Using the 12V 18AH Batteries in a car

[Racer26]

I'm having problems with my car, its 12V battery is not holding a charge well at all. I've had to boost it 4 times in the last 72 hours.

Ordinarily I would say that our robot batteries are not well suited to automotive use, however my car is no ordinary car.

I drive a 2001 Honda Insight. Its a 3 cyl- 995cc Gas-Electric Hybrid. 99% of the time, it uses its 144V IMA battery pack to start the engine. The 12V battery is simply there to energize the computers. Once the engine is running, the car uses its on-board DC-DC converter to keep the 12V system operational (there is no alternator).

If the 12V battery is dead when you go to start the car, the computers won't power up to initiate the IMA start.

Climate-wise, where I live, we frequently see overnight lows in the -15 to -25C range. If it is extremely cold out (-30C or lower I believe) the car will try to start using a 12V starter and the 12V battery.

Would a robot battery be sufficient under such conditions? They're quite a bit cheaper than typical low-end car batteries, which IMO are overkill for the application.

[Alan Anderson]

You can "jump-start" the hybrid vehicle with a robot battery (or even with a couple of 6v lantern batteries). But I would not want to leave one connected full time in a system designed for a larger lead-acid battery. The charging circuitry is likely to be unsuitable for a robot battery.

[MrForbes]

Low end car batteries cost at least $50 around here, which is similar in price to the robot batteries.

If I were in your situation, I'd look to see if I could find a riding mower battery. They are flooded lead acid, and are usually closer to $25. But at this time of year, you may not find any

[Mark McLeod]

Would a snowmobile battery be appropriate?
Probably easier to obtain this time of year up north.

[Racer26]

Originally Posted by Alan Anderson

You can "jump-start" the hybrid vehicle with a robot battery (or even with a couple of 6v lantern batteries). But I would not want to leave one connected full time in a system designed for a larger lead-acid battery. The charging circuitry is likely to be unsuitable for a robot battery.

This is certainly possible to do. I believe its even possible to "jump-start" it (since you're not cranking the engine) with 8 D-cells in series.

Originally Posted by MrForbes

Low end car batteries cost at least $50 around here, which is similar in price to the robot batteries.

If I were in your situation, I'd look to see if I could find a riding mower battery. They are flooded lead acid, and are usually closer to $25. But at this time of year, you may not find any

The low end car batteries I can find are more like $80-100+tx (which is 13% here). A riding mower battery *might* work.

Originally Posted by Mark McLeod

Would a snowmobile battery be appropriate?
Probably easier to obtain this time of year up north.

A snowmobile battery might just be the ticket. Good idea. I'll research those.

[Al Skierkiewicz]

Even for small motors at this temperature the current required will be like putting a short on the battery. Even though the robot battery can produce 600 amps fully charged, it can only do that for a short period of time.

[Alan Anderson]

Al, the Insight's 12 volt battery doesn't run a starter motor. It runs the powertrain control computer (and a few other incidental 12 volt loads). It doesn't need to supply much current at all in order to start the system. Once everything is up and running, the hybrid powertrain's batteries keep the 12 volt battery charged.

[Racer26]

Originally Posted by Alan Anderson

Al, the Insight's 12 volt battery doesn't run a starter motor. It runs the powertrain control computer (and a few other incidental 12 volt loads). It doesn't need to supply much current at all in order to start the system. Once everything is up and running, the hybrid powertrain's batteries keep the 12 volt battery charged.

Being totally correct, the Insight's 12v battery does OCCASIONALLY run a starter motor, but only in extremely cold temperatures, or when the 144v battery is flat (generally doesn't happen), in fact, its only happened to me once the entire time I've owned the car (almost 2 years)

The OEM battery for an Insight has about 270CCA, and Al seems to be approximately correct in its rated AmpHour capacity. Its definitely a small engine that doesn't require much oomph to start (995cc, 3cyl, takes a whopping 2.6qts of 0W20 oil to fill it). Honda doesn't even sell the original battery anymore, instead offering up a typical Civic battery, rated for around 500CCA as the replacement part.

I've seen our robot batteries used in an automotive application before on a dune-buggy, running a 4cyl GM Engine IIRC, but I don't think it runs in the winter.

Having looked at the datasheet for the Enersys battery, it seems to show that its operating temperature range ends at -20C. I will definitely see winter temps below that in a given year, so while it might work, its probably not the optimal choice.

Kind of makes me wonder though, what ordinary car batteries are typically rated for in terms of operating temperature range... surely car manufacturers aren't putting MIL spec batteries in our cars...

[Mr V]

You really should start the vehicle with the 12v starter at least once per year. If you take it to a reputable Honda dealer, that pays their technician the proper rate for an oil change service for an Insight, and the technician doesn't "forget" to do it so they can bill more hours, they will "exercise" the 12v starter at least every other oil change if not every oil change. In other words the 12v starter is never properly exercised unless the owner does it on their own or the vehicle is operated in conditions where it won't use the IMA to start the engine.

This can be done one of two ways. You can either turn off the IMA battery pack with the switch under a cover under the mat in the cargo area (Honda recommended method) or you can remove the #2 fuse.

[Racer26]

@Mr V: You seem to know a lot about my car. Are you an insight owner too, or are you just looking this stuff up? Most people barely know these cars exist.

I know my 12V starter works fairly well. I had an issue with my HV battery last year where it blew the 100A semiconductor fuse, resulting in the car starting on the 12V for a period of a few weeks while the parts came in. I was just saying I've only ever had the car start on the 12V once due to weather conditions and such. Perhaps you're correct though, maybe I should intentionally force it to start on the 12v once in a while, just to keep the 12v starter running nicely, albeit unrelated to my current battery problems.

My father actually runs a repair shop, so he does the routine maintenance and most repairs. I live about 1hr from my workplace, so I do about 1000km (~600mi)/week. I change the oil 8-9 times a year (about every 6000km, sometimes as much as 10000km). Honda specs 12,000km cycles in most of the continental US, and 6,000km cycles in "heavy-duty" climates, meaning lots of dust (like the deserts of the western states) or extreme hot, or "Canada"). Naturally, I find it reasonable to believe that if a 12,000km cycle is ok in Buffalo, NY (according to Honda's guidelines), that stretching it past 6000km in Southern Ontario won't hurt anything.

[Mr V]

Originally Posted by 1075guy

@Mr V: You seem to know a lot about my car. Are you an insight owner too, or are you just looking this stuff up? Most people barely know these cars exist.

I know my 12V starter works fairly well. I had an issue with my HV battery last year where it blew the 100A semiconductor fuse, resulting in the car starting on the 12V for a period of a few weeks while the parts came in. I was just saying I've only ever had the car start on the 12V once due to weather conditions and such. Perhaps you're correct though, maybe I should intentionally force it to start on the 12v once in a while, just to keep the 12v starter running nicely, albeit unrelated to my current battery problems.

My father actually runs a repair shop, so he does the routine maintenance and most repairs. I live about 1hr from my workplace, so I do about 1000km (~600mi)/week. I change the oil 8-9 times a year (about every 6000km, sometimes as much as 10000km). Honda specs 12,000km cycles in most of the continental US, and 6,000km cycles in "heavy-duty" climates, meaning lots of dust (like the deserts of the western states) or extreme hot, or "Canada"). Naturally, I find it reasonable to believe that if a 12,000km cycle is ok in Buffalo, NY (according to Honda's guidelines), that stretching it past 6000km in Southern Ontario won't hurt anything.

Nope not an Insight owner, a former mechanic that has taken training on hybrid vehicle service. At the time I took the classes the only Hybrid cars on the road were the Prius and Insight, though we did briefly cover the just being introduced Escape.

[Mr V]

Yes it should work fine. The DC-DC converter should monitor the charge current and voltage and no overcharge the battery. It is not like the FRC battery is that much smaller than the tiny battery that the Insight is equipped with.

The bigger issue I see it connecting it to the car which is equipped to connect to a battery with automotive post connections. For the ground you could probably get away with leaving the factory cable dangling and make a new one but for the positive depending on where it goes it may be difficult to substitute something else. You really don't want to cut the end off of a $50 battery cable to save $30~$40 on a replacement battery. Then add in the cost of the new ground cable and you are likely creating a false economy and it would be cheaper in the long run to replace it with the proper Group 51 battery.

[Al Skierkiewicz]

The cross reference I just checked says the replacement battery is 41 AH vs the 18 AH FRC battery.