exchange 12 volt battery?

An easy solution I found is to buy a sealed lead acid jump starter.. I wasy one today at Bimart.. for 54.00... it has jumper cables... up to 300 cold cranking amps... "which you don't need anyway to boot the computer"... very handy.... just charge it up from time to time and keep it handy in the car.. good for jumping folks too without having to tap into your car system and risk frying something!
Its the best of both worlds.. because you really don't need an extra battery except for emergencies.. this would be a portable one!....

 

Hi Hobbit.... I did purchase that little unit i told about... but I got a better one at Costco for 49.00 that is 450 Cold cranking amps and with 1100 peak amps.. the bimart one was only 300.00 CCA with 900 peak I believe.
Not that that is needed with the prius, but it is actallly heavier and basically more battery for less money!

Greater if I ever need to be a good Samaritian and jump somone else!....

Let me explain the way I understand it.. keep in mind I don't own a prius yet because my 2006 is not yet here, but I am doing lots of reading and if you pm me I can send you links and info I have.... but you may already have it I don't know?
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Anyway.... the 12V battery is only to run the accessories while the car is not on AND to boot up the computer when you want to turn the car on (ready mode). Once the car is on and in the "ready" mode as indicated on the front light panel,... the 1400 watt inverter is powering the 12Volt to the accessories "as well as charging" the 12V battery that .... like I said... is for pure accessory mode (powered up without the car being in "ready" mode).

The reason you even need the 12V battery at all, is so you have lights, tunes, instrument etc when the ICE 'internal combusion engine" is not running. You need to be able to see till you get things going.

Once the big inverter is running.. it pulls from the 201 volt main battery bank to supply the 12V... if you sit in ready mode burning enough AC power that the main battery voltage (201 volt) begins to drop, "which the inverter is running off of", then the ICE will kick on to charge everything back up to nominal voltage!

If you have power amps running your tunes and were not in "ready" mode, you would be limited only to what the regular 12V battery could supply... It wouldn't take long at all to drain it and then you couldn't get the computer up to charge it back so I don't recommend it!... The use of capacitors would be a waste as they are drained in miliseconds and the main inverter will supply plenty of juice when in ready mode anyway.

For running large power amps, if you will be "showing them off" :lol: for over 3 minutes or so, I would put it in "ready" mode so the main inverter can replenish your 12V battery from the main 201 volt battery, plus if anything gets low, the ICE will kick on to charge it all back up!
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If you were to drain everything down without the "ready" light being on.. you would risk damaging the 12V battery... but no big deal if you immediatly charge it back up...
Lead Acid does not like being discharged and "left" that way!....the plates sulfate up... now I don't know if this applies to gel cell too or not... good question, but I think so...the only difference between the two is that one has liquid "H2S04" (Sulfuric Acid) while the other one is in a gell form instead of liquid.

But heres the trap!... if you drain your 12V battery down listening to tunes while in pure accessory mode, you have no battery left to boot the computer to get the car in "ready mode" to now charge up your 12V battery!.. your screwed and will need a jump!

The 12V battery doesn't even need to be that large as CCA "Cold cranking amps" is not needed o boot a computer.... in fact something more one the lines of an RV or deep cycle battery would be better served... the plates are thicker, but less CCA but more longevity for deep cycle drainage.

IN fact by adding another 12V battery.. that will do absolutely nothing to the cars performance since thats all being carried out with the main battery thats 201 volts.

True, you would get more time in your car running the accessories without it being in "ready" mode but I just explained how risky that was... however...

My original suggestion was to have another one wired in parallel just as a backup.
You wouldn't want to permantly hook them together as that would most like drain both of them should an accessory get left on all night, then you would be no better off than with one?
But rather have it rigged so during the ICE being on, the charge from the main inverter could also charge the backup battery, but during discharge, a diode would prevent current from going that way. In this fashion the backup battery would never be able to be discharge right?
But should you run down your system somehow, or the regular 12V just get weak and not start one cold morning, you could flip a little swich that "bypasses" the diode which now allows current to travel into the cars accessory circuit as well as charge the main battery. ONce you got everything up and running again, you would flip the switch back.
If you ever ran down the system, you would just go to your jumper and your fixed!
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I just killed two birds with one stone by buying this portable battery jumper/air pump on one!
Should my system ever drop.. I can simply put power from a double male 12V jumper that comes with the little unit and plug right into the cigarette lighter or 12V accessory outlet!.. Since the prius does not need serious CCA, that would be enough to fire up the computer and get everything up again till I could replace the real 12V battery at my liesure!
I don't even need to open the hood!

If anyone notices I have any of my wires crossed here, I welcome to be corrected...
thanks...

 

when you use the term

what do you mean?

Isn't what your talking about is if the 12V is dead?...wouldn't if you put a male plug into the 12V plug and it is charged with 12Volts.. wouldn't that energize the 12V circutry?

It sounds like what your saying is that 12V plugs are actually switched with a "normally closed" switch that it will not open unless its energized with the proper 12Volts?
If thats the case.. .that means the car kills the outlets to keep from completely draining the battery to zero?

Even if thats the case, wouldn't the 12volts fed in through the outlet activate the swich to open it, or would it be coming in from the wrong side?

 

thanks.. that was a very good explanation about the cigarette lighters.... and yes.. trying to operate "without" a 12V battery at all would be dangerous for regulation and any voltage trash or spikes that may get in the system would not have the battery to absorb them.
I'm not sure why anyone would ever try to run without the battery.. they would have to pull it out while running or at least while in accessory mode?
Even if the battery was total trash and dead, it would still suffice to aid in regulation and/or absorb spikes.

But anyway.. if the voltage was so low that the outlet was truly turned off, you could plug the external battery into the 12v plugin try to and see if it would energize the relay...It sounds like the voltage would be on the wrong side of the switch to do any good, but if not.. then yes you would have to open the hood.. but still.. the whole point is to not have to be dependent upon finding somoone else for a jump.... you carry your jump with you!

 

The part about this that is confusing.. we have talked about so much now.... I understand what you are saying, but I was questioning whether if you introduced 12V from an external battery to the outlet, whether it would release the switch to allow flow into the system so the computer would boot, then the inverter would take over to get you where you
really need to go.... however, I decided that the power was most likely on the wrong side of the switch.

And I know, if the batt is dead you can't even get started, but what we were talking about, is if you ran it down playing tunes with high power amps, or if you left a light on... then you would have to have a way to get it all going without finding another car for a jump. The external batt. seemed to be a very easy solution.

 

Hey.. thanks for trying to test it!..
Ill test it once I get mine sometimes....

 

When I get my car... before I log in a bunch of settings I don't want to loose.. ill just run my battery down far enough that the 12V jack dies.

then confirm that it won't work anymore cause the battery is still too low, then Ill plug in my 12V plugin from my external batt in that same jack to see what happens.
If everything comes up.. I'm good!... if not.... then I'll have to pop the hood.. oh well!

 

If the MFD will light up with 12v supplied to the cigar lighter, that means power is gettng somewhere!... the real question is, will it also get the car in accessory or ready mode! If it can get to there, then all the rest should work I would think.

 

I believe "Bill Merchant" if I remember right, sent me instructions on MOD to do just that...

But I like the protective feature... so I chose not to investigate.

I think they did that on purpose so someone wouldn't inadvertently plug in something to the 12v outlet and forget it... like a stereo.... halogen work lamps etc etc and so pull the lead acid battery so low that it ruins the battery.... 12V batteries don't appreciate getting pulled too low.. Its really hard on the plates... they get sulfated and its tough to get the sulfates back off the plates when recharging, if the discharge was too low, or brought very low and then left there for hours... even overnight , you will often loose a portion of you battery charge/discharge capacity.

I am unaware whether its possible to run it down by other means.. for instance headlamps etc.... but I think it must be possible... hence the need for the extra gel cell!

I suppose if it were a realy issue, one could tap into the 12V side that powers the accessories etc and tap a 12v outlet there that could be used for jumping....

But that seems a bit of overkill?.... I mean just how often will we really need to jump it and when we do..... I can get out of my car and jump it under the hood.