PingPing 48v 20ah battery pack application

They aren't up to that kind of discharge rate. You would need Four in my opinion to handle the peak amps. Three might cut it depending on the amp limit of your controller. Peaks no higher than 180 amps (very short ones) for three of them paralleled. Even that's going to be a bit weak on giddy-up. My Motorcycle runs a perm 132 motor which is more efficient than an Etek (similar in design). With a 250lb curb weight and 160lb rider, I'm running a 275amp current limit to get good punch. A total of 3 KWH aboard.

Let's talk about range. You want 25 miles at 50 mph. Two 20ah pings at 100% discharge would only yeild 1900 watt hours maximum. That's about 75 watt hours per mile. Pretty lean for 50 mph! You need 50% more battery to get that range on a nice efficient light wieght motorcycle and to have a little (very little) to spare for a headwind and the like.

Aerowhatt

I agree, you need about one amp hour of pack per amp hour of average draw on the entire pack. The pings can punch out about 5 amps per ah for a short burst, and about 3 amps per ah for a short while without damaging them, like to climb a hill for a few minuites. But the average draw on the cells needs to be around 1.5 c or less to garantee the longevity of the pack. So 80 to 100 ah is a minimum, and you want to use diodes to protect the bms from damage. You might also want to look at Hi-power cells, similar in price and performance. They have larger cells avaliable in a plastic case. A few folks I have heard about are happy with them in bikes. About $4000 should be you battery system budget. 100 ah at 60v would be nice!

Ouch. So my quest now should be to find these cells (or equivlent) for less than $2.60 ea. Do people actually use cells like these, or do they usually use prismatic cells? Which are better? Or is there something like a bigger cell that is more practical for large applications like this?

Thanks for all your help. It's looks like Pings packs aren't strong enough for my project. That's one multi-thousand dollar mistake avoided! Thanks!

I've been down the road of using hundreds of small cells to make a large battery pack. About four or five years ago I had a big pack made from 18650 cells they were 1.8ah each. I wouldn't do that again. The results were OK but the longevity wasn't that good. The value wasn't there for the investment.

Consider going a little different route, which has been very successful and gratifing for me. My Bike runs on 36 volts 42 AH of premium lead SLA's and 40ah of pings. Total cost of $1600.00 rounding up! The bike has very deep pockets when it comes to peak amps. It has plenty of range (around 35 miles) in stop and go urban sprawl riding. Most trips between charges are 25 miles or less and the SLA's rarely see more than a 60% DOD and have a BMS on them. Therefore, I expect somewhere around 800 cycles from them. Considering that you want a 48 volt system you could do it for around $2000 in battery cost and have a little more range than mine does.

I've mentioned this system several places before and people seem reluctant to try something different. I've got over 3000 miles on this set up and also three eGO Cyles running a similar arrangement. I can't imagine getting more bang for your buck in any other arrangement. Weight wise my motorcycle has 97 pounds of lead onboard and 37 pounds of LiFePO4.

The Perm motor won't be more efficient enough to make a significant difference in your battery needs. It is a better motor but at twice the cost of an Etek one must think twice. The fact that the Perm is manufactured in Germany and the Etek in China made the price difference justified IMO.

If you wish to try this kind of set up. I'd be willing to walk you through the details off line or on.

Aerowhatt

2 Pings ~$1500 + 2 Optimas ~$400 = $1900 = Very attractive! .vs ~ $4k Lifepo4 alone (ewww!!!)
I'm liking it!

Oh wait, how would I get 48v out of this? Maybe I'd have to get 4x LA batteries... then I'd need smaller/cheaper ones. That would work out.

So sure, how did you do it? What special considerations did you take with the different battery types?

You need 4 SLA's and connect them (as a 48 volt SLA string) in parallel with the Pings. I was thinking more like 4 Odyssey batts at ~170 each. $680 + ~1500 for two pings = $2180.

As far as controls. I keep them paralleled full time except for a once a month overnight balancing Charge for the pings. Since this higher voltage balancing charge would overcharge the SLA's, the pings are disconnected with a manual circuit breaker during the balancing charge. I've tripped the overcurrent on the ping BMS units a couple of times in unusual circumstances. You feel it happen and just reset at the next opportunity. The manual circuit breakers will handle any catastrophic failure before it becomes a marshmellow roast.

Aerowhatt

Since you are starting from scratch. It might mot be a bad Idea to go with U1 size SLA's. You have far more choices in brands and performance. Since they are used in so many wheelchairs and power chairs they are less expensive. Volume, economy of scale and all that good stuff. The B&B EVP35 is an amazing performer that I have a lot of experience with. Powersonic and CSB make some high performance U1's as well. They would run more like $480 for a set of 4, knocking $200 off the the battery cost. Plus your racks would be set up for a very avaialble size of battery that will have a lot of market share for some time to come.

Aerowhatt

Wow, $89 ea for 34ah. Good deal! God only knows what shipping will cost though. But maybe I can find them locally. My spreadsheet is liking this, big time. Thanks again for all the great info!

Do you have a recommended charger for this configuration?

Be careful, not all U1's are created equally. Imagine the max amp draw on a power chair that tops out at 7 mph. That's a completely different application than doing the heavy lifting of a 250 peak amp system. There are only a few models that are up to this kind of task. To my knowledge none of them are only $89. Don't buy anything without a spec sheet. You want 1 hr discharge capacity to be as high as possible and internal resistence to be as low as possible. If the spec sheet on a certain model doesn't show this data then move on to another.

For charging I've proven to myself that bank charging, or else string charging with a balancing BMS is not optional, it's required. You pay for the extra equipment costs with the longer life of your first pack.

For specific chargers I need a few parameters. Are you going to have an onboard charger? What kind of turn around time do you want to shoot for?

Aerowhatt

I was referring to a different Hi Power, I have seen em on ebay, they are large prismatic cells. Not the batteryspace ones. Still gonna cost you to go fast for a half hour, unfortunately. It's the reason I'm on a bicycle, not a motorcycle or an electric car.

That's a pretty good price on the CSB EVX. Those will be fine. I'd call and make sure that is what they are actually going to send. Some of these online battery sources have started substituting "comperable" brands and models. You don't want this to happen at all. You end up with UB's or some other substandard "replacement".

If you are going to only charge at home then bank charging is likely the least expensive way to get individual care for each unit. It's more wiring up front but also let's you check individual batteries from a single plug in. There should be lot's of info about bank charging on the forum if you search for "bank charging".

From a deep discharge you will be putting back in around 65 amp hours (including two pings). A 6 or 7 amp charge rate would do that in 12 hours.

Aerowhatt

The ebay vendor is named Dy-Power, but they seem to come and go. Series connecting a few Ping packs and sla's works fine as long as you protect the pings with diodes, by the way, A 35 ah sla and a 20 ah Ping would deliver a similar ammount of usable amphours.

The ebay vendor is named Dy-Power, but they seem to come and go. Series connecting a few Ping packs and sla's works fine as long as you protect the pings with diodes, by the way, A 35 ah sla and a 20 ah Ping would deliver a similar ammount of usable amphours.

You do need diodes if the ping packs are series wired. Not if they are wired in parallel though. They just waste power and provide "protection" from a situation that is all but impossible to run across.

Aerowhatt

Yes, that charger will work well for bank charging. Made in the USA is a plus too!

I use what I already had to charge my hybrid chemistry pack. I have two chargers on board. A soniel 36 volt 6amp unit which is the brains of the operation. Also aboard is an Iota 48-15 switch mode power supply, which is tuned down to the float voltage of the SLA's. It puts out 18 amps at this voltage. The chargers are switched so that I can use just the soniel or else both chargers at the same time. When using both, the bike pulls 1000 watts from the wall plug and the initial charge rate for the 82ah (total) pack is 24 amps. This gives me a really fast turn around for opportunity charging.

The Sla's are equiped with powercheq balancing units to prevent the usual battery damage from pack voltage charging.

Aerowhatt