Thread: Low cost BMS
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Old 07-08-2011, 05:31 PM   #12 (permalink)
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Originally Posted by sawickm View Post
What type of battery does your BMS work with Lion or SLA? Both would be nice, most DIY'ers can only afford SLAs. All of the BMSs on the market are only for Lions.

It would be nice if you could also interface your master controller to "Adam's" open source 6Kw charger

It would be great to see a ReVolt open source Motor Controller, DC Charger, BMS, and LCD Display all connect to each other as a complete system !!!

It is designed for Li cells - they are what I am using and they are far less tolerant of abuse than SLAs, so a BMS is an imperative.

I could easily make it work with single SLA cells though, its just a software modification as the micro will work down to 1.8V quite happily. But SLAs are not usually used in single cell configuration, you just buy a 12V battery - attaching a board to each cell might be a bit tricky.
Having said that, I'm sure there are people out there who could do it!

I can't see much point in using a bms that doesn't monitor individual cells ie just looks at 12V batteries. Its a lot of trouble and expense to only do 1/6 of the job.

Maybe I'll put something in the s/w so the user can choose either SLA or Li, if there's any interest shown. Its only a matter of changing the range the ADC works over and altering the master s/w to suit.

I have a description of the way the whole thing works, but the .pdf file is way too big to add here as an attachment.

Unfortunately, Adam's charger design is quite illegal in most countries, including this one (New Zealand). I'd be surprised if it was legal in the US, but you never know!

My charger interface comprises a pair of normally open contacts and that is pretty universal in that you can make it work with anything.

As I said, it is my intention to modify the Cougar LCD design a bit and incorporate the bms master function into it, so that will be a big step towards having an integrated system. Initially, I am doing a stand alone version to make sure everything works as expected and to cater for those who don't have/need/want the Cougar LCD.
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