Battery trickle charging in freezing weather

[Eric Fairclough]

At what temperature should one take a trickle charger off of a battery? It is in the teens here and i do not have it on but wold like to put it on. I had to keep it outside this winter with a waterproof car cover on it. Thanks in advance. Eric

[Gerry Proctor]

Re: Battery trickle charging in freezing weather

It depends on what type of charger you're using and what kind of battery it is, Eric. If the charger has an automatic maintenance switch, then you don't have to worry about temperature. It will cycle on and off to maintain a certain voltage. If it is a constant charger, then you need to monitor the battery voltage to determine when it needs a charge and when to take it off. You do not want to continue to put current into the battery once it holds a steady 12.6 volts.

As to the battery itself, if it is a maintenance free battery in very good condition but is sitting idle, you may only need to hit it every couple of weeks or so. A good battery that is idle should only loose around 10 percent of its charge per week or so depending on what climate its in. A poor battery requires a lot of attention. Something like an Optima redtop, you may not have to do anything at all.

[Jim T.]

Re: Battery trickle charging in freezing weather

When I do not intend to drive my 68 or 70 for a week or so, I remove the bolt (wrench size 5/8) that secures the negative battery cable to the frame. Real easy to do to prevent any drain on the battery, real easy to reinstall. The battery can still be charged also. I think this is a lot easier than doing it from the battery, only takes about a minute.

[Eric Fairclough]

Re: Battery trickle charging in freezing weather

I have a postive disconnect switch on the battery positive. I turn the green knob to disconect it the put the charger on it. I have a trickle charger that turns itself on and off when needed. I was wondering if the battery acid will freeze in cold weather and if it is frozen is it bad to have the charger trying to charge frozen battery acid? Thanks Eric

[Duke W.]

Re: Battery trickle charging in freezing weather

As a battery discharges the freezing point of the electrolyte increases, so there is a risk of freezing the battery if it is discharged. If you keep the battery charged with a trickle charger or battery tender, freezing is unlikely at temperatures abouve -20F. Also, the chemical reaction of the trickle charger itself will keep the battery warmer than the surrounding air.

On the plus side, the colder the battery temperature, the lower the inherent discharge rate.

Duke

[Michael W.]

Re: Battery trickle charging in freezing weather

Eric,

My long suffering daily driver sits outside in temperatures as low as -30 degrees C without battery (or starting) problems. As long as the battery is fairly well charged the freezing temp of the acid is so low that it's not a concern.

Sounds like you're doing the right thing by keeping it charged.

However, if you think or know the battery is frozen, DO NOT put a charger on it! There is an explosion hazard here. Remove the battery and bring it in the house allow it to slowly warm up to room temp sitting in a PLASTIC pan, or better yet bring it to the battery shop for testing. Chances are that if it is frozen, it's junk.