Method to extend Hymotion Battery by 25%

120 A123 M1 cells configured for 13.4V (about 1kwhr) could power a 12V inverter in your trunk, and then provide the 700 Watts required by the chargers in the Hymotion battery pack while you are driving the car. This would pump about 1 Kwhr into the Hymotion battery in the first hour, extending the usuable amount of kwhr from the present 3kwhr to 4kwhr.

Can the Hymotion chargers work while while the pack is being used?

Cost- Buying 36v Dewalt battery packs (10 cells per Pack) off of Ebay would cost between 960 and 1200$. So increasing the cost of the whole system by 10% would improve the overall system by 25%

Charging- These cells require an inteligent charging system that load levels every cell at the end of each charging cycle. This charger would have to be designed for the 13.4v system. This by the way is why the Hymotion pack does not allow the hybrid system to charge this battery.

Ron

 

Good question. The Hymotion battery pack comes with it's own chargers, 3 of them. So if you wanted to add to the pack you would have to integrate another charger some how. Doing the 12v pack and going through an inverter allows you to disconnect the whole thing and take it out, Leaving the Hymotion system intact and uncompromised.

Another way to do this would be too use a 36V UPS. Then you could just hook up DEwalt 36v battery packs to the UPS, so your packaging is taken care of sort of, and you can recharge the Dewalt packs with their own dewalt chargers (4 to 12 of them). Tahnks-

Ron

 

Thanks for that info. Too bad, I can't think of any reason why that would be necessary. Guess you could charge the system whenever you are out of the car shopping or whatever.

Ron

 

Chargeing these batteries is not trivial. They require a sofisticated charger.

Standard UPS's use female spade connectors to connect to gelcel lead acid batteries. You would have to change those to male spade connectors, probably 10 guage ones. You would have to package the Dewalt battery packs and make up a cable harness that would match the individually packaged battery packs. Just push the spade connectors into each battery pack. You may want to come up with some way to secure the spade connectors to the packaging structure (and this structure should restrain the battery packs also) so they don't try to back out of the battery packs. The whole package needs to disasemble quickly so the Packs can be taken out and charged individually in there own chargers. An interresting job for amature and expert alike!

Ron

 

If you believe A123 their M1 cells will last several thousand cycles in full cycle mode. Even then they will retain 80% of capacity. Keeping them above 20% charge will help them do even better. These cells have two great advantages over previous generation cells, the first being long life. The other is huge discharge/recharge capability. Their middling capacity and difficult recharge habits has made it difficult to use the latter advantage of huge current capabilities, except for the electric motorcycle dragster that uses these cells.

A123 has promised their new cells being tested by GM for the Volt has far more capacity with the same low internal resistance (.01 ohm). We can only hope for that and some moderation in price!

Ron

 

I forgot to mention that Hymotion is using a 5KWR battery pack, but is only using 3KWH of that capacity. This means that they are leaving 40% of capacity on the low end. So figure 40%-100% use of capacity. Charging to 100% capacity will not shorten life because it is done very slowly and carrefully with internal charging circuits. This battery pack will be rediculously under stressed, as it is capable of putting out over 90KW but will never have to provide more than 22 KW. You could charge this pack to 90% of full charge in as little as 5 min. It will take over 6 hours to charge this pack. Hey Hymotion, how about adding a 220V charger so we can do a full charge in 1 hour at least! Thanks-

Ron