Fitting mobility 12volt AGM battery.

Thank you again for your response, dolj. You have been very helpful and informative.

Once I get the charger, I will perform the battery load test that you described and post the results.

Regarding the terminals on a new battery, I was still thinking of getting the RA12-33 model, for which I was unable to find any with M6 terminals. The 33 ah model is shorter, so a couple of extra inches on the top would probably not be a problem. If I end up getting the 55 ah model, I will definitely get one with the M6 connectors.

While a part of me would prefer to just bite the bullet and get the 55 ah model, it's probably overkill for my purposes. I don't leave the car idle for more than a few days at time, and do not draw an an usual amount of battery current when I drive. At most, I have the radio, GPS, and cell phone (running Torque) drawing from the 12v battery. Based on the current readings I've observed on Torque, things like the headlights, AC/Heat and windshield wipers each draw considerably more current than those small accessories.

With that said, your advice does not fall on deaf ears. When I install a new battery, I intend to make things as simple and straightforward as possible, while of course being safe and cautious during the install.

Thank you again for the time you've taken to help me out. It is much appreciated.

 

The voltage measurements you took on your car quoted in your post were measurements from the MFD or at the battery terminals? TIA.

 

I measured at the Aux plug with a DVM. I have noticed that I get a slightly higher reading (by about 0.2V), if I measure directly at the battery - not sure why.

As far as the above test is concerned, the absolute voltages are not really important. It is more important all readings are taken from the same place.

hope this helps.

 

I noticed the same thing between measurements at the battery Vs at the front. My 12V has a resting voltage of about 12.2 (front) and after having the headlights on for a minute or so, has returned to about 12.1. I think I am going to have to look at a replacement soon.

Are you still on your original battery or a replacement? If a replacement, what brand and how long have you had it.
TIA.

 

Although that is not the greatest, it also is not horrible. When you should be worried is when the voltage drops by 0.1V every 10 secs. Just keep regularly charging in the meantime.

No, I've just recently changed my 12V as I felt that having to charge the old one daily was becoming to much of a chore. After all it is not a PIP.

I changed it out for a mobility battery and couldn't be more pleased with the performance of it.

I chose a Vision 6FM55 12V 55Ah(10hr) on the recommendation of the specialist battery place I used. He was the first person that I talked to that didn't think I was a loon for what I was thinking of doing and applauded me for it, so that was very encouraging. I bought the battery on 15 Apr this year and installed it about a week later, so have been running it in the car for about a month.

Out of the box it was 13.1V and I charged (using a CTEK MXS 5.0) it overnight - it reached the trickle charge stage in about 4 hours - and was 13.9 V when I took it off the charger. After settling for 24 hrs it was 13.5V and lost about 0.01V every 24 hrs from internal discharge over the days prior to install. All of these voltage readings were OPEN voltages, i. e. there was nothing at all connected to the battery.

As I say, I'm very pleased with the performance of the new battery.

 

Does this have a vent hole that you can connect the vent tube to? I have looked at the above link and it's not clear. TIA.

 

Here's an update regarding my 12V battery. I got the charger, and charged up my battery overnight. After charging, the battery measured at 13.0 volts (I think, I didn't write it down). I had do some driving first thing in the morning before I did the load test. After making a few short trips totaling about 16 miles, I let the car sit for 1 hour, and did the following tests:

• voltage at the terminals measured 12.3-12.4V
• Turned on ACC - MFD showed voltage of 12.2
• Turned on IGN - voltage dropped to 11.9 and remained steady for a couple minutes
• Turned on headlights & started stopwatch (cell phone & radio also running on 12V battery) - voltage at 11.0
• Voltage climbed to 11.3 within 45 seconds

• 5 minutes - 11.2
• 8 minutes - 11.1
• 11 minutes - 11.0 - 11.1
• 12 minutes - 11.0 steady
• 15 minutes - 10.9 - 11.0
• 17 minutes - 10.9 steady
• 20 minutes - 10.8

From what I can tell, this battery is not in very good shape. It’s sufficient to power the car, but does not hold a charge well. The voltage while under a load starts out too low and drops too quickly.



It looks like I’ll be in the market for a new battery in the near future. I’ll be taking a trip over the Memorial Day weekend. I’ll probably order the battery before I leave and install it after I get back. As always, feedback or suggestions are welcome. Thanks to dolj and others that have chimed in.

 

No, it in fact, it doesn't have a Prius friendly vent hole built in. As detailed by the OP in this post, the Vision battery has the more generic vent arrangement for these type of batteries so I was going to look at a way of retrofitting the vent tube so that it looks like it belongs at a later time.

I wanted to take my time coming up with a design before taking to the new battery with a drill. As the battery is new, I don't feel I need to hurry, as the vent is really a safety mitigation in the event the battery charge circuit faults and starts to over charge the battery. Given that these batteries are designed for indoor use and charging, I don't feel the day to day running risk is great at all.

I believe that any risk at the moment is minimal, and I wanted to see how bad my (old) OEM battery is before doing any destructive testing on it to see exactly how the OEM vent hole is constructed, then replicate it.

So far, I am really happy with the way the battery is behaving and also the in-car charging.

I appreciate that other people may have a different appetite for, and/or appreciation of, the risk of not venting directly to the outside atmosphere.

 

In documenting the test procedure, I noticed that I led you astray by using incorrect terminology. Where I said "Switched IG-ON: 12.6V", I should have said what I meant and that was "Switched ACC-ON: 12.6V" (I've gone back and edited my original post, for the benefit of others). The whole test is conducted in ACC-ON mode as the idea is to have as little initial current draw as possible, take measurements and then introduce a constant current. The important thing is to see voltage drop over time with a constant amperage draw. This would explain why your initial voltage drops seem lower than mine.

Having said that, your results are still useful.

While I agree that your voltage starts out low, I don't believe that the voltage is dropping overly fast. I'd agree if it dropped to 10.0V in 30 secs. You are getting a drop of 0.1V over 15 min and a drop of 0.2V over 20 mins, which in my opinion is not to shabby. I do agree that you will be in the market for a new battery sooner rather than later, but I'd probably just regularly charge this one for the moment and see how it goes. The Prius will only start to complain if the voltage drops below 10.8 (i think) on initial start up and the initial voltage will bounce back after that initial draw. That's why I think regular charging and/or driving will probably see you ok for a while yet.

All said and done, I don't know your specific circumstances or your appetite for experimentation, so you may just elect to change out your battery and be done with it.

All the best for which ever route you take.

 

Hello guys Have a question here , we all know Prius don't have starter and alternator like conventional car . Can Prius use starter battery which is maintence free sealed and with vent plug ? Thanks

 

Thanks britprius super fast reply . Mine is Prius c which the battery located at under rear seat . I'm from Malaysia , Toyota here cutting our throat with oem yuasa battery price near usd300 , been searching for other alternative found Varta blue dynamic battery which is sealed and with vent hole price at usd 80

 

I think you meant Amp-hr or Ahr or A*hr , amp/hr or amps per hour wouldn't make sense for battery capacity. For example a 60 Ahr battery would give 15 Amps for 4 hours or 60 Amps for 1 hour. Using 60A/hr or Amps per hour would imply the Amps is dependent on the time such that 5 hours would imply 300 Amps and 0.5 hours would imply 30 Amps in other words the Amps out is dependent on time connected which is clearly not the case. Look at almost any rechargable AA battery for example you'll see something like 1200mAh which is 1.2A-hrs at 1.5 V (there is no "/" or "per". Other than this small point, I think you are spot on with most of the other info.

 

We've actually covered the units thing before in this thread.
Seems to be a difference in convention between the US and the UK.

He most assuredly does not mean "Amps per hour".

 

Hello Dorji et all,
As it turns out, I never got the chance to attempt the JIS adapter thing. Back in June of '14 I was driving outisde Erie on i 90 east, ran into a small boulder on the road, and messed up the undercarriage of the car. The unibody was kaput; the small boulder/rock also tore a hole in the oil pan, tore a gash in underside of the engine, along with some other things. Insurance valued car at about 3K, , repairs would have cost more like 10K , so it was scrapped.

Leaving me with a 12V battery- and some fun exploring alternative uses (I am back in PGH and mom wants me to get rid of it, as its taking up space and is heavy).I want to thank all the folks here- britprius, dorje and the like, for all your support. This thread has been fun and educational to read.

Sincerely
Sam

 

Sorry to bring up a older post but seems like you guys know batteries pretty well. I am in need of a new battery and have been trying to find something better than the OEM one that's $200 here in CA. I've been researching a little but I really know very little about battery systems. Price isn't all that big of an issue I just want something better for my situation.

I have a fairly large sound system for yr standard 2005 prius and I would like to maximize my system but also not tax the car in anyway. Not worth breaking or frying anything just to play yr music loud, but would be nice to be able to optimize something that works better than OEM for my situation.

My current system lets just say is about 1600 watts on the low side and can pull over 150 amps easy. I know ill never be able to pull anywhere close to max power in the prius nor do i want to i just want something a little better for my cars electrical system.

I was thinking of just going with the RA12-55 but I know their are some good audio battery companies like KINETIK and XS Power that sells good batteries. I was wondering if the KINETIK HC1400 REV would be a good option or something similar?

KINETIK HC1400 REV
MAX Wattage 1400
BCI Group Number 22/51
Height w/out Terminal 8.33 in
Width 5.43 in
Length 9.49 in
Weight 38.6 lbs
Terminal Configuration 3/8 in
Nominal Voltage 12 volts
Reserve Capacity
Capacity - 20 Hour Rate 55 Ah
Capacity - 10 Hour Rate 51.15 Ah
Internal Resistance 10 mΩ

any recommendations or input would be awesome i'm sure i'm not the only aftermarket audio guy looking for a decent battery that will work better then the OEM. Thx.

 

You can buy the 45Amp-Hr battery from the dealer for considerably less than $200. Price search on line for Toyota dealers who sell parts online. You might find a dealer who will price match or lower their price considerably.

Look online at other toyota dealers for parts discount coupons. Hooman in Long Beach seems to have a regular 20% off one part coupon which is good for the first week of every month. 15% off during week 2, 10% week 3. Costco has 15% off at participatin dealerships.

Bosch and Exide make a fully compatible 45Amp-Hr battery for the Prius too. Search for a good price.

You will have to research the Kinetix or XS Power battery. Will those fit the Prius 12V battery compartment? Are those an AGM battery, traditional wet cell battery, sealed wet cell?

Easiest just to get a Toyota, Bosch, or Exide, and leave the car READY, so the 12V won't get drained.

 

Bugger...

I took this up with the company that has a 90Ah and a 75Ah AGM that *might* fit to see if they would let me test fit it, turns out they are very unwilling to have anything to do with it. (I think it was discussed earlier that the 90Ah wouldn't fit, but had overlooked the 75Ah that I also wrote down.)

The only thing they are wlling to do is deliver me a battery when I order a specific one, that's about it...

Guess I will simply try to find a direct replacement for the 55Ah versions mentioned in this thread instead of actually doing some contributory work...