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Continue with LiPo or go LifePo4?

#1

Both my Zippy 4 cell 14.8v LiPo batteries are showing signs of ballooning and need replacing. I use these with a buck converter which drives my MiniPa50 amp and MCHF fine but can’t cope with the current draw of the SLA-817 Amp. At the moment if I want to use that I’m back to a 7.0Ah SLAB.

I was watch Survival Tech Nord’s video about building a home made LifePo4 pack out of individual cells and a balancer. A subsequent eBay search came up with a seller shipping 12V 12Ah LifePo4 batteries including charger for £109. They weigh in at 1.2kg - the 5AH LiPos are around 0.5kg each, plus the weight of the buck converter. The cost of replacing both LiPos is around £50.

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When I started totting up the cost of individual LifePo4 cells, a charger and balancer there won’t be anything in the cost between going DIY and choosing one of these. I’d be happy to drop the need for a buck converter - another point of failure - what do you guys recon?

Regards, Mark. M0NOM

#2

there not cheap but light and worth it.

Also via e bay well spotted in look out for a good LP4 battery and not to heavy and run ya radio for a while too.

Karl

#3

I’ve got one of those Ultramax 12Ah batteries. Works fine.

But it’s little used now as I’ve scaled down to the 4.2Ah 4S1P 30C LiFePo4 Zippy Flightmax from Hobby King. I have two of these but rarely carry more than one on the hill. Happily drives my 857 (often at 40W or 50W) or 817 plus amp. I usually work no more than an hour from a summit so have plenty of capacity spare.

See the photo. I obtained some bullet connector to T-connector adapter. Cut off the T end and replaced !with Power Poles. All that is under the Duct Tape. All up it weighs 504g.

Edit: I’ve done more than a hundred activations now with this set up… so it is field proven.

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#4

Interesting, for some reason when I was on Hobby King yesterday I couldn’t find LifePo4s… weird. Can you tell me what charger you use with that please?

Mark

#5

Got a 8600 me self done me well when out and about
But mine is boxed so it not get bounced about to much

But a bigger one would be good and other one be a back up.

karl

#6

One of these. Bought with the bats.

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#7

Just to be clear… I’m not pushing Hobby King, but these work fine for me.

Plenty of other choice out there if you look.

#8

Not pushing these… but this is the one.

Then I added this - cut off the T end and replaced with Power Poles.

My charger is not available any more. This would do it.

I run the charger off a 12V PSU from Maplin!

Edit: when I am in the camper van I power the charger directly off the leisure battery.

#9

Good idea to keep them protected. I have the radio, battery and other “bits” in a padded bag - originally designed for a tablet computer - got it free from Tesco with some coupons a few years back when they were also giving out small laptop backpacks. Fits the 857 just right and doesn’t weigh much.

This is the bag, 857, battery (as above), notebook for recording QSO when it rains too much for VKPortalog on my phone, pencil ,power connector cable for the 857, small multitool, assorted connector bits. Still over 3Kg…

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#10

Hi,
Hobby King Aus only have 2 12 v nominal LiFe on their listing now. There were none two weeks ago.

I prefer these to LiPo. Importing any batteries with Li in them is likely to fail if you are an individual over here and hope for air delivery. HK prices and delivery are very competitive.

73
Ron
VK3AFW

#11

Am I right in thinking that LifePo’s are easier for storage? I believe I read that they should be stored fully charged. My LiPos spend a week at a time not being used so having to discharge them after an activation where they may have only been hit very slightly wasn’t something I ended up doing very often, maybe hence the shorter than expected life span.

Mark.

#12

So this is the dilema - two 4.2Ah batteries and a charger are the same price as the one 12Ah…
As I said before I do appreciate the flexibility of having two lighter batteries, but then you’re getting 12Ah for the price of 8.4Ah with the bigger battery…

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#13

In my experience, two 4200 mAh Zippy LiFePOs are enough for up to three hours of intensive CW operation at 100 W. I’m very happy with mine; after about 30 activations in FK/VK/ZL, where I discharged them to less than 10 V more than once (in the heat of the moment, erm pile-up), they still measure 4150 mAh each on a 1C discharge. Unfortunately I forgot to measure them when they were new :wink:

Bonus: you can take two 4200 mAh batteries on a plane, but you can’t take a 12 Ah.

#14

Know what you mean… but in reality I only carry one 4.2Ah most of the time and have the other in the car as a spare.

They better had be… I don’t give it any thought. I use them, charge them, or use them, then forget to charge them and remember to charge them the night before the next activation… I know… a bit sloppy :slight_smile:

#15

Why go for the 30C discharge ? i am looking at at getting a couple of the 4000 mAh LiHV batteries. At 10C discharge.
More than enough amps for portable use. The battery charger you are ordering will charge LiHV

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73 Neil

#16

Is that another “chemistry” again?

If so I can’t comment.

I’ve only ever used SLAB and LiFePO4.

The LiFePO4 just seem to come in 30C format… as you say it’s not needed for our purposes, but as long as it is “too much” it is better than not enough (well in current draw capability).

#17

Good question, reading the description i think that they have tweaked the battery somehow to maintain voltage over time, at the expense of current draw. 40 amps though is plenty for a portable rig .
Also they are cheaper, saving Mark £28.22 on his invoice !!.

Incidentally i noticed you chopped the original plugs, chopping off the originals = Void Warranty.
IMHO its best to go with adaptors, plenty of different types available .

73
Neil

#18

Hi, no that’s not correct. I was conscious of warranty claims process.

I bought two 5.5mm Bullet connector to T - connector adaptors. It is these that I adapted by removing the T end and replacing with PowerPoles. The Bullet connectors were retained on the actual battery.

#19

Mark, just check your LiPOs are actually swelling up. After a while the plastic casing can bulge out giving the appearance that the battery is swelling, but underneath the battery is fine. This has happened to one of my 2200mAH Zippy batteries bought around 2014. I have three 4000mAH batteries of 2009 vintage and they are still running fine after approximately 400 activations.

73, Gerald G4OIG

#20

My advise is go for LiFePo4. More recent tecnology, no fire risks, no restrictions when taking planes, I started activating SOTA with a SLAB and later changed to a LiFePo4 - 4S2P. I have used it with not any single issue on several activations. It lives at the bottom of my rucksack wrapped in bubbles plastic and surrounded by polyexpan pads for protection.
73,

Guru