Battery Replacement Paranoia.

c good

Original poster
Member
Dec 8, 2011
635
I'm going to be needing a new battery soon as it is getting weak. I don't want to screw up any actuators in my HVAC system so I'm thinking of adding a memory saver during the install of new battery. I've heard mixed reviews on the OBD II port version, and mixed reviews on the cigarette/accessory port versions. So.....here's my thinking. One in the OBD II port. One in the cigarette lighter port. Any potential problem or conflict with these two in place?

I know it sounds crazy, but I've already replaced one actuator and it was a PITA....I don't want to do anymore if I can help it. c good
 

RayVoy

Member
Nov 20, 2011
939
If your careful, you can use the battery from a donor car. Connect them as you would if you were getting a boast (+ to + and - to -).

In the telephone industry, we "hot changed" batteries all the time.

You need to connect the jumper cables so that the battery cables are free and accessible, be very careful of the positive, don't let it anywhere near the body (battery neg).
Install the new battery and reconnect the terminals. Remove the donor.
 

c good

Original poster
Member
Dec 8, 2011
635
Thanks for the input Rayvoy. I've though about this also, but the side terminal cable lugs are well insulated and would be tough to connect a set of jumpers to during the swap. Was just wondering if two memory savers would be a problem......Roadie......paging Roadie....:smile:
 

northcreek

Member
Jan 15, 2012
3,374
WNY
I just bought a cig lighter extension cord,cut off the female end,put alligator clips on that end and connected it to a donor battery...just watch the polarity...Mike.:thumbsup:
 

MAY03LT

Member
Nov 18, 2011
3,426
Delmarva
A little overkill but as long as the battery in each saver is ok that would work.

I've used both and they both work great. I think the mixed reviews come from folks who don't wait for everything to time out before disconnecting the battery. Most of them are only protected to 4-5A which isn't a lot when a lot of juice flows when a door is opened.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
You can easily use the ground on the fender, and the megafuse stud in the fuse block for the +12, for the aux battery. No need to touch the insulated screws on the main battery.

But you probably already know my opinion - weak actuators should be ENCOURAGED to fail at a time and place of your choosing, even if it's tough to replace. Don't coddle them and just hope you never discharge your battery when you're far from home in a very hot or cold place. Weak actuators are a ticking time bomb and need to be defused, even if means killing them off.

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C-ya

Member
Aug 24, 2012
1,098
So what happens if no circuits are powered up (no lights on, no radio, etc.) when you disconnect the battery to replace it? My truck failed to start this morning, but I did have lights and indicators and what not and such. I'd like to get a new battery and just replace it. Must one use an external voltage source? What are we hoping to accomplish by keeping the circuits alive? I am gathering that it may adversely effect the climate control system if there is no voltage, but is there anything else to worry about?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Besides killing off weak HVAC actuators, a battery disconnect will also cause the PCM to lose its memory, which will result in bad idle if you have a sticky/dirty throttle body. But no GMTN member will ever have such a bad throttle body because we all know to clean it before it gets to that point. :wink:
 

C-ya

Member
Aug 24, 2012
1,098
OK, so nothing major? My throttle body is clean. Just want to make sure there will be no adverse effects when I do a quick swap.
 

c good

Original poster
Member
Dec 8, 2011
635
C-ya said:
OK, so nothing major? My throttle body is clean. Just want to make sure there will be no adverse effects when I do a quick swap.

"Nothing Major" is a relative term. HVAC actuators have a high failure rate with battery disconnect. Just do a search on them. Also, they are a huge PITA to replace and also expensive to buy. I've done one already....really don't want to do another one for a simple battery disconnect when a memory saver could save the day. How "quick" you are makes no difference. Any loss of power forces a recalibration of the actuators. Roadie has taught me well. :smile:
 

C-ya

Member
Aug 24, 2012
1,098
Must've gotten lucky, then. I hooked the lawnmower battery up to the truck while I pulled the battery out and ran to Auto Zone. When I got back, I bumped the cable on the hot side and it sat there and sparked for a few seconds. Couldn't figure out what that was about... "Screw it," says I, and I unhooked the cables and finished hooking the new battery up. Got in, started up and drove to work. Checked all my flow paths and they all worked as advertised.
 

c good

Original poster
Member
Dec 8, 2011
635
Glad to hear you took some precautions and it worked out. Thanks for the update. c good
 

BaDAppLe

Member
Jun 28, 2012
51
I replaced a weak battery in my 06 TB with no substitute power, and had no problems at all.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
BaDAppLe said:
I replaced a weak battery in my 06 TB with no substitute power, and had no problems at all.
But you know that's just statistical evidence that some (perhaps most) folks have no problems. For folks who worry about the actuator issue, it's a real worry.

I've disconnected my battery 50-60 times, and other than the 3rd or 4th time where I lost a weak actuator, I never have a problem either. But then removing the dash to get at an actuator is not a worry. Actually, I'm considering throwing the dash away altogether if it annoys me one more time.

dash03.jpg
 

c good

Original poster
Member
Dec 8, 2011
635
:smile:
the roadie said:
But you know that's just statistical evidence that some (perhaps most) folks have no problems. For folks who worry about the actuator issue, it's a real worry.

I've disconnected my battery 50-60 times, and other than the 3rd or 4th time where I lost a weak actuator, I never have a problem either. But then removing the dash to get at an actuator is not a worry. Actually, I'm considering throwing the dash away altogether if it annoys me one more time.

dash03.jpg

:rotfl: Classic shix......so true too.....
 

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