12V Battery Replacement - GreenHybrid

GaryG · #1 (**permalink**) 10-01-2007, 06:53 PM

My Hybrid Tech stated that he had to use the built-in Jump-Start Procedure 3 times before my Hv battery would start the ICE . He said it was getting near 3yrs old and the heat here in Florida takes a toll on it so I should consider replacing it.

Suggestions have been around that our standard car battery should be replaced with a deep cycle battery. After thinking about that for a while, I decided I would stay with a battery that met the specs of the original OEM. I have been noticing a drop in my battery SoC even while my generator was charging my Hv battery. I thought the 12V battery was taking a big adjustment from the DC/DC converter to top it off when I seen those drops in the SoC . It seems that this is happening more often now. For all of the reasons above, I've been looking for a replacement. After all, if replacing a 12V battery may improve my mileage by holding a charge longer, it may be worth it.

At first, I thought just go to Sears and get one of their best Diehard batteries. Sunday I was in Costco and thought I'd take a look at the replacement they recommend from their line. Costco listed a 96R, 500 CCA for a replacement, but they had none in stock. Today, I called Sears and they said they only had a Diehard Gold that would fit. When I ask for the specs, they gave me a 40R, 590 CCA. I told them that Costco's book said I needed a 96R, 500 CCA, but he said Ford recommended their 40R battery as a replacement.

At this point, I did some research to find out what the difference was, and looked at the battery in my FEH for the specs and measurements. I found that the 40R and the 96R had to do with the measurements and CCA ratings. The stock Motorcraft battery was a BXT - 96R, 500 CCA. I've always thought the stock Motorcraft batteries were junk and I would never replace one with another.

After digging into warranty and size, I found the Sears battery would not fit, and I had the same problem in a Ford Focus I own a while back. I was not about to cram a big battery in the holder again. The generic 96R was very close to the stock replacement size, but I would still not have a perfect fit in my stock battery holder as the stock Motorcraft battery.

Both the Costco and the Sears batteries had a 3yrs replacement and 100 month prorated warranty. The Sears wouldn't fit and the Costco 96R was not in stock, so I did some research on Motorcraft batteries.

The higher end Motorcraft battery offered the same warranty as the Sears and Costco battery. At this point, I called the dealership and ask if they carried the higher end "MAX" Motorcraft battery. They told me no, but they had the stock BXT - 96R that was the stock battery for the '05 FEH for $85 which was $2 less than the Sears that didn't fit. Then, I found out that the BXT - 96R Motorcraft battery had the same warranty as the Sears and Costco battery, which was 3yrs full replacement, 100 month prorated coverages.

I had no idea I have 6 months of full replacement value on my stock battery. Any recommendations or ideas of what I should do?

GaryG

DavidH · #2 (**permalink**) 10-02-2007, 03:49 AM

You could experiment and put in a deep cycle battery.

I cannot imagine anything on our vehicles that needs anywhere near the cranking amps needed to start the engine. The highest current could be the electric power steering,

WaltPA · #3 (**permalink**) 10-02-2007, 04:05 AM

I thought a deep cycle battery was for deep cycles. A deep cycle is when you drain the battery dead, or near dead, and then recharge it.

I would think that our application is the exact opposite. Since we don't even use the 12v for starting, we hardly drain it at all. We use just a little bit of power from the battery initially for some electronics, and then recharge it.

Actually, what we might really need is some sort of NiMH or Lithium based 12v battery. Some technology that might be better suited for light draws and constant recharging?

DavidH · #4 (**permalink**) 10-02-2007, 06:25 AM

Deep cycle batteries have thicker plates, so they last longer. They have the greatest life when they are not completely drained, then recharged. Golf carts also use this type of battery, so they do produce good amperage, just not 500 amps!

Starting battieries have thinner, closer spaced plates to increase the surface area. THis gives a lower internal resistance (higher cranking amps). But, thinner plates mean lower life.

GaryG · #5 (**permalink**) 10-02-2007, 08:14 AM

Quote:

Originally Posted by WaltPA

I thought a deep cycle battery was for deep cycles. A deep cycle is when you drain the battery dead, or near dead, and then recharge it.

I would think that our application is the exact opposite. Since we don't even use the 12v for starting, we hardly drain it at all. We use just a little bit of power from the battery initially for some electronics, and then recharge it.

Actually, what we might really need is some sort of NiMH or Lithium based 12v battery. Some technology that might be better suited for light draws and constant recharging?

I agree Walt, also I'm concerned a deep cycle may not be able to stabilize the voltage as good as higher CCA battery. If the DC/DC converter has times where it falls short to provide the steady amps needed to to run the heavy electrical loads, the system components could be damaged. We not only have electric motors for power steering, we have them for brakes, 2 coolant pumps, fuel pump, 2 battery fans, radiator fan, HVAC fan, seat adjustment, windows, wipers, lights, CD players, warning systems and safety systems. The Jump start system also needs a quick dump of the 12V battery battery and I'm just concern a deep cycle battery is not meant for our vehicle even though we don't have a 12V starter.

The car batteries are now offering much longer warranties and that's what shocked me with the OEM Motorcraft battery. My question was meant to ask should I go ahead and change my 12V battery when I have 6 months left on a full replacement warranty? The Tech was saying the battery is still good enough after draining it three times for the jump start procedure, but I should consider changing it. I think what he was saying was I can't get it replaced under warranty, but it needs to be replaced before it gets that bad. Also, has anyone replaced their 12V battery and was it covered under warranty?

GaryG

DavidH · #6 (**permalink**) 10-02-2007, 08:48 AM

One poster says light loads, another says heave loads. But, are there any high peak (+100 Amps) loads?

Mark E Smith · #7 (**permalink**) 10-02-2007, 10:43 AM

I am not sure what would be gained by using a deep cycle battery. You certainly don't have a proper use for a deep cycle battery and the constant topping of of the SOC of the 12v battery might hurt the deep cycle battery. The largest load is the "jump start" and a deep cycle may not be able to deliver a high enough amperage. I would get a good high cca auto battery.

WaltPA · #8 (**permalink**) 10-02-2007, 11:08 AM

Quote:

Originally Posted by DavidH

One poster says light loads, another says heave loads. But, are there any high peak (+100 Amps) loads?

There shouldn't be any high peek loads.

The HV battery takes care of the heavy loads. The only loads the 12v "sees", is the control for the HV battery (turn HV battery 'on", etc). Basically, the power to enable the car when you turn the key 'on'.

guerinkeywest · #9 (**permalink**) 10-02-2007, 11:11 AM

I'm leaning towards deep cycle on this one. I have worked extensively with marine battery systems and think that the lower number of plates but thicker plates wins this discussion if this discussion is about long reliable battery life. We do not need hundreds of amps, even when it is used to charge the traction battery. The amount of 12 volt current we will need is probably limited by the 12 volt to 330 volt inverting electronics and that probably limits it to 50 amps (Guessing but I would really think 20 amps is a better guess) as the cost of high current switching supplies get real high. If you can use lower current and a little more time then the dollars saved will be high. How many minutes does it take to charge the traction batteries?

WaltPA · #10 (**permalink**) 10-02-2007, 11:49 AM

Someone has mentioned that the emergency "jump start" does not involved up-converting the 12v to 330v to charge the HV battery, but instead just heats the HV battery using the 12v to power the coils. Apparently, just heating the HV battery can/could get enough extra out of it, to do one more ICE start.