How much power does it take to start a Leaf from the 12V Battery

knightmb said:

Learjet said:

would a clamp on DC ammeter work to measure this? could use peak mode?

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You can, but I find that when dealing with currents below 10 amp they are highly inaccurate unless you spend a lot of money for a very expensive one that is sensitive enough. I'm measuring currents down to the thousandth of an amp, so I don't know of any DC clamp on meters that good.

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Actually, they're very accurate (+/- 1ma), and not that expensive;

https://www.amazon.com/BSIDE-ACM91-Auto-Ranging-Temperature-Capacitance/dp/B07G84XDWH/ref=sr_1_5?crid=3Q6EHCMFM0JFU&keywords=dc%2Bclamp%2Bon%2Bamp%2Bmeter&qid=1638579297&sprefix=DC%2Bclamp%2Caps%2C207&sr=8-5&th=1

lorenfb said:

knightmb said:

Learjet said:

would a clamp on DC ammeter work to measure this? could use peak mode?

Click to expand...

You can, but I find that when dealing with currents below 10 amp they are highly inaccurate unless you spend a lot of money for a very expensive one that is sensitive enough. I'm measuring currents down to the thousandth of an amp, so I don't know of any DC clamp on meters that good.

Click to expand...

Actually, they're very accurate (+/- 1ma), and not that expensive;

https://www.amazon.com/BSIDE-ACM91-Auto-Ranging-Temperature-Capacitance/dp/B07G84XDWH/ref=sr_1_5?crid=3Q6EHCMFM0JFU&keywords=dc%2Bclamp%2Bon%2Bamp%2Bmeter&qid=1638579297&sprefix=DC%2Bclamp%2Caps%2C207&sr=8-5&th=1

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I'm sure they exist, but according to the reviews the DC clamp is not accurate down to the claimed specs

lorenfb said:

Actually, they're very accurate (+/- 1ma),

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Don't confuse the precision (able to resolve down to 1mA) and accuracy (how close is what it says to reality). DC clamp meters (AC are much better) suffer badly from drift, and to a smaller extent from stray magnetic fields. I often test in both directions (get a positive and negative result, and average the two ignoring the sign) to cancel out most of the drift and stray fields.

So typically their accuracy is way worse than their precision.

Stanton said:

Thanks for posting the data!
I have been using a 20 AHr Lithium starter battery for almost 8 years now (you can search my name for the thread), and at one point determined I could "start" my Gen1 Leaf with about 12 V @ 10 AHr. The larger "stock" lead-acid starter batteries they put in EVs are definitely overkill, but it's probably easier to use something already spec'd for their smaller ICE vehicles (although LiFePO4 starter batteries and EVs are a match made in heaven).

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Yeah, I do remember, it is the reason I'm using the same on both myself and wife's Leaf now, both 20 AHr Lithium 12V batteries from the now bankrupt Stark Battery company :? after reading about your success with it.
Mine is +6 years old now and was transferred from my 2013 Leaf to my 2020 Leaf after trade in. The one in my wife's Leaf is around +5 years old and was part of a solar bank for a while before I moved it to her Leaf.
Glad to read that yours is going on 8 years now, gives me hope that mine will last at least that long. So far, both of them appear to be very healthy, I suspect since the Leaf only charges them to about 80% of their rated capacity due to the voltage difference between Lead and Lithium, works out really well for us.

coulomb said:

lorenfb said:

Actually, they're very accurate (+/- 1ma),

Click to expand...

Don't confuse the precision (able to resolve down to 1mA) and accuracy (how close is what it says to reality). DC clamp meters (AC are much better) suffer badly from drift, and to a smaller extent from stray magnetic fields. I often test in both directions (get a positive and negative result, and average the two ignoring the sign) to cancel out most of the drift and stray fields.

So typically their accuracy is way worse than their precision.

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Buy one and test it for us! I've got two in that price range and they correlate to readings in the 1-2 ma range with my $450 Fluke.
For what's being done here, these low-end current VCMs are more than adequate.

lorenfb said:

I've got two in that price range and they correlate to readings in the 1-2 ma range with my $450 Fluke.

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Maybe they have gotten better, wonderful if so.

Learjet said:

I have one seems to work ok. Also, I have a DC ammeter in my RV that use a coil over the wire vs. a shunt....hall effect I believe its called?

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I thought Hall effect sensors only worked with magnetism and it turns out that is true. It also turns out that they are a vital part of DC clamp ammeters, which makes sense I guess when you consider the relationship between electricity and magnetism. I found this video to be a great introduction to the concepts. https://www.youtube.com/watch?v=SH0AMdRiYTE&t=882s

Not to side bar this important discussion too much, but has anyone determined the power/time relationship using the Setec (or equivalent) CHAdeMO vehicle to load system? What state does the Leaf have to be in to actually draw from the CHAdeMO - assuming it's the same as charging? If no load is being drawn, what is the "parasitic" draw - and does it change depending upon how long it sits idle?
As the Setec seems to be the only viable V2L CHAdeMO enabled unit available, the idle draw is probably specific to it's "idle" usage and might be the major consumption?

V2X has progressed much of this:
https://mynissanleaf.com/viewtopic.php?f=37&t=32620

Marktm said:

Not to side bar this important discussion too much, but has anyone determined the power/time relationship using the Setec (or equivalent) CHAdeMO vehicle to load system? What state does the Leaf have to be in to actually draw from the CHAdeMO - assuming it's the same as charging? If no load is being drawn, what is the "parasitic" draw - and does it change depending upon how long it sits idle?
As the Setec seems to be the only viable V2L CHAdeMO enabled unit available, the idle draw is probably specific to it's "idle" usage and might be the major consumption?

V2X has progressed much of this:
https://mynissanleaf.com/viewtopic.php?f=37&t=32620

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My guess would be, anytime the main battery is being used, the 12 volt system is also running the DC to DC converter and the 12V battery is probably just in float charge all the time. Good question though, do you mean that the ChaDeMo is plugged in but not being used, what would the 12V power draw be while it is in standby?

I'm hoping V2X will be able to give us some data.
- Overall energy efficiency when at various loads (V2L)
- When Setec unit is kept on, but no load, what is the idle load? What state does the leaf remain at?
- When Setec unit is shut down, but CHAdeMO is connected, what is the idle load - might change over time?
- Similar questions if the system is set up (safely) for V2H via the home panel, requiring a robust grid disconnect routine/system. IMO, this can possibly be done using a center tapped transformer on the Setec output (e.g. SURT003 or similar with NEMA L14-30R output).

Given that 200w is plenty to close the contactors and get the car into ready mode, it would seem like a modestly priced LiFePO4 battery like this would be adequate:

https://relionbattery.com/products/lithium/rb12

12Ah, 20A should work well, based on the testing by knightmb. Under $200 is definitely in the right ballpark.

Once the car is running, I wonder how much load is actually placed on the 12V battery. Would that load typically exceed 200w? Seems unlikely, unless you added a non stock, powerful stereo system.

I might just try this, if I ever need another 12V battery. Unfortunately, I recently bought a new lead acid one so that's going to be a few years...

i think you can see the 12V loads on the energy info monitoring screen on the center display. Seems that it was around 300 W +/- 100 in my 2012.

there should be no loads on the 12v battery when the car is running... maybe an occasional spike when something turns on until the converter adjust for the increased load...this would be very quick...the DC to DC converter is handling the loads and charging the battery when running the battery just becomes a sort of "shock absorber".

This 12V AO Lithium LiFePO4 battery looks like an ideal lead acid replacement:

https://aolithium.com/products/12v-33ah-lifepo4-deep-cycle-battery

ISO9001/UL/CE/UKCA/UN38.3 certified, 422Wh capacity (33 AH), 40A max discharge - looks perfect and at $200 USD very reasonably priced too.

alozzy said:

This 12V AO Lithium LiFePO4 battery looks like an ideal lead acid replacement:

https://aolithium.com/products/12v-33ah-lifepo4-deep-cycle-battery

ISO9001/UL/CE/UKCA/UN38.3 certified, 422Wh capacity (33 AH), 40A max discharge - looks perfect and at $200 USD very reasonably priced too.

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Oh, more than enough power (12.8v x 33AH = 422 watts nominal) and cheaper (per capacity), more capacity; than when I bought my 20AH over +7 years ago for $238.97. Batteries of this type are now cheaper with over +50% more capacity than when I bought mine, technology marches forward!

For sure, LiFePO4 batteries in particular have become much more affordable, so many vendors and competition. Thanks to the competition, the features and quality have gone to too.

AO Lithium has a 100Ah battery (UL listed), with a max discharge rate of 200A, for $630. Sounds a little pricey, until you factor in the build quality, the 200A continuous discharge, and smart BMS with BT connectivity. I'm tempted to buy one of those for emergency power, as I already have a 2000W inverter.

With 1.2 kWh of capacity, you can run several lights and a fridge and easily top it up by charging it with the LEAF's DC-DC converter too. They ship within continental US for free, but unfortunately shipping to Canada is pricey.

I have had a ~20 AHr LiFePO4 battery in my car for over 7 years now. If I were to replace it at this moment, I would seriously consider one of these (https://antigravitybatteries.com/products/starter-batteries/restart-oem/atx20-hd/); a bit more power than necessary, but the price point is better than what I've seen previously. The biggest thing to remember on these Lithium starter batteries is: get one with a good BMS/voltage protection (not made in China).

That brand battery IS made in China !
Why dont you get one made in USA ???

mrlithium said:

That brand battery IS made in China !
Why dont you get one made in USA ???

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You are responding to a post over 3 years old! Companies change where things are made all the time. My first Optima yellow top AGM purchased maybe 7 years ago?? was made in the USA, my second for my other Leaf 5 years ago was made in MEXICO! Ingersoll Rand is another company notorious for outsourcing has most of it's products made in China. Blame our government for making it conducive for outsourcing American manufacturing jobs to foreign companies and to a degree Americans for letting them get away with it by not really caring where a product was made, just looking for the cheapest or just the American or big name on the label. Truthfully for some things, it's darn near impossible to get made in the USA.

Yea, its 3 yrs old, but, i couldnt help it. I just saw this and felt compelled to correct the last poster as someone online might read it. And, AG's batteries are STILL made in china, as opposed to one I saw that are made in USA; LithiumMoto.