Signature Series

[SparkE]

"There is no easy way to get to 12v battery"

That is a BIG no-no in an EV. The 12V battery *will* have to be replaced at some point (every 3-6 years) and it shouldn't be made difficult or complicated.  And if the accessory battery ever gets completely drained, the vehicle won't work (unless there is a "hey, re-charge the 12V battery" button, like the Ioniq EV has). Without that sort of button, there should at least be "jump start connectors" to attach a jumper cable. (Once the vehicle is powered up, the DC-to-DC converter from the main traction battery can usually keep the 12V full - unless you turn the EV off again too soon.)

But a place to jump, and a place to attach a charger, needs to be thought out and delivered.

[DanCooper]

I have an old pickup truck that I only use to haul firewood and trash and plow snow.The battery would be dead every time I tried to start it. I put on a solar charger ($25) that sits on the dashboard. Now it starts every time. This would be a good application for a small solar panel on an EV.

---

It would be nice to have a 12V trickle charger that runs off AC while charging. It would be nice if they put one in, but it woud be easy enough to add.

[ricschug]

So it makes no sense to put a 5yr battery (lead-acid) behind a 10 year battery (Li) so let me ask. Do we know that the 12v battery is really Lead-Acid or is it maybe Li.

[SparkE]

Price is the reason most EV companies used lead-acid. Yes, a Lithium battery would be better.

BTW, since I started regularly saturation-charging (charge to 100%) my L-A batteries, they don't die so often anymore ...

[Trik]

Could they simply be reducing the Voltage to 12v from the main Battery bank?

[SparkE]

Could they simply be reducing the Voltage to 12v from the main Battery bank?

It's possible - some Hyundai electrics do that. Most vendors don't.

[ricschug]

So I guess we really do not know what AM is using this is all just conjecture? Perhaps someone from AM can tell us? I suspect AM will have some type of owners manual and a service manual for the FUV. If I could dream I would love to see some of this in its early form and while I'm at it can we have an API too.

[PAX]

Could they simply be reducing the Voltage to 12v from the main Battery bank?

Trik, There is definitely a 12V battery.   It is in back end of battery box-  There must be some way to keep it charged all the time.

Interesting that i am repowering a 1992 Dodge Caravan EV built by Dodge (made 52 of them) Originally It did not have a 12V battery but the big pack ran a DC-Dc converter full time. This set up bothers me as there is a steady drain on the big pack when just sitting  and I can visualize a case of low pack charge, head lights left on and draining the big pack- big bucks down the tube.   I am redoing that to have a 12V battery with the DC-Dc turned off when vehicle is off.   I will put a 12v safety unit on, that will turn the 12v circuit off if the 12v battery gets low. When you get in and there is no 12V you can push a button that starts the 12v battery for 10 seconds.   I have one on our EV truck - my wife left lights on one time. She calls me and I tell her about the button and she started it right up and I went back to important things. I only put an old 16AH battery in the truck.

[Trik]

I made the same discovery with my dc-dc converter, I use mine for lights, so I had to rewire it to only Energize with the light switch. Pretty amazing how quick small constant drain will pull the battery down.

[DanCooper]

A modern DC-DC converter need not draw any significant power while it is not providing output current. Or it can be automatically switched off when the vehicle is powered down. The problem is that its cost is proportional to the peak current. Lead-acid batteries are the cheapest way to provide high peak currents. Lithium ion batteries aren't so good at that either.