Test/review of VBatty 32700 3.2V 7000mAh (Grey)

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Forsythe P. Jones
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You wouldn’t want to use an 18650 charger for LFP cells since the voltage is different. There is another type of hobby charger with wire leads, that can often be configured for different voltages. But, you want to have some kind of cell balancing when charging. You really should know what you are doing before attempting something like a series battery pack (parallel is simpler). If you just want a 6 volt LFP pack, Bioenno is a popular brand among ham radio types. They aren’t the cheapest but they are well made. They have 6 volt packs in 3ah and 12ah and come with optional plug-in chargers:

https://www.bioennopower.com/collections/9-6v-series-lfp-batteries

The ones I’ve seen people using were 12 volt, which is more popular.

will34
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Wire them in series with a 4S Lifepo4 BMS, preferably with active balancing function, and then charge it with a hobby charger or inexpensive dedicated 12V chargers.

Lifepo4 are quite robust and will go a long way even without ever balancing them in low drain applications.

Scimmy
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Thanks for the replies, it is for ham radio use although I’m sure it will have many uses..

I’ll do some reading on BMSs and balanced charging before going ahead. One concern is wiring the batteries together but I’ll see what I can find out.

HKJ
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Scimmy wrote:
I know it’s an older thread but it’s very useful.. I’m quite interested in combining 4 of these in series for a project. Are these too big to fit into commercial hobby chargers that would be used for 18650s ? I’d quite like to get a 4 cell holder if possible but will consider connecting them together permanently (solder?) and finding a suitable charger..

They do generally not fit into cradle chargers, but there are exceptions.
You can check my list here: https://lygte-info.dk/info/roundCellChargerIndex%20UK.html

A hobby charger can charge one cell or four in series with the correct wiring, but you will have to make your own connections/wiring.

If you are in doubt about what a hobby charger is, check here: https://lygte-info.dk/info/HobbyChargers%20UK.html

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Barkuti
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Despite not supported by specifications, if you are willing to file down the positive pole bulge to some extent I can recommend the very affordable Lii-100 charger to charge these cells. It can easily be opened (uses standard small Phillips screws) and modified. The fit ends up being tight, but works.

I know this from experience, used it to help with charging some of these big cells for testing purposes:

 

 

A Lii-202 should also work (filing down its positive pole bulges, too), however being dual slot its measured lack of width will result in the cells lying somewhat off-center with both slots filled, although I'm fairly sure it will also work.

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Scimmy
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Many thanks for the useful info, much appreciated

Hobbyfotograaf
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One year later, a new test of these cells in my outdoor solar light (the LiFePo4 cells are 3 years old now).
The cells lost 61mAh, that is about 1% in one year:

There is a bms in the battery pack, but there is no balancing, the difference between the cells was only 0,001V

alpg88
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As impressive as it looks now, i’d like to see those results again after several years or several hundred cycles,

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