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Zippy 4200mah battery - have I killed it ?

An alternative battery, but bigger and heavier, might be the RoyPow 6Ah. I’ve just bought the 12Ah version to use in my campervan. The 6Ah is 0.9Kg. The voltage under load when I tested it yesterday was around 12.7 to 12.5 when drawing 7A to power my IC-7300 at around 40W output power. Under a lower current it would be about 13 volts I think.

www.amazon.co.uk/RoyPow-Phosphate-Rechargeable-Replacement-Scooters/dp/B08S74VW95

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It’s not all lost. I once discharged a Turnigy 5000mAh LiPo a bit too much and my charger refused to charge it.

I found a trick on the web to try to revive it and worked: I charged it with the lowest possible current in NiMH charging mode and just long enough to bring the cell voltages above the threshold (NiMH typically have lower battery voltages than LiPo so they will charge a cell below 3V).

It worked fine and I’ve used this battery countless times since then. Of course I am extra careful with it now; it’s always in a LiPo safe bag; I am around when charging it (at low current), and I don’t leave it plugged in.

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You might be right. Just set a NiMH charge for a couple of mins and raised the voltage to 10v.
Now on a LiFe balanced charge.

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We await the outcome with bated breath John.

So do I. :slight_smile:
Currently balance charging and at 45% fuel (as the charger shows it), it was 10%

Be careful John stop NiMH charge when you have the necessary voltage and check individual element voltage maybe you got one dead, if all are OK go to LiFePo4 again, I put mine at only 0.5a.
Éric

Thanks for the warning. I gave the batteries a quick charge and checked the overall voltage and got 10.xV
I then tried with the plug in volt meter that connects to the white plug and this worked.
I then switched mode on the charger and set it to LiFe - Balanced charge.

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You can’t read your individual element voltage ? just to know if all element are OK !

I can via the plug meter and the current status as seen by the charger is

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For 4$ you can buy this one and using on the field
image

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You mean like
image

from pic above? :slight_smile:

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Yes it’s almost the same, what was interesting is to know that they were the voltages of each element before and independently of the charger

Before the suggestion from SP6SUD the plug in volt meter refused to show any voltage.
I then gave the batteries a quick charge with NiMH set and the voltage came up to 10v.
From memory it was around 2.2v per cell

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Along with the charging time from yesterday afternoon, 3hrs of charge last night and then another hour this morning. Finally the battery is charged.
Oddly, the battery pack seems less puffy than before.?

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Just be sure you disconnect it after use. I had a wonderful 8400 maH battery that I killed by leaving one of these plugged in. They draw power from one cell, you can imagine what happened…

Mark.

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I don’t leave this meter plugged and will remember to unplug from radio when not in use.

Hurrah!
Are you going to bench test it under load before venturing out to the hills?

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I have the radio hooked up to the FT857 and showed 13.2v on power up. :slight_smile:
Maybe at dinner time I might go HF mobile.

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As you have a smart charger, measure the cell internal resistances. They’ll give an indication of whether the cell is healthy. They’re very low for LiFEPO that have not been used much. My 4S2P has internal resistances around 6 to 11mOhms (milli Ohms). My 4S1P has seen many more charge/discharge cycles and shows 13 to 25mOhms.

I was stripping a 9 cell laptop battery yesterday that has 9x 3000mAhr LG cells in it. New cells of this type are in the 50-60mOhm range but all of the cells I recovered are 170-190mOhm. That suggests they are tired and a few tests show they’re not brilliant. Often from a laptop battery you find a few knackered cells and the rest reasonable but this pack looks to have been well used which was why it was replaced.

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Hi Andy.
Just looked in the manual for the charger and found the menu option for the resistance.
The battery I had issues with;
009
005
005
005

The other battery for comparison (shows 14.2 on radio power up)
013
011
011
007