Alternator delete with regen braking modification for better MPG

[Daox]

Alright, I got the meter. I'm trying to figure out where to put it. I think I'd like to 3d print a small bracket and slap it up under the HVAC controls. Its not critical to have it in my field of view and there isn't much room up by the gauge cluster. I also don't like slapping gauges on top of the dash.






Does anyone know of some good double sided tape that will hold up to summer heat? I know there has to be good stuff out there, I just don't know what to look for.

[MetroMPG]

Look for "mounting tape". I have used some Lepage's brand inside my junky Miata, and it hasn't peeled off in the summer heat. It's super sticky and the package describes "50 kg of holding power" (if you use the whole roll, which is a few metres worth).

[Daox]

I got the new amp hour meter installed today. It seems to work very nicely. However, I was quite disappointed that it does not handle the regenerative braking / charging the way I would have liked. It simply adds ANY current to the totals on the gauge. It never subtracts them. No matter what way the energy flows it adds.

It should still work for my purpose, just not as well as I had hoped. Here is a short video showing what I mean.

[Daox]

I did make the commute with the new gauge installed this morning. I learned a bunch of interesting info:

1) Power usage:
- 2A with they key in the ON position
- 6.5A with the engine running
- another 2A for running lights
- more testing to come on this...

2) The alternator can indeed spit out it's rated power, at least briefly. The highest I saw was actually 91A for a short period. I'm not sure what kind of continuous power it can output, but that is of little concern for my setup. When things are more setup, I plan to get some video of things working. It's too slapped together right now to do so.

3) The Mirage is pretty darn efficient when it comes to power use IMO. I figured that it would use a lot more power with being a newer car. If I am using 7A on my 30 minute commute, that means I only have to regen/charge 7Ah a day. That is not that much energy. I highly doubt it can all be done by regen, but with a small solar panel I am sure I could get away without plugging in to charge under most circumstances.

[Daox]

I reset the amp hour meter before heading home today. I opted to not use any regen just to get an idea of how much power I actually use on my normal commute. I will say this is a very ideal case. I ran no accessories at all, no fan, no headlights, etc. This is how much electricity it takes to run the car, period. I also used P&G which reduced usage further.

The voltage is reading high because for whatever reason on the last little bump start kicked the alternator on for some reason beyond me at this time. That actually kicked it up from around 2.5Ah to 2.7Ah.

[Mitz]

I got the new amp hour meter installed today. It seems to work very nicely.
...

Daox .. how and where'd you put the meter shunt into place if I may ask?

[Daox]

Great question. I haven't had a chance to post all about the install yet. Here is the shunt setup.

[MetroMPG]

Could you possibly put the meter on a switched line so it only counts regen current?

[Mitz]

Could you possibly put the meter on a switched line so it only counts regen current?

IMO that would complicate things. The simplest would seem to use a meter w/ a Hall sensor instead..


https://www.aliexpress.com/item/33012844858.html

you'll have to locate and identify the alternator charging output wire and put the sensor onto that wire.

[Daox]

I would really rather have a meter that counts up and down based off of use and regeneration / charging. There has to be a meter that does both. For now though, I'll probably stick with what I have and focus on getting the operation of the regen working the way I want.