Car battery charger/maintainer: CTEK vs Battery Tender?

[samgab]

My car sits for months on end, whilst I walk to work etc.
Recently I went to start my car and all I got was clicks... The battery had discharged.
I used my hobby charger yesterday to give it a charge, using "PB" mode.
But I think I should get a dedicated car battery charger/maintainer.
The
CTEK MXS 5.0
and the
Battery Tender 5.0 Amp
caught my eye.
Anyone own either of these, or their older model equivalents?
Thoughts, experiences, opinions?
Other options I should also consider?
In a follow up post I'll put up the charge profile from the hobby charger, just out of interest.

[Gene]

Hi samgab,
I notice you're in New Zealand where the standard current is 220V or thereabouts. I don't know anything about 220V so I can't comment on that.

I have one of the original Battery Tenders that I bought over 20 years ago. It has been a Godsend and has extended my vehicles batteries to almost unbelievable longevity.

I put all my batteries on the Battery Tender once a month, (weather permitting because we get heavy snow storms here), and my motorcycle battery just died after 11 years!

My recommendation to you is don't go for the 5 amp battery chargers but go for one that has a 1 amp or lower charging rate.

It will be kinder and gentler on your battery.

[samgab]

Hmm, thanks for the feedback Gene.
Battery tender have this model, with international voltage, works on our 240V AC at 1.25A charge rate.
And CTEK have this model with a 0.8A charge rate.
Battery tender have a 10 year warranty, and CTEK have a 5 year warranty.

[samgab]

I put this chart up, just because I find this sort of thing interesting, and it relates to this thread:


Using a Hobby charger, Turnigy Accucell 8-180 to be precise.
The battery is a 12V, maintenance free, 36Ah SLI Bosch battery.
I have no idea how old it is... It came with the car.
I selected a 3.6A rate, which meant that when it went into constant voltage mode, it cut out when it reached 1/10th of that, or 0.36A.
It uses the proper algorithm for charging PB batteries, and although it says 14.7 V is the fixed voltage - due to voltage drop I guess - I was measuring 14.4V at the battery, which I'm happy about. 14.7V seems a little high.
The 36Ah battery took a total charge of about 10Ah, or 100Wh.
The peak Wattage draw was about 52 Watts, which caused my power supply to heat up a bit at the heat sink.
That was at ~3.6 Amps and ~14.7 Volts. The power supply is rated for 13.8V and 6-8 Amps, or 82-110 Watts, so it should comfortably handle that rate.

Anyway, it was an experiment more than anything, and I'll get a dedicated charger/maintainer like the ones mentioned above.

[Gene]

samgab,
To me, even 14.4 volts is high. Ideally, your battery should read around 12.7 volts and no more than around 13.2.

I have no experience with the CTEK charger but I would go with the Battery Tender you linked to as they have been tried and proven for years and 1.25 amps is a pretty ideal charging rate.

[deadrx7conv]

Get a solar panel, like what VW uses on their new cars in shipping and when sitting on the dealer lot. Ebay usually has a good choice of <5w 12V solar battery tenders.

[samgab]

samgab,
To me, even 14.4 volts is high. Ideally, your battery should read around 12.7 volts and no more than around 13.2.

I have no experience with the CTEK charger but I would go with the Battery Tender you linked to as they have been tried and proven for years and 1.25 amps is a pretty ideal charging rate.

Cheers for that... RE the voltage. That was tested during the charge, which is correct. They go up to ~14.4V whilst being charged, then when the charge voltage is removed, they quickly drop back to about 12.8 depending on battery state, state of charge, and temperature etc. I did a whole lot of reading about it. http://www.batteryfaq.org/ is a fantastic source of info for this type of battery. As for rates, the manufacturer recommends 1/10 C for the bulk charge portion, which with my 36Ah battery would be 3.6A... 5A would be a bit high. But I'm thinking of getting a higher capacity battery in due course, something like a 45-50Ah, in which case 5A rate would be ideal. But lower won't do any harm, just be slower to get to the next phase of charging. And the 5A CTEK one has a 0.8A mode as well for smaller batteries.
I'll see if we have a local dealer or supplier for the Battery Tender brand... I prefer to have a local dealer when getting something with a 5 or 10 year warranty; if there is a problem, shipping costs and delays can be a problem.

Get a solar panel, like what VW uses on their new cars in shipping and when sitting on the dealer lot. Ebay usually has a good choice of <5w 12V solar battery tenders.

Thanks, except my car is stored in a dark garage, no access to the sun

[Bobby_C]

I've been using 2 battery tenders (Plus and Junior) for all my motorcycles. They're great. The Plus charges at 1.25a and the Jr is at 750mAh.

[samgab]

Oh yes, I should update:
I went with the CTEK MXS 5.0, because it has good local dealer support, and it seemed like a really good product.



After using it for over a Month now, I am extremely impressed, and cannot recommend it highly enough.
It works really well, you can select a low charge rate of 0.8A for smaller batteries, or 5A for higher capacity ones.
It has a multi stage method of charging:
STEP 1 DESULPHATION
Detects sulphated batteries. Pulsing current and voltage, removes sulphate from the lead plates of the battery restoring the battery capacity.
STEP 2 SOFT START
Tests if the battery can accept charge. This step prevents that charging proceeds with a defect battery.
STEP 3 BULK (AKA CC or Constant Current mode)
Charging with maximum current until approximately 80% battery capacity.
STEP 4 ABSORPTION (AKA CV or Constant Voltage mode)
Charging with declining current to maximize up to 100% battery capacity.
STEP 5 ANALYZE
Tests if the battery can hold charge. Batteries that can not hold charge may need to be replaced.
STEP 6 RECOND
Choose the Recond program to add the Recond step to the charging process. During the Recond step voltage increases to create controlled gassing in the battery. Gasing mixes the battery acid and gives back energy to the battery.
STEP 7 FLOAT
Maintaining the battery voltage at maximum level by providing a constant voltage charge.
STEP 8 PULSE
Maintaining the battery at 95–100% capacity. The charger monitors the battery voltage and gives a pulse when necessary to keep the battery fully charged. It goes into this mode if the charge is left connected to the battery for weeks on end, so the battery doesn't received a constant trickle of charge, which isn't good in the VERY long term.

I thought it seemed crazy, but my car actually runs better when first started now. It used to bog down a bit when putting on the throttle from idle when first started, but now it doesn't do that. I suspect it was because the car sits, sometimes for weeks on end without being started, and the battery was hovering right around the very minimum amount of charge available to start the car, and it got so low just before I bought the charger that the car wouldn't even start. So I think that the engine was having to work harder to provide a high amperage charge rate to the battery every time the car was started, whereas now, with the battery fully charged all the time, it doesn't have to do that. That's my theory anyway. Whatever the case, I'm glad I got this charger, and I'm sure my battery will last much longer using it.

[hank]

Teardown of the CTEK: http://www.eevblog.com/forum/index.php?topic=5337.0

I've got the same problem, vehicles needed occasionally for long trips on bad mountain roads, rarely used otherwise.
Been using solar panels with charge controllers, and a little Battery Tender every year or so, but batteries do need more exercise than I give them. CTEK sounds tempting, thanks for raising the question

Ctek sounds tempting.

[samgab]

Teardown of the CTEK: http://www.eevblog.com/forum/index.php?topic=5337.0

I've got the same problem, vehicles needed occasionally for long trips on bad mountain roads, rarely used otherwise.
Been using solar panels with charge controllers, and a little Battery Tender every year or so, but batteries do need more exercise than I give them. CTEK sounds tempting, thanks for raising the question

Ctek sounds tempting.

After owning the CTEK MXS 5.0 for a while now, I'm still very happy with it. It seems to be very high quality, and works really well. It's so simple, you just plug it in and forget about it. It's done a good job of rescuing my poor previously neglected car SLI battery, and I'm having no trouble with it now. Certainly a worthwhile purchase I'd confidently recommend to anyone.

[brosna]

Must say Ctek is a great charger a little on the pricey side for some models. You get a great product that works.
It is one of the best for optima style batteries.

[Norm]

Hi samgab just wondering how satisfied you are with MSX 5.0?

I recently purchased a Ctek 7000 to charge a 110 Ah AGM battery in our caravan, mainly used to power a caravan mover. No time yet to evaluate the unit, evidently Chinese AGM batteries require 14.7V charging voltage, which the Ctek will supply using to snowflake mode.

As the 7000 is mounted in the caravan I'm tempted to buy a MSX 5.0 to maintain an identical battery that serves as back up in the ham shack and for general use around the house, I have a number of 7Ah gell cells (the 7000 isn't recommended for batteries below 12Ah).

I'd also be interested in any other reports on Ctek products.

Norm

[samgab]

Hi samgab just wondering how satisfied you are with MSX 5.0?

I recently purchased a Ctek 7000 to charge a 110 Ah AGM battery in our caravan, mainly used to power a caravan mover. No time yet to evaluate the unit, evidently Chinese AGM batteries require a slightly higher charging voltage, which the Ctek will supply using to snowflake mode.

As the 7000 is mounted in the caravan I'm tempted to buy a MSX 5.0 to maintain an identical battery that serves as back up in the ham shack and for general use around the house, I have a number of 7Ah gell cells (the 7000 isn't recommended for batteries below 12Ah).

I'd also be interested in any other reports on Ctek products.

Norm

Hey Norm. In a word: Very! It's really good.
Just this weekend my flatmate flew back from a Month on a work trip and found his car battery was dead as a Dodo. Plugged it into the MXS 5.0 overnight, on the recondition mode, and today it's good as new, and holding a charge well. Of course, any car battery charger can do that, but I usually just leave it plugged into my car battery in the garage using the comfort connector, and it's doing a great job of keeping it topped up and ready to go when I need it.
The MXS 5.0 will handle low A/H cells no problem, using the 0.8A motorcycle mode.
It also has the snowflake mode which is useful for AGM batteries, so with that plus motorcycle mode, I'd say all of your requirements are covered.
Not meaning this to sound like ad copy, but I highly recommend it.

[Norm]

Thanks for the reply samgab, I'm very tempted, I think I'll be buying after Christmas is out of the way.

Norm

[OutlawPete]

Hi,

Really interesting posts regarding the Ctek and as a result I am considering buying one.

Have a TDi which I rarely drive, but which battery keeps going flat resulting in constant jump starts.

The Ctek seems like it could prevent that but have a few questions for those who have used it .. hope that's okay.


First problem is that I do not have a garage, nor a driveway - so how could I power the device?

My car is parked outside my home on a public road and so I couldn't even run an extension lead outside (for fear of a lawsuit, should someone trip over it).

Could I get some sort of rechargeable power pack that would allow me to connect the Ctek to it?

Also, I seen many people saying that they just leave them on the car, but what is powering it then when the car is idle for weeks?

TIA and sorry for jumping straight in with 20 questions in my first post

[samgab]

Hi,

Really interesting posts regarding the Ctek and as a result I am considering buying one.

Have a TDi which I rarely drive, but which battery keeps going flat resulting in constant jump starts.

The Ctek seems like it could prevent that but have a few questions for those who have used it .. hope that's okay.


First problem is that I do not have a garage, nor a driveway - so how could I power the device?

My car is parked outside my home on a public road and so I couldn't even run an extension lead outside (for fear of a lawsuit, should someone trip over it).

Could I get some sort of rechargeable power pack that would allow me to connect the Ctek to it?

Also, I seen many people saying that they just leave them on the car, but what is powering it then when the car is idle for weeks?

TIA and sorry for jumping straight in with 20 questions in my first post

G'day and

Your situation is not ideal for a mains powered charger like this.
As your car is a diesel, you really do want to have a maintenance charge on your car battery.
But you really need a mains supply to power the CTEK and other chargers like it.
I am fortunate enough to have an internal garage to keep my car in, with power outlets, so I just plug the charger into the comfort connector when I get back from the occasional times I need to use my car.
I'd say a better solution for you, inasmuchas you're parked out on the roadside, with no easy power supply, would be to get a solar trickle charger (edit, for the car battery, not for a charger for the car battery, that would be just unnecessarily complicating things; charging a battery to power an inverter to power a battery charger to charge your car battery...).
Not ideal, but better than nothing.
The other thing you could do is if you know your car isn't going to be used for months, disconnect the battery and bring it inside and leave it connected to the CTEK charger inside.
After it finishes its' charge cycle, it goes to maintenance charge which uses very little electricity, then after about 10 days or so, it switches into an even more economical mode, where it just monitors the battery voltage, and gives a pulse of charge if the voltage drops below an ideal level.

Edit: Remember that running a car lead acid battery so flat that you need a jump start is very damaging to the battery, and greatly reduces it's life, it's the quickest way to kill a car battery.

[OutlawPete]

Hi,

Thanks for the reply ..

Solar trickle charger is interesting. Is there any meters available that would make it possible to test if the solar charger was in fact: 'charging'?

Just to update: I have needed to jump start (with an SOSBooster) the car twice more, which means that something must be drawing on the battery (as the alternator appears fine).

An strange issue I have noticed is that the passenger foot-well keeps getting wet when it rains (no driving needed) and I'm wondering if that is effecting some of the electrics beneath the passenger seat (Audi A4 and I think there is a CPU there?).

I was thinking maybe I should just disconnect the battery when I am not driving it and if that works, then for sure - there must be a drainage issue of some sort.

Will give the solar powered trickle charger I go first though - might be just enough to balance out whatever draw there is currently.

[Norm]

Hi,

Thanks for the reply ..

Solar trickle charger is interesting. Is there any meters available that would make it possible to test if the solar charger was in fact: 'charging'?

Google "watts up meter"

It can be placed between any charging source, it will measure the output from the solar charger to the battery.
It can also be used to measure power drawn from a DC source.

Norm

[samgab]

Hi,

Thanks for the reply ..

Solar trickle charger is interesting. Is there any meters available that would make it possible to test if the solar charger was in fact: 'charging'?

Norm's post above. Also a standard digital multimeter connected into a break in the circuit will give you a milliAmps measurement of the charging level.

Just to update: I have needed to jump start (with an SOSBooster) the car twice more, which means that something must be drawing on the battery (as the alternator appears fine).

Lead Acid batteries have a measure of self-discharge. Also cars have electronic items, such as alarms that have a small draw on the battery (again, a digital multimeter can tell you what the draw on the battery is with the car off, just connect it in a break in the circuit where the battery connects to the car. Or, your battery could have not been properly charged in between these occurrences.

An strange issue I have noticed is that the passenger foot-well keeps getting wet when it rains (no driving needed) and I'm wondering if that is effecting some of the electrics beneath the passenger seat (Audi A4 and I think there is a CPU there?).

Possibly. Obviously water ingress into the car, especially where there are electronics is not ideal... But if the water was causing a short you'd probably see a quite different effect... eg: jump starting wouldn't help you.

I was thinking maybe I should just disconnect the battery when I am not driving it and if that works, then for sure - there must be a drainage issue of some sort.

It's an idea, but remember the two other considerations: 1: has the battery been fully recharged or just been given a little buffer charge, leaving it still almost dead. and 2: lead acids have self discharge. That means that even left by themselves without any drain on the battery they will go flat by themselves. They really need for either the car to be used frequently, or if it isn't, they need some kind of maintenance charge going into them. Again; running a lead acid battery flat will quickly kill it.

Will give the solar powered trickle charger I go first though - might be just enough to balance out whatever draw there is currently.

It might be the way to go. Have a look at the options available, there are several. Have a read of the information available at http://www.batteryuniversity.com about the best voltage to maintain lead acid batteries at, and make sure the solar panel is designed for lead acid car batteries and will maintain it properly.

It really depends on how often you use the car.
If it really is quite infrequently, I think I would just buy a CTEK charger, disconnect the battery and keep it inside charging/maintaining for the long term times of disuse. Also, your car isn't going to be stolen with no battery in it. No thief is going to muck about installing a battery before stealing a car, they'll just move on to one that has a battery in it.

[Norm]

Norm's post above. Also a standard digital multimeter connected into a break in the circuit will give you a milliAmps measurement of the charging level.

One of the nice things about the watts up is everything is cumulative, so you could see at the end of the day / week or whatever period you choose exactly what has gone into the battery.

I always charge my standby110Ah AGM battery in the radio shack this way, it lets me keep a good eye on battery performance, I can if I wish discharge the battery and get the same sort of readings.



The screen is currently showing Ah at the start of the second line of the display but will scroll through and display Peak Amps, Minimum Voltage and Watt hours.

Norm

[HotWire]

I have a CTEK, Battery Minder, and solar on 3 different batteries. I like the CTEK display, but the Battery minder also runs for years without problems. It too is excellent. The solar panel charges a 12v deep cycle lead-acid battery for power outages. It can also start a car if need be.