Battery Type

Rhino said:

Oh, thanks.

So best (if going for the Shorai battery), to just get their BMC as well? $50 or something there abouts.

I currently have a battery 'tender' that came with the 848.
I assume it would not be compatible.

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From here:
Frequently Asked Questions


Q. Can I use Lead-Acid battery chargers or charger/tenders?
A.Yes. HOWEVER, you may NOT use a charger/tender if it has an automatic "desulfation mode", which cannot be turned off. We have confirmed with Deltran, makers of the "Battery Tender" brand, that their products do NOT have a desulfation mode, and are therefore OK for use with Shorai LFX, for example. But the best possible charger/tender for Shorai LFX is the SHO-BMS01, which will be released on about March 15th 2011, we expect. It uses the 5-pin BMS port in the LFX batteries, in order to monitor, diagnose, and balance the individual cells during charge. And it also has an optimized storage mode that will give the longest possible service life to your LFX.

Thanks Champ.

I'll get their own BMC then.

I'm not sure it's really needed. Unless your bike sits for long periods of time, these batteries just do not discharge like a regular battaery. I've had mine sitting for a couple weeks in cold weather and still fires right up. Tho I do note that on cold mornings the battery initially turns over slowly.

My streetfighter is the first duc that I don't keep on a trickle charger anymore thanks to the shorai.

Rhino said:

Oh, thanks.

So best (if going for the Shorai battery), to just get their BMC as well? $50 or something there abouts.

I currently have a battery 'tender' that came with the 848.
I assume it would not be compatible.

Click to expand...

You don't HAVE to necessarily buy the charger/tender from the battery manufacturer, as Shorai is marketing their own charger/tender. As Shorai themselves point out the Deltran Battery Tender is compatible with their LiFe batteries. I don't know if the converse is true that a Shorai charger/tender will be compatible with a lead acid battery. This may impact your decision to buy one charger for everything or one for the Shorai and another for everything else, especially if you have a lot of toys.

The key, essentially, is that the charger/tender you use for your Shorai or probably any other lithium iron (whatever) battery does not have a "desulfation" mode. Deltran's do not.

I have four Deltran Battery Tender Pluses and each bike gets hooked up after I get home from riding, get the bike cleaned and put away and stays connected until I ride that bike again. I've got one regular, sealed, lead acid battery that is now coming into its 8th year and it cranks every time without hesitation. After replacing other batteries at about the 4 year mark I just went to the constant tender approach and haven't had any problems at all, since.

After reading the numerous battery posts I'll probably get a Shorai at some point depending on what I experience on the Pani with the OEM battery.

Check Amazon for the price of the Deltran Battery Tenders and then compare that to the Shorai or other proprietary manufacturer's price. I think the Battery Tender Plus lists in the low US30.00$ range. And, they have a pretty good selection of other smaller tenders as well.

Rhino: If you have a Deltran Battery Tender, you should be good to go. If not, you may want to check with Shorai directly.

Bottom line - be sure BEFORE you connect your new 180.00$ battery to any charger/tender check to see that they are compatible.

Though, now that I think about this for a few minutes, the choices may be somewhat complicated by the mains or utility frequency differences. North America (at least) runs a 60 Hz utility frequency while most of the rest of the world runs at 50 Hz mains frequency. So, obviously be mindful of this when you purchase your charger/tender. I think Deltran has a "European" version.

For what it's worth...

Rhino said:

Thanks Champ.

I'll get their own BMC then.

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How long do you plan on letting your baby sit around doing nothing?? LiFePO4 can easily sit on the shelf for a year without dropping too much voltage. (assuming you don't have accessories that are draining power with the ignition off)

BMC= Battery Management Circuit.

It will monitor each cell individually during both charge and discharge. Shutdown the battery if any cell/s fall below x volts, usually about 2.7v - 3v/cell is a safe for LiFePO4. Also stop charging at 3.6v/cell. LiFePO4 can go as high as 4.2v/cell without damage.

LiFePO4 ideally have a 2 stage charge cycle. CC/CV. The first 80% is done at Constant Current, then the last 20% is done at Constant Voltage.
It is important that the charge voltage does not go above 4.2v/cell. Usually for true LiFePO4 chargers, they peak at 3.6ishv/cell.
So in the automotive case, most alternators are regulated to 14.4V (max). This being the case, charging a 4cell LiFePO4 pack from an automotive alternator without a BMC is safe, so long as the voltage regulator doesn't fail.

In addition to this BMCs are more important in high cell count packs or extreme abuse uses.

PS. When making reference to the number of cells for charging and discharging, it is common to only describe those that are connected in series. eg. an auto battery is actually a 4 cell pack 13.2v or 3.3v/cell (nominal).

The correct way to describe an "8" cell auto battery is 4s2p. Which is 4 cells wired in series, 2 cells wired in parallel.
In the auto industry, the assumption is that every pack is 13.2v, so manufactures describe packs by the full count of cells. The more cells the more AH.

If you plan on using a LiFePO4 (Shorai type) battery, I wouldn't worry about a "tender" as such. Just get one of these. At 13.2V, you can charge at 3A
http://www.hobbyking.com/hobbyking/...er_Discharger_1_6_Cells_Dual_Power_COPY_.html

or.. I prefer this setup..

http://www.hobbyking.com/hobbyking/...thium_Polymer_Battery_Charger_Version_2_.html
+
http://www.hobbyking.com/hobbyking/store/__9205__25A_14v_DC_Power_Supply_for_Chargers_350W_.html

You won't use it much, but should you find for some reason the battery has been drained, 15mins and it'll be pretty much 90% charged (from flat)

iiiofiv said:

Though, now that I think about this for a few minutes, the choices may be somewhat complicated by the mains or utility frequency differences. North America (at least) runs a 60 Hz utility frequency while most of the rest of the world runs at 50 Hz mains frequency. So, obviously be mindful of this when you purchase your charger/tender. I think Deltran has a "European" version.

For what it's worth...

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This doesn't really matter any more.. Just about all power supply units used in this area are switch mode PSUs. 50Hz, 60Hz, 110v, 240v... doesn't matter, they will take anything.

littlejohn said:

How long do you plan on letting your baby sit around doing nothing??

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Isn't usually longer than a week.

But the 848 is a pig to start normally, when it gets cold, worse.
So when the weather cools, I tend to have it on charge over night to make sure it'll start in the morning.

Won't be an issue?

Keep in mind the battery kit Shorai unit has 18AH vs. 6.5AH for the stock battery. Almost triple the energy storage in the a battery and they have very low self discharge rates (They don't lose much charge just sitting), meaning less need for a charger. Shorai has 270CCA vs. (I don't know what the stock one is).

Chris

Rhino said:

Isn't usually longer than a week.

But the 848 is a pig to start normally, when it gets cold, worse.
So when the weather cools, I tend to have it on charge over night to make sure it'll start in the morning.

Won't be an issue?

Click to expand...

Nah.. not at all.. That won't even be a drop in the ocean for a LiFePO4 pack.
The real advantage with any lithium based battery, is they have really low internal resistance. What this equates to is a relatively low drop in voltage under load. Where a Lead acid battery will sag dramatically under high load, as much as down to 6v. This is the reason why the you feel the 848 is a pig to start.
In comparison, even an average 4s (13.2v) LifePO4 pack will only sag down to about 11v, but really good packs (A123 cells) will easily hold 12V under heavy load.

turnone said:

Keep in mind the battery kit Shorai unit has 18AH vs. 6.5AH for the stock battery. Almost triple the energy storage in the a battery and they have very low self discharge rates (They don't lose much charge just sitting), meaning less need for a charger. Shorai has 270CCA vs. (I don't know what the stock one is).

Chris

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This is not quite accurate. Shorai's quoted specs are what they believe are Pb equivalent. ie. Their 18Ah is not actually 18Ah. It will deliver the perceived power of a 18Ah lead acid battery. It's difficult to know what the actual capacity of the Shorai batteries without dismantling the packs.
Currently there aren't any LiFePO4 cells (prismatic or otherwise) available that would allow them to make a 4s 18Ah pack with the size and weight they specify.
Also, CCA is such marketing BS, I dont' know how the auto industry has been able to get away with it. Perhaps because it's some arbitrary number they put on a sticker.
The real indicator of a battery's performance is sometimes referred to as C rating. This determined by the max amps that can be drawn for the entire discharge cycle whilst maintaining less than 10% sag in voltage.
Some badge manufactures will inflate the C rating by only measuring discharge for a short period of time.. like 60s.

littlejohn said:

This is not quite accurate. Shorai's quoted specs are what they believe are Pb equivalent. ie. Their 18Ah is not actually 18Ah. It will deliver the perceived power of a 18Ah lead acid battery.

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As far as Amp Hours? So the 18Ah is still a good number as comparing it to a lead acid? I presume the reason is that since the Shoria doesn't drop voltage as easily or quickly, they fudge the number to make the lead acid equivalency?

Chris

Littlejohn, thanks for the corrections, updates and insight.

Rhino said:

Oh, thanks.

So best (if going for the Shorai battery), to just get their BMC as well? $50 or something there abouts.

I currently have a battery 'tender' that came with the 848.
I assume it would not be compatible.

Click to expand...

Battery Tender should work as it does not have auto desulfation

turnone said:

As far as Amp Hours? So the 18Ah is still a good number as comparing it to a lead acid? I presume the reason is that since the Shoria doesn't drop voltage as easily or quickly, they fudge the number to make the lead acid equivalency?

Chris

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Thats correct. It will crank like an 18Ah Pb battery. But if you have something that is only pulling low amps, lets say 1 amp (for the sake of easy maths) then the Shorai battery isnt going last for 18 hrs. Unlike an 18Ah Pb battery which will be able deliver 1A for 18hrs.
The so called "reasoning" behind using the "Pb eq" number is to make it easier for consumers to choose the right battery.. but I'm calling this marketing BS. Its got more to do with having a bigger number on the sticker than the next brand.
Its quite confusing because if you have 2 brands of LiFePO4 batteries. Both are roughly the same size and same weight and have very little difference in price, but one has a much higher Ah rating, then most will choose the one with the higher Ah.
The reality is.. without the ACTUAL capacity being stated anywhere, the Shorai could be a lower capacity than the other brand with the alledge "lower" Ah number.
This is the thing I dont like about Shorai... but they are cheap though

iiiofiv said:

Littlejohn, thanks for the corrections, updates and insight.

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You're welcome.

tstephenson said:

Battery Tender should work as it does not have auto desulfation

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Yes.. sort of.. But lithium based batteries dont like being on a float / trickle charge, which is what a tender does.
IMO, if you have to buy a tender and you intend on using a LiFePO4 battery, then you're better off buying a proper multi-chemistry charger like one of the ones I linked to earlier. Pick one that can deliver at least 100w and can charge > 15v packs and you can easily put enough juice back to crank in under 30mins.
having said that.. if you plan on running a LiFePO4 battery, the likely hood of it being so flat it cant crank over will be fairly low. Unless you dont touch the bike for more than 6 months. In which case it would be best to disconnect the battery terminals.

Disclaimer: Im assuming that the bike doesnt have a dodgy alarm that pulls more than a few milliamps.