Lithium Battery Owners - Some Useful Data

[TucsonJim]

I attended the Las Vegas rally this weekend (lots of fun by the way) and the owner and CEO of BB made a great presentation about his company and products. Here were some tips I gleaned from his presentation:

- Be careful if you have a very large battery bank and you're trying to charge it from the alternator in your tow vehicle. It can put a very heavy load on the alternator if the battery bank is in a low state and damage the alternator. BTW, this is true for any type of battery construction.

- If you operate the LiFePo batteries in a very hot climate, the batteries will increase in capacity, but it can also shorten their cycle life. For example, you might get 108 aH from one battery rated for 100 aH, but you might only get 2500 full charge/discharge cycles out of a given battery vs. 3,000.

- Partial discharge (as compared to full 100% discharge cycles) will greatly increase the lifetime of the battery. The batteries could last 15-20 years.

- Storage in extreme cold will not damage the BB batteries. However, if the BMS will not allow them to charge if too cold.

- BB recommends disconnecting the 7 way connector when the truck/trailer is parked for a long time. Otherwise, there can be feedback into the truck's battery on some models.

BTW, they had a $50 discount on the batteries at the rally if you bought one battery, and $100 each if you purchased two or more. I bought one more battery, but was able to finagle the $100 savings since I'm already an owner. Now, I'll have 300 ah in my bank. Oh... Don't tell the Mrs. But I also bought the new fangled Victron 712 monitor that allows me to monitor the battery bank via blue tooth and a smart phone app.

Jim

[HawgWild]

H Jim, I had Darin from BB take a look at my trailer. Wife and I decided to get 3 batteries, 3000w inverter / charger, and BMS to get us started before we do solar. Heard my wallet yell “ouch,”. Guessing we’ll do it all at once. They recommend Zamp panels, but I need to do more research. We were happy with the deal he made for us so what the heck. The Rally was a good time!

[howson]

- Be careful if you have a very large battery bank and you're trying to charge it from the alternator in your tow vehicle. It can put a very heavy load on the alternator if the battery bank is in a low state and damage the alternator. BTW, this is true for any type of battery construction.

That's why if I install a charging system from the truck to my BBs I'm probably going to go with Victron's Buck-Boost setup. More expensive than the many alternatives I've researched, but I like that the Buck-Boost can be programmed for a maximum amperage allowed from the truck's alternator.

Thanks for the post.

[DaveMatthewsBand]

I have a dumb question... how do I know (measure) how much electricity is going into my battery bank from the truck when it’s connected?



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[Cate&Rob]

I have a dumb question... how do I know (measure) how much electricity is going into my battery bank from the truck when it’s connected?

Hi Ed,

You need a DC ammeter. There are wired in (usually a shunt) versions or "clamp" meters. This is a good one for a reasonable price. https://www.bluesea.com/products/811...imeter_-_AC_DC (there are others of course). A caution . . . many similar looking meters will only measure AC current. Isolate a section of the charge wire from the truck to the RV, clamp this meter around this single wire . . . and you will know the charge current coming from the truck.

Rob

[gbkims]

Have to get a meter around the charge wire from the truck.

Something like:
bayite DC 5-120V 400A Mini Digital Current Voltage Amp Meter Gauge with Hall Effect Sensor Transformer.

Just saw this AC/DC Clamp On Meter with Bluetooth on Amazon, supposed to do send readings to your phone, ordering now.
Clamp Multimeter, BTMETER BT-570C-APP Auto Range AC DC amp Clamp Meter 4000 Counts, Resistance, Cap, Hz, Duty Cycle, Temperature
by BTMETER

[DaveMatthewsBand]

Hi Ed,

You need a DC ammeter. There are wired in (usually a shunt) versions or "clamp" meters. This is a good one for a reasonable price. https://www.bluesea.com/products/811...imeter_-_AC_DC (there are others of course). A caution . . . many similar looking meters will only measure AC current. Isolate a section of the charge wire from the truck to the RV, clamp this meter around this single wire . . . and you will know the charge current coming from the truck.

Rob

Thanks Rob

Won't the current change with the speed of the truck?
Higher revs = more current?

Ed

[Cate&Rob]

Thanks Rob

Won't the current change with the speed of the truck?
Higher revs = more current?

Ed

Hi Ed,

If you want to monitor this while driving the more permanent monitor in the first link of Gene's @gbkims post would probably be more appropriate.

I don't know about lithium batteries, but for lead/acid batteries the rate of charge is usually more dependent on the state of charge of the battery bank than on the speed of alternator/generator.

Rob

[TucsonJim]

Another way to monitor the alternator charging current is to install a Victron 712 meter in your trailer. It runs about $205. Since it can be blue-toothed to your smart phone, you can have your passenger monitor all the parameters including charging current and state of charge while you're driving down the highway. And since you can monitor all the parameters with your phone, you don't have to get all fancy with trying to mount the display inside the coach where it's visible. You can simply mount it in the battery storage area.

Victron 712

Jim

[DaveMatthewsBand]

Another way to monitor the alternator charging current is to install a Victron 712 meter in your trailer. It runs about $205. Since it can be blue-toothed to your smart phone, you can have your passenger monitor all the parameters including charging current and state of charge while you're driving down the highway. And since you can monitor all the parameters with your phone, you don't have to get all fancy with trying to mount the display inside the coach where it's visible. You can simply mount it in the battery storage area.

Victron 712

Jim

Thanks Jim
Can that Victron tell the difference between the input from the solar and the input from the truck? Or just total input?


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