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This all seems like a lot of work, and I'm not sure what your end goal is with improved deep cycle performance. What are you running that you need improved deep cycle performance of your 12v battery?
Keep in mind his LFP if installed properly will continue to provide adequate current to start his RAV4 for 10+yrs whereas us with more standard battery tech ie AGM, ect will be replacing our batteries more often
 

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This all seems like a lot of work, and I'm not sure what your end goal is with improved deep cycle performance. What are you running that you need improved deep cycle performance of your 12v battery?
Not running anything, jut the vehicle and wondering if the battery life is less or more than my Subaru that lasts somewhere between 3 and 4 years but closer to 3.
 

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A properly maintained lead acid battery should last 8 to 10 years. Replaced the original one in my 10 year old tacoma last winter. Still working but rolled over engine slow. The rav4 hybrids have been having some battery issues so only time will tell if batteries will hold up in them.
 

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Without getting into great detail, what would be the average expected life of the 12v battery in a standard/stock Hybrid model?

I’m going to start shopping for one in a month or so and also wondering what the dealer would charge for a trailer hitch? I’m guessing it would cost somewhere around $500?? Thanks
Roughly, about 5 years. I change them out in my hybrids after 5 years, just to be ahead of a dead battery. Of course that depends on where you live. Hot summers and cold winters are harsh on batteries.
 

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Roughly, about 5 years. I change them out in my hybrids after 5 years, just to be ahead of a dead battery. Of course that depends on where you live. Hot summers and cold winters are harsh on batteries.
Excellent, thanks for the reply and that’s much better than my Forester which is about 3.5 years, max. I guess there’s less use on a hybrid battery due to the drive batteries I would guess.
 

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A properly maintained lead acid battery should last 8 to 10 years. Replaced the original one in my 10 year old tacoma last winter. Still working but rolled over engine slow. The rav4 hybrids have been having some battery issues so only time will tell if batteries will hold up in them.
Guessing the only possible maintenance would be in keeping the terminals clean, other than the filters on the hybrid batteries?
 

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^^^ AGM batteries are pretty maintenance free, from my observation. They always look new when I change them, and the posts are clean too.

This reminds me that it is time to change the 12V on my 2016 Sonata Hybrid!
 

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Yes, an AGM battery is maintenance free in a regularly used auto. The maintenance comment was more for broad lead acid battery usage such as recreation products and infrequently used auto when periodic "maintenance" charge is recommended and also non maintenance free varieties requiring electrolyte level checks. Not really applicable to frequently used autos as is the theme here.
 

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Discussion Starter · #29 · (Edited)
In case anyone is considering this approach, further testing has revealed another hurdle. When the battery is near-full, the rav4 system voltage drops below 12.7v and remains below 13.5v for long periods. No combination of driving mode, A/C, headlight, fog lamp and defog switches prevents the drop below 13.0v. I assume this is intended to save fuel by reducing DC-DC converter output. But it is poor implementation by Toyota to let system voltage when driving fall below the open circuit voltage of the auxiliary battery. GM Spark EV got this right back in 2014!

Obviously this complicates the use of a ‘battery protector’ to cut-off the dashcam circuit at 13.0v, so that subsequent charging current is not >50A/1C. Variations in system voltage below 13.0v while driving will trigger cut-off. A work-around is to add a 12v / 40A relay to power the dashcam when the ignition is on (as illustrated below), leaving the protector to work when the ignition is off. Ensure that all protectors and relays suit capacitive and inductive load effects in the dash-cam (How (not) to destroy a relay | HW-group.com). Parking mode may not activate correctly unless power to the dashcam continues when the car is turned off. Thirty sec in Park before switching the car off will ensure battery protector restore, if set at 13.5v. I have updated the compiled guidance elsewhere. These procedures are too complex for many owners. Programming car DC converter output voltages would solve all this. Limiting charge current would allow 12.7v dashcam cut-off. A car owner can not make these adjustments without help from the manufacturer. Currently this is withheld by Toyota.
Relay.jpg
Relay2.jpg
 

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Thanks for the insights ddd324. I actually bought an AliExpress voltage cut-off (and a Viofo unit), then did not use either. One reason I paid a bit more for a Victron BatteryProtect (apart from ability to use LFP-friendly voltages) is the Victron unit's very low standby current drain (specified at about 9mW, which is also what I measured). The XH-M609 unit specifies "Power consumption: Less than 1.5W". I don't think it can be that high, but I would want to measure it before use. Those digital displays are power-hungry if they stay on, and some units that use a relay actually draw more current after cut-off (because then they open a NC relay), which seems crazy. Once it enters 'deep sleep' mode, my rav4 draws less than 100mW of parasitic drain (probably more like 10mW, but I have only tested it with a clamp meter, which has limited DC current resolution). Another 1.5W after cut-off by a 'battery protector' would kill a 50Ah car battery within a few weeks. Every mW counts after voltage cut-off if you plan to be away for long.
I've gotten myself one of those Victron battery protectors to keep my dashcam in check. What a wonderful device! Thanks for the tip, @RGeB!
 

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Discussion Starter · #31 ·
One tip if you mount it near the 12v battery (as in my photo above). Although this location is above a channel (good to keep water off), the metal there is very thin, so use a suitable diameter stainless screw. I was a bit concerned about the possibility of loosening with vibration (eg off road), so I ran a bead of (silane-modified polymer) glue around the edge and over the screws.
 
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