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Electronics => Projects, Designs, and Technical Stuff => Topic started by: DeanCording on April 17, 2018, 03:11:11 am

Title: Aldi 2Ah & 4Ah LiPo Battery Packs
Post by: DeanCording on April 17, 2018, 03:11:11 am

Aldi have their 2Ah & 4Ah LiPo battery packs on sale this Saturday 21/4 for $29.99 and $39.99 respectively. Both battery packs are rated at 20V.

The charger unit ($19.99) is easily gutted and modified to work as a power supply base.

I bought these last year for use as a power source for a DPH3205 buck-boost power supply module.

On the positive side:

• both packs use Samsung INR18650-20Q 2000mAh cells - 2Ah 5S - 4Ah 5S2P
• 15A continuous discharge current for 2Ah pack
• 30A continuous discharge current for 4Ah pack
• 12.5-13V dropout voltage
• Measured capacity reasonably close to rated capacity - 4Ah - 80Wh claimed but cells rated 72Wh - 65Wh measured at 5A draw
• Reasonably slow voltage drop over discharge range
• Onboard battery charge and discharge protection
• Percentage capacity remaining display

On the not-so-positive side:

• Uses a generic microcontroller for the BMS so there is no way of telling exactly how it works
• No individual cell monitoring or balancing
• 4Ah battery pack drops out at low discharge current draws

The low current draw dropout behaviour of the 4Ah battery pack is strange.  Below 350mA, the battery will shutdown after a couple of minutes and needs to be totally disconnected and reconnected to restart it.  Between 1A and 350mA, the battery pack will dropout for about 200ms before restarting automatically. Above 1A there are no dropouts.   The 2Ah battery pack doesn't exhibit this behaviour.  I've sort of minimised the problem by stuffing a couple of 33000uF caps into a gutted charger base along with a couple of diodes and charge rate limiting resistor.

Title: Re: Aldi 2Ah & 4Ah LiPo Battery Packs
Post by: DeanCording on April 17, 2018, 04:28:46 am

A 3d printed connector for these batteries is available from https://www.thingiverse.com/thing:2770920 (https://www.thingiverse.com/thing:2770920)

Title: Re: Aldi 2Ah & 4Ah LiPo Battery Packs
Post by: wilfred on October 07, 2018, 10:54:56 am

I found some Aldi stores near me in Eastern Melbourne have these, 4Ah $30 and 2Ah $20 and chargers $15
Forest Hill had several dozen.

When does Aldi tend to reduce prices on clearance items?

Although I don't know why they need to clear them if they regularly sell skins of various tools.