Tesla is just starting to put lithium 12v batteries in for the accessories. They have same life cycle as main battery. Elon wants 48V or higher to run accessories but no one makes the switches and systems that run off of high voltage.
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why is there a 12 volt battery in the hybrid
- Thread starter hondabuster
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The 12v battery is used to supply 12+ volts to close the contact from the hv battery which activates the circuit to provide 14.3-14.5 volts to the 12v busbar and walla the 12v circuits have enough current to maintain 12volt draws and charges battery. I believe I saw somewhere the 12v battery is only 25amp (not sure) in maverick. Also if hv battery is too week then 12v can start the ice then will generate current to charge hv battery (indirectly).
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25 amps sounds really weak. Surely it can make more cranking amps... I think it would have to to turn the motor over, especially if cold.
Now your making me wonder what the amps are in my 12v Prius battery ?
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The 12v system doesn't start a hybrid vehicle, the HV system does, it simply doesn't need a lot of cranking amps. The biggest draw on it would be the vehicles computers, stereo system, and the 120v plugs. You would need a battery with more amps than what most hybrids have to jump start it. Toyota basicly tells their hybrid owners that if they allow the main HV battery go flat you need to tow the car to the dealer to get it going again. From the manual it looks like Ford has a system for jumping it, but I doubt the onboard battery would do it.
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Almost all of the time all it does is close the contacts to energize the hv battery 12v recharge circuit which I believe it can do when it's SOC drops to a certain point or all hv battery circuits when key is inserted. I have not confirmed this but is from several things quite a few have said. Some from lithium ion liquid temp controlled university studies. Ie: said batteries Should be placed in storage mode when SOC drops below a certain point. Also contacts to isolate hv battery has been quoted by some threads here. Somewhere I saw a picture that someone was claiming about the battery. I will confirm size.
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I do recall seeing a place that was referred to be used when 12v battery was dead. I am believing that if hv battery appears dead the hv contacts may just be open and hv battery most likely is not totally discharged, at least I hope that is the logical case. In which case that point may just be where 14.4+/- volts can but placed on the bus.
Starting on Page 282 of the owners guide show instructions and pictures on how and where to jump start the hybrid version.
That's a big part of it. Virtually every automotive electrical component made to date is designed around the 12v system. Everything has been proven to be safe and reliable and creating and entire new ecosystem of things for what would likely be a proprietary new system is cost prohibitive. Far simpler to use the existing supply of 12v components.
Lead acid batteries are also much cheaper and easier to make. Lithium production has choke points - china controls a lot of it. I'd guess that people in the business are looking to other less strategically vulnerable technologies. I just read that there is an iron based battery chemistry that is very promising. It will be interesting to see how this all shakes out.
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Pretty sure all hybrids use 12 volt to start the engines.
Mav uses 12v to power 12v circuits and close contacts from hv battery to provide hv current to the starter generator in the transaxles which then starts the ice.
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Once and only once my 23 Hybrid Mav went dead. A simple jump got it running perfect again. Upon the suggestion of the dealer during a recall appointment they ran a test on the 12v and in result replaced that battery.
If you somehow cut the HVB out on your Maverick, it will not start. No starter. It uses one of the high voltage motor/generators in the transmission to start the ICE.
The 12 volt battery is only there to run the computer, dash lights, radio, outside lights, heater blower, etc. Take the HVB out of the circuit and all those things will run FOR A LITTLE WHILE, but the truck will not start.
It may even be that NOTHING will operate if the truck is programed to go possum if the HVB isn't detected.
Someone should try it and see.
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