Best vs. cheapest battery maintainers.

I have used several brands over the years. Can anyone recommend one that can be permanently mounted under the hood, and then plugged in kind of like a block heater? It would need to be able to handle the heat.
 
I have used several brands over the years. Can anyone recommend one that can be permanently mounted under the hood, and then plugged in kind of like a block heater? It would need to be able to handle the heat.
These are my 2 options:

1) Any trickle charger that has a 2 or 3 prong electrical wiring plug without the charger unit built in to it.
2) Any trickle charger plug with a built in unit, plugged into a 3 prong heavy duty electrical extension.

If it was me, I would buy option #1 like this one.
https://www.amazon.com/Battery-Tend...t=&hvlocphy=1026177&hvtargid=pla-434255813726
 
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I have used several brands over the years. Can anyone recommend one that can be permanently mounted under the hood, and then plugged in kind of like a block heater? It would need to be able to handle the heat.
I see the Schumacher SC1300 is approved for under-hood mounting and does not have a universal fused disconnect like most others do. You can do more research. The Deltran ones are rated for 50°C (122°F), so it depends where you mount them. Typically you'd use a quick disconnect, which you can buy separately, so you can use the maintainer for more vehicles. But I can see the advantage of mounting it on the vehicle so you don't lose it. I've lost a couple.
 
The problem with under the hood mount are, you don't know if the battery is already fully charged, You have to lift the hood in order to find it out. Also, the disadvantage is you have to drill in the engine compartment to bolt the unit in. Plus, you don't have the advantage to hook the maintainer to another vehicle.
Whereas, quick connect attachment (already included in a lot of trickle charger) bolted permanently to the + & - post is much more convenient because you don't need to lift the hood. You just have to find the perfect route to access the quick connect wire plug in. No drilling, just plug & play
 
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I see the Schumacher SC1300 is approved for under-hood mounting and does not have a universal fused disconnect like most others do. You can do more research. The Deltran ones are rated for 50°C (122°F), so it depends where you mount them. Typically you'd use a quick disconnect, which you can buy separately, so you can use the maintainer for more vehicles. But I can see the advantage of mounting it on the vehicle so you don't lose it. I've lost a couple.

Makes no sense to me to mount a charger on a car -

just install a pigtail and feed the lead outside to your maintainer.

This way you can look at the charger and see whats happening.
 
Makes no sense to me to mount a charger on a car -

just install a pigtail and feed the lead outside to your maintainer.

This way you can look at the charger and see whats happening.
I have pigtails on three cars and a motorcycle currently. Its the only way to go. You can add a splice to lengthen it, so you don't even have to open the hood.
I had one mounted to the car (no longer have the car), an older Ferrari that came that way (dealer installed). It worked, but as stated, not the best way to go for various reasons.
 
Lesson learned. Long pigtails introduce enough resistance and voltage drops with the higher amperage smart chargers to defeat their logic. Pigtail extensions should be used with lower amperage chargers, or those which use constant voltage strategies. Also, at 5 amps or more, the typical 10 amp blade fuse drops 0.5 volts, which is, again, enough to confuse a smart charger.

im looking at you, noco….
 
Lesson learned. Long pigtails introduce enough resistance and voltage drops with the higher amperage smart chargers to defeat their logic. Pigtail extensions should be used with lower amperage chargers, or those which use constant voltage strategies. Also, at 5 amps or more, the typical 10 amp blade fuse drops 0.5 volts, which is, again, enough to confuse a smart charger.

im looking at you, noco
What abnormalities have you observed?
I occasionally run 12 ft extensions with my Battery Minder, Granite Digital Save a Battery and Griots battery maintainers and noticed no issues. I monitor them through a bluetooth enabled monitor that graphs their voltage outputs...never seen a problem. They cycle through their logic as expected and shown in their IFUs.
 
What abnormalities have you observed?
I occasionally run 12 ft extensions with my Battery Minder, Granite Digital Save a Battery and Griots battery maintainers and noticed no issues. I monitor them through a bluetooth enabled monitor that graphs their voltage outputs...never seen a problem. They cycle through their logic as expected and shown in their IFUs.
Post #135


I’ve tried it with and without extensions. They do make a difference, but the noco still seems to go to float way too soon. I have the 10 amp version, however, which will worsen the problem. A smaller unit wont incur as much v drop.

I’ve switched to a ctek, which doesn’t push as many amps, but does effectively put a better finishing charge on the battery.
 
I have a Battery Tender Plus been using it for almost 5 years now, my Camaro with the AGm when I had it stayed on it and now my Jeep is hooked up so far so good.
 
Post #135


I’ve tried it with and without extensions. They do make a difference, but the noco still seems to go to float way too soon. I have the 10 amp version, however, which will worsen the problem. A smaller unit wont incur as much v drop.

I’ve switched to a ctek, which doesn’t push as many amps, but does effectively put a better finishing charge on the battery.
An extension should make absolutely no difference for maintaining a battery because the current for than is very small, causing negligible voltage drop. At 10 amps output you're mot maintaining, but charging a low battery.
 
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Am I the only person that bought a NOCO 5? It seems to do the job, says it's temperature compensated, has AGM setting, etc.
Oh, and it doesn't get hot while charging which is a big plus here in FL.

There are multiple types of temp compensation.

The noco 5 is "ambient" as in there is a temp sensor somewhere in the body that (last I looked at the profile) decides when to add some more voltage when it's cold. It's pretty much one way and cannot tell if you are cooking the battery.

Better more accurate temperature compensation happens with a probe connected to the batts, or a temp sensor in the positive clamp like the CTEK 25 amp charger.
 
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As an amateur radio operator, I try to avoid electronic equipment that produces RF interference, i.e "electronic noise". I find the CTEK MUS 4.3 to be a great unit that produces no electronic interference. I have two. One stays attached to my Corvette for its November to April slumber in the garage. The second unit keeps my AGM 12 volt battery charged that powers all of the 12 volt equipment in my amateur radio shack.
 
Post #135


I’ve tried it with and without extensions. They do make a difference, but the noco still seems to go to float way too soon. I have the 10 amp version, however, which will worsen the problem. A smaller unit wont incur as much v drop.

I’ve switched to a ctek, which doesn’t push as many amps, but does effectively put a better finishing charge on the battery.
Maybe a NOCO thing...plus the higher amps. I have a Battery Minder that has a 2, 4 and 8 amp setting. Never a problem with the 12ft cord. All my others are 3 to 4 amps...again no issue.
 
There are multiple types of temp compensation.

The noco 5 is "ambient" as in there is a temp sensor somewhere in the body that (last I looked at the profile) decides when to add some more voltage when it's cold. It's pretty much one way and cannot tell if you are cooking the battery.

Better more accurate temperature compensation happens with a probe connected to the batts, or a temp sensor in the positive clamp like the CTEK 25 amp charger.
That wouldn't help much on the MB. The battery connectors are remote from the battery itself. Not under the back seat like my old Caddy's but under a cover. I like to use the battery charger under the hood without removing the covers, which BTW includes the cabin air filter housing. I suppose I'm just going to have to be happy with ambient sensing, unless I get into a situation where I'm trying to rescue a few disconnected batteries.
 
Let's not overthink this temperature compensation thing. I have a Battery Tender Plus (which claims to have temperature compensation) on my summer car in the garage. I have a Battery Tender Jr. and a MOTOPOWER MP00205A (not temperature compensated) on a couple of mowers out in the shed. Theoretically the locations should be opposite, but I've never had a problem.

As for battery location, my current daily is a 2005 Dodge Magnum SXT with the battery in the back, but gets driven at least once a week, so no need for a maintainer. But if I had a fancy Magnum not driven in the winter, but kept in the garage, I'd connect a battery maintainer to a convenient boost point under the hood, not the actual battery in the back.
 
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