Enginer kit with Deep cycle batteries

[menardsy]

Hello,

I wonder if it would be possible / wise to use Deep Cycle batteries with the Enginer system instead of its lithium battery? It would be much less expensive with deep cycle / SLA batteries (< 1000$ for 4800 kwh (12v x 4 x 100Ah)). This weight about 200 pounds. I think the DC-DC converter from enginer is around 500$. This would make a plugin hybrid for under 1500$!

Sylvain

[MJFrog]

Originally Posted by menardsy

Hello,

I wonder if it would be possible / wise to use Deep Cycle batteries with the Enginer system instead of its lithium battery? It would be much less expensive with deep cycle / SLA batteries (< 1000$ for 4800 kwh (12v x 4 x 100Ah)). This weight about 200 pounds. I think the DC-DC converter from enginer is around 500$. This would make a plugin hybrid for under 1500$!

Sylvain

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.

[djras]

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).

[menardsy]

Originally Posted by MJFrog

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.

I am sure I could live with the trickle charge principle of the enginer kit. I don't want to modify the Prius system in an intrusive way.

The full charge voltage of the deep cycle battery is between 13.0 and 13.5v. Once completely depleted (which should be avoided) the voltage is 10.5v (hence 42v for the 4 batteries). Perhaps the Full-Empty voltage range is too wide to work with the DC-DC converter.

I would not use the Enginer charger to charge the 4 battery but probably charge them separately.

If the voltage range is compatible with the kit, deep cycle battery can be depleted up to 80%. With 80ah battery this give roughly

12v * 4 batteries * 100ah *0.8 = 3840 watt/hour which is not that bad.

[visitor1]

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.

[menardsy]

Originally Posted by visitor1

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.

I contacted Enginer and they could sell me the kit (including the 5kw converter) without the BMS and lithium battery 1100$.

I was thinking about using flooded deep cycle battery because they are much less expensive.

The way I see it, I was thinking about using high amp relays to switch the batteries from serie to separated individual connection so that they could be charged separatly with dedicated charger for each battery. Anyway, I don't think that I am going to do this until next summer (It's winter here in Canada and quite cold right now).

Enginer told me that their kit would work with 4 12v battery, but that I should expect a shorter range than with lithium batteries.

The life cycle of deep cycle batteries is indeed quite short ( 250-500 cycle) which make them usable for about one year if you discharge/ recharge them everyday. They last about 8 times less than the lithium, but they also cost 8 time less. So I think it is good to tryout the enginer system without spending too much at first. Than you can upgrade later.

[dan2l]

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

[seilerts]

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?

[menardsy]

Originally Posted by dan2l

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

Hi Dan2l,

Thanks for your advice. I think a 100ah deep cycle battery can provide 100a continuously?

I must admit that it is far from being the best system with Lead Acid batteries but I wont be able to afford 5k$ this year.

I also tought I could use LiPo battery but I think it is too hazarous (spontaneous combustion!).

I must admit that more and more I am looking at Deep Cycle, more and more I think I am not going this way. Basically because ot the 100a requirement from the enginer converter. Lead acid battery ah capacity is directly dependant on the amp load. The 100A dicharge rate would probably greatly reduce the AH capacity of the batteries...

Sylvain

[menardsy]

Originally Posted by seilerts

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?

Hi Seilerts,

I did not ask the price for the converter only. I think therir kit include the metal box to install batteries and converter. I sould ask them indeed how much is the converter and harness only.

Not sure if I will go the Lead Acid way because of the 100A requirement from the converter...