Kolb-List Digest Archive

Thu 02/14/19


Total Messages Posted: 4



Today's Message Index:
----------------------
 
     1. 06:30 AM - Re: Back-Up Battery (Denny Baber)
     2. 07:29 AM - Re: Back-Up Battery (Rick Neilsen)
     3. 01:28 PM - Re: Back-Up Battery (Jerry-TS-MkII)
     4. 03:10 PM - Re: Back-Up Battery (chris davis)
 
 
 


Message 1


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    Time: 06:30:30 AM PST US
    From: Denny Baber <baberdk@gmail.com>
    Subject: Re: Back-Up Battery
    Good info on Lithium batteries. Also, they need to have the cells "balanced". They only charge until the cell with the most charge is charged and only discharge until the cell with the least cell is discharged. If there is a great difference between the cells it will seem like the capacity is reduced so it is a good idea to balance the cells on the ground to increase capacity. We only need the battery to use the starting motor but it is a nice back-up if the charging system fails. The Rotax has two ignition systems that are independent from the charging system and each other so I haven't heard of ignition failures as much as fuel problems. Dead stick landings are usually affected more by stalling than the wings falling off so I think practice is more important than three batteries. Respectfully, Dennis Baber Cape Coral, Fl baberdk@gmail.com 305-814-7218 Stay Curious


    Message 2


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    Time: 07:29:41 AM PST US
    From: Rick Neilsen <neilsenrm@gmail.com>
    Subject: Re: Back-Up Battery
    I installed a Aerovoltz iron lithium battery in my redrive VW powered Kolb MKIIIC in the summer of 2014. The battery has provided great service. The plane sits all winter while I'm in Florida and shows no measurable discharge. I take my balancing charger out to the plane every spring and check the battery cell balance. So far the voltages are within .1 volts and the balance charger can't improve that balance. These LiFe batteries don't seem to catch fire but they don't like to be over charged so I monitor the voltage while flying. Areovoltz has published a advisory to not use their batteries with some Rotax charging systems that have caused a battery melt down. The battery weighs 10lbs less than my old lead acid batteries and has lasted one year longer so far. Denny I don't understand what you are trying to say "Dead stick landings are usually affected more by stalling than the wings falling off so I think practice is more important than three batteries" Rick Neisen Redrive WV Powered MKIIIC On Thu, Feb 14, 2019 at 9:32 AM Denny Baber <baberdk@gmail.com> wrote: > Good info on Lithium batteries. Also, they need to have the cells > "balanced". They only charge until the cell with the most charge is charged > and only discharge until the cell with the least cell is discharged. If > there is a great difference between the cells it will seem like the > capacity is reduced so it is a good idea to balance the cells on the ground > to increase capacity. > We only need the battery to use the starting motor but it is a nice > back-up if the charging system fails. The Rotax has two ignition systems > that are independent from the charging system and each other so I haven't > heard of ignition failures as much as fuel problems. Dead stick landings > are usually affected more by stalling than the wings falling off so I think > practice is more important than three batteries. > > > Respectfully, > Dennis Baber > Cape Coral, Fl > baberdk@gmail.com > 305-814-7218 > > Stay Curious > >


    Message 3


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    Time: 01:28:05 PM PST US
    Subject: Re: Back-Up Battery
    From: "Jerry-TS-MkII" <12flybellaire@gmail.com>
    Reference cell balancing: A small PC board is included in most serious "cordless" applications. Multi-function. During discharge, it measures the total output current, and limits that. Much like a active resettable fuse. Most are not adjustable, but instead selected for the particular application current. Cells can be assembled in parallel to boost current capacity, but that is not ideal, unless each has it's own current control, and tied together with high current diodes. Still basically in parallel, but also protected. And each cell voltage is monitored, and if one cell is higher than others, a small leakage current is established, that lowers the high cell voltage. It is minimal loss. The device also watches the minimum total voltage and will shut it down, if too low. During charge, the charging current and profile is regulated, AND the cells are kept balanced, again by slight current bypass, for any cells which are too high. If you simply take a rectified alternator output it will always be higher voltage than the peak system battery voltage, to charge it to the max. (approx 13.8 for lead acid). With any of the high energy density cells, the charge regime is very specific for the type of chemistry being charged. So that is why the above control board is used (required), to charge properly, from a poorly regulated engine source. And also why one pack can be "on-line" while the other is charging unencumbered to it's proper maximum voltage and rate. With most of these cells having a voltage of about 4 volts.. 3 cells will never be higher than 12.6V. If a diode is used, that will drop .5-.6 volts so the 3 cells will supply 12.1 max, down to 10.5. Some equipment can stand the higher voltage provided by 4 cells (16.8 minus .5-.6 for 16.2 max). A starter motor would probably be fine with the slightly higher voltage. Electronic devices are usually regulated internally but.. look at the specs before proceeding. Switching supplies can be used to boost or drop the battery voltage.. but that adds significant complexity and cost for the high current applications. The battery control boards are mass produced, and rather inexpensive. Each will have specific cell count, and output current range. Jerry Read this topic online here: http://forums.matronics.com/viewtopic.php?p=487589#487589


    Message 4


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    Time: 03:10:13 PM PST US
    Subject: Re: Back-Up Battery
    From: chris davis <capedavis@yahoo.com>
    George 2Which aerovoltz battery do you have and what did t cost ? Thank u Chris Sent from my iPhone > On Feb 14, 2019, at 10:29 AM, Rick Neilsen <neilsenrm@gmail.com> wrote: > > I installed a Aerovoltz iron lithium battery in my redrive VW powered Kolb MKIIIC in the summer of 2014. The battery has provided great service. The p lane sits all winter while I'm in Florida and shows no measurable discharge. I take my balancing charger out to the plane every spring and check the bat tery cell balance. So far the voltages are within .1 volts and the balance c harger can't improve that balance. These LiFe batteries don't seem to catch f ire but they don't like to be over charged so I monitor the voltage while fl ying. Areovoltz has published a advisory to not use their batteries with som e Rotax charging systems that have caused a battery melt down. The battery w eighs 10lbs less than my old lead acid batteries and has lasted one year lon ger so far. > > Denny I don't understand what you are trying to say "Dead stick landings a re usually affected more by stalling than the wings falling off so I think p ractice is more important than three batteries" > > Rick Neisen > Redrive WV Powered MKIIIC > >> On Thu, Feb 14, 2019 at 9:32 AM Denny Baber <baberdk@gmail.com> wrote: >> Good info on Lithium batteries. Also, they need to have the cells "balanc ed". They only charge until the cell with the most charge is charged and onl y discharge until the cell with the least cell is discharged. If there is a g reat difference between the cells it will seem like the capacity is reduced s o it is a good idea to balance the cells on the ground to increase capacity. >> We only need the battery to use the starting motor but it is a nice back- up if the charging system fails. The Rotax has two ignition systems that are independent from the charging system and each other so I haven't heard of i gnition failures as much as fuel problems. Dead stick landings are usually a ffected more by stalling than the wings falling off so I think practice is m ore important than three batteries. >> >> >> Respectfully, >> Dennis Baber >> Cape Coral, Fl >> baberdk@gmail.com >> 305-814-7218 >> >> Stay Curious >> >>




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