Battery and alternator questions
 

Over the winter I've had the battery in the HHR die on me twice. So I'm planning ahead on what to replace it with, but I have some questions that my google-fu isn't handling.

First of all, the HHR battery is mounted in the rear with the spare tire. It is vented to the outside. How much does a battery regularly vent, and hazardous are the fumes? Where do batteries without hook ups for venting tubes vent from? Are there holes that vent lines can jury-rigged too, or does the entire thing need to be vented?

Since I EOC, I would like to get a dual purpose or deep cycle battery. Finding one that has the vent hook ups as been problem, and space next to the spare might be tight. An AGM battery might be ideal, but they require a lower float charge, and I haven't had luck on finding out how to adjust it, if possible, or what exactly the HHR is even putting out.

If, for what ever reason, I'm stuck with an OEM battery, would using two to spread out the strain of FASing be worth the effort?

Re: Battery and alternator questions
 

Generally battery gasses are not a problem, unless there's something wrong with your alternator and its overcharging the battery. You can get a gel cell for the car, they are sealed and don't have vents, but they are expensive. Just about any lead acid battery is going to require vents.

Re: Battery and alternator questions
 

With what I knew, I wasn't to concerned with fumes. I could always seal up the cover of the spare well and drill a couple of vents. Just better to get some other opinions.
I took a look yesterday and the vent line was already broken. Not having seen a new battery, I don't know if it was a part of the car, or of the battery the snapped.
An OEM battery starting cost starts at around a $100. Like the ecotec oil filter and Prius 12 volt battery, the price is likely do to the vent hook up and limited specific application for the battery.
The hassle now is finding another battery that meets my required specs without going through a car model search.

Re: Battery and alternator questions
 

$100 isn't too bad. Around here you pay $65 at Walmart or $80 at a parts store for a cheap battery.

Re: Battery and alternator questions
 

They range up to $150, and I found an Optima yellow top on Amazon for $172.

Re: Battery and alternator questions
 

Just remembered the scangauge has a voltage display. The lowest reading on it is 13.8vlts, which is the highest an optima can take as a float charge. And I'm not sure when the voltage climbs if it the system is ramping up into charge mode for the battery.

Re: Battery and alternator questions
 

Be better to figure out why you keep killing batteries than to just be replacing them. Most lead batteries are not going to vent anything if they are below 14.25 volts and if you find that your dead batteries are running dry then check for over charging. EOC is going to be draining the battery and depending upon how long it can add up to a lot of amp hour cycling of the battery. Might be a good idea to measure the draw under those conditions.

Re: Battery and alternator questions
 

This is first battery that has given me problems in a vehicle that is regularly EOCed. This is the second battery that has been placed in the car. The first was replaced under warranty do to a bad cell. That was before I took possession of the car 3 years ago.

I'm sure EOCing is shortening its life. It is just a starter battery, and not meant for repeated deepish cycling. At moment, I'm not worried about the battery stranding me. The couple times it left me in a jam, may actually have been the computer overriding the ignition. It has a battery saver mode that prevents the starter from firing up when the battery is below a certain threshold, 10 volts I believe. I've backed off EOCing to be safe, because I have seen the voltage dip that low.

While I don't feel pressed to replace it now, I want to be ready for when the time comes to replace it with a dual purpose battery that can shrug off the EOCing. The first hurdle is the venting. Not that I'm worried about fumes. In fact, I just noticed the vent line is broken, and may have been since I got the car. The vented requirement just eliminates the ease of basic part look up menus.

The second hurdle is the float voltage. I have found the optima product that will work. Except it, and all AGM batteries, can't tolerate the higher float voltages that car charge systems equipped with traditional lead acid batteries might put out.

Re: Battery and alternator questions
 

How long do you EOC? I think you'd need to go at least 5 minutes with your headlights on to drain the battery down low enough to shorten its life.

But if you live in the mountains, then a 5 minute+ EOC is very possible...

Re: Battery and alternator questions
 

If you're going down a mountain, you're better off to DFCO down the mountain. Battery is not depleted, and the engine braking helps keep your brakes from overheating.

Re: Battery and alternator questions
 

With a little luck, I can EOC for nearly a mile in some locations.
The car doesn't DFCO without downshifting or starting at highway speeds. Both which means losing too much speed for a coast.
To keep costs down, starter battery plates are made of a foamed alloy to increase surface area. Which is fine for their intended job, but doesn't last once it starts getting used as a deep cycle. On top of that, this battery is probably the smallest one GM could get away with, and I likely didn't let it fully charge between EOCs at times.

I did get a chance to check the voltage between the battery posts with the car running after a drive. Voltage was below 13.8, so I won't worry about an AGM. Just got to fix up the wife's car first.

Re: Battery and alternator questions
 

In my Buick, I run dual batteries. One is a regular starting battery, and one is a marine deep-cycle (27 series).

I have a high-amperage switch that connects them when I want, and disconnects them when I want to run some hi-amperage stuff off of the deep-cycle without affecting my primary battery. (Mostly the electric fans and nitrous bottle heater while I'm at the dragstrip between rounds).

A better option is a battery isolator. That would allow you to run most of your components on the deep-cycle (if you re-wire accordingly), without discharging your starting battery, but whenever system voltage is high enough it will recharge both batteries.

And BTW I have an extra isolator that I'd be happy to send you for the cost of shipping - NIB...

(The disadvantage to the isolator system is that you can't start the engine from the deep cycle, so if your primary battery dies then you have to get out some jumper cables. In my Buick, there are times when I need a WHOLE lot of amps to start the engine, so I frequently have to use both batteries as "starting" batteries, and the high-amperage switch allows me to do this. But if you install the system as I describe above, you should be fine.)

-Bob C.

Re: Battery and alternator questions
 

You should have the battery back up to 14-14.25 volts before you shut it down or else get a 110 volt charger to top it off from the grid. What kills a battery fast is leaving it not fully charged. Also getting down to 10 volts is too low, 10.8 volts is a dead battery I.E. 100% discharged which will really shorten the battery life. Engine off coasting a mile is not a problem but not charging afterwards is a problem.

Re: Battery and alternator questions
 

The battery isolator sounded like it could be the ideal solution. I figure the lights, fans, and radio are the main draws while off. Could I just wire the second battery into the main fuse panel? That seems to be the simplest way, but I haven't played around with automotive electrical systems. The main hold up was cost, but if you are willing to part with an isolator, I won't complain.

The battery was replaced within the first year. It's a 6yr battery coming on 5 years of age. So replacing it before winter would be prudent.

When I measured the voltage at posts the engine was running. The info I had said this was a measurement of the float charge on the battery, not the battery's voltage. This was after a 50 to 60 minute drive without EOCing, and the scangauge reported 14.5 volts at times, so the system did enter charge mode during the ride.