Where are you storing jumper cables?

[ntsqd]

My latest second battery install has a battery bank switch combined with a Blue Sea Systems ACR. I trust deep water marine components far further than I trust "overlanding" equipment. This is my first ACR, prior to it I've used BEP Marine VSR's for decades. I started with those on the advice of a OZ outback commercial vehicle builder. It was only lack of availability that made me switch. I have it wired so that regardless of which battery is the current starting battery, both will get charged by the alternator or any future solar system. Our CTD camper is wired so that either the alt. or the solar will charge both sets of batteries.

If you really don't want something left on to drain a battery you might install a Low Voltage Disconnect.

 

[TeCKis300]

So the starting battery is drained, right?
I have an Odyssey group 35 charged by a Redarc BCDC 1225D as my 2nd battery which I thought was a fairly bullet proof setup, or at least as bullet proof as the Redarc. It's been rock solid for 2 years and I've drained that 2nd battery pretty hard once or twice with the Redarc charging it up 100%. So am I in the scenario where I might have issues?

Is this what you're talking about? Not sure as you seem to say that the 2nd battery is discharged.

That's one of the use case pitfalls to be aware of. Actually, @ntsqd is the other.

A smart charging system cannot charge/tender multiple batteries at multiple states of charge. Because they are multi-stage chargers with charging profiles that respond to variables including batteries state of charge. If we look at the cars smart alternator regulator as a battery charger, it can only "see" one battery. When using something like an ACR, it ties two independent batteries together. If the two batteries are not balanced, e.g. one is depleted and one is charged, the regulator may not see an average and perhaps only the charged battery, and not provide excess charge current to charge the other battery. What will happen over time is one of the batteries will systemically be undercharged causing premature failure of one, or possibly both because of constant micro-current as the batteries attempt to balance.

That's the difference today, in that we have smart alternators. Not the old school bulk alternators that always provide excess current, where an ACR can work. These require the use of DC-DC chargers. The alternator maintains the starter battery, DC-DC charger maintains the aux. Which then goes back to a potential pitfall you point out in the video.

 

[ntsqd]

I'm very glad to not have a smart alternator, because then I'd have to get smarter about how to charge batteries in both directions. A DC-DC charger only works in one direction, so what do you do when there's solar on the house battery? A pair of DC-DC's connected opposite of each other?

Be clear that a smart alternator isn't there for the battery's benefit. It is there for the whole computer network masquerading as a vehicle going down the street. That network wants a very stable and consistent system voltage.

 

[TeCKis300]

I'm very glad to not have a smart alternator, because then I'd have to get smarter about how to charge batteries in both directions. A DC-DC charger only works in one direction, so what do you do when there's solar on the house battery? A pair of DC-DC's connected opposite of each other?

Be clear that a smart alternator isn't there for the battery's benefit. It is there for the whole computer network masquerading as a vehicle going down the street. That network wants a very stable and consistent system voltage.

I hope you don't take this discussion the wrong way and I agree with some of your thoughts. There's just more complexity as I mentioned earlier than meets the eye.

Did you swap to an old school alternator? Smart alternators in use since the early 2000s are driven by the need for fuel efficiency. Alternators pull only what mechanical energy they need. This also has the benefit of being gentle on batteries for long life, and sidesteps the need to water batteries any longer. This has the unintended consequence of making previous strategies no longer viable, and modifications more complex.

Personally, I don't like the DC-DC charger setups either for what you state. You bring up is a good point about solar, that it further complicates the configuration when you want it to charge both banks with a single array and controller. Similarly, solar chargers cannot tender multiple batteries at multiple states of charge. ACR or not. A solar charger can only sense a single battery.

These are not unique challenges to cars, and RVs deal with all this "fun" too.

Want the easy button? Wire two batteries as a single large bank to sidestep all the complexities of managing multiple batteries/banks. No ACR. No DC-DC charger. Real expanded reserve for everything. Low voltage disconnects would be good for auxiliary things that can be left on after the car is off. And carry a lithium jumper as the ultimate mitigation.

KISS Dual Battery Upgrade

There’s been a lot of discussion on batteries and battery systems. Here’s my attempt to offer an easy button. The task of a battery first and foremost is to offer power and reserve capacity. There’s many battery setups and systems talked about. But perhaps some of those are solving a problem...

forum.ih8mud.com

 

[bloc]

I hope you don't take this discussion the wrong way and I agree with some of your thoughts. There's just more complexity as I mentioned earlier than meets the eye.

Did you swap to an old school alternator? Smart alternators in use since the early 2000s are driven by the need for fuel efficiency. Alternators pull only what mechanical energy they need. This also has the benefit of being gentle on batteries for long life, and sidesteps the need to water batteries any longer. This has the unintended consequence of making previous strategies no longer viable, and modifications more complex.

Personally, I don't like the DC-DC charger setups either for what you state. You bring up is a good point about solar, that it further complicates the configuration when you want it to charge both banks with a single array and controller. Similarly, solar chargers cannot tender multiple batteries at multiple states of charge. ACR or not. A solar charger can only sense a single battery.

These are not unique challenges to cars, and RVs deal with all this "fun" too.

Want the easy button? Wire two batteries as a single large bank to sidestep all the complexities of managing multiple batteries/banks. No ACR. No DC-DC charger. Real expanded reserve for everything. Low voltage disconnects would be good for auxiliary things that can be left on after the car is off. And carry a lithium jumper as the ultimate mitigation.

KISS Dual Battery Upgrade

There’s been a lot of discussion on batteries and battery systems. Here’s my attempt to offer an easy button. The task of a battery first and foremost is to offer power and reserve capacity. There’s many battery setups and systems talked about. But perhaps some of those are solving a problem...

forum.ih8mud.com

Do you think a parallel-wired dual battery setup would change the level of lithium jumper that is needed to start a vehicle? I know the starter wouldn’t draw any more watts, but would having two discharged batteries impact the ability to apply current to the rest of the system during the starting process?

 

[ntsqd]

None are a 200, so no smart alternator(s). Vintage when they were deployed seems to vary, even within a specific brand. Some models got them early in their production run, other models didn't get them for years. Tundras appear to have gotten them later than 200's by quite a bit.

On that one, large battery bank idea; that too has potential problems. My second ever dual battery system came to me wired in parallel by the OEM. So I left it that way as it seemed like a simple way to have such a system, and eventually kilt a battery dead. It seems that this particular OEM grounded both batteries to the engine block, but not on the same bolt. The resistance across the block between those two bolts was enough to set up the vicious see-saw discharge cycle. I revised the grounding scheme to where both batteries were connected directly like terminal to like terminal, and then connected to the appropriate locations. Curiously enough, that is how our only 5 years newer CTD came wired by the OEM!
Easy enough problem to head off, but you have to know about the potential problem first.

 

[TeCKis300]

Do you think a parallel-wired dual battery setup would change the level of lithium jumper that is needed to start a vehicle? I know the starter wouldn’t draw any more watts, but would having two discharged batteries impact the ability to apply current to the rest of the system during the starting process?

Potentially. Low/dead batteries can be a load on the charging source/jumper. Saving grace is that lead acid batts generally have larger internal resistance. To your point, potentially can impact a jumper if it were marginally sized for the job to begin with. Lithium batts are monsters in their ability to deliver high C-rates so generally should be fine. This is where that 10mm wrench as part of the stock tool set could be handy.

None are a 200, so no smart alternator(s). Vintage when they were deployed seems to vary, even within a specific brand. Some models got them early in their production run, other models didn't get them for years. Tundras appear to have gotten them later than 200's by quite a bit.

On that one, large battery bank idea; that too has potential problems. My second ever dual battery system came to me wired in parallel by the OEM. So I left it that way as it seemed like a simple way to have such a system, and eventually kilt a battery dead. It seems that this particular OEM grounded both batteries to the engine block, but not on the same bolt. The resistance across the block between those two bolts was enough to set up the vicious see-saw discharge cycle. I revised the grounding scheme to where both batteries were connected directly like terminal to like terminal, and then connected to the appropriate locations. Curiously enough, that is how our only 5 years newer CTD came wired by the OEM!
Easy enough problem to head off, but you have to know about the potential problem first.

Good catch and good call. Making a bank with multiple batteries needs to be done with consideration as there's minutia here too. To ensure even draw and charge so the batts stay balanced. It's addressed in the thread I detailed.

 

[Jelder]

I have a little duffel bag with an air compressor and jumper cables that takes up just a bit of space in the back.

 

[Sinister]

My Noco and all emergency gear are in my ROAM adventure box. I don’t carry cables anymore. I have used the Noco more in 2 years then I ever used jumper cables, and mostly for helping out other people.

 

[phmilo]

I do marine electrical for a day job. The charging relays are what you want for a dual batter system. Use a deep cycle for the loads, and isolate the starting battery. Blue sea and Victron both make really good models that also have emergency parallel via switch. They are automatic for isolating the batteries and protecting the starter in normal use.

 

[biff44]

This. You can use a GB150 or GB70 with a fitted case for storage and be set for anything. Far more versatile than jumper cables. One important thing often missing with jumper cables is another vehicle!

Edit: I see I didn't answer the question, even for the NOCO. I have a Husky tool bag from the Home Depot strapped to a cargo D-ring. Everything I carry is in either that for my long shovel/axe/saw/jack pad bag on the other side of the cargo area.

i am having a hard time not laffing when i see the GB150 ad: "3000 amp"

to handle 3000 amps, the wire diameter would have to be 1 inch each!

 

[ntsqd]

3k amps for any distance of significance we use buss-bars in our load banks at work.

It is kind of interesting to play with the conductor sizing formula when looking at really short lengths. The Ampacity goes up radically! In theory what a 1 inch long section of 18 ga. can carry is amazing. Not that I'd ever try it....

 

[kcjaz]

i am having a hard time not laffing when i see the GB150 ad: "3000 amp"

to handle 3000 amps, the wire diameter would have to be 1 inch each!

the 3000A is a peak rating, not CCA. Not sure the time duration for the peak rating but it is probably milliseconds. IMO, the peak amp rating is not really important for a jump starter but it seems all manufactures rate there battery packs this way. The peak amps and watt-hour ratings gives you some idea of the capacity the jump starter has but I'd prefer to see CCA for these things.

At any rate, I love my Noco's. They work pretty much as advertised and stay charged for a very long time.

 

[bloc]

the 3000A is a peak rating, not CCA. Not sure the time duration for the peak rating but it is probably milliseconds. IMO, the peak amp rating is not really important for a jump starter but it seems all manufactures rate there battery packs this way. The peak amps and watt-hour ratings gives you some idea of the capacity the jump starter has but I'd prefer to see CCA for these things.

At any rate, I love my Noco's. They work pretty much as advertised and stay charged for a very long time.

Because ‘murca. More is bettar!!

I also really like my noco GB70. Considering getting another for my second vehicle this Black Friday. Just yesterday I missed an opportunity to help someone out because I drove the vehicle it doesn’t live in to work.

 

[ntsqd]

Just proved to 4 others the utility of my XP-10HD, repeatedly. It started a friend's 408 stroker 3 mornings in a row on a trip where the Optima starting battery was starting to fail. No prior warning that the ~4.5 y.o. Optima was going away. His stop on the way home was for a new one, and he has ordered an XP-10 just to have. The XP-10 was charged for part of a day between the first and second starts, but never had or achieved a full charge. Had no trouble successively turning over a 408c.i. engine that is just barely past it's break-in miles.

While the XP-10 also holds a charge for a very long time I've located a Hella timer relay that I need to set up one of my power points with. Then the it will get 20-30 mins of charging on every engine start. The vehicle that I keep it in is used to provide support for desert racers, it needs to have all of the various equipment batteries (Milwaukee Fuel M12 & M18 batteries as well) ready to go at a moment's notice.

 

[bloc]

I seem to remember reading that lithium batteries stay healthier if they aren’t stored at 100%.. so my strategy is to make sure the Noco doesn’t actually get low, but also avoid keeping it completely full indefinitely.

Could be wrong about this though.

 

[ntsqd]

You might be onto something there. It's part of why I'm thinking such a short charge cycle. I don't DD that vehicle, so it would sit for periods of up to weeks at a time w/o getting a charge.

 

[bloc]

You might be onto something there. It's part of why I'm thinking such a short charge cycle. I don't DD that vehicle, so it would sit for periods of up to weeks at a time w/o getting a charge.

I can't speak for yours but mine wouldn't care about weeks at a time. 4 months is more of an issue.. and even then it will be between 50 and 75%.

 

[Sandroad]

i am having a hard time not laffing when i see the GB150 ad: "3000 amp"

to handle 3000 amps, the wire diameter would have to be 1 inch each!

Not really. The high amp supply capability refers to the almost instantaneous locked rotor amps just before the starter motor begins to spin. Once it’s running the amps drop way, way down. If you play around with ampacity calculators you’ll see even a #3 AWG wire can handle 3000A for the distance and time involved. I don’t know the gauge of wire used in the NOCO units, but it probably meets specs.

 

[ntsqd]

I can't speak for yours but mine wouldn't care about weeks at a time. 4 months is more of an issue.. and even then it will be between 50 and 75%.

About the same for the XP-10. Sits for a month or more and it's still showing ~75% on it's SoC indicator LED's. That was about the SoC when I used it to start the Cummins and it had been sitting for way longer than a month since being charged.

Not really. The high amp supply capability refers to the almost instantaneous locked rotor amps just before the starter motor begins to spin. Once it’s running the amps drop way, way down. If you play around with ampacity calculators you’ll see even a #3 AWG wire can handle 3000A for the distance and time involved. I don’t know the gauge of wire used in the NOCO units, but it probably meets specs.

We call that "In-Rush" current around here. Just had to upgrade from a 50A breaker to a 60A breaker (there is no 55A in the 285 series breakers that I could find) on my 4rnnr's OBA Puma compressor because 3A isn't enough overhead and cold re-starts would pop it. Imagine that!