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Author Topic: Battery for 100W (20.5A) Backpack Portable Operations?  (Read 10378 times)
AD0GI
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« Reply #15 on: March 30, 2015, 08:34:49 PM »

I know that they make LiFePo4 for starting motorcycles...

The Battery Tender BTL35A480C is an example of this.  One review for this battery on Amazon is from someone who bought it for use with a 100W ham rig.  He gave the battery 5 stars but I am not sure he actually used it for his intended purpose.  It seems like he might just have it in the closet thinking that it will work in case of an emergency.

Having researched this battery type further, I have come to believe that they are designed to put out A LOT of power quickly to turn over an engine but are not good for the use being discussed here.

Something like the CTC CLFP128198, intended for powering electric wheelchairs and similar uses, may be a better fit. I am still trying to figure it out.
« Last Edit: March 30, 2015, 09:32:49 PM by AD0GI » Logged
AD0GI
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« Reply #16 on: March 30, 2015, 09:08:42 PM »

Thank you for all responses.

I understand that total pack weight will limit the distance I can go comfortably.  The easiest of the hilltops I have in mind are only about 1/4 mile from a parking spot.

I do not intend to operate at full power all the time, if at all, but would like a battery that would allow such operation of a TS-590s.  If all I can get out of the pack is 2-3 hours, I'm OK with that.

At this point, I am just trying to determine what is achievable with what I have and without buying a new rig.
« Last Edit: March 30, 2015, 10:50:55 PM by AD0GI » Logged
KK5DR
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« Reply #17 on: March 31, 2015, 03:45:36 AM »

Don't forget to factor in the receive current draw as well. If the radio in RX mode draws 2.5A or more, I would not consider it for backpack operation. You would have only a few hours of use on a large marine deep cycle battery before you would need a charge.
Many radios that are not what you would call "qrp" do not react well when the supply voltage drops below 11vdc. Some radios will shut down when the voltage drops below 10v.
True qrp radios like the KX3, 703, etc have very low current draw in RX mode, and reasonable current draw in full power TX mode.
Just something to keep in mind.
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G4AON
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« Reply #18 on: March 31, 2015, 04:34:38 AM »

I think hauling that amount of gear 1/4 of a mile is a huge undertaking. As others have said, either look for a smaller and lighter radio or limit your use to "vehicle" portable where weight of batteries isn't a problem.

I use a TS-480SAT with a Varta 85AH AGM battery, however the battery weighs 25 Kg and isn't something you would want to carry far. There is a table of the current consumption of my TS-480 and some worked out arithmetic covering running the 480 and a laptop on my web site at: http://www.qsl.net/g4aon/batteries/

73 Dave
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KU7PDX
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« Reply #19 on: March 31, 2015, 08:30:14 AM »

I had thought that a LiFePO4 would be the way to go until I read "Power to the Public Service Operator" from the March 2015 QST.

The author does not indicate which specific makes and models of LiFePO4 batteries he looked into but does state that the "maximum discharge rating" (C-Rate) of them were low compared to batteries of other chemistries and none would handle the current draw of the TS-590s at full power.

The author is incorrect about LiFePO4 batteries. Take the Zippy Flightmax 8400mAh battery from HobbyKing (http://www.hobbyking.com/hobbyking/store/__14074__ZIPPY_Flightmax_8400mAh_4S2P_30C_LiFePo4_Pack.html). It has a constant discharge rating of 30C and a burst discharge rating of 40C. You take the capacity of the battery and multiply it by the rating to get the maximum current, in this case 252 amps constant, 336 amps burst (odds are these are exaggerated for this battery though).

The point being that a burst draw of 20 amps (less than 3C) is completely within this battery's capability.

Don't believe everything you read in QST. Grin
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73,
Chris - KU7PDX
KB1GMX
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« Reply #20 on: April 03, 2015, 01:12:45 PM »

When dealing in Lithium tech batteries you have to be exceedingly specific.

One reason is there are various types that are not the same LIFEPO4, LIpoly, LION,
and others, are not the same thing or simply misnomers depending on how the term
is used or misused.

In general lithium gives good to excellent power for their weight.  Their offer many
features and liabilities.  Features, lighter, smaller, long life. Liability, charging must
be controlled though it can be fast, overheating from charging or rapid discharge
can cause a runaway condition (fire),  and over discharge can render the battery
unsafe or sharply reduce its life. 

In general lithium based packs fall into two general cases, assembled batteries without
any protection (model air and car batteries) where high current demands  and rapid
recharge are desirable and the other case is assembled packs with charge and
discharge protection.

For the hobby and raw  high current cells and packs the risk is that they can supply
immense currents for short times and cause overheating in the battery or wiring.   
This can and has caused fires.   That places the safety burden on the user/designer.
Those being excessive charge current, over current on discharge, and discharging
to too low a voltage per cell.  The too low a voltage is a problem as the lithium can
plate out become a elemental form that is reactive with oxygen and water with risk
of fire.

The other general case is cells and battery packs with BMB (battery management board)
or CMB (charge management board).  These are protected batteries and are generally
safe from over charge and excessive discharge.  They will disconnect from the charger
or load if current in or out is excessive, the battery under charge conditions exceeds the
safe voltage for its design, or if the battery is allowed to discharge to near the minimum
safe voltage. As a result of the boards used often the battery can supply 10s of amps
but the board may limit you to maybe a few.  The limits vary obviously depending on
battery size and the expected use.

Last item if the gear is not optimized for Lithium tech there is the voltage problem.
The general spec per cell is a nominal (average over discharge) of 3.3V or 3.7V
the 3.3V cells top out fully charged at about 3.6-3.8V, and the 3.7V types are
typically 4.2V fully charged.  That means for a radio designed around the nominal
automotive voltage of 13.8V we have a mismatch.  Four of the 3.3V type will
run from 14.8 fully charges to about 11.2V nearing cutoff (2.8V cell).  That means
you maybe get 60% of the total amphours purchaged before the equipment quits
on low voltage.   For the 3.7V tech we can't use four cells directly as fully charged
its 16.8V and high for commercial gear to safely use.  With three cells we get to
only 12.6 fully charged and at cutoff we are under 9V.    In all cases once below
about 60% of a full charge we are running near the radio quitting when under
the TX load the voltage falls further.

If you choose the right battery Lithium tech is excellent.  the laptop, tablet, and smart
phones cannot run near as long without it.  So what you pick and how you use it
important to getting the desired result.   The advantage is savings usually near
half maybe more weight over lead tech.  Another feature of Lithium tech is you can
partially charge and use it without life penalty, in fact of you charge to less than 95%
and discharge you get more cycles.  Another advantage is they can store at less
than full charge where led must be kept charged or sulphating is a risk. NiCd and
NiMh are ok but left dischaged can internally short and be come useless.  Charging
Lithium tech is also generally good if the right charge system is used as for most
types charging at 1/3 to 2/3rds the Amp/hour value is the usual range, making for
fairly fast charge rates.  The entry cost is that the batteries are generally more
expensive and the charger is as well.  The payback is if the battery is treated
reasonably its life is very long in number of charge recharge cycles compared to
NiCd and others.  I have batteries That are now in excess of 15 years old and still
delivering better than 85-90% of rated new capacity.  In in Laptops I've gotten
in excess of 7 years before replacement due to a individual cell in the pack failing.
This is of course for name brand of known quality.

It still comes down to even though a small battery can easily supply 20A its doesn't
mean you can do it for long as overheating or plain running out power are both likely.
that and running out of power when things are getting fun is a seriously huge
disappointment.  The worst part of that is for the first half hour calling CQ (high duty)
and getting responses only to find the radio quits on TX due to lack of power.  The
painful part is by spec the 590 1.5A RX (no signal) and its 15% voltage tolerance
(means 11.7 volts its the lower limit, or over 15.8V, 13.8 plus or minus 15%).
Even for lead acid 1.95V is greater than 80% discharged and with 6 cells your down to
11.7V that radio is not going to behave well.  The type of battery chosen cannot fix that.
Going to larger only postpones it as a function of normal discharge the battery voltage sags



Allison
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AD0GI
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« Reply #21 on: April 03, 2015, 07:53:16 PM »

When dealing in Lithium tech batteries you have to be exceedingly specific.

The specific battery I am considering at the moment is the CTC LFP128198 with the following specs:

Nominal Voltage: 12.8V
Nominal Capacity: 19.8Ah
Minimum Capacity: 19.2Ah
Charge Voltage Cutoff: 14.6±0.05 V
Discharge Voltage Cutoff: 10.0V
Maximum Charge Current: 19.8A
Nominal Charge Current (C/5): 4.0A
Maximum Discharge Current (Pulse)(5C): 100.0A
Pulse Time: 30 seconds
Maximum Continuous Discharge Current (2C): 40.0A
Nominal Discharge Current (C/2): 10.0A
Cycle Life: >1000 times
Operation Temperature Range: -20°C to 60°C

The Maximum Continuous Discharge Current is twice what I need to run the TS-590s at full power and the Nominal Discharge Current is what I expect to use most of the time, transmitting at about 15W.
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W8JX
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« Reply #22 on: April 04, 2015, 06:02:34 AM »

When dealing in Lithium tech batteries you have to be exceedingly specific.

The specific battery I am considering at the moment is the CTC LFP128198 with the following specs:

Nominal Voltage: 12.8V
Nominal Capacity: 19.8Ah
Minimum Capacity: 19.2Ah
Charge Voltage Cutoff: 14.6±0.05 V
Discharge Voltage Cutoff: 10.0V
Maximum Charge Current: 19.8A
Nominal Charge Current (C/5): 4.0A
Maximum Discharge Current (Pulse)(5C): 100.0A
Pulse Time: 30 seconds
Maximum Continuous Discharge Current (2C): 40.0A
Nominal Discharge Current (C/2): 10.0A
Cycle Life: >1000 times
Operation Temperature Range: -20°C to 60°C

The Maximum Continuous Discharge Current is twice what I need to run the TS-590s at full power and the Nominal Discharge Current is what I expect to use most of the time, transmitting at about 15W.

As others stated I would not use a 590 portable. Even at 15 watts it will likely draw about 10 amps. Also you will not be able to use/recover full rated capacity because it is to a cutoff of 10 volts. If you insist on using a 590 portable, you really want a bigger battery. If you can find cells from a Chevy Volt, they are rated at about 43 amp hours. individual cells are about 3.5 pounds each so 4 in series would be about 14 pounds. In service those cells handle up to 300 amps discharge so powering a radio will be nothing for them. 
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KB1GMX
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« Reply #23 on: April 04, 2015, 09:16:05 AM »

AD0DGI...

Yep on receive that battery will run the radio for maybe 7 hours or a tad more.

Then the battery will be below the usable range for the radio to operate. Why?
THe battery cuts off at 10V or about 90% give or take of the usable capacity.
that means of the 19.8AH you get maybe 17.9AH usable before cutoff. 
However that misses the fact that the radio stops working properly at much
higher than 10V. Lets say the radio woks to maybe 11.4V that's the  roughly
75% discharge point ( I', being generous and it varies with load current) so
now of the 17.9 you only get 13.425AH or maybe still 7hours RX the receiver
is likely to go longer and is dependent on volume setting and if other features t
hat consume more power are used. 

Now for TX you can either hunt and pounce or call CQ.  If we assume CQ the
first 15 minutes will be easily 50% duty or maybe more.  If hunt and pounce
your running the antenna tuner as you portable antenna is likely not wide band.
Either way your eating power at an accelerated rate and since that 13AH of
usable battery you have maybe 1.4 hours of total transmit time.  That varies
depending on how fast the transmit gets unhappy.  I assumed for that the TX
will run down to 11.4V, it might or might not.    However we persist
if we assume the TX/RX is 5:1 that means you might work for 2-3 hours,
because the TX current is high the remaining power for RX is more limited.
Assuming the battery is fully charged and has a few cycles on it (needed
to get it to full capacity) You make it to about 3.5hours maybe. 

In the end to run 10A to get 15W is terrible.  I've run a PRC1099 manpack that
easily does 20W and less than 4.5A (absolute peak).  One receive at max
volume its nearly .3A way less (1/6th the 590).  My TenTec Triton (1978 build date)
on receive is under .4A and TX at 25W is a mere 8A, (At 10A I see 40W on the Bird)
much better.   A K2 at 10W (its a K2 without the 100W amp) is a mere 2A on TX
and under 300ma on RX.   I also believe that you will not keep your hand off the
power knob if the results are poor.

Why is the 590 so hard on battery.  Mostly because of the extra bits and the DSP.
Most of the DSP used plus displays to give you all that neat user experience eat
power.

If battery operation is important enough to haul a half mile (1/4 miles out and back)
then consider that battery, radio, mic or key, cables, antenna are all putting you
over 50 pounds.  It will likely be more as the first time you going to bring things
you may or many not need. 

I suggest you have a go at at it.  If your serious about doing it often you will realize
your hauling a lot of weight for limited time and the TS590 is not at all efficient use of
costly battery at any power level.  Experience is a good teacher.


Allison
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N6ORB
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« Reply #24 on: April 04, 2015, 02:36:26 PM »

The claim that lithium chemistry batteries can't supply high power doesn't match my experience. I have a Buddipole 4S4P battery pack rated at 10 amp-hours. I just tried putting my K3 into tune mode and observed that the internal ammeter showed a current draw of 16 amps when connected to my power supply. Replacing the power supply with the lithium battery showed the same 16 amps. I have operated my K3 portable using the Buddipole battery and haven't noticed any apparent reduction in output power as reflected in signal reports received.

BatteryUniversity.com has a lot of information on batteries of all types. Of particular interest is the following page:
http://batteryuniversity.com/learn/article/bu_206a_finding_the_optimal_runtime_and_power_ratio_of_li_ion

One battery in a comparison of power outputs is an A123 APR18650M1, a lithium iron phosphate (LiFePO4) with 1,100mAh and a continuous discharge current of 30A.

Dave, N6ORB
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W8JX
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« Reply #25 on: April 04, 2015, 05:53:51 PM »

The claim that lithium chemistry batteries can't supply high power doesn't match my experience. I have a Buddipole 4S4P battery pack rated at 10 amp-hours. I just tried putting my K3 into tune mode and observed that the internal ammeter showed a current draw of 16 amps when connected to my power supply. Replacing the power supply with the lithium battery showed the same 16 amps. I have operated my K3 portable using the Buddipole battery and haven't noticed any apparent reduction in output power as reflected in signal reports received.

BatteryUniversity.com has a lot of information on batteries of all types. Of particular interest is the following page:
http://batteryuniversity.com/learn/article/bu_206a_finding_the_optimal_runtime_and_power_ratio_of_li_ion

One battery in a comparison of power outputs is an A123 APR18650M1, a lithium iron phosphate (LiFePO4) with 1,100mAh and a continuous discharge current of 30A.

Dave, N6ORB


I have a Chevy Volt and its 440lb  370v 43amp Lithium battery pack is heated and cooled as needed and will produce 110kw (300amps)on demand (that is max main electric drive motor draws) with easy and can see charge rates of 50kw (about 140 amps) using regenerative braking on steep down grades or heavy braking. Car only uses 70% of batteries capacity in normal operation to extend battery life. Point of this is that lithium batteries can take and produce a lot of current as long as you watch temperature. Nissan Leaf has had battery issues/short because they had poor temperature management of battery pack. They redesigned battery in 2014 and offered cheap lifetime replacement to deal with issue. Tesla also uses good temp control of its battery pack. Cars like Prius have a very limited capacity 200 volt NiMH battery that can only produce a peak of about 12 to 15kw for a very brief period of less than a minute.

Getting back to post if OP really wants to do portable with a 590 they should look for a light weight 6 or 700 watt inverter generator weighing 25 lbs or less. 3 or 4 lbs of fuel would likely last all day.
« Last Edit: April 04, 2015, 05:56:53 PM by W8JX » Logged

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Ham since 1969....  Old School 20 WPM Extra
AD0GI
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« Reply #26 on: May 22, 2015, 03:23:01 PM »

In case someone finds this thread looking for a similar battery, I thought I would pass along the following...

Using RX only to cycle the 19.8Ah CTC battery I mentioned in an earlier post, it is taking 13 hrs to discharge to 12.8V and 15 hrs to reach 12.6V.  12.6V is as deep as I have discharged it so far.

I think that the reason I am getting more time than some had estimated here is that I am drawing 1.32A rather than the 10A nominal discharge current that the battery is rated for and LiFePO4 batteries maintain voltage much further into their discharge curves than similarly rated SLAs.
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