Wanted - Battery Charge and Discharge Controller\Monitor

[StuartsProjects]

Does anyone know of a decent battery charge and discharge device that you can fit between a eBike battery (36V in my case) and a charger or load.

I wanted to test the capacity of the batteries for eBrompton and have tried one of these;



But it just does not work properly, the high voltage cutoff does not work and it fairly easily gets into a state whereby although there is 2A of charge current flowing, it displays 00.00A and you have to reset and calibrate it. But its cheap, £19, and I guess it could be a knock off of the real thing from Drok.

Any suggestions for an alternative that has display of voltage, current, Ahr, maybe time, and with working high voltage and low voltage cutoffs ?

 

[saneagle]

It's a lot more logical to fit one between the battery and controller so that you can see the actual usage and battery state when you're riding.

150A DC Digital LCD Watt Meter Power Battery Analyser Solar Caravan Tool UK | eBay

Everything all in one unit! This is the perfect troubleshooting tool. Works on all wind turbines, solar panels and hydro systems up to 60 volt DC input. It can also work on AC three phase systems after the rectifier.

www.ebay.co.uk

The Best Value Wattmeter

The problems with cheap wattmeters is that they require fairly heavy wiring, and they're not very waterproof. Luckily there's a solution that costs virtually nothing to solve those problems. You need one of this type...

www.pedelecs.co.uk

If the wattmeter has a single solid state shunt, you can unsolder it and put it between a couple of connectors to save making your own shunt, but you must solder the signal wire to the shunt too.

I still use those same wattmeters for testing after nearly 10 years.

 

[StuartsProjects]

150A DC Digital LCD Watt Meter Power Battery Analyser Solar Caravan Tool UK | eBay

Everything all in one unit! This is the perfect troubleshooting tool. Works on all wind turbines, solar panels and hydro systems up to 60 volt DC input. It can also work on AC three phase systems after the rectifier.

www.ebay.co.uk

I have a couple of those, they do not do what I want, hence the question.

I did write some Arduino code for that 'Analyzer' to read the commands to its LCD display so the data on the display could be sent to a serial port for logging on an OpenLog for instance.

 

[saneagle]

I have a couple of those, they do not do what I want, hence the question.

I did write some Arduino code for that 'Analyzer' to read the commands to its LCD display so the data on the display could be sent to a serial port for logging on an OpenLog for instance.

I'm not sure what you're on about, but they do exactly what you asked for in your OP.
I say again, that idea seems just plain daft when you can measure the actual battery capacity according to its actual discharge in use rather than a derived value that involves assumptions and guestimates. You only need it on the bike while testing/measuring if you're worried about it spoiling the looks.

 

[StuartsProjects]

I'm not sure what you're on about, but they do exactly what you asked for in your OP.

I wanted a device with "working high voltage and low voltage cutoffs"

 

[Bikes4two]

I wanted a device with "working high voltage and low voltage cutoffs"

• Sorry to be dumb, but when you say working high voltage, what function/functionality are you looking for here?

 

[StuartsProjects]

• Sorry to be dumb, but when you say working high voltage, what function/functionality are you looking for here?

A device that can be set to cut off the connection to the battery when the battery voltage reaches a set point.

The device in the first post does have a setable high voltage cut off but it does not work.

 

[WheezyRider]

You could use a couple of 431s to create a voltage window sensor:

https://www.ti.com/lit/an/slva987a/slva987a.pdf?ts=1686581531051&ref_url=https%253A%252F%252Fwww.google.com%252F

 

[StuartsProjects]

You could use a couple of 431s to create a voltage window sensor:

https://www.ti.com/lit/an/slva987a/slva987a.pdf?ts=1686581531051&ref_url=https%253A%252F%252Fwww.google.com%252F

Whilst I am well able to design electronic stuff and PCBs, one of which has been in Earth orbit, I was after a solution that was ready built.

I could mix and match a XH-M602 board (described in the eBrompton thread) and one of those 'Watt power meters' described above, and I have a couple on the shelf, but if there is a single unit that does it all, then that is the way I would prefer to go.