RacinToday

I have searched threads about use of a battery maintainer but they all seem old and contradictory on this subject: Should I disconnect the battery cables from the car before connecting the charger?
I just got a ctek 3300. Instructions do not say much about that other than to use in vented area.
The manuel says to disconnect batter.
Forum users say not necessary.
I say help.

Vlocity

I don't think it is necessary to disconnect the cables.

However, I recently added a shutoff switch to mine and I do switch the car off during the charge phase.

Here is a link to my recent post. I added a designated two pin connector so that I don't have to dig down to the battery in order to charge, the ctek 3300 looks like a nice unit.

https://rennlist.com/forums/showthre...ferrerid=19521

Regards,

Ken

springer3

It is not necessary to disconnect the battery cables. However, if you have a big drain, or if your alternator has defective diodes, the battery will not charge. I think the instruction to disconnect is to guard against defective equipment in the car.

joey bagadonuts

I think I'd follow the manual. At least you'd have recourse if you blow up your battery (which I'm sure is unlikely).
http://www.hrpworld.com/index.cfm?fo...action=product

Many trickle chargers plug into the cigarette lighter, so it would seem that unplugging is unnecessary. But if your charger is not designed to work that way, I'd say follow the manual.

Btw, are you planning to drive during the winter? If not, I'd recommend that you remove the battery, park it in your nice, cozy basement and then give it a good charge when the weather improves. That's kinda' how we do it, here, in the tundra.

Indycam

Its not necessary to disconnect the battery to charge it .
When you are driving along in your car and the alternator is charging the battery , the battery is hooked up .
The max amps on your charger is 3.3 , the alternator is 165 iirc .
A system that can handle 165 is not going to notice 3.3 .

Frank 993 C4S

It's not necessary to disconnect, however I do it both ways: On my RSA, I clip the charger directly to the battery and disconnect the battery from the car. On my turbo, I simply plug the charger into the cigarette lighter and don't disconnect the battery.

darth

Dear Racin Today

The only danger is if the battery is defective and has an open cell. A good battery acts as a buffer to limit the voltage of the charger (i.e. which can put out opwards of 35 volts ) to the battery voltage. If the electronics in the car have this voltage applied to them they will likely not survive.
There's also the danger even if the battery is good and the connection to the battery is compromised by corrosion, is intermitten or if you decide to pull the battery cable off the battery post with the charger still connected in which case the charger voltage will be applied to the sensitive electronics.
If you want to be safe disconnect the battery at least the small red one which supplies the electronics in the car.

Bill

Indycam

Darth
You know in boats , shore power chargers are built in to charge the batteries and run the electronics ?
Radar , sat nav , radios , computers , plotters etc etc etc

N51

+1
Good advice from someone likely wearing an Hawaiian shirt. Relax.
It's all pretty simple.

darth

Dear Indycam

No personal experience, but it sounds like there's some over voltage protection built into the electronics or the shore charger itself.

Bill

darth

FYI

The alternator is regulated to put out a maximum of around 14.8 Vdc which the electronics in the car can handle. The charger depending on how well it's designed can put out a lot more voltage and if it is a really poor design it may not be fully filtered meaning the DC voltage is just a half way rectified AC voltage which could peak even higher than the DC voltage measured. To get an idea of the output voltage one can measure the open circuit voltage simply by connecting a voltmeter to the charger while it is not connectted to the battery and if you have a true RMS meter (i.e. most meters are averaging meters) you can get an idea of the voltage which will be applied to the cars electronics. If you take that RMS value measured and multiply it by the root of 3 you'll get an approxmate value of the peak voltage. Check the spec sheet on the charger to see if it is regulated or not and the output voltage. To be absolutly sure contact the manufacturer and ask if there is over voltage protection built into the unit (i.e. doesn't sound like there is as you mentioned the manual suggests disconnecting the battery first) or an oscillosope can tell if the output is regulated or not and what the peak voltage is. Or you can make life simple for yourself and just avoid all the hassel of investigating and disconnect the battery first as the manual suggests.

Hope this helps
Bill

Indycam

Dear Darth
You know in RVs , battery chargers / inverters are built in to charge the batteries and run the electronics while parked ?
Nav systems , radios , computers , TVs etc etc etc

http://www.donrowe.com/inverters/pro...r_charger.html
I own a prosine 3000 .

darth

Dear Indy

I'm not sure if you're asking a question. But I'll comment on those devices . They are a combination inverter/charger. The inverter part converts a dc battery source to 120 Vac much like a UPS. The charger essentially takes the place of an automobile's alternator. It would have to increase the voltage probably somewhere around 14.8 volts so that it can pump current into the discharged battery which normally sits at 12.5 volts or less depending on the charge. Very nice units hence the price.

Hope this helps
Bill

Indycam

Dear Darth
I own one .

darth

Dear Indy

I've built them at a fraction of the price.

Bill