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Battery voltage drop

I installed a 1000 watt inverter in 2005 Honda 4 cyl to operate oxygen concentrator for wife’s oxygen supply while on the road.

If I stop for a long traffic light or traffic jam the battery voltage drops to 10 volts which shuts off the inverter.

What do I need to correct this? Higher idle speed? bigger capacity battery? alternator or voltage regulator fix?

You need a higher output alternator and probably a bigger battery (bigger in terms of reserve, not CCA). I think that you can probably find the higher output alternator by checking with a sound shop that installs way-over-powered car sound systems.

I am thinking a second battery with the ability for the inverter to run off the second battery when the car is at idle.

Raising idle speed would be more than a adjustment

Rather than stero shop I would contact shop that modifies vehicles for exactly this type of need,(medical modifications)who knows maybe some type of insurance coverage.

They may say for your wife to use oxygen bottles while in transport.Is this idea not possible?

I agree the first step is the alternator. That is a large draw. After that if you experience additional problems, I would go for the battery.

Thanks for the advice. I will check for a bigger alternator first.

Upgrading a 4-cyl Honda will be difficult if not impossible. Trade for a Grand Marquis and have a P-71 (police) alternator and battery installed. The standard alternator might be OK, just install a group 27 100 amp-hour battery which will power the concentrator for a half-hour with the engine turned off…

I think this well be easier than most are thinking. How much power does the concentrator actually use? 1000W is about 80 amps. I doubt that the 4 cyl engine alternator can come close to that and you need some power for the cooling fans, ignition,…

I would be surprised if LOTS of high output alternators are not available for 4 cyl Hondas since so many people modify and customize them with huge audio systems. Some of those systems probably use more juice than the oxygen concentrator in question. The question would be, are they reliable? Google [Honda alternator “high output”]. My second hit yielded a 200 amp bolt-on replacement. Wiring upgrades will almost certainly have to be included as well, at least between the battery and alternator.

Other solutions include:

A custom tuner might be able to alter the idle speed and it might help a lot. Depending on the alternator design a couple of hundred rpm can make a big difference. An auto electrical shop might have some ideas about installing a different design alternator to boost output at low RPM. Some can build you a custom alternator and might not charge that much for it. They might also be able to find a smaller pulley to increase alternator speed. I would start with the auto electrical shop or a with a smart, knowledgeable indy mechanic. The factory-trained mechanics won’t be so good at this unless they are audio enthusiasts.

Caddyman has a point, the big Fords had a 130 amp alternator prior to 2001 when the police models went to 135A. In 2004, they boosted the police model all the way to 200A. You can rewire to change alternators, IIRC.