I don't know if this has been discussed before but here goes... Has anyone figured out a hack that would allow one to simply charge the limited traction battery pack in a Gen3? A lot of my driving is my commute to work, which is about 4 miles round trip, local roads, all flat. Currently I can get 35 to 55 mpg on this trip depending on whether my SOC is high or low when I start out. A full charge could get me 55 or better. Conceivably, a light duty charger, and very little electricity could boost the battery for this kind of driving. Anybody?
Check out Mike at Is it too late? I think not if we act now - MIMA Honda Insight Modified Integrated Motor Assist. He is producing an overnight charger that could meet your needs.
Hmmm, interesting, thanks, ... his site seems pretty technical and skewed towards Hondas. I just sent him an email though. I'm probably looking for something simple that doesn't exist...like a trickle charging system that you can insert into your cigarette lighter, simply to bring the standard HV battery up to a relatively full SOC overnight.
are you saving anything this way? You'll be paying to run a charge, and for the green folks, adding to your carbon footprint.
I don't know much on the Insights but it seems it's battery has less capacity than the Prius ones. Reading that the "overnight charger" supplies a bit mor than 1 Amp I doubt that this will be enough for the Prius batt. But this guy writes about some gained knowledege on Prius and he may be able to provide some good ideas for a charger that fits our batteries.
Is it worth it? It would of course void the warranty, and if done incorrectly could do some expensive damage.
8 miles a day over a months time is not going to make much of a addition impact on your wallet over trying to use a charger. The extra money to created a intelligent charger, the adapters and modifications to the Prius just would not be worth it.
Yes it's possible. Hook up a 240V DC power supply to the HV battery terminals, put the car in READY, and turn on the power supply. It needs to supply more than 2 amps to do anything (as the prius will happily eat that much just sat in READY) and the higher the better so you can keep the charge time (and therefore parasitic loss) to a minimum. 10-12amps would get you from 2 bars to 8 bars in 15 minutes or so. once at 8 bars, turn off your power supply, and shut down your car. Job done. you'll be sticking ~400wh wh into the car, the equivalent of 1/30th a gallon of petrol, you may be able to go 1.5 miles in EV mode. This is basically how the Enginer PHEV system works, using a 48VDC to 240DC converter to charge the HV pack while driving. The real trick is finding a 240V DC power supply that supplies 10+ amps. Be warned, if the car isn't in READY you could destroy your car (fire). if the car is in READY but you forget it's charging, the ICE will start to burn off charge and waste fuel/generate fumes. I don't know how quickly it can burn off the charge, so it's possible you would still be charging the vehicle above 8 bars, and this will ultimately cause a vehicle shutdown and/or fire.
My goal is not necessarily to save money. While I am concerned about carbon footprint, it is not my primary motivating force either. I just don't like sending my money to unfriendly nations in the middle east.
I was thinking of something more like a very low capacity, overnight, trickle charger...something which I know cannot be done, but something that could be plugged into the cigarette lighter. LOL
Can't speak for the GEN III, but in the GEN II, when the car is turned off, the sockets are turned off.
Your safest bet is to convert it into a plugin. With your driving distance, a gallon of gas will probably last you a few weeks. The Prius has a very sophisticated battery management system. It keeps track of what going into the pack and what comes out of the pack. It compensates for minor variables in charging and discharging. The Enginer DC converter is within that range so the car won't give any error codes when operating. The HV battery's operating SOC is 40 to 80%. Anything over or under is out of spec and can damage the HV battery. That's why when SOC has reached outside of the charge, the engine starts up to either charge the battery or discharge the battery. If you mange to rig a charger to the HV battery, how do you know when to stop charging? When you drive on electric you're running the battery from 7 bars down to 2 bars all the time and could reduce the battery life. When you convert it to a plugin, the kit charges the HV pack to 245v then drops down to 235v and only supply enough power to keep the system in ready mode. It will not overcharge the battery. Also the conversion kit keeps the battery at 6-7 bars for several miles. A cheap 2KW plugin kit is $2000. It would last a couple of days. It takes 3 hours to charge. You could probably find a used 4KW kit for less than $3000.
Don't forget...I'm only looking to charge the traction battery, once, while the car is off at night. I'm not looking to interface with the operation of the car...simply charge the pack up to start the day. I don't want to charge it up to 100%, simply to the top pip. There's gotta be a charger out there that would shut off when a certain voltage is reached, and since a slow charge is adequate, temps shouldn't be a problem. Anything can damage the car...or void the warranty. Idon't think what I am suggesting is "crazy". It's much simpler than adding a whole conversion system
Yes I get that. The concept is simple. However it's not. The traction battery is not a laptop battery where you can charge overnight. The HV battery can't be charged over 80% SOC or you risk damaging it. There are no charger out there that can monitor SOC. Most charger cut off charging when certain voltage has been reached. The voltage climbs fast when the battery is at 100% charged. 40% SOC and 80% SOC at rest are the same voltage. Also such battery charger is not cheap. Cheap ones don't last long. Installing it would be a bitch too. The HV terminal that's easily accessible has the contactor between it and the battery cells. Turning off the car disconnects the contactor. Hooking up the charger to those terminal will not charge the battery when the car's off. You're most likely have to disassemble part of the battery to get to the battery terminal. It's not worth the money and hassle just get a few mpg more. If you want to do it, do it right. Adding a conversion kit will not void the warranty. Adding a charger to charge up the hybrid battery will void the warranty. The Prius has been around in the US for more than 10 years. If charging the traction battery is possible, people would have already done it. Instead, people convert to plugin. It's proven to work.
Hi Fjpod, Flan is mostly correct. You can not trickle charge NiMh cells like lead cells. You must have the Prius computer on and monitoring the traction battery. So you need a high power charger to power both the Prius and to charge the cells. However, I think you are missing the first opportunity for improvement in your mpg. Do you have a ScanGauge? Are you watching your temperatures? For your commute you are waisting more power warming the car up than anything else. So first get a ScanGauge and do grill blocking to get the warm up done as quickly as possible. I even run my EBH when it is not real cold out to get better mpg in the first 5 miles. Thanks, Dan
Yeah grill blocking. The cheapest way to improve your gas mileage. You can buy pipe foam for $.99 a piece. You'll probably need 2.
