stevecolletti

What does the battery do if it is discharging (while driving) due to an alternator or other charging issue?

I'd hate to have the battery just shutdown the car while driving.

mikymu

Sound great. Will let you know if they like to do a group buy or track season special

mikymu

So you are saying what happen if alternator dies? Well, the battery will drain very fast since it has smaller reserve compare with OEM. I can't say how long it takes to drain your battery. It all depends on what's running at the time. OEM battery will not last long either in that situation

stevecolletti

Thanks, mikymu, for the tutorial and the info.

Do you know if the 'intelligence' will still shut the battery down with a reserve, or without, though? I can certainly imagine situations where I'd like the choice.

I'm interested in a group buy in any case.

Robert Linton

Have had two years of good experience with old models of Voltphreaks batteries. Just ordered two of the latest models with the protection features.

GTEE3

mikymu,
great write-up, and discussion!

russo

Awesome information, next item on my list to do.

mikymu

I believe the battery will shut down with reserve so you can always start your car back up again

That's great to know and the protection features are a must for our car

any time!

Sounds great. I have no affiliation with Voltphreaks but will pass on info if they have a sale or group buy

vph_tony

Tony from Voltphreaks here. The shutoff can be choosen at time of purchase to be with reserve, or when the battery is completely empty. With any small battery though, you don't get much runtime. (Making these numbers up as it depends on the car, electronics, etc) for example taking the VPH750 running after alternator failure, if the higher cutoff setting (with reserve) gives you 25 minutes of runtime, the lower cutoff setting (letting battery drain completely) might give you 30 minutes of runtime. If the VPH750 was set without a cutoff, which is what happens with a lead-acid battery, you might get 30.5 minutes of runtime (this will ruin a lithium battery, and damage a lead-acid battery).

Most professional racing teams are using the VPR-S40 with 31Ah, and the shutoff set to shutoff the battery when it's completely empty. Some non professional racers choose the shutoff with reserve setting, while others choose the shutoff without reserve. You can't switch between the two. Having a reserve is very handy because it avoids a jump and/or carrying a spare battery around, plus alternator failure is not something that happens every day, and even if it does, the additional runtime (30 minutes versus 25 using the example above), while helpful, may not matter, since your car will not run on battery power alone for long anyways.

Note that without any sort of shutoff, a standard lead-acid battery after a short time will still run out of power and "shutoff".

Another concern of the shutoff for many users, that they will lose their memory settings, etc, and that this issue won't happen with a lead-acid battery that doesn't contain a shutoff. That's not true, since without a shutoff, you'll still lose memory settings if you let the battery completely drain. It is true that with the shutoff, you may be able to park the car for 3 weeks, while without the shutoff, you might be able to park the car for 3 weeks and one day. What the shutoff does (when it's set to shutoff with reserve) is reduce the time very slightly that you'll be able to park the car before you lose memory settings anyways.

mikymu

Tony, thanks for the clarification. Another note is the comparison between Odyssey PC680 battery and VPH750. In order to get the equivalent of the VPH750, you need a 24 pound Odyssey PC925 instead of the lighter PC680

stevecolletti

Thanks, Tony.

I think your default setup is great for the RS, where the car is relatively new and electrical is fairly trustworthy.

We've owned a few vintage cars and have had some screwy electrical problems over the years, so I wanted to understand how this protection scheme would effect them. I usually use Odyssee batteries in them due to their weight, deep cycle and long-term storage (when kill switch enabled).

For that application, I'd probably want the battery to act as it does now, not allowing the car to start if it was below a threshold, but allowing it to fully discharge (if necessary) when the engine is running (though I'd like some sort of indicator that it has hit the threshold).

Thanks

mikymu

Rad aka NJ-GT gave me a good suggestion that I should put some form of cover between the Li-ion battery and the fuel tank below just in case something happen to the battery that it won't damage the fuel tank case as shown below.



It's a pretty easy mod. You can get a thin aluminum sheet form your local hardware store. Trace out the shape of the heavy OEM battery tray and cut it with a metal sheet cutter.





Test fit the aluminum sheet and I wrap the sharp edge with door edge molding





Finally I cut out a none slip plastic mat from Lowe's for the aluminum sheet and the cover between the Li-ion battery and the fuel tank case is done

Erik

Now that you've had the battery for a little while, any issues yet ?. I tagging this thread and as soon as my original battery dies, I'm following you into the lightweight class

mikymu

No problem what so ever. I could park my car for 1 week without trickle charger and no issue

TRAKCAR

Again great DIY pictures from Mikymu. Thanks, you're a handy guy!

Erik; The light weight batteries are good for 0.2 seconds at least..