Good morning everyone,

I have a general question regarding use of any type of battery charger / maintainer on the HV battery. I have a 2008 escape hybrid. Currently my battery is working great. Just coming up on 100K miles.

My question is can you, or is it beneficial for the longevity of the battery, to use any type of battery charger and maintainer on the HV battery? I live in Alaska and use maintainers on all my batteries that sit out in the cold during the winter months. This car stays in the garage, but we do not drive everyday. My girlfriend also leaves for 3 months at a time on work contracts, so having something for long term storage (1 week or more) sounds beneficial, but I wanted to ask people who are much more informed on the workings of hybrid batteries than I am.

I have seen many posts about the HV battery dying after sitting and discharging for a week or more. I don’t have that problem but would like to take as best care I can of this thing. For the record I am not super savvy on battery lingo, just looking for some general thoughts on if this would be a good idea to maintain the battery and if a specific brand or type of maintainer is best.

Thanks everybody and happy thanksgiving

-Tanner

 

NiMH is different from lead acid.

Drive your vehicle regularly at least 3 days per week, average of 10-20 miles per drive - vehicle must come up to full operating temp.

If going to leave sitting for more than 2 weeks:

Disconnect negative terminal from 12V battery
Put 12V battery on float charger.
Disconnect data plug (10mm bolt head - loosen and remove, bolt does not come out - part of plug) and jump starter plug from front driver side of HV battery.

Upon return:
Reconnect HV battery plugs.
Put at least a 10A charger on the 12V.
Press HV jump button
Wait 15 minutes
Press HV jump button
Wait 15 minutes
Start vehicle.
Turn off interior heat and any other accessories.
Allow car to idle 15 minutes OR until the engine automatically turns itself off.

At that point it is safe to resume normal operation.

 

Thanks for the response.

Can is do any damage to the vehicle to have the 12V battery hooked up to a 1-2A battery charger maintainer? I keep all of my batteries on a noco charger.

-Tanner

 

If the charger continuously delivers 1-2A, it will destroy the battery. If it's designed to maintain full charge of the battery in a "float" state, then it's fine.

Regardless, the 12V should be disconnected from the vehicle.

 

Got it, I have a 1 amp noco genius that isn’t supposed to overcharge. With the ignition off does that not isolate the HV battery?

Long term I think the hybrid is not the right car for me. Works great right now, but I don’t drive regularly enough and the cold weather is pretty tough on it too. Long term I’ll have to figure out something better.

Wanted to thank you for your help on here, you’re a real wealth of knowledge! The eCVT fluid change info is especially helpful. I’m just coming up on 100k maintenance, so it’ll get a flush now and with each oil change.

Thanks again,

Tanner

 

Owner's manual explicitly states to disconnect the 12V battery or HV battery discharge will occur.

 

Any insight as to why disconnecting the hv disconnect plug would not keep the hv battery from discharging while keeping the other stored module’s memory intact? I am just trying to understand the system, not disputing your (or Ford’s) recommendations.

 

Yes. The HV disconnect's only function is to physically break the circuit roughly splitting the pack into two halves for safety purposes. It can't prevent discharge. Even if it could, when ignition is off, the HV battery is isolated from the vehicle via the relay mentioned in the Jump start thread, i.e., when the ignition is off, it's like the big orange power cable is disconnected.

Internally the battery is wired extensively with a sensing harness monitoring the pack every 10 cells. That's 26 different connections to the battery computer feeding voltage information. When measuring voltage, one must allow a very small amount of current to flow.

Give this, neither the relay or the hv disconnect can prevent discharge.

Disconnecting the 12V de-energizes the battery computer disabling monitoring and presumably prevents this "internal" discharge.

Unplugging the data plug from the battery completely isolates the battery from the car at all levels and is a further safety precaution. It's also useful for troubleshooting an excessive discharge situation.

 

That makes sense. Thanks for the info.

 

I am just trying to understand the system, not disputing your (or Ford’s) recommendations.