How to increase battery capacity?

[MPBK]

The batteries in this car is way too small.
To give you an idea, I go down a long hill (batteries are fully charged at the bottom) and then take a somewhat steep up hill. The charge is gone half way up the hill.

I think doubling the battery capacity would be about right for this car.
Is it as simple as connecting another set of batteries in parallel to the existing ones?
Anyone has done that and can share experiences and tips?

[Eli]

Enginer PHEV.

[retepsnikrep]

There are quite a few threads on here about increasing gen 1 battery capacity with lithium and parallel cells. If you have the skills etc perhaps you can transfer those type of mods to the I2. The threads should certainly give you some food for thought. Try a few searches.
Eli has mentioned the enginer phev kit which is for the G2. That's an option.

[drosky]

I'm going to bump this thread because I have a very similar question. I just bought a 2012 Insight and I'm new to this forum, and so far I have read through only a portion of all of the previous threads and posts on battery capacity and such (there are a lot of them ).

To me, this topic breaks down in to two scenarios:

1. the PHEV scenario, where the goal is to increase MPG (and accel) under all driving conditions by essentially using stored energy provided by charging an extra battery at home from the grid. This is great for people who want increased MPG under all conditions, but it is a fairly expensive option because in addition to an extra battery, there is is an entirely separate bms, power converters, etc., and the system must be charged from the grid each night.

2. A simpler scenario, where a user, such as myself, is happy with the nominal 50 MPG or so that is obtained under "normal" driving conditions, but who lives in a hilly area where the IMA battery constantly "full cycles" and runs out of assist on even moderately long hills, resulting in reduced fuel economy. The battery then fully recharges before the end of the next downhill stretch, wasting a lot of regen potential. In this case, a simpler, and hopefully cheaper, solution would be to just add pure battery capacity and not a full PHEV system.

Basically the idea would be to just parallel extra battery capacity, and still use the IMA's existing charging, discharging, and bms capability. The idea isn't to increase the nominal MGP, as with a PHEV system, but just to enable the IMA to assist the ICE over the larger ups and downs encountered in hilly areas.

Again, I haven't read the entire back history of all of the threads yet, but has anyone heard or seen any more on this in the year since the original poster started this thread? I'd be very interested in this. From my limited reading, it seems like with some work, the actual terminals of the HV battery are available and it might be possible to parallel an external battery, but I am probably greatly oversimplifying the difficulty of actually doing it

[2Slow4u]

There is a great big thread out there about people increasing capacity with 20Ah A123 cells.

[Cobb]

Long answer short you can rebuild the pack with higher capacity cells. All you need to do is make a new case with cooling, a fooler so the ima system uses the larger capacity and a BMS to keep the new cells healthy.

I think you can just upgrade the cells to larger capacity, but with that investment you want to protect and extend your investment as these things seem very temperamental and all it takes is one bad or not fully charged cell to trigger a charge cycle.

[drosky]

Originally Posted by Cobb

Long answer short you can rebuild the pack with higher capacity cells. All you need to do is make a new case with cooling, a fooler so the ima system uses the larger capacity and a BMS to keep the new cells healthy.

I think you can just upgrade the cells to larger capacity, but with that investment you want to protect and extend your investment as these things seem very temperamental and all it takes is one bad or not fully charged cell to trigger a charge cycle.

Yes, I realize that just adding cells in parallel with the existing ones was an oversimplification, but I'm hoping there is something between the full PHEV solution and doing nothing. I will look for the aforementioned thread on the A123 cells, I appreciate pointing that out (hope it's I2 related, not I1). I always try to search forums before posting, but boy, there were so many threads on batteries, and they often diverge after the first post or two. I appreciate having a few extra terms to search on.

This is the first hybrid I've owned, and so far I really like it, but based on my experience in this hilly area, Honda's choice of such a small capacity battery causes a lot of the potential of the IMA motor to be wasted, especially since there is still plenty of room under the rear deck of the car. It seems a shame that so much of that room is filled with styrofoam

[Cobb]

Actually the least you use of the hybrid system the better your mpg. Honda increased the battery size in the civic and it didn't work. That's why we and the crz have the smaller battery.

The way you cheat the system is by charging the pack outside of the ima system.

[drosky]

Originally Posted by Cobb

Actually the least you use of the hybrid system the better your mpg. Honda increased the battery size in the civic and it didn't work. That's why we and the crz have the smaller battery.

The way you cheat the system is by charging the pack outside of the ima system.

Yah, I pretty much believe that after observing how it seems to work. Without outside energy, the absolute max fuel economy is always limited by what the ICE can deliver on a perfecty flat highway at a constant speed. All the IMA can do is get the average economy closer to the max by allowing the engine to operate in an efficient zone more of the time and recovering some of the energy lost in braking and deceleration. If you just increase the battery, that equation doesn't really change. I wasn't really thinking it would improve MPG, just help it hold assist on longer ascents and descents, but maybe that doesn't really even matter beyond a certain point, since on long, steady ascents, the CVT will ensure that the ICE is operating at the maximum possible efficiency.

So yes, if you can keep the SOC consistently higher by bringing energy in from the outside, you will get more assist and better MPG, and that's what the PHEV units do, I just wish they didn't take up such a large part of the already limited cargo space

[Cobb]

Its not like we can add a container under the car and fill it with liquid energy..............

I had my charger die and drove around with the insight with all its own electrons on board. There is a gap or jerk when the ima checks out and lets the engine take over and it does the regen thing.

Ive tripped the ima system and it instantly bumps the rpms a thousand, however the hand off when the ima system decides to recharge could use a bump in rpms.

I still stand by my original theory that if you decide to drive the car inefficiently, the ima system decides to use this excess engine output to recharge the battery.

If you drive any of the prius it does this weird thing where it charges and assists all at the same time or so it looks like. They got the E CVT hand off down pack so its not that noticable at all as it switches between engine, assist and regen all at the same time.