It’s interesting how we can often talk about and promote a product but don’t take the time to fully understand its capabilities or appreciate the benefits that it will deliver, here is an example from one of our customers a few days ago.
Recently I had a customer inquiring about lithium batteries for a mobility scooter. This particular fellow wanted to increase his battery capacity in an effort to make a 3-hour one way trip to visit a friend before recharging and making his way home. His goal was to increase the capacity on his existing 24 volt 85 Ah AGM battery pack by switching to a 24 volt 100+ Ah Lithium battery pack
Due to the high amperage draw of his scooter, he was barely able to make the 3-hour drive to visit his friend He would then plug in and recharge during his 4-hour visit and attempt to make the 3-hour return trip home. The problem was that his lead acid batteries would not fully recharge in 4-hours so he would not have enough power to make the return trip home. Because of this, he figured the solution would be to switch to Lithium batteries as his scooter would not allow for larger lead acid batteries to fit in the existing compartment, larger capacity lithium batteries however would fit in his existing battery box.
My solution puzzled him (he was not aware of Peukert’s Law) when I explained that he could go with the same capacity Lithium battery pack (actually slightly less capacity) and get more run time out of it and fully recharge it during his 4-hour stop.
Here is the math:
Lead Acid Battery Pack 85 Ah @ 20 hr rate = 66 Ah @ 3 hr rate, 66 Ah X 80% DOD = 52.8 Ah usable capacity. A lithium Battery Pack 80 Ah @ 20 hr rate = 80 Ah @ 3 hr rate, 80 Ah X 90% = 72 Ah useable capacity. The net result of an 80 Ah Lithium pack over an 85 Ah lead acid pack is an extra 20 Ah or 36% at a 3 hr rate, paired with a Delta Q IC900 charger the battery pack could easily be recharged within 4-hours to make the return trip home.
The other considerations not factored into run time is the weight of the Lithium pack being 51 lb’s less than the lead acid pack and the fact that the lithium operates at a higher voltage than lead acid, both will contribute to slightly increased run time.
We have a happy customer.