You are kind of between a rock and a hard place. Not sure how you can get home unless you borrow a charged 12 volt battery and use it to get home. Then charge the hybrid 12 volt before you connect it to your car.

If you have to jump the battery in the typical way (as you describe in your other post) you should be sure not to start the other vehicle. If left off it should only provide about 12 to 12.5 volts. You do not need any significant current from the 12 volt to start the hybrid. It uses the HV hybrid battery to start the engine. Then you can only hope that Toyota was smart enough to limit the charging current from the HV to the 12 volt. However, other posts I have seen about using their car as a generator in a blackout through an inverter would suggest the current is not limited to 5 amps. There are reports you can get 700 watts or more. That would be over 50 amps! As soon as your vehicle starts it is going to put about 14.7 volts on the battery that has zero volts or much less than 12 volts.

That means that even if you jump with a non running vehicle, your vehicle is likely to overcharge (too much current) as soon as you get it started. That is the reason why it would be best to borrow a battery to get home.

If you replace the OEM battery with a Optima, they do not have a 5 amp limit on their AGM battery. Is that because it is a different battery design than the OEM? Or, they are not as conservative as Toyota? No idea...

 

Good point.

Is there a cheap current limiter one can easily employ here?

Their charging tips on the below page say not to exceed 10 Amps, but definitely seems to be a better battery (in this regard) than the OEM one.

OPTIMA® YELLOWTOP® Charging Information

 

I wonder what the ramifications would be of borrowing the 12V from my 2010 Prius either temporarily or permanently. Just curious.

 

It should work just fine. It is just a smaller battery with less reserve capacity. Reserve capacity in the hybrid application only means it can sit longer (weeks) without being recharged or driven. I suspect even a motor cycle or riding lawnmower or other small 12 volt would work in a pinch if it is charged up.

On a permanent basis the issue is how long will it sit without discharging too much. I believe the Smart Key system if you have one is the main current draw.

 

I might actually try the 2010 Prius battery in my 2007 TCH which still has the OEM Panasonic. My suspicion is that the Panasonic might quit in the next year or so (yesterday morning it showed 12.44 Volts (neither fully charged nor fully discharged according to the manual specs IIRC)). So, I might get the opportunity to try it soon. If it will work under normal use, the Optima Prius battery could be attractive for TCH since the Optima comes with the requisite single vent already provisioned.

Just comparing specs between the D34 and the D24on the optima site,

Optima Prius battery and Optima D34 aside from the differences in capacity and CCA, one difference I see is that the Prius one shows 0.0046 ohms internal resistance whereas the D34 shows 0.0028 ohms. Anything of concern here?

Also anyone out there that has turned the Prius (or any other lowere capacity) 12V battery in their TCH on a long term basis?

 

No concern. Higher internal resistance would indicate fewer parallel circuits or resistance due to lighter construction. Resistance reduces the current capacity of the battery, so lower resistance is better.

The current draw on the battery is never all that large as it does not start the engine. Worst would be having your headlights on with the engine off. Not sure if the car is smart enough to maintain the connection to the HV battery (and the charge circuit) until the headlights turn off. If it does, that reduces current draw on the battery even more.

I think the only need for a large battery on the Prius and Camry is that they seem to have a higher than normal load on the battery when totally stopped. They seem to keep more computers and the radio transmission for the Smart Key powered up when totally "off". For example it is still monitoring your HV battery temperature when "off", and will start up the vent fan if it thinks it is too hot. This stuff adds up and slowly drains the battery. Older conventional vehicles may only have the clock powered up when totally off. Bottom line is that the capacity of the battery has little to do with starting, but really keeping voltage up when the vehicle is "off".

 

Ron,

Thanks for allaying my concerns. Particularly after learning my 2010 Prius also in fact has a temperature sensor (on the clamp as opposed to on the battery itself; see the below conversation at PriusChat), it makes me feel much better as far as trying the Optima Prius battery in the Camry. Because now I don't see the 2007 TCH is the odd man out as far as the temperature sensor is concerned.

http://priuschat.com/threads/why-no-...n-prii.121379/

Can you confirm your 2012 has a sensor on the clamp as well?

Thanks.

 

Just checked, and I can give you a very positive "I'm not sure!". Can't see anything on the ground wire. It seems to go straight back and is bolted to the body. However the hot side has an elaborate flat and right angle connector that is covered with red and black plastic. It seems like there is more there than there needs to be for a simple battery connection. It is cold here and I didn't want to pry the plastic covers off for fear of it breaking. I could not see a separate wire coming from the bracket, but it is covered with one of those flexible wire cover tubes, so it is possible there is a small wire inside that tube. In any case if you replace the battery whatever is on that bracket will remain in service.

 

Ron,

Thanks for checking. It seems like they have a different design now on the 2102s than they did in the 2010 Prii described here:

http://priuschat.com/threads/should-.../#post-1465156

At least we now know the 2007 TCH is not such an odd ball out when compared to the Prii, in terms of sensing battery temperature, and the 2012 doesn't seem to be an odd ball out either, when compared to the Prii (in terms of potentially sensing at a distance from the battery).

I am growing more confident of trying the Prius Optima in my 2007 TCH. As it is, I am fairly conservative with the Accessory mode on my TCH and the rest of the draws for smart key and such can't be much worse than for the Prii. Add to it the fact that the Prius Optima is 6 or 10 lbs less heavy and the ready provision for the vent (I hope the vent is compatible with the TCH's, but if not perhaps more easily managed than having to deal with some serious resins, etc.).

All in all, I am going to give the Prius Optima a try in the TCH when the time comes and update everyone here.

Thanks again.

 

srivenkat, we don't specify the depth of discharge on those cycles, but the standard industry test is typically around 80%. Obviously, the shallower the discharge cycle, the more times a battery can be cycled. Thanks for the heads up on the 2010 Prius listing. I have been told that will be added to the search at our month-end update. Our DS46B24R Prius battery does have pencil post terminals, which are significantly smaller in diameter than typical SAE automotive terminals. The D51 and D51R (reverse teriminal configuration) YellowTops are basically the same size with SAE size terminals.

Ron AKA, we suggest a maximum charge rate of 10 amps for battery chargers. For vehicle charging systems, we don't have a maximum amperage rate as long as voltage is between about 13.7-14.7 volts.

Jim McIlvaine
eCare Manager, OPTIMA Batteries, Inc.
www.pinterest.com/optimabatteries