Replace OEM battery before doing plug-in conversion?

I would say it depends on what type of conversion you plan on doing. Connect the PHEV battery in parallel with the OEM using contactors (like Plugin Supply)? Or by using a DC-DC converter (Enginer)?

 

Enginer works by supplying a trickle charge to the OEM battery. Therefore, you are still relying on the OEM for most of your power. If your OEM battery is weak, the benefits of the PHEV will be worse. However, with the PIS method, you draw power directly from the PHEV pack when it is needed. I would think that the OEM battery condition is much less important, then.

Hopefully someone with direct experience with PIS will chime in, but I don't think the PHEV pack would make replacing the OEM battery much more complicated than normal. Certainly not with Enginer (it is just two wires that connect to the OEM battery). If you had someone else replace the OEM, though, they would have to know how to deal with the PHEV (or you would have to do that part).

 

I have a Hymotion plug-in conversion module in my '09, which I installed with help from a friend. That's a 5 kW battery that takes up the spare tire well. It's presence makes accessing the OEM battery just slightly more difficult, not really a big deal at all, IMO. Hope that helps....

dh

 

you may want to replace your 12v if you haven't already done so. a weak 12v can deplete your hybrid battery.

 

I'd replace it with a optima yellow top or other performance 12V battery rather than an OEM replacement. I did mine myself, took about 45 minutes to remove the OEM battery, install my yellow top and put the interior trunk (boot) panels back together.

 

why an optima? and why the yellow? my 04 12v is oe, and i think its dying. i'll use the optima if there is any mileage benefit.

 

Optima batteries are sealed, deep cycle, shock resistant, and have absorbed glass mat rather than the liquid filled lead plates. DS46B24R YELLOWTOP® Prius® Auxiliary Battery 8171-767 :: OPTIMA® Batteries

Here's a prius chat thread: Optima vs. OEM 28800-21171 | PriusChat

From Clevland, posted on: optima vs oem battery - BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3)
"Do yourself a favor and buy an optima "yellow top" battery and be happy. It's the best of both worlds: A starting battery & A deep cycle battery. It can withstand much more vibration and current draw than the standard factory battery that comes with the car. It's the latest in battery technology: absorbed glass mat (AGM) cells. These are the best because they are totally sealed, can bemounted even upside down (if you so desire) and they can come back to full strength from even almost total discharge. It also recovers quickly reducing the strain on your alternator. The factory battery cannot do any of these things. The yellow top is available [for the Prius!]...Optima batteries are very stout for their size and should give you years of trouble free service. "

 

cleveland sounds like he works for optima...

i went ahead and bought the optima, cause i been using the red tops in my chevelle, and i like em. but the factory battery lasted almost 9 years; that's a personal record. i was wondering if ultimately there is any real benefit. since i made the mistake of ordering it from advance, of course when i went there to pick it up the next day they didn't have the correct battery. and of course they never even checked to see if they had it so they could order it if it wasn't in stock like the website said it was. so i had to get a battery w/ normal posts, and a marine + clamp to make it fit. the silver lining is now if i do need a battery in a pinch, a 51 series will fit.
i think the car was actually getting kinda "lazy". locks seem to actuate a bit qicker now, that kind of stuff. tested the old battery @ 11.6V. midtronics tester didn't pass it but i tested it @ 300 CCA. later i found out it should have been tested @ 361 CCA.

 

When I installed my yellow top, my thermos coolant pump started working again and my dash lights were brighter. My gas mileage did improve after I replaced the battery with the optima.

 

i got 8 years out of my oe battery, but i think the quality has gone downhill as there seem to be a lot more failures in the gen III batteries at 1,2 and 3 years old. i think i would use the optima if i needed one, but you have to be careful who you buy from and make sure it is charged up before installing.

 

i think any new battery would have helped if the old one was dying. but i've never liked exide batteries, or any of the may-pop batteries they sell at most parts stores, so i figured the optima would be a good choice. i'm not sure if my mileage has improved. and, i suspect they've started pumping the winter blended fuel. my mileage always drops about 5 mpg in the winter, possibly due to the winter blend. so i was thinking, would higher octane fuel help to counteract the lousy winter fuel? i'll need to check the owner's manual about fuel.

 

The OP was questioning whether or not to replace the OEM HV traction battery not the aux battery. I wish they had been clearer on this since the Optima choir is singing again - for the wrong reason. Stick to the topic.

If the OP is going to spend $$$$$$$$$ on a plug in conversion on an "old" car, he/she should definitely replace the OEM HV traction battery with a factory new one since few have the knowledge/skill to eliminate the OEM HV traction battery entirely and replace it with a custom lithium ion pack.

 

No higher octane fuel will have the reverse effect stick with the correct grade.

Exide make a very good direct fit battery for the Prius and it is a deep discharge AGM battery with a higher amp/hr capacity than the Optima or the OEM battery at about $160. Made in Chicago I believe part number FP-AGM51JIS with 4 year full replacement guarantee.

I have no affiliation with any battery company.

 

The yellow top is not the recommended battery for starting use this should be a red top.

 

perhaps exide makes good AGM batteries, but their lead acid batteries used to suck.
why would higher octane fuel decrease mileage? keep in mind the USA winter blend petrol is really lousy gas.

 

High octane fuel has fewer calories ( the amount of energy stored in a given amount of fuel). This also applies to so called winter blend fuel.

 

Does Optima make a red top for a Prius? Why the red top vs the yellow top? When you search for a battery on the Optima website they show the yellow top Pt# 8171-767 DS46B24R Prius Auxiliary.
DS46B24R YELLOWTOP® Prius® Auxiliary Battery 8171-767 :: OPTIMA® Batteries

What red top model number fits the Prius?