Needing a new HYBRID battery, best option?

Connecting modules in parallel halves the effective internal resistance of the combination. This could potentially double the current draw for a depleted pack.

Yes, I have studied electricity and electronics.

 

Hmm. Good point, I’d be willing to try it...

 

@2k1Toaster is the battery expert.

 

One could introduce a fixed resistance in the wiring of parallel batteries.

 

That would waste energy in the form of heat though. I'm game to try the larger battery. Maybe change out the coolant to a different kind or increase water percentage for better heat transfer.

(I'm the one with the LiFePO4 12 V. Supposedly with lower internal resistance)...

moto g(7) power ?

 

Thanks. I sent him a message at/through his web store clarifying the capacity of his battery. Maybe I should send another....

 

Mine was doing that at first... then the battery cooling fan started blowing like mad.. then the screen came up with a warning saying that the HV battery needed service. Then while driving to the dealership to drop it off a few days later, the red ! of doom came on and I had to limp there on surface streets instead of taking the highway.

 

That means one of your modules is not operating within spec... The oldest most beat up pack I've rebuilt many times would do that often. I'd simply take a screenshot of the block voltages and clear the error codes via Dr. Prius App. Once the error codes were clear, the fan shuts down and all is well again. Sometime this would happen several times in a day and then go weeks without any issue. But you have to be careful about doing this because you can cause more damage if you do this too much. In my case I was having a hard time figuring out which modules to replace and this method helped me to determine that. I could do it all in less than 30 seconds while driving. Very easy to do once you practice... Of course if I didn't have spare packs to swap out, I'd not be as comfortable doing that. Whatever the dealer says about your car will most likely be for the sole purpose of taking as much money as possible. Taking a 12 year old car to a dealership for repairs is like walking around the most dangerous part of town with huge stacks of money hanging out of your back pocket. Find an honest local mechanic that doesn't specialize in high level thievery to get your car fixed.

 

It's about 50/50 of the months now that we have stock. When we have lots of extra stock, we have fleets and shops that generally buy them up in bulk and then keep coming back for more. Which is great, but means it is still growing faster than we can stock them. Our shipment due to arrive Jan 7th, arrived Jan 16th. We sent out all the orders the next day. We currently have some stock, but basically only a couple weeks worth. We are going to be out for a while because the next shipment coming in, is already almost all spoken for by larger bulk orders. :/

The best would be to just use larger capacity cells to build the pack. This wouldn't be hard. But it would be useless. There were lots of tests done on Prii "back in the day" adding multiple packs in parallel. Sure you get more pure-EV mode, but since it all comes from gas anyways, the fuel economy doesn't go up. The extra weight is a problem and there is almost no benefit unless you live on a giant mountain. The benefit is only when you can recharge and use the extra capacity.

 

2k1Toaster, thank you for the input!

Wouldn't you say/agree it would last maybe twice as long before going bad at the least?

(I know I'm probably a long ways away from replacement at 28k miles or so, but it would be interesting to see how many would choose such an option in your store)....

moto g(7) power ?

 

With proper balancing a few years out, maybe. Doubtful that a 2x capacity will give 2x lifetime but maybe something.

Over time, the cells will become unbalanced. Even with larger capacity, it will still unbalance. So grid charging when that starts happening will help. But the age will still kill the battery eventually. Even a perfectly balanced pack, will eventually get too high an internal resistance or vent bits of electrolyte over the lifetime.

And then the kicker is the cost. The majority of the cost is in the battery. The plastic and wiring is cheap (relatively) for us to make in bulk. The batteries are expensive in raw materials, labour, etc. One of the reasons why our pack is a higher price point than the super cheap Chinese packs that have been around for a decade is because we actually use 6.5Ah capacity cells unlike most others. Some claim 6.5Ah or even 8.5Ah (!!!!) but just aren't. Ours are. Your average consumer won't notice until 4 or 5 or 6 years out. But we do it right. If we were to use 13Ah or higher type cells, the cost generally goes up linearly due to the higher material costs.

The pack may cost almost 2x as much for the 2x capacity. And get you maybe 1.6x-1.8x the life expectancy. It therefore would make sense to just buy multiple new packs instead of 1 bigger new pack assuming the labour is cheap enough or possible.

 

Cycling the battery from charged to discharged and back to charged is what wears them out. It would take double the time to do so with double capacity. I expect longevity to at least double. But alas, I do not have the capability to engineer such a product. I think your business would be more profitable if you offered such an option, but ultimately that’s up to you. (Especially with the knowledge that energy capacity cost is linear. Labor rate is not. I expect it to go higher in the future, as with inflation). As long as the inverter can handle charging the larger battery, which I suspect it can...

 

Congratulations on all your hard work to realize such a successful idea! Very impressive!

 

Yes cycling kills them but also just age. As it is now, we have most batteries dying because of age and not overdone cycles. Toyota very cautiously programmes the full cycle range to be 40%-80% which increases the life by a couple orders of magnitude!

An infinitely large capacity battery would still die an early death due to aging and would be infinitely expensive.

 

Since ours is a very low mileage Prius I'll have to confirm/disprove that for you. We're at 28k miles in short of 8 years...

moto g(7) power ?

 

Yours at that low of miles is actually being stressed MORE by not being balanced as often and sitting for long periods of time without being used. A Prius is lost happy when it is READY.

You will probably get to 10-12 years without grid charging.

 

I'm not going to go drive my parents' car just to get the mileage up. That defeats the purpose of a Prius of saving fuel.

I'm reminded of someone at a store complaining "the customer is always right". I guess that doesn't apply here because I haven't purchased anything from you, but geez...

moto g(7) power ?

 

That personal attack was not called for. It is well known here that the Prius functions better when driven more mikes than 27k in 8 years. I have a little more than that on my 3 year old Prius and consider that at the low end of acceptable use.
From what I know of @2k1Toaster here I feel an apology is in order.

 

jzchen is stuck on the notion of having more capacity. As has already been stated, there's no free lunch. Greater capacity means gas motor is going to have to run longer to maintain that capacity.

The Prius is a pretty incredible piece of engineering. You have a 4000 pound car that is being pushed around by an 88 pound battery. My 1993 Sentra weighed in at 1600 lbs and even with an efficient 4-cylinder engine did not get as good of gas mileage. You should concentrate on trying to maintain what Toyota has provided instead of trying to screw around with it

jzchen owes 2K1Toaster an apology

 

OP is not who you think, there was a threadjack back there a ways.