Can I Run Equipment Off The Starting Battery In The Rx400h

[Robl45]

Hi,

As the subject says, can I run a charger for my RC helicopters off the 12 volt battery in the rx400? I'm assuming if I leave the car in ready mode that the gas engine will kick in and charge the battery if needed. I'm just concerned with all the crazy electronics and stuff that I might break something. The charger would draw around 25amps or so for 20-30 minutes at a time.

[Jim Clark]

Although the 25 amps seems like a small amount, what little I've read so far leads me to believe these cars and their "small" 12 volt batteries are "sensitive" to any abnormalities. I would email or call Lexus USA and ask a tech rep if it's OK.

[SOMEONE ELSE'S GOT MY NAME]

Put another way, 'don't do it'. If you use the search tool, you'll find several folks here either that have left something on, or a door open (which leaves a low powered lamp running), only to find less than the required power left to boot up the high voltage system. Why risk it? Now, some have replace the existing 12v battery with a small Optima battery (meant to deliver cranking power), and that kind of setup WILL allow you to have enough spare amps left for boot ups, later on down the road.

[Robl45]

but I would leave the system in the ready mode, if the battery starts to drain, won't it kick the engine on automatically?

[RX400h]

I believe you're thinking about the batteries that help power the vehicle, not the starting battery.

[Robl45]

when the car is in the ready mode, I assume the batteries are connected? So if I hook to the starting battery, won't it drain the main drive motor battery until it kicks on the engine?

[Jim Clark]

when the car is in the ready mode, I assume the batteries are connected? So if I hook to the starting battery, won't it drain the main drive motor battery until it kicks on the engine?

I don't think that is correct. I believe it would only drain the starter battery. Again, call a dealer or Lexus USA and ask a tech rep.

[williz]

when the car is in the ready mode, I assume the batteries are connected? So if I hook to the starting battery, won't it drain the main drive motor battery until it kicks on the engine?

I don't think that is correct. I believe it would only drain the starter battery. Again, call a dealer or Lexus USA and ask a tech rep.

if the car is in "ready" mode, the 12V battery gets loaded from the cars high voltage system. if the high voltage battery's getting low the engine kicks in and the generator fills up the high voltage battery's.

so as long as the car stays in ready mode your 12V batt will be fine.

but you should see if the 25 amps are not too much for the cigarette lighter. i think all 12V connectors have 15 amp fuses!

[SOMEONE ELSE'S GOT MY NAME]

The high voltage system WILL put power back to the 12v battery ... however it only recharges at a few amps per hour. It won't crank back 20 or 30 like a regular ICE alternator would do. Thus, the 400h makes a poor source as a 12v generator. You'd eventually run your high voltage batteries down into the 'pink' zone, bringing the ICE on line, to replenish the high voltage pack, which in turn, trickle charges the auxiliary 12v power. That's simply a waste of gas, to trickle back 3 or 4 amps.

[Robl45]

I would connect directly to the battery, as the cig lighter or the a/c plug out back will only handle about 100 watts and I need more like 250 watts.

[williz]

The high voltage system WILL put power back to the 12v battery ... however it only recharges at a few amps per hour. It won't crank back 20 or 30 like a regular ICE alternator would do. Thus, the 400h makes a poor source as a 12v generator. You'd eventually run your high voltage batteries down into the 'pink' zone, bringing the ICE on line, to replenish the high voltage pack, which in turn, trickle charges the auxiliary 12v power. That's simply a waste of gas, to trickle back 3 or 4 amps.

the 12V battery (empty with 9V) gets fully charged (12,8V) from the high voltage system in about 1 hour. so the recharging current must be more than 30 amps. 3 to 4 amps would mean a charging time of more than 10 hours for a 45 amps/h battery like the one in the RX400h.

[Gryphon]

Run out to Costo and buy a Powerstation model PS500M for $80 and you'll have a dependable 12v power source that will also recharge, albeit slowly, from your Lexus 12v outlet.

Tom

[Robl45]

I rented a prius recently and it did seem to say that it recharges the 12 battery at 4 amps or so.

So that being the case, obviously the car is not running off of 4 amps, nor is it just running off an alternator without being filtered through something. So, there has to be a place to connect high powered devices such as car stereo amps to the car and such. Does anyone know where that place would be?