LiIon solar charge controller with load output regulation?

pack

That's what we have right now.

Those usually are not able to follow the precise charge regimen for LiIon batteries. The end-of-charge voltage for LiIon must be accurately regulated. It's only a small band between not reaching capacity and

*KABLAM* :-)

Also, LiIon has a much wider voltage range over the useful discharge range. 3-cell is too low in voltage at end-of-capacity, 4-cell is way too high when full.

6-cell lead acid is what we have right now but the gripe is that it makes the whole unit too heavy to carry.

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Regards, Joerg

http://www.analogconsultants.com/

It's not all that difficult, today.

That's why they make buck/boost regulators. ;-)

SLACs are nice but have a fairly low power density.

I figured you were going to bring weight into the discussion.

Yes, if you want to use LiIon cells then your life gets more difficult.

Somewhere out there on the web is someone selling a LiIon battery that's supposed to be a form-fit-function replacement for a 12V car battery. I'm not sure how they're doing it (I suspect on-board electronics), but if you're lugging more than one car battery now, and you can get the capacity you need from one of these gizmos, then it may be your meal ticket.

Particularly if they have a motorcycle version...

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www.wescottdesign.com

Where, where? :-)

We'd need something between 25Ah and 30Ah, 12V. Unfortunately the power hardware is picky regarding those 12V. Especially some of the motors really lose steam when that drops to less than 11V. And a 3-cell LiIon will, big time.

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Regards, Joerg

http://www.analogconsultants.com/

I know, but we are looking for a fairly cheap off-the-shelf solution. Figuring that we can't be the only one with such a wish. Although the

20A peak power requirement is unusual, outside the normal camping utensil range.

Sure, I could roll my own but the client would rather not want to do that. Then you have to go through engineering phase, all new EMC, and all that.

Wot's a SLAC? I guess you don't mean the National Accelerator Lab :-)

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Regards, Joerg

http://www.analogconsultants.com/

SLAC == Sealed Lead-Acid Cell

Ah, thanks. But that's what we'd like to get rid of, on account of its weight.

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Regards, Joerg

http://www.analogconsultants.com/

Maybe you'll have to go with 4-cell and drop some volts on the load side. Inefficient, sure, but it'll get around the voltage "mismatch".

That would be my choice, use a sync buck on the load side. But that part of the product is done and they don't want to change it.

Also, all the controllers I found so far only supported 3-cell LiIon :-(

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Regards, Joerg

http://www.analogconsultants.com/

Hi,

I found these ones, look pretty cool:

cheers, Jamie

Thanks, Jamie! Those look promising, will inquire whetehr they are reasonable in cost and can work with a solar panel.

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Regards, Joerg

http://www.analogconsultants.com/