As soon as someone gets hold of one of these, I'd love to see the inside of it, especially the shunt, because I have a way I'd like to use such a meter that I must be able to replace that shunt with a different one:
What I want to do is have a "fuel gauge" for the pack Ah that counts up to the full capacity as I charge up the battery (it's ok if it's a negative number), then counts down to zero as I use it up. It ought to be easily possible with the Cycle Analyst, AFAIK, but I don't know enough about this one to tell if it would work.
The only three requirements are that
A) I can use my own shunt
B) the meter will read regen current as negative
C) that it will go into negative Ah
If it won't do C) I'd have to reverse the current thru the shunt so it reads negative during *use* instead of during *charge*, which is fine with me, but it does still require that it will count backwards as regen current passes back thru the shunt.
I have to be able to use my own shunt because the charging shunt is different from the discharging shunt, so that it makes up for the fact it takes more power to charge the batteries than I get back out of them. Like the old electromechanical EV meters from early last century.
I'm working on a way to do this electromechanically with recycled parts, but haven't got the idea worked out yet. If I can do it in one of these meters, that would be great, once I can afford one, as it is likely to be more reliable than my own contraption.
Basically I don't want to have to "know" how much power a particular pack has in it, and subract that out manually for myself. I want it to count down automatically. Sure, I know it's not fully accurate, because of Peukert effect (especially with the SLAs I use), but it is easier than the other method.
I experiment with different packs sometimes, built of different combinations of different sized SLAs, and I don't want to have to remember which pack is on there which time. I want to just stick the appropriate charging shunt in there (if more than one is needed, which is likely), rundown the pack, recharge it, then go do whatever testing/riding/etc. and be watching it count down to zero on it's own.
One advantage of this kind of metering system is that since the batteries aren't ever fully discharged, I'm only metering what I put in, so that while I might indeed have power left when I get to zero on the meter, I can plan my trip and driving/riding style by the amount it *shows* I have left.
Using the idea of resetting the Ah usage meter as it normally would be used by most people, whenever starting out on a ride with a fresh charge, then keeping in mind the "known" capacity of the pack, and subracting as you go, may end up wrong easier (for me, anyway).
Better to think you're running out of gas and have half a tank than the other way around!
