The SGII may not be using the same data as the OEM gauge put out by the PCM. However, the OEM gauge cannot be adjusted to the actual gas used from the gas pump. The SGII can be adjusted to better match the gas fills. My '09 FEH Tank gauge is ~4% high and I can reduce that % with my SGII.

GaryG

 

I don't have the SG-II, but based on my reading I believe this is reason the SG-II is better. I have a 2009 MMH without Nav. It displays the average MPG since the last reset. I believe the SG-II gives you several other items - Instant fuel economy - which would be useful when fine tuning your driving, average MPG per day and per tank as well as the state of the hybrid battery charge. It also makes a lot of other information available.

As others have mentioned, it appears that it can be fine tuned. My MMH seems to indicate about 1.5 miles better than what it actually gets. Being able to fine tune it would be nice.

There are a lot of reviews on Amazon, I would suggest browsing their reviews. I'm still debating whether one would be worth the purchase price.

 

I don't own a FEH just a FE! I'm not obsessed with MPG. I've read in a few different posts about watching your SOC of the battery pack for overcharging. You mean to tell me that a FEH can overcharge the battery pack? This is something that you have to constantly watch???

 

Could you produce the "source(s)" for this incorrect statement in the FEH?

 

Sure, this thread, last post: https://www.greenhybrid.com/discuss/...tml#post202149. Seems like I've seen this mentioned before but not sure if was mentioned here more than once though!

 

I believe there is a subtle but important difference in the term "making sure not to overcharge in L" and actually overcharging the HVBattery. I'll let PravusP clarify for you but,

When using the most advanced hypermiling techniques it may be advantageous not to "over use" the "L" mode. (or not to try and put more charge in the HVBattery than the software wants to)

At all times, the PCM controls and prevents actual "overcharging" of the HVBattery - which in the case of the FEH actually means going over a value of approx. 60% in the State of Charge (SoC).

that's my guess on where the mis-iterpretation occured.....no FEH owner has to drive around worrying about overcharging the HVBattery

 

I think he meant that you should not attempt to put too much charge into the battery, because at a certain point the software will not allow any more charge, which changes the performance characteristics of the FEH - and you want to know the characteristics if you are hypermiling. I myself do not hypermile, and I don't worry about excessive levels on the SOC.

The end user cannot undercharge or overcharge the battery. The basic limits are about 32% to %66 on my 2008, but generally it stays between 40% and 60% (The 2009 has a wider range under normal operations).

 

If it's not possible for the end user to under/over charge, why is it mentioned at all? If the pack is only kept at 66% max there's lots of room for error! Any talk of Ford going to a Li-Ion pack? It's much simpler to charge, no voltage depression to deal with and should be able to maintain >90% charge.

 

There is a difference between the user doing something harmful to the battery, and a hypermiler trying to make the most MPG out of the system. Let me reiterate that the driver CANNOT cause harm to the battery.

The 66% is an extreme, I've only seen it once. Generally the SOC will max out at 60%.

Don't mistake the technology. An NiMH battery can hold 100% of the charge, but all of the hybrids keep the charge/discharge lower because the battery lasts longer. It is not a matter of capacity. Under federal laws, the hybrid battery has to last either 8 or 10 years, depending on the state in which it is bought. The manufacturers have to eat the cost of a replacement battery if it fails early, so they are very cautious in their engineering.

As for LiIon, these batteries, under current technology, require a long time to recharge (or they overheat), and they have a somewhat limited charge/discharge cycle. For my laptop battery is was 500 cycles (the same for my mobile phone), but newer batteries may last longer. After a certain number of charge/discharge cycles, LiIon batteries begin to lose their ability to retain a charge.

 

The preferred state of charge for the hybrid battery is 53%. This is when the MG1 stops charging the hybrid battery and further gains in it's state of charge (SOC) occur thru regenerative braking. This is the largest SOC (68.6) I have experienced during normal driving:

GPSMan1 has obtain a high 70 reading. It is correct the SOC range is limited for durability purposes. There are 22 know Escape PHEV vehicles
running around in the country for fleet testing. This does not include how many Ford has in their headquarters. The electric Telsa only allows charging up to 95% capacity for durability reasons.