Florabest hedge trimmer battery

[Andrew Middleton]

I have a florabest hedge trimmer. When trying to charge the battery it starts off red and after a few minutes it starts to flash green and red. Is the battery dead?

[newshound]

That's typically a sign that the charger has decided not to continue. What type of battery is it?

[Dave Plowman (News]

That is normally some form of cell equalisation. Does the display eventually change to something else?

[Paul]

This isn't the device in question. It'a a Florabest 40V pack and charger. It's Lithium and Samsung cells. The pack is equipped with a fuse.

Reading the chip number off the 20 pin TSOP, and looking up that part and its datasheet, may give various codes it's capable of delivering. I can't read the chip number via the video. I got a high res video and that chip is glossy and clean, not a lasermark in sight. Not even signs a cretin sanded off the part number. Just... no number.

PSU +--------------------+ +----------+ | Button| | Red |--------| Pack LED| Fuel | |--------| 5*18650 LED| Gauge | |--------| Charger IC ??? LED| 25% increments | Green | Shoe | LED| +----------+ +--------------------+

The PSU is the one flashing codes. Does that mean the PSU is overheating or weak ?

The pack has a Battery Management IC chip, which should control charging in CC and then CV mode. Unless there is a clever serial bus on the third pin of the shoe, I don't see how the PSU is easily going to learn what the Battery Management chip thinks about the whole process.

The printed circuit board in the PSU is labeled COM BAT+ BAT-, implying no serial link on the shoe.

The PSU can tell, from current draw, what is going on. Zero current is "charging complete". Finite current drawn is charging. You could flash a green LED for that. If the PSU is smart, I don't see anything on the single sided PSU PCB (cheap!) to handle the smart aspect. It would seem the PSU is dumb as a post. Consequently, I can't even see it flashing a green LED or a red LED on its own.

If they wanted charge status, they should have moved the PSU red and green LEDs, to the pack.

I would have to guess the PSU has a problem. It is fan cooled, using a laptop fan motor. The fan is pointed at the SMPS heatsink. The PSU printed circuit board has two halves. The mains front end is one half, and has a bridge rectifier on its heatsink. There are some filter components on the mains side, for preventing noise-on-mains.

The SMPS is the other half of the PCB. There really should be a chip for controlling the Switch Mode Power Supply, but I don't see it. The switching element (MOSFET???) is bolted to the heatsink that the blower points at. Don't be rough on the fan, as fan bearings can be sensitive to abuse.

Usually, if heatsinks get too hot, there is a thermal cutout. That could be why the red LED is flashing. Check and make sure the cooling fan still rotates. The cooling fan has two wires, and has no third wire for RPM or seizure output.

The video is a bit deceptive, because the videographer removed the cable from the shoe half of the PSU casing which runs to the PCB. The video makes it look like the two halves of the PSU come apart easily. When actually, the cable must be removed when the two halves are ajar. And the cable must be carefully returned to its mate, while reassembling the unit. The cable is keyed and only fits on one way, at the PSU PCB end.

It's possible your 20V unit is designed a similar way to this 40V one. Just a guess.

Paul

[fred]

WelI done Paul. I like a man who knows what he is talking about