Solar panel to trickle charge battery when parked - Insight Central: Honda Insight Forum
 
Go Back   Insight Central: Honda Insight Forum > 1st Generation Honda Insight Forum > Modifications and Technical Issues

Insightcentral.net is the premier Honda Insight Forum on the internet. Registered Users do not see the above ads.

» Auto Insurance
» Featured Product
» Wheel & Tire Center

Reply
 
LinkBack Thread Tools
Old 09-10-2004, 01:17 AM   #1 (permalink)
Member
 
Join Date: Aug 2004
Location: Chandler, AZ
Posts: 75
Default Solar panel to trickle charge battery when parked

I know this concept has been thrown around a lot on this forum, but I'm going to be brave and bring it up again.

My plan is to place a fairly large (approx 4' x 1.5') solar panel on the front dash while the car is parked to take advantage of the intense Arizona sun out here. I figure I'll give it a go and see if it messes anything up in the IMA system. If the computer has a hard time dealing with it, then I'll be out $150 (assuming I don't permanently damage anything) and I'll figure out some way to sleep at night. In the mean time, if anybody has any knowledge about where the best place to hook up the leads into the battery circuit, I'd greatly appreciate it. Or if anyone knows a website that sheds some light on this subject (specifically hooking up a solar panel to the Insight IMA system), that'd be awesome.

Thanks!

-Dan
__________________
2001
5-Spd
64 Lmpg
Rusttree is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 09-10-2004, 07:13 AM   #2 (permalink)
Senior Member
 
Join Date: Feb 2003
Location: Laval, Québec, Canada
Posts: 830
Default

You'll need a DC to DC converter. To bring the voltage from around 12 volts to around 150 volts (not sure exactly). Maybe a search on the internet could bring something easy to be done (few resistors, condensators and a transformator).
__________________
Yves,
2000 #45, Cnd
Yves M. is offline   Reply With Quote Quick reply to this message
Old 09-10-2004, 07:34 AM   #3 (permalink)
Member
 
Join Date: Aug 2004
Location: Boston, MA
Posts: 39
Send a message via AIM to DonWatson3558
Default

Rusttree:

As you probably know, I have been exploring solar options. I have decided to start small, and learn as I go.

My first crack at solar will be to use a solar panel (with controller) to charge the 12v battery instead of the IMA battery. My thinking is this ... The IMA battery is resposible for keeping the 12v battery charged. Possibly (?) by keeping the 12v fully charged, it will pull less power from the IMA battery, and will thereby reduce the burden on the IMA 12v power drain. By reducing the power drain for the IMA battery, it may have 2 benefits: (1) give it a better chance of keeping SOC at full ... an interest of mine to help with car slowing down slopes, and/or (2) give the IMA system more power to propel the car. I will have to see what happens once I get it in place. The 12v charging seems a bit safer for now, although I would like to ultimately do as you have described and hook it to the IMA batteries. I have the panel and controller on order, adn should be here soon. Here is the panel I have purchased:

http://www.mrsolar.com/Merchant2/mercha ... _Code=MSOS

This is the charging controller (to prevent overcharging of the 12v battery):

http://www.mrsolar.com/Merchant2/mercha ... _Code=MSOS

Both of these devices should act as building blocks for improvements to the system at a later date.

An early expansion option on this would be to add a 3rd battery (LIth Ion probably) to sit between the solar panel and 12v controller. This might act as more than a trickle charger by providing a significant amount of stored solar energy to support 12v devices (stereo, a/c fan, etc.) while driving, and once again, releive the IMA battery from at least part of this responsibility. Of course, the Lith Ion battery would require it's own controller (different than 12v controller) to keep it from overcharging.

With regard to Yves M's note about the DC to DC converter ... Seems like you would certainly need a 12v to 144v converter IF you connect your panel directly to the IMA batteries. From what I have learned so far, it seems rather clear you should not do this. Rather, others suggested I hook the panel to the frontend of the IMA battery controller (which likely has it's own 12v to 144v converter), and also lots of other features such as battery temp sensors, overcharge protection, etc. I would suspect the regen charging systems in the car produce 12v power which is fed to the IMA battery controller. If so, you might be able to hook the panel at the same point. However, if the IMA battery controller is only "turned-on" when the car is started, you might be back at square one ... it may just ignore your solar power source while parked.

This idea is not my own. it was suggested to me in a private email.
__________________
2004 CVT Insight, Purchased July 20, 2004, #262
2005 Toyora Prius, White, Package 5, Purchased 4/18/05
DonWatson3558 is offline   Reply With Quote Quick reply to this message
Old 09-10-2004, 05:25 PM   #4 (permalink)
Member
 
Join Date: Aug 2004
Location: Chandler, AZ
Posts: 75
Default

Don,
I like your idea of focusing on the 12V battery in lieu of tackling the big sucker in the rear. From what I understand, if you could keep a substantial amount of energy flowing into the 12V'er, it would allow the system to concentrate mainly on recharging the IMA, rather than using its excess energy to keep the 12V electric system running. I'd have to run the numbers to see if it's substantial or not. Anyone have an idea the average load the 12V battery bears to keep the electric system running (assuming normal driving conditions: radio playing, fans, etc)?

In terms of charging the IMA, I had a similar thought about introducing the charge at the beginning of the MDM. But there is one extra complication here. Apparently the IMA Generator makes AC current. I suppose an DC-to-AC converter could be introduced, but I'm guessing there might be a problem with frequency and phase interference with the two voltage sources (one coming from the IMA Generator and the other from the solar panel). And, as you noted, there's a high probability the MDM will shut down when the car is off.

So that puts us back to using a DC-DC converter to bring the solar panel voltage up to ~150V and connecting that directly to the 144V battery. Actually, there's a document out by the NREL that says the actual voltage ranges between 139 and 158. Thanks to Yves for sending me the link for this:
http://www.eere.energy.gov/cleanciti...al_Insight.pdf
As long as an appropriate regulator is in place, I don't see how this could be a major problem.

Thoughts?
__________________
2001
5-Spd
64 Lmpg
Rusttree is offline   Reply With Quote Quick reply to this message
Old 09-11-2004, 01:59 AM   #5 (permalink)
Premium Member

 
Join Date: Sep 2003
Location: Bobs Lake, Canada
Posts: 2,332
Default

If you charge the IMA battery up without the computer's knowledge, it will be amazed to find an unusually high voltage on the IMA pack when it awakes. It will rightly determine that it has made a mistake in calculating the charge on the battery and will probably initiate a recalibration routine that will discharge the battery and charge it up from scratch. I've never tried this, but those who live in hot climates report recalibrations being triggered by higher than expected battery voltages due to heat. Force feeding the IMA pack would most likely have the same effect. I worked in power conversion for a decade and would enjoy a project like this if Honda was paying my salary, gave me access to their knowledge base, and if the Insight had a much larger battery pack. However, as things stand, the words warranty and lethal power come to mind. Surprisingly a modest 12 volt battery can hold more watt hours than topping up the IMA, so that is where I would do any mods to my own car. One scenario would involve super caps, rectifiers and a relay, but a simple aproach would be to just replace the power lost through internal leakage of the battery.
__________________
Kip Munro

The laws of physics don't need changing, but rather our attitude and values. 72.8 LMPG
b1shmu63 is offline   Reply With Quote Quick reply to this message
Old 09-11-2004, 03:38 AM   #6 (permalink)
Member
 
Join Date: Aug 2004
Location: Chandler, AZ
Posts: 75
Default

I've definitely had the same thought, but you also have to consider that the system is apparently able to handle a voltage change when the car is off. For example, if you're an idiot who goes to California for the weekend and leaves the headlights on in the Phoenix Airport parking lot for 3 days only to come back to a dead battery, as well as a AAA membership that mysteriously got cancelled and pay $50 to get it reinstated. Not... that I would know anything about that personally. But the point is it would seem logical the IMA computer would be able to handle a different battery voltage when it's woken up then when it went to sleep.

Also, I may be completely wrong about this, but it was my understanding that a fully charged battery is the ultimate goal of a recal. So if it detects the battery is fully charged, I don't see why it would try to change that.
__________________
2001
5-Spd
64 Lmpg
Rusttree is offline   Reply With Quote Quick reply to this message
Old 09-11-2004, 07:57 AM   #7 (permalink)
Senior Member
 
Join Date: Feb 2003
Location: Laval, Québec, Canada
Posts: 830
Default

My instink tells me that the recal is not triggered by a total voltage difference but by sub-pack voltage differences within the pack. Then to try to have all sub-packs with equal voltage, the recal is executed.

We have all speculated that a total battery voltage diff would have a recall but it was not tried out.

Maybe a test without the solar cost:
Buy a very small 12vDC to 120vAC inverter (like the one you put in the cigarette lighter) and put a bridge, capacitor and voltage regulator to 155 volts. Of course, while you have the IMA battery accessible, look at the voltage to see if we are in agrement to the voltage. Put that inverter into the IMA battery (probably where it meets the PCU) and hook it up to a 12V batttery. Once the voltage has rized (example from 145 to 155 volts), try out the car.

Maybe do it 3 times. If all is well, thaen persue further solar charging stuff.

The way I see it, a trickle charge of 2% of the battery capacity is OK. The IMA is 6.5 AH for 144v.
2% of 6.5 is 0.325A at 144v or 3.9A at 12V
(for a 12V source with a converter to 144vDC)

Therefore solar panel giving a constant 3.9 A would be OK as it would trickle charge the IMA. And this is for 24 hours a day. Since the solar is only a few hours, more amps can be put into the IMA for the few hours of sun there is.

What do you guys think of this. Any comments. I think that connecting to the IMA directly would be OK but a test is needed to prove/disprouve the idea.
__________________
Yves,
2000 #45, Cnd
Yves M. is offline   Reply With Quote Quick reply to this message
Old 09-11-2004, 08:48 AM   #8 (permalink)
Senior Member
 
Join Date: Dec 2003
Posts: 489
Default

Charging the IMA directly is probrably not the best idea because to my knowledge that will force recalibrations.

However, you could probrably hook the solar panel up to the battery controller, to both power the battery controller and charge the IMA through the battery controller - this should alleviate the recalibration issue.
Foxpaw is offline   Reply With Quote Quick reply to this message
Old 09-11-2004, 02:00 PM   #9 (permalink)
Member
 
Join Date: Aug 2004
Location: Chandler, AZ
Posts: 75
Default

Ideally, yes, but again that depends on whether the battery controller shuts itself down when the car is off (the probable case). And since the whole purpose of this project is to recharge the battery when parked, that's extremely important.

Yves, that's a good idea to test it out first before buying the expensive solar panel. I'll look into those links you emailed me to build the voltage converters. Heh, looks like I have a reason to go back to Fry's Electronics for the 15th or so time since I moved here last month. Awesome store, we didn't have anything like it back East.

One thing I'm still a little confused about is the actual wiring of the IMA system. So far I haven't found a physical schematic that shows which wire is which. I'll probably be purchasing the eletrical systems service manual soon, but if anyone can help out in the meantime, that'd be great.
__________________
2001
5-Spd
64 Lmpg
Rusttree is offline   Reply With Quote Quick reply to this message
Old 09-11-2004, 04:05 PM   #10 (permalink)
Senior Member
 
Join Date: Dec 2003
Posts: 489
Default

It does shut down the battery controller when the vehicle is off, because there's no power to the battery controller. You can easily fix that by just powering the battery controller with the solar panel though - which should cause the battery controller to operate when the vehicle is off but there is power from the solar panel.
Foxpaw is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Insight Central: Honda Insight Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Powered by vBadvanced CMPS v3.2.2

All times are GMT -4. The time now is 03:03 AM.



Powered by vBulletin® Copyright ©2000 - 2014, vBulletin Solutions, Inc.

Content Relevant URLs by vBSEO 3.3.2