Adding regenerative braking to the Mirage

[Daox]

I do not have the Amazon meter yet. It should be here in day or two though. It will definitely help shed more light on how well this thing works.

That being said, there is a decent hill right before I turn into the industrial park at work. Of course the turn is right at the bottom of the hill, so it's often that I DFCO down it. Today I flicked the alternator on during the decent. Wow, I actually noticed the braking power. I was surprised that it was that noticeable. As we have mentioned, it is probably only providing about 1hp of braking power. I am not doubting that, but the fact that it's so easy to feel.

[Ecky]

Originally Posted by Daox

I do not have the Amazon meter yet. It should be here in day or two though. It will definitely help she'd more light on how well this thing works.

That being said, there is a decent hill right before I turn into the industrial park at work. Of course the turn is right at the bottom of the hill, so it's often that I DFCO down it. Today I flicked the alternator on during the decent. Wow, I actually noticed the braking power. I was surprised that it was that noticeable. As we have mentioned, it is probably only providing about 1hp of braking power. I am not doubting that, but the fact that it's so easy to feel.

I'm imagining the braking power will likely be larger the lower your battery voltage is? A larger delta between alternator voltage and battery voltage?

[Daox]

I would guess that too. When I pick the alternator on, it kicks the voltage up to 15v. So the larger the voltage difference the more amps that will flow. The ammeter will show us just how much though. Looking forward to testing it out.

[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.






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.

[Daox]

I got the new amp hour meter installed today. It seems to work very nicely. I have not tested it against my other ammeter yet.

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.

https://www.youtube.com/watch?v=XZNt...ature=youtu.be

[mpg_numbers_guy]

I wonder if it's possible to hook up two of these (or two simpler units) to measure amps in vs amps out, by connecting them to your alternator switch - so one unit measures power draw when the battery is discharging, but then when the alternator is on the other unit is measuring power put back in the battery.

Was looking at an amp-hour meter today - https://www.amazon.com/AiLi-Battery-...dp/B07CTKYFTG/ - that might better indicate what's going on; you could compare the ah in your battery before and after a trip to see what your net gain/loss was. That in conjunction with your current instrumentation would provide a better idea of what is going on. It's a bit more pricey ($39) but less than comparable meters (the Victron one is $200 ), and one could always return it if it didn't work.

If only I was back home and if only my current 12V wasn't only a year old; this thread is making me want to do an alternator-equivalent delete on my car!

[Daox]

I believe another of these gauges would work if you put one on the cable from the alternator. However, I would much rather have one gauge that works the way I would like. It seems from the description that the gauge you posted would do this.

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.

[Piotrsko]

Batteries aren't 100% efficient. You'll need about 10-12ah to recharge 7ah use. And this is on the main battery lead including the starter circuit?

[Daox]

Excellent point about recharging.

Yes, the ammeter shunt is right off of the negative battery terminal. All power use goes through the shunt. I even moved the charger wire to go through it after taking the picture.

[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.