though if you're using this in a standalone config (just using the alert pin), maybe the chip would freak out. The I2C pins are open drain output, and I'd expect the host to pull them up. I agree that the pullups are a little weird. and I haven't checked to see if added resistance from said switch would throw off the monitoring. This would require control circuitry (presumably that's not an issue given that the fuel gauge tends to be hooked up to a microcontroller anyway) and appropriate read-outs as well, though. If you're trying to save money (or weight!) in a live monitoring case, perhaps it would be better to switch the fuel gauge to each cell independently, e.g. In that case I'd say it would be indicative.but still not a certainty. So if you put a monitor on only a single cell, you can't really be 100% sure that a reading on 1 cell is going to be indicative of readings on the other cells unless your balancing charger was quite recently used and indicated no problem. The balancing charger will also help indicate when such a situation is more likely to occur because the batteries end up charging/discharging differently, and you might get a new cell (or typically a whole new pack). That's a tricky question to answer, The main reason for using a balancing charger in the first place is so that you don't get, say, 2 batteries at 3.4V and 1 battery at 4.3V and everything still looking fine at 11.1V total. Perhaps somebody else knows of an Arduino-hacker-friendly multi-cell monitoring solution looking at the comments, it does seem a common request (and by looking at the lack of answers, one perhaps not yet catered to). Of course you'd have to actually be present in order to notice the red light, but you could try hacking it into input signals for the Arduino - though at that point, measuring directly seems just as sane :) It's intended for continuous monitoring and gives visual indication when a cell goes low. There's also some off-the-shelf field fuel gauges you could try, like the AKE PM3C.
However, it may be easier to dig up a protection circuit (amazon, ebay, the usual, since that's your more immediate goal.Īlternatively, you could try measuring the voltage of each cell directly on your arduino and do your own guesswork on 'charge', since that's what most of these ICs do (in a wide range of algorithms with trademarked names, though granted some also add ambient temperature and such into the mix), or just go by the voltage itself (cut off at 3.3V, 3.4V if on the cautious side). The I☬ multiplexer approach could work for you. There's a few chips from TI (probably Maxim as well) that could do the job, but you'd have to design a board around it, etc. If there is another easier way, I'd love suggestions.Īh, same project as 4 months back, then :) Yeah, I'm familiar with the RC batteries (I fly a heli from time to time) - unfortunately I don't know of anything like this product, but for a 3S (or 2S, or 4S, etc.). In the R/C world this capability is part of the electronic speed controller (ESC). I need a way to protect the LiPo from discharging too much and my plan was to use 3 of these fuel gauges and with an arduino to monitor the battery and turn off when the LiPo got too low. I mentioned earlier in an earlier post that I'm trying to make a cell phone battery charger that uses the R/C battery to recharge my cell phone. This is a good example: Īnyway thanks for the advice, haven't been able to find another similar device, but I'm not sure I'm looking in the right places.
This is usually called the balance connector. They come standard with connector that breaks out each cell so that each cell can be charged evenly. It is a LiPo 11.1v 3S (three cells in series). The battery is usually used for R/C applications. Well see it is one battery, but multiple cells.