![]() They do not control charge current, a separate charge control PCB is needed for that. These protection boards prevent overcharging and deep discharging, and also disconnect the output in case a short-circuit is detected. I bought a bunch of tiny 15×3.5 mm ones on AliExpress a while ago which are a pretty good fit for these cells, I only need to cut a bit off the tabs to ensure there is no risk of bridging when soldering them onto the PCB. Otherwise, it is highly advised to add a protection circuit. Using the bare cells like this is OK in projects that have LiPo-aware power management in the project's circuit itself. Only do this if you know how to do it safely, and while having some emergency procedure in case things do go wrong (like Big Clive's fire containment pie dish). The cells themselves are fragile pouches of chemicals, and puncturing or deforming them can lead to them heating up and possibly bursting into flames. I ordered one to see how it is constructed and whether it is a practical source of compact high-quality cells.Īn obvious advance warning: in general it is a bad idea to rip apart things containing LiPo cells. The Conrad battery proves to be of the first variant. The downside is that this circuit may limit the maximum current draw, and it will cause a faster self-discharge. The other variant has a booster circuit to offer true 9 Volts across most of the discharge cycle. This makes it a bit wrong to call this variant “9V” and it is unsuitable for some applications that require higher voltages. The simpler variant relies on 2 cells in series with minimal extra circuitry, and it can only reach up to 8.4 V when fully charged and cuts out around 6 V. ![]() I found out that there are ‘Li-ion’ variants of the classic PP3 9V block batteries. An option would be to buy an RC battery pack, but those cells tend to be bulky due to their higher current rating which is overkill for what I need. I was especially looking for relatively compact cells with a decent capacity, around 500 mAh. This is why I have started looking for a reliable local source of reasonably priced LiPo or Li-ion cells. Unfortunately (or maybe fortunately), people seem to be more aware of their environment where I live, and I haven't found such things littered across the streets yet. Surprisingly these units-despite being single use-contain rechargeable cells, most likely because it is the most cost-effective way to get the required current rating in a small form factor. Sure, one could just order cells that are shipped by boat, but sometimes waiting a month just is not acceptable and as always with cheap Chinese things, you're never sure of the quality.Īpparently a good source of cells are disposable vape units, as demonstrated by Big Clive. There are also stronger restrictions on shipping Li-ion or LiPo cells via airplanes, which may further complicate things. Obtaining cheap LiPo cells has become more of a hassle since there have been efforts to make shipping things from China less attractive.
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