Enginer kit with Deep cycle batteries

Well, yes and no. I've considered going that route myself, but haven't pulled the trigger. Major things to consider:

1. Battery charger. Will the Enginer charger work for these batteries hooked in series, or does it need an individual charger for each battery? These are different chemistry than L-ion cells, so how best to charge them?
2. BMS. There's nothing available for this to my knowledge. Maybe it wouldn't need one???
3. Voltage to converter. Nominally, 4 12v deep cycle batteries would put out 48v while the converter is expecting 52-56v(?) input. In actuality, the batteries should be putting out ~13.5v when fully charged. That puts the voltage to the converter @54v which SHOULD work. But how far down can you pull their voltage before the converter shuts down for low voltage input??? What would the REAL system capacity actually be?

The last point to consider is that the Enginer system is designed to "trickle charge" the Prius battery, not replace it or convert to an all-EV system. i.e. it runs best as a "blended mode" system. If you can live with these constraints, then go for it.

 

The charge & discharge rates for Lion and deep cycle batteries are considerably different too. The deep cycle batteries probably can charge at 1/10 the rate of L-ion (or less).

 

Did you research/find options where to get 48Vin to 240Vout DC/DC converter (5KW) for this approach? Is your 4 (12V) SLA weight estimate low? Curious how you make out doing this, including your plan to charge individual 12V cells or 48V pack. I do like the lower system cost & batteries w/o BMS, but I think SLA cycle life is lower too.

 

Hello Menardsy,
I do not think you will be happy with LeadAcid. The Enginer system needs capability of 100a from the batteries. If they do not provide that the converter will shut down prematurely. All the people I know that have gone less on the battery pack were very displeased.

Thanks,
Dan

 

All you need from Enginer is the 5 kW converter and HV wiring harness. Can't believe that they would charge $1100 for it. If you are not tied to the Enginer form factor, then you have a lot more flexibility to address keeping the 5kW converter cool during the summer. Anyway, if you have a serious spirit of adventure, get 9x6V flooded golf cart batteries from Sams/Walmart etc, and get an individual on-board charger for each one. Put Hydrocaps on the batteries to reduce gassing/watering issues. Sure, everyone will say, don't use a flooded lead acid battery in the cabin, but you are already doing some serious modifications, so why not go all-in?

 

Gen II has a <14 amp limit. More current than that will trigger a fault. Maximum voltage is, 250V? Max continuous power delivery is then 3.5kW, which, at 90% efficiency of the converter, 3.9kW required from the pack. You'll never see 100A. Bottom line, you'll see 70A on average, and 60A-80A during the course of operation.

 

Be sure to check with Enginer which converter you get, as I think the 2 kWh system ships with the older 3 kW converter, 10A current limit. You'll definitely need 13A-14A continuous to make it, but it will be tough to do without the traction battery SoC dropping too low. How long does it take you to complete the trip? You'd need to be able to make it without dropping out of EV mode, otherwise its just not worth it.

One thing that might help, use as a ballpark figure 250 watt-hours/mile for the energy requirement. Then you can compute the average power requirement. For example, at 15 mph, the power requirement is 3.75 kW, which is about the limit of what you can get out of the Enginer kit. If your commute takes half an hour, you'll be ok. At 20 mph, that's 5kW, which means the traction battery has to supply 1.25 kW for 7 miles@21 minutes, or 438 Watt-hours. That is just barely what you can get from the traction battery before dropping from EV mode, if you start out at full SoC.

 

you wil neeed to buy new dlead acid batterys every 1 or 2 years......
so its not that cheap on the long run

 

From my experience I would not use lead acid batteries in any conversion for several reasons. My first attempt at a plug in hybrid used lead acid and after only 8 months of use, about 200 cycles, they were ready for the recycler. The SAME set up with Lithium lasted over 3 years and 1100 cycles. The lithium batteries were 1/3 the weight yet delivered more than twice the power. Lead acid have greatly diminished capacity at higher draw rates. So while a 100 amp-hr battery would give a full 100 amp-hrs pulling 5 amps over 20 hours, you will likely find it will be dead in 30 minutes pulling 55 amps which you will see with the Enginer kit.

The last reason I would not use lead is I would hate having several hundred pounds of sulfuric acid in the back in the slight chance of an accident.

If you need to save some money try the 2 kwh Enginer kit as you can always upgrade the batteries.

If you want details on some of my testing with lead acid versus lithium and my results with the Enginer kit feel free to visit our home page at hrivnak.com

 

If you are going to use lead acid batteries forget using Enginer kit. I would just install 20 x 12v batteries in series and use it with a BMS2 (BMSplus version2). More energy efficient. Anyhow Lead Acid are crap. Maybe deep cycle. Lithium would be best.

Maybe you could use 20 of these Lifepo4 12v 20ah batteries on EBay

http://www.ebay.com/itm/4-cell-20Ah...&ps=63&clkid=5393339026258968597#ht_648wt_689

20 x $124= 2480 excluding delivery.

 

As an Enginer user, I'm hoping you can help answer a few questions, (as I am still trying to determine best possible inexpensive PHEV add-on ideas to my Kia hybrid):

- For this 240V PHEV add-on battery approach you suggest, wouldn't you need interface high power contactors between stock battery, plus you need to be concerned with overcharging of the PHEV add-on battery? Thus, more system cost needed verse Enginer?
- I realize Enginer dc/dc (28Vto240V) converter current limits pure EV mode, but in blended mode, I believe it helps to recharge the stock battery - correct? Thus, you get the MPG % improvement using stock battery more often?
- I realize you wall charge the 48V pack while stationary, but are you aware of anyone creatively recharging their 48V Enginer pack while driving car? I'm wondering if there is an "fairly" efficient way to do this with any car? I realize there are converter power loses, but one idea I had while reading this thread of SLA deep cycle is to connect a seperate dc/dc brick converter (ie. ~200W, 12Vto48V) from the car's 12V line. My kia hybrid has the 12V SLA car battery in the trunk near the 270V stock Li-Ion battery, so I can wire everything in trunk.

 

I suspect this would be hopelessly inefficient and possibly dangerous as well.