REVIEW: Hymotion Battery Plug-In Prius

Have you used the ScanGauge to check what the traction battery bus voltage is just before starting out in the morning when the Hymotion pack is fully charged, and along the way as the SOC drops?

 

TheForce,

Would you say the P&G technique is more or less efficient while operating in EV mode on a Grid charge, than it is when you revert to normal hybrid mode, where we know it's a highly efficient technique?
Would a different technique be more efficient while on the Grid charge?

 

IMHO P&G is not advised in all electric mode. Avoiding brisk acceleration (or pulsing) would be advantageous. Otherwise, the usual avoidance of deceleration would be key.

 

Hey TheForce,
Thanks for posting your experience with the Hymotion mod...very encouraging/motivating!
Do you know anything about the solar mod by SEV (Solar Electric Vehicles) and if it could benefit/compliment the hymotion upgrade? Seems like they'd go great together. Any info would be great.

Thanks!

 

I was wondering the same thing. For $2,000 it would be a great way to extend all electric or super hybrid mode...

 

I would agree, at something like $2k it might be worth while. They claim 215W output. In most places you'll do well to get ~5 "peak sun" hours per day, which would put you at ~1kWh charging per day. To get a better number you can use the site below, pick your location, put in 1kW, set the derate factor to 1.0 and set the tilt angle to flat (0). Take the annual output, divide by 365 to get the average daily output and multiply by 0.215 to size for the system. For Phoenix, AZ that gives me a number of 830Wh per day. Realistically you will lose a little more for charging efficiency but we'll ignore that for now. The Prius seems generally agreed to use between 200-250Wh per mile depending on speed, so the 830Wh would give you an extra 3-4 miles of EV range per day. To make use of this you would really need to have a situation where you deplete your supplemental battery enough on your morning drive that you can store that much power to use on the way home. Assuming you got 10 years of use out of it, at 4 miles per day you'd get 14600 miles out of it. For $2k that would be about 13c per mile, more expensive than gassing a Prius currently, but not too bad.
PVWATTS v. 1

The problem is that as far as I know SEV is not in production, they are asking $5k, and they only sell it in combination with their own battery pack which is not grid chargeable. Last I knew they had not responded to anyone's requests about possibly purchasing the panel by itself.

I think most folks have concluded that you would be much better off putting solar panels on your house to offset your home charging. That works out to more like 2c per mile from what I have seen. As an example:

20 miles per day EV range = 7300 miles per year
7300 miles * 0.3 AC kWh/mile = 2190 kWh/yr
2190 kWh/yr / 1600 AC kWh/yr / DC Rated Watt = 1.37 DC kW Solar Required
Upfront Cost =~ $7/DC Watt * 1370 DC Watt = $9581
Rebates and incentives = -$7106
Net Solar Cost = $2475
Warrantied System Lifetime = 20-25 years
Net Cost per mile = 1.3c - 1.7c per mile

Assuming gas costs an average of $4.00 per gallon for the next 20 years, the annualized ROI for your upfront solar investment would be 15.65%. If you assume gas starts at $3.50, and goes up 2% per year for the next 25 years your annualized ROI goes to over 21%. My guess is even the second case is conservative.

Rob

 

Great info, thanks!

I called them and they emailed me this PDF file which was very helpful. They said that the panels are in production and there is a waiting list (2-4 months) at this point so they're taking deposits ($500).

$3500 solar panel alone
$4500 with battery
$7200 with plug in option

 

i dont get this

"(’04 model) 240 VDC, (‘05

-’08 models)

288VDC, 3.8kWh Battery Storage for the​

plug-in PV system"

i think it needs to be.

"(’03 model) 288 VDC, (‘04

-’08 models)

240VDC, 3.8kWh Battery Storage for the​

plug-in PV system"
​

​

 

Cool test, and very cool pic! I think there is one of two things going on here. They are either moving the spoofed SOC around based on conditions (as I believe cal-cars does), or more likely they are decoupling the spoofed SOC and CDL/CCL. As long as the charge/discharge limits are high, I believe the HV controller will keep putting in charge or taking charge out. I think its up to the Battery ECU to decide when to lower the limits (if they're not being spoofed too) and it wouldn't care about the spoofed SOC, only the real SOC of the oem pack.

Rob

 

NICE

 

The Force, could you describe how much fan noise you hear when your pack recharges? As you know, I'm getting partial recharges. Happened again last night, after a hot day. So I'm leaning toward heat as the problem again.

When mine charges, there is a just the faintest whisper of fan noise and it's clear that the batteries are not being cooled. It's quieter than the quietest PC I own. This is after opening up the hatch and pulling up the floor. Ad as far as I can tell, there is no air movement out of the exhaust duct. The pack is drawing air in the quarter-sized hole below the battery casing (you pointed this out as an air intake in your original post). But that can't be the only air intake for cooling the batteries -- the exhaust duct must be 10 square inches in cross section, that hole looks like it might be a square inch total.

When I talked to Hymotion, I got conflicting answers on whether or not the batteries are air cooled during charging. My pack definitely does not do that -- at least not to any appreciable degree. I was just wondering whether you hear something that sounds like a fairly substantial exhaust fan running, and whether you can feel any air coming out of the exhaust duct as you charge.

 

TheForce,

Thanks for the data on regen. I still think the topic is unclear, but bit by bit ..

Can you calculate the potential energy on your downhill cost ? I'm keen to get a semi-quant feel for how much regen is possible.

 

I wasn't clear. I meant wheel to battery regen efficiency

 

Thanks, I was afraid of that. That probably means mine is charging as designed. It's just not going to do a full charge in one pass with a hot battery. And if I try, it'll hit some temperature-determined safety limit. That's not a good situation. I'll post here if I hear anything more from Hymotion.

 

It may not be good that your system is hitting some safety limit. However I think it is a really good thing that the system is shutting down WHEN it does hit that safety limit
Keep at em, let us know how it goes.

P.S. One other thought, if you think it may be a combination of your house wiring and heat, can you plug it in closer to your electrical panel?

 

chogan2, are you able to monitor your hymotion's battery SOC as you charge ?