battery charger

[THAW]

Unless you are disconnecting the batteries and charging them separately, does the precision of the charger for ideal charging matter?

Ok, but my question was a response to @THAW regarding how the charger is connected to the battery impacting charging precision, not about old school chargers. The implication of my question is that charging both batteries at the same time has more affect on charging precision then long cables.

For a charger with a given Amp rating and a basic AGM charging routine including constant-current Bulk, constant-voltage Absorption, and constant-voltage Float stages, it's not clear to me transition thresholds would be significantly different between a single battery and a slightly larger-capacity bank, assuming the same temperature. Perhaps tail current would vary if the charger estimates capacity, but that's unlikely to have a meaningful effect if the batteries in the bank are all in decent condition.

The concern for long runs of unknown gauge factory harness wires and body ground paths is excessive voltage drop interfering with voltage/current regulation. It may or may not be an issue depending on the attachment point, but whether charging an individual battery or a bank it's preferable to connect the charger's built-in wiring/connectors near the battery/batteries.

I just added some 6' SAE cables to my JL and JT to facilitate charging the batteries without opening the hood. While I agree with @THAW 's long cable comment in theory, I was looking for specific information related the impact longer cables have on battery charging. Not only did I not find any information related to cable length, I found NOCO sells 10' extensions to their cables with no mention of the extension affecting charging.

Manufacturer-recommended extension cables with stated compatibility for the charger model are clearly acceptable. Still, I'd be curious about the voltage drop on the 16 AWG 10' extension in conjunction with the 10 A charger.

Since the ideal agm charging rate is .1C to .2C, for the 12Ah aux battery that would be 1.2A to 2.4A. For connected batteries, if I connect a 10A charger to the main battery, I wonder what the charging rate is to the aux battery. Whatever it is, it's probably not as bad for the aux battery as this 15V charging that I see occasionally.

If both batteries in a bank are in decent condition, presumably the individual current acceptance at a given voltage will be roughly proportional to the individual battery capacities.

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[Mguy]

I'm interested (seriously) in how a charger can simultaneously precisely charge a 200 CCA and a 800 CCA battery, do you have any info or a specific charger in mind?

Two dissimilar AGM batteries, paralleled in a less than ideal load management system and charged by single voltage regulation, is always less than desirable. More than once (and here's an example, at post 20), I've said on this forum that the two batteries are seen by the JL with a composite state of charge. Since AGMs strongly prefer multi stage charging, it's generally expected that with sufficient amps, the better the voltage regulation, the better the charging, even in a less than desirable composite situation.

For better voltage regulation, there's Victron chargers high up at the top. Better value is with Sterling. Victron stuff can sometimes be quirky and sometimes opaque, Sterling is usually the opposite. Both companies respond to customer tech questions.

Of course, it's up to JL owners to decide whether really good charging is the right treatment for their lousey two battery stock system. I expect that if an owner is going to use an expensive high end charger, he or she would be separating the batteries for charging. Basically obvious, but this forum sometimes surprises.

 

[THAW]

Do NOT charge a 12 Ah AUX (ESS) battery separately with a 10 Amp charger. That's 0.83C, well above the generally recommended max 0.3C rate.

 

[Rhinebeck01]

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[Mguy]

Do NOT charge a 12 Ah AUX (ESS) battery separately with a 10 Amp charger. That's 0.83C, well above the generally recommended max 0.3C rate.

Doing so will cause hyperbolic expansion at the flux battery connection and resulting degradation of the vehicle-speed envelope--in addition to charging the aux battery.

 

[THAW]

More than once (and here's an example, at post 20), I've said on this forum that the two batteries are seen by the JL with a composite state of charge.

Incorrect; JLs don't measure "composite state of charge".

The IBS tracks independent CR[an]K battery SoC; otherwise, JLs measure voltage (always under load or charging current) at several modules, including while the CR[an]K battery is briefly disconnected. To the extent voltage equalization between the batteries occurs when the engine/alternator is off, CR[an]K battery SoC estimation treats the AUX (ESS) battery no differently than any other load or charging current.

Doing so will cause hyperbolic expansion at the flux battery connection and resulting degradation of the vehicle-speed envelope--in addition to charging the aux battery.

A recommendation for prolonging battery life by separating the AUX (ESS) battery to charge it with a 10 Amp charger is ass-backward.

Victron Blue Smart IP65 Charger manual:
"Low current mode is recommended when charging lower capacity batteries with a high current charger; charging at an excessive charge current can cause premature battery degradation and overheating."
The 12 Volt 10 Amp charger has a minimum battery capacity of 33 Ahs for the standard setting. Low Current mode is 3 Amps.

 

[Mguy]

Incorrect; JLs don't measure "composite state of charge".

The IBS tracks independent CR[an]K battery SoC; otherwise, JLs measure voltage (always under load or charging current) at several modules, including while the CR[an]K battery is briefly disconnected. To the extent voltage equalization between the batteries occurs when the engine/alternator is off, CR[an]K battery SoC estimation treats the AUX (ESS) battery no differently than any other load or charging current.


A recommendation for prolonging battery life by separating the AUX (ESS) battery to charge it with a 10 Amp charger is ass-backward.

Victron Blue Smart IP65 Charger manual:
"Low current mode is recommended when charging lower capacity batteries with a high current charger; charging at an excessive charge current can cause premature battery degradation and overheating."
The 12 Volt 10 Amp charger has a minimum battery capacity of 33 Ahs for the standard setting. Low Current mode is 3 Amps.

Hey Lucy, try this website for getting a response to your electrical pedantic semantics.

 

[Terrymo]

Incorrect; JLs don't measure "composite state of charge".

The IBS tracks independent CR[an]K battery SoC; otherwise, JLs measure voltage (always under load or charging current) at several modules, including while the CR[an]K battery is briefly disconnected. To the extent voltage equalization between the batteries occurs when the engine/alternator is off, CR[an]K battery SoC estimation treats the AUX (ESS) battery no differently than any other load or charging current.


A recommendation for prolonging battery life by separating the AUX (ESS) battery to charge it with a 10 Amp charger is ass-backward.

Victron Blue Smart IP65 Charger manual:
"Low current mode is recommended when charging lower capacity batteries with a high current charger; charging at an excessive charge current can cause premature battery degradation and overheating."
The 12 Volt 10 Amp charger has a minimum battery capacity of 33 Ahs for the standard setting. Low Current mode is 3 Amps.

I actually contacted tech support at NOCO about charging a 12ah power sport AGM battery when we had quads with their 10 amp charger. I was told it may be ok but it would be better to use a lower amperage charger and suggested I contact the battery manufacturer for their recommendation on charging amperage. I know that’s not very specific but that’s about where my battery knowledge and interest stops.

 

[Mguy]

I actually contacted tech support at NOCO about charging a 12ah power sport AGM battery when we had quads with their 10 amp charger. I was told it may be ok but it would be better to use a lower amperage charger and suggested I contact the battery manufacturer for their recommendation on charging amperage. I know that’s not very specific but that’s about where my battery knowledge and interest stops.

In the electrical equipment manufacturing world the enginneering department follows Ohm's Law. However, in the legal department, the law followed is different,

(low)(amps) + (low) (voltage) = (low)(liability)

 

[Terrymo]

In the electrical equipment manufacturing world the enginneering department follows Ohm's Law. However, in the legal department, the law followed is different,

(low)(amps) + (low) (voltage) = (low)(liability)

From my one semester of beginning electronics in high school I think I remember a battery accepts a charge, but a little hazy on formulas like E = I x R
Anyways you guys can debate about plastic boxes full or chemicals and the roundness of the earth on your own.

 

[THAW]

Don't be fooled by conspiracy theories. Battery chemistry, not liability, is the reason a 10 Amp charging routine is not recommended for a 12 Ah battery.

The oft-mentioned NOCO 10 is a great charger for JL applications. If it's your only charger, leave the CR[an]K and AUX (ESS) battery in parallel.

That is, don't use the NOCO 10 on a separated AUX (ESS) battery; there aren't any AGM battery or AGM smart charger manufacturers who recommend a 10 Amp charger for a 12 Ah AGM battery. @Mguy is out on a limb believing it'll prolong battery life; everyone who understands the science of constant-current bulk charging knows a 0.83C charge rate is likely to do more harm than good.

 

[BRuby]

Formulas aside - from an anecdotal real world smart charging perspective - our 7 yo aux 200 original has been perfectly fine on the NOCO5 while our 7 yo main original perfectly fine on the NOCO10. Always charged separately.

Further it does not seem optimal to charge a 12ah with a NOCO10 - nor charge the main with an old school continuous 1A trickle charger. Our Porsche was on a 3.6A CTEK and it lasted ok but was not optimal - so is now on the 7.2 NOCO which should do a lot better.

In this pic the 5 in the front left is on the aux - and the 10 behind on the main. 7 years and running. No problems at all. Both should last for a good few more years easy. Always stored outside exposed to the elements 24/7. Jeep used only in the winter to get to very chilly ski resorts. Definitely works for us - but ymmv.

 

[THAW]

Formulas aside - from an anecdotal real world smart charging perspective - our 7 yo aux 200 original has been perfectly fine on the NOCO5 while our 7 yo main original perfectly fine on the NOCO10. Always charged separately.

Further it does not seem optimal to charge a 12ah with a NOCO10 - nor charge the main with an old school continuous 1A trickle charger. Our Porsche was on a 3.6A CTEK and it lasted ok but was not optimal - so is now on the 7.2 NOCO which should do a lot better.

In this pic the 5 in the front left is on the aux - and the 10 behind on the main. 7 years and running. No problems at all. Both should last for a good few more years easy. Always stored outside exposed to the elements 24/7. Jeep used only in the winter to get to very chilly ski resorts. Definitely works for us - but ymmv.

Using a charger religiously as essentially a maintainer (i.e. not allowing the battery to become discharged) helps ensure a too high charger Amp rating doesn't damage the battery.

In any case, a 5 Amp charger is a much closer match for the 12 Ah AUX (ESS) battery than a 10 Amp charger.

 

[BRuby]

Using a charger religiously as essentially a maintainer (i.e. not allowing the battery to become discharged) helps ensure a too high charger Amp rating doesn't damage the battery.

In any case, a 5 Amp charger is a much closer match for the 12 Ah AUX (ESS) battery than a 10 Amp charger.

Yep both your comments are 100% valid based on 25+ years using our various NOCO and CTEK smart chargers. What kills batteries fastest are multiple deep discharges. Unknown to many is the specific model of a smart charger plays a huge role in what actually works and what actually fails for a particular battery. As this knowledge comes from actual user experience vs speculation or educated guess or projected estimation.

 

[wazzabie]

The 3.6l etorque does not have the aux battery. If I charge the main will this also charger the 48v battery?

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