The chemistry of typical current gen LiHV and LiPo race batteries are the same these days. It's just up to the vendor what kind of sticker they put on the battery. Some of the battery manufacturers are actually now starting to market the LiPos as better than LiHV with claims that they hold better voltage when you're limited to 8.4V charge limits. It's a bogus claim, but there it is.

7.6V is storage voltage for both LiHV and LiPo. "Nominal" isn't being used properly here.

Nominal is absolutely being used here properly.

Your charger will put the battery at whichever storage voltage you tell it to, what matters is what the resting voltage of the pack is at 50% charge. Every pack that I have that says 7.4v is 7.4v when at 50% capacity. Every 7.6v pack I have is 7.6v when at 50% capacity.


If your batteries say 7.4v on them but are actually 7.6v then you have an advantage over anyone who is using a pack that is actually 7.4v How does that square with you being club president? I guess you have to check everyone's batteries at 50% capacity now to make sure it is fair for everyone.

If you look at the discharge voltage curve for current gen LiPo vs LiHV when charged to 8.4V, their graphs look the same. Both LiHV and LiPo have the same recommended storage voltage of ~7.6V. If you're only charging your HV pack to 8.4V then you're not starting at 100% capacity, so your effective nominal voltage will be lower.

SMC regularly get asked why they don't offer LiHV packs for racing. Here's their response. https://www.smc-racing.com/Regular%20vs%20LiHV
Feel free to take it with a pinch of salt since it's from one of the battery manufacturers, but if there actually was a benefit to LiHV packs, they'd sell them.

You're kidding, right? The rules allow HV packs. They don't allow charging higher than 8.4V. They need to be on an approval list (eg ROAR, BRCA etc). I buy the batteries available at our local hobby shop. Are you suggesting I'm doing something wrong here?

That is just not true. You can set your storage voltage to 7.6v and it will charge a non-HV pack to 7.6v, which will happen above 50% capacity (nominal) where the voltage starts to climb for the last bit of the charge. The charger doesn't care and the non-HV battery is not hurt by sitting at 7.6v because it is still much lower than the 8.4v limit of a full non-HV pack. I don't know how else to make you understand that which voltage you tell the charger for storage mode doesn't mean anything. Storage mode is just something to trick uneducated people into leaving the pack close to nominal voltage. I don't use storage mode and never will. I understand to leave the packs close to nominal if I am not using the pack for a while.

Go run your car for 1.5x the length of a normal race. Bring the car into the pits and put the pack on the charger. BEFORE you start charging your pack will be at either 7.4v or 7.6v. If you charge an HV pack to 8.4 it will still rest at 7.6v at 50% charge. If it is a non-HV pack it will rest at 7.4v.


^ Ignore the part of the red or green line above 4.2v (charging an HV pack to 8.4v) and the HV pack still holds a higher average voltage than a non-HV pack. If your packs are HV cells labeled as 7.4v cells then they have an advantage over anyone running true non-HV cells. There is a difference in chemistry between LiHV and LiPo and that manifests as a difference in nominal voltage.

I never said you had to storage mode them at the same voltage. What I said was that the general recommendations for what voltage to use for storage mode is the same for both LiPo and LiHV.

It's usually 7.6V-7.8V after ~10 minutes.

Is that graph supposed to be for the same battery pack? Those curves look very similar. If you take the red line, truncate it to 4.2V (since you're only charging to 4.2V), and then shift it left it to the same starting point, you end up with basically the same average voltage over the run.

I've attempted to do just that - I just copied the red line and moved it left until the starting voltage roughly lined up - it's the new orange-like line. With my crappy artistic skills, and without knowing the source of this data, these discharge curves look very similar.



I wouldn't say I have a battery advantage with my pack. Everyone I race against has similar calibre batteries. Nobody runs a shorty in the class I run.

You don't move the curve to the left, it stays where it is because the verticle axis is voltage and the horizontal is capacity. All you have to do is start at the same verticle point (4.2v) and follow the line exactly where it is. If you don't believe my that the two lines represent different voltages I will graph it using Excel and give you the cell data that shows the red line is always at a higher voltage.

You absolutely do shift it to the left. The X axis is how much charge has been discharged since it was charged to the starting point. If you only charge a LiHV battery to 8.4V, that's where the curve starts from. The amount of energy delivered is the area under the curve from the starting point to the finishing point. Let's assume that in a typical race you draw ~2500mAh and only charge to 8.4V. For the blue line, that's starting from 0mAh at 8.4V and finishing at ~2500mAh at ~7.4V. For the red line, that's starting from ~300mAh at 8.4V and finishing at ~2800mAh at ~7.4V.

But there is no set thing that says the capacities have to line up, which is what you are doing when you shift the line left. You have to disregard the capacity of the HV pack above 8.4v because you are not charging above 8.4v. What really matters is voltage over time. Starting at the same voltage (8.4v) the HV cells stay at a higher voltage over the same amount of discharge time as the non-HV because the non-HV packs are 7.4v nominal.

Don't believe me, look at it from the other way. If you run both packs down to lvc set at 7.0v and then put 50% of the mah back into the packs the HV pack will still be at 7.6v and the non-HV pack will still be at 7.4v

My charger can easily prove me right. If you'd like me to make a video where I start both packs at 8.4v and discharge them at the same rate and time I will. The voltage for the HV cells will remain above the non-HV cells for the entire length of the discharge. Would that be enough for you to admit you are wrong and I am right?

You start the race at 8.4V. Your capacity usage since you charged it to 8.4V starts at 0. Since we're interested in voltage over time, the time starts when you start discharging. 15 seconds into your race, you may have discharged ~125mAh. If you don't move the red line to the left to compensate for when you start, the graph tells you your voltage will be higher than 8.4V. That's just plain wrong. If you're not going to understand something as fundamental as that I've got no more interest in continuing this discussion.

The only reason a LiHV pack is labelled with a 7.6 nominal voltage vs a current gen LiPo is because the average between 8.7V and a flat battery (roughly 6.2V) is higher than 8.4V and a flat battery. It's not because the curve itself is different. If you only ever charge to 8.4V on a LiHV pack you're effectively lowering your capacity and nominal voltage.

I'll go ahead and post the video of an HV pack and a non-HV pack discharging at the same rate for the same amount of time, both starting at 8.4v and you will be able to see that as the packs discharge the HV pack holds higher voltage under load and at rest after discharging.

Even the SMC packs from the link you provided earlier show 7.6v even though they don't label them as HV.

to me it looks like they are the same battery. For the most part voltage is an indication of capacity. they are a function of each other when the total capacity is the same. if you look at both batteries at 4 volts per cell and add up the MAH you pretty much get the same capacity and voltage. the negative slope to 0 might be slightly shallower on the low voltage cell. there is a deeper negative slope on the first 1/3 of the HV (a knee) that levels off to about the same rate after the knee.

Let's try this a different way using your own example:


Both batteries are charged to just under 4.2V/cell (since your data starts =just under 4.2V/cell for the blue curve). For each battery, this means we are at the green crosses at the start. Had we charged the HV battery to it's 4.3V/cell limit, we would have added another ~300mAh, but we didn't. The horizontal separation of the two green crosses is 300mAh. Now imagine two scenarios.

1) Run to 3.0V/cell cutoff: Now we are at the purple crosses for each battery. For each battery, the separation of the vertical lines is the same 300mAh we started with. In each case, we removed ~ 3000mAh from the battery, and we ended up at the same 3.0V/cell. For any capacity removed from each battery, the voltage is the same in each case along all parts of the line.

2) Run a race requiring 2000mAh be removed from the battery. Now we start at the purple crosses. For each case, we travel 2000mAh to the right, and end up at the turquoise crosses. In both cases, we end up at ~ 3.7 V/cell. The turquoise crosses are separated by the same 300mAh difference we started with.

It is correct that, according to that data, if we only charge the HV battery to the same 4.2V/cell, it offers no advantage over a conventional LiPo battery.

I cant say I have any hard evidence however most of the battery mfg want you to store a battery half charged. They claim that fully charged and close to LVC damages the battery over time. so maybe an LIHV running at LIPO levels will last longer? Im stretching here to help out the arguments for LIHV.

Both batteries charged on the same charge profile to 8.44v. Both packs have very close to the same IR at the same voltage. Both batteries were very close to the same temp at the start of the discharge. Only difference is the Motiv pack is not HV and the Power Products pack is HV.

This video is a single shot of both packs being discharged at 20 amps for 4 minutes and 15 seconds. 1308mah's were discharged out of each pack. The HV pack held a higher voltage through the whole run, just like I said.

Anyone who can produce a single shot video replicating every aspect I have proved here showing different results is free to post it here. Otherwise you can all finally shut up over this.

Are you seriously trying to show that a 6100mAh LiHV performing better than a 5000mAh LiPo (which looks puffed) from two different manufacturers means anything here? That Motiv pack looks like it's from a 4+ year old product line. Have you not noticed that I've repeatedly said "current gen" LiPos are the same cells as LiHV? Not the older generation ones.