it to after flying. I used my O2 door portal, some people stick it through the baggage shelf like Peter described above which is a great solution for J's. You don't need to use their big connectors on the aviation approved cables, I used the older cable intended for cars because the connectors were to big to fit behind my O2 portal door, but its still fused.  Very easy minor mod for simple battery minder connection.

The external power plug isn't intended for anything more than intermittent use. 

Do you connect the cable directly to the battery?

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13 minutes ago, Cabanaboy said:

Do you connect the cable directly to the battery?

Yes, the positive connector goes directly on the battery terminal with an in-line fuse nearby, and the negative can be grounded anywhere on the airframe.   I wanted to make mine accessible via the ground power electrical plug hatch, but there just wasn't room, so I ran it though the baggage bulkhead where there was an existing hole and grommet.   

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4 minutes ago, EricJ said:

Yes, the positive connector goes directly on the battery terminal with an in-line fuse nearby, and the negative can be grounded anywhere on the airframe.   I wanted to make mine accessible via the ground power electrical plug hatch, but there just wasn't room, so I ran it though the baggage bulkhead where there was an existing hole and grommet.   

thanks, is this the cable below? Where did you ground it in your plane?

image.png.e7e22059244406dcc7396af0c31cf371.png

Edited by Cabanaboy
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26 minutes ago, Cabanaboy said:

thanks, is this the cable below? Where did you ground it in your plane?

image.png.e7e22059244406dcc7396af0c31cf371.png

Similar to that.   You'll need to make sure the ring terminal is the right size for your battery and that the connector polarity is correct for the minder.  The exposed contact on the connector should be ground, the recessed contact should be the positive battery connection.   I attached the ground to the avionics shelf in the back near the battery.   In my case there was a fortuitous bolt and anchor there that was no longer doing anything useful, so I just used that.  Personally I'd use some good wire with tough insulation for at least the portion from the positive terminal to the fuse.   

Pics below.   The red wire goes to the battery positive terminal.   I used the old-timey-style glass fuse, and just grounded to the avionics shelf.   Looks like I need to get the shop-vac in there, too.  This airplane was parked outside in southern Nevada for twenty years and accumulated some dust.

20190824_144150.jpg

20190824_143702.jpg

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