prius dual auxillary battery

I hope that you are kidding about connecting it in series, and realize that parallel would be correct.

Just in case of a weak 12 volt in a remote place, I have a 7 amp hour "helper battery" which is always trickle charged when the Prius in in ready mode, but can only be used for booting up when an added dash button is pressed. The circuit is quite simple.

No comment on adding regen motors to the rear wheels.

 

If you're serious about this, use a "battery isolator". It will ensure you do not overcharge one battery while undercharging the other.

You will also want to use another sealed battery, either another gel cell type or a glass mat type, such as an Optima. They are available in smaller sizes - a #51 is the smallest I've seen in the Optima line.

Both types will not spill electrolyte if broken in an accident. An important consideration.

Not sure exactly why you're doing this, but if it's just to increase the battery capacity, just replacing the stock 12V with a larger battery is the best way to go. I'd go this way with an Optima #51 - but you -WILL- want to manufacture a proper hold-down/battery tray for it and ensure the battery compartment is properly vented. Even sealed batteries can vent from time to time.

 

<div class='quotetop'>QUOTE(lurgetaxa @ Aug 13 2006, 10:51 AM) [snapback]302594[/snapback]</div>

Sorry, but it is not clear just which battery you are talking about. There is a Traction Battery and an auxillary battery.

 

More fundamentally, don't forget the science involved. There is simply no "free lunch." Assuming you could rig something to the rear wheels to feed charge to the aux battery, the car would have to overcome the added load imposed at the rear wheels to generate that energy. A Prius can add energy only two ways that I can think of: out of the gas tank (some of which gets recovered and "reused" via the traction battery) and from a tailwind (I suppose a tow truck might also suffice, but that would be cheating... ). Even rolling down hill, all you're doing is recovering some of the energy the car took out of the gas tank to get you up the hill in the first place. Yeah, a system such as you mention might result in minor deviations in the flow of energy within the total car, but it would be a wash overall, with the penalty of added weight and complexity. An interesting idea, but IMO, one that needs to remain merely an idea.

 

Well, the simplist way to charge an extra battery that you don't want to connect to the system is to add a solar panel and charge from it. If you use a "cargo screen" (horizontal window blind over the hatch area) you can put a small solar panel on top of it, or you can place one on the dash. You would need to securly fasten it to prevent it from decapitating you in the event of an accident though.

You can then connect the battery to the system through a diode so power will only go to the car, not from it to the extra battery.

Note that if the stock 12V battery is fully charged, very little power goes to it from the Hybrid system, just what is being consumed by the vehicle electronics and a tiny bit of "waste".

Just from reading your messages, I think you may need to read some books on how electricity and electronics works. Otherwise you will cause expensive damage to this complex electronic car!

 

How about a simple approach.

For the 2006-2007 Prius:

Obtain an identical stock traction battery and integrate with the existing traction battery.

Would this increase capacity as there is now more storage? Theoritically, if wired properly, the computer would notice a small difference in a slower decrease in energy coming from the battery(ies) and slower charge time. I wonder if this would trip an error code?

I surmize that we could place the second traction battery in the black tray under the cargo floor. There will be a cooling issue that would need to be addressed.

If this theory works, there could be secondary "kits" offered commercially (perhaps under the 8-10K price). Of course, only geared for professional installation (like the Prius Plus products).

Benefits would be better capacity and better range in EV mode. This should result in better MPG.

Just an idea...

 

<div class='quotetop'>QUOTE(lurgetaxa @ Aug 13 2006, 01:51 PM) [snapback]302594[/snapback]</div>

Not to put too sharp a point on it, but this idea is just plain silly. Your "regenerator" is not going to be more efficient than the one built into the Prius, so you will add weight, cost, and complexity for no gain.

Tom

 

<div class='quotetop'>QUOTE(rex-n-efx @ Jun 28 2007, 11:24 AM) [snapback]469537[/snapback]</div>

I REALLY like this idea. Let also add a battery charger and a cord you can run into you house at night to connect to the electrical grid. We could call it a PHEV. We can start a websight to help other people who want to make PHEV. We could call it calcars.org or similar.

Maybe some small start up companies will make kits to drop in to the spare tire well to make this a quick conversion for about $10,000. They will most likely only sell to fleet users at first. Maybe we could get the US government to offer a $3,500 tax rebate for poople to make this conversion, and just maybe, the added demand might entice more companies to come out with lower cost drop in conversions around $5000-6000 price point.

We will have to wait and see. Some new killer battery technology leep forward could really serve as a catalyst too.

 

<div class='quotetop'>QUOTE(NoMoShocks @ Jun 29 2007, 12:10 AM) [snapback]469833[/snapback]</div>

This has been done. Do a search of this forum and you will find more information.

Tom

 

The Prius 12V battery is *not* a gel cell (and contrary to the NCF book, neither is it an AGM battery).. It is actually just a regular flooded plate lead-acid battery (you can feel and hear the electrolyte sloshing around inside if you take the battery out)..

It's my contention that even though it does not need to perform any engine starting, the battery is still sized too small, and further, the simplistic method of fixed output levels from the converter results in a severely current-limited charge that ultimately shortens the battery life (I have designed charging systems for lead-acid battery technology in a number of deployed telecom products- the service life of these batteries is projected to be in excess of 20 years, but the customers typically replace the batteries as a matter of course every 10-15 years).

Anwyays, you have nothing to worry about when it comes to the 12V battery charging current affecting the available traction battery power.. As I said above, the 12V charging rate is exceedingly small (if the battery is dead, it wouild take you nearly 48 hours of continuous driving to reach full capacity again).. Unlike a conventional alternator, a typical 15-20 minute drive on the Prius will *NOT* put any significant amount of charge into the 12V battery. Because of this, I believe that there are a lot of Prii ouit there are driving arouind with chronically undercharged 12V batteries, which is detrimental because it increases the likelihood that the battery will go dead if you leave it for an extended period, and more importantly, lead-acid batteries tend to sulfate and go dead prematurely if they sit around at partial charges, so as I stated earlier, based on my experience, it's my belief that the Prius 12V charging system is flawed and is in fact slowly killing the 12V batteriy...

A second battery in parallel (not series; that would make 24V and blow every single circuit in the vehicle) would improve your overall capacity, but because of the slow charge rate, wouild still eventually go dead. Additionally, you need an isolator (basically a diode), if you're hooking up two batteries in parallel, but this actually makes the situation worse because of the Prius' converter.. The diode would basically guarantee that neither battery would ever reach full charge no matter how long you drive the car..

A better solution would be to install a larger battery (I put in a Honda Civic battery which has slightly larger physical dimensions, but can still be made to fit in the space available), and an auxilliary charging system (I've got a 15W solar panel- my calculations show that if you want to place the panel inside the car, behind the glass, due to the losses from the solar absorbing glass as well as shadowing from the car itself, you will need a minimum of a 5W panel to get any meaningful charge to the battery; anything smaller (eg, those small 1 and 2 Watt panels) will slow the discharge rate, but will not be able to add any charge to the battery)..

 

<div class='quotetop'>QUOTE(qbee42 @ Jun 29 2007, 09:27 AM) [snapback]470009[/snapback]</div>

Someone has discussed adding a second traction battery?

I didn't find it on a search.

All I found was this thread.

Perhaps I should have started a new thread.

 

i believe a good sized m/c batt. would work as long as you modify the terminals.

 

This thread is about ten years old. I wonder if there is more up-to-date information about adding an auxiliary battery and the use of an AGM battery as an auxiliary battery, particularly in the Gen III Prius.

 

What's the charge rate in Ah?

 

Yes , I just replaced a new 6 month old AGM (Yes it was an AGM) FROM Advance AP. No questions asked. And the replacement new one came with 26 month free from this date. No prorate. But I had my YellowTop. From 2015 still on the shelf. I am considering seeing how far the yellow top will go. And having the other new one with the negative connected to ground with an a/b switch for emergency. This 6month failure was a short in the battery. I could either use a marine switch or a solenoid if I cared to bother remoting it. But why.

 

why not just install a larger battery?