Completely discharged battery hypermiling? Air seat radio off. Left headlight out.

[bobmutch]

I have a 1998 Volvo s70 that I have been hypermiling.

Here are some of the techniques I am using or am working on using.

Pulse & powered down glide, power down glide to stops, min braking, drive lower speed without impeading traffic, park to min reverse, avoid full stops (20% less gas when starting from 5mph), speed up for hills, glide down hills, ridge riding in rain, avoid bottom hill stops, drive when warmest, turn lights off during day, keep seat warmer/air heat/radio/high beams/left night light off.

So most of the road I am driving on are back roads and 80km (50mph). I pulse to 90km (55mph) put my autotransmission into neutral power off with key and glide to 65km (45mph) then restart the engine.

My surge takes me 0.4km and my glide is usually from 0.6km to 0.8km.

So today my completely discharged my battery. So I now I have my heat fan, radio, and heated seat turned off. Stopped using my high beams. Dimmed my dash lights. And I even removed my right head light power.

In the day time I plan on removing the power to both head lights.

I have a higher end battery that is only 2 years old.

Is it restarting my engine that is draining my battery and if this is the case what am I to do?

[SVOboy]

If you leave the engine off for a long time you might drain your battery, especially running headlights, radio, and fan. 2 years old isn't all that new for a battery, especially if your alternator is starting to go. I'm sure long periods of EOC are hard on batteries, but there's not much you can do unless you want to get a deep cycle battery or stop EOCing. Definitely trying to run all that stuff while EOCing is a bad idea though. I basically never EOC at night due to the draw of the headlights.

[comptiger5000]

The ideal solution is a deep cycle battery and a charger. The deep cycle won't be hurt by draining it deeply. If it's on a charger at night, you'll know it's always fully charged at the start of the day, and you should be good for a while.

[usergone]

Pretty much, if the engine is not running, the alternator is not charging the battery. If the battery is being drained by accessories, then, yes, it will go dead if not recharged. The starter will DEFINITELY put a big drain on the battery, and it takes more than a minute or two to recharge the battery from what the starter drained.

On a side note, are you sure your transmission is safe to engine off coast with? Engine on coasting with it in neutral should be much easier because you wouldn't have to stop/start the engine with the ignition.

[bobmutch]

@comptiger5000 what kind of a deep cycle battery would I get for me 1998 Volvo s70? Also what is a good charger a deep cycle battery.

Today I unpluged my headlights and will run tonight with the left light only. I will keep the heated seats off, the radio off, and the heated air off. The battery is still discharged so I need to pick up a cheap charger so I can charge that up tonight.

I am looking at a 2000 Honda Insight and would plan on getting the MIMA and FAS and perhaps an addition battery pack to supliment the IMA. I find this stuff very interesting.

[ConnClark]

I would like to note that deepcycle batteries aren't designed to deal with high current loads encountered when starting a car. Trying to do so with one will shorten its life significantly.

[bobmutch]

@ConnClark so what do I do. Sounds like I shouldn't turn the car off when I am gliding. That's nuts cus some times I glide like 1km.

[SoobieOut]

Originally Posted by ConnClark

I would like to note that deepcycle batteries aren't designed to deal with high current loads encountered when starting a car. Trying to do so with one will shorten its life significantly.

I just purchased a Yellow Top Optima battery (D51R), it is dual purpose Deep cycle and starting. Also holds it's charge for a year without loss.

Optima batteries are expensive, but it helps that I work for the company that makes them.

[ConnClark]

Originally Posted by bobmutch

so what do I do.

Give up on engine off pulse glide. Your electrical system isn't up to it.

[comptiger5000]

Connclark - A deep cycle can start an engine fine. It just outputs less burst current, so you need a somewhat bigger battery than you would with a starting battery. Starting engines off marine deep cycles is common in boats. A dual purpose starting/deep cycle like an Optima yellow or an Odyssey will work fine as well.