07-22-2020, 05:38 AM
Brian,
To answer your question....How many BB batts do you need? It depends on Richard's question. What are you gonna do? More batts equal more time to run without generator. 4 BBs will allow you to park, watch TV for a while, run the 12V water pump for a shower and still have battery left in the morning. 6 will extend that time...8 will extend that time more and 12 will extend that time even more.
You will be limited by the available space. If you have 4 8D batteries, I suspect you will be easily able to install 8 BB batts.
They are essentially drop in replacements.
I would definitely research the battery state of charge (SOC) options for the Xantrex. Here is why....With Lead-acid batts, the voltage will drop as you use energy out of the batts. With lithiums this does not happen. They keep the voltage high until the very end. This means you will not ever know how much stored energy you have left. A state of charge system will count the amps in and subtract the amps out and tell you how much (in percent) you have left.
The BBs are 100 Amp-hour (Ah) capacity batts. So are most of the 8D AGMs and lead acid batts. This is misleading though. You can not really use more than 50% of the lead acid battery capacity without seriously degrading the battery. You can use almost all of the capacity of the lithium batts. So one BB has almost twice the capacity of a single L-A battery. AND...AND...AND... they weigh 1/3 as much.
CONS: So getting lithium batts is pretty much a no brainer? Not so fast! There are a couple of huge downsides with Lithium batts.
1). They are heckin expen$ive. Nuff said about that.
2). This is more important. Lithium batteries have very little internal resistance. This means that if they are empty they will accept as much current as you provide them. 8 batteries will consume hundreds of amps on re-charge. The inverter probably can handle this with no problem....but the alternator cannot. The alternator will put out its maximum to recharge the batts and will eventually get hot and melt down if not robust enough. The more batteries you have the more this is a problem. BB batteries do not talk to each other so if one is empty, they will all be empty and will all pull as many amps as they can. (See State of Charge above).
A good idea if boon docking is to crank the generator to charge the batteries BEFORE you crank the engine. Just cranking the engine will cause the isolator to start sending a massive amount of current to the batts. (Potentially melting the isolator too).
I know this is a lot of random thoughts (hopefully some use to you)....but the path to lithiums is paved with dead electronics.
Cheers,
bill
To answer your question....How many BB batts do you need? It depends on Richard's question. What are you gonna do? More batts equal more time to run without generator. 4 BBs will allow you to park, watch TV for a while, run the 12V water pump for a shower and still have battery left in the morning. 6 will extend that time...8 will extend that time more and 12 will extend that time even more.
You will be limited by the available space. If you have 4 8D batteries, I suspect you will be easily able to install 8 BB batts.
They are essentially drop in replacements.
I would definitely research the battery state of charge (SOC) options for the Xantrex. Here is why....With Lead-acid batts, the voltage will drop as you use energy out of the batts. With lithiums this does not happen. They keep the voltage high until the very end. This means you will not ever know how much stored energy you have left. A state of charge system will count the amps in and subtract the amps out and tell you how much (in percent) you have left.
The BBs are 100 Amp-hour (Ah) capacity batts. So are most of the 8D AGMs and lead acid batts. This is misleading though. You can not really use more than 50% of the lead acid battery capacity without seriously degrading the battery. You can use almost all of the capacity of the lithium batts. So one BB has almost twice the capacity of a single L-A battery. AND...AND...AND... they weigh 1/3 as much.
CONS: So getting lithium batts is pretty much a no brainer? Not so fast! There are a couple of huge downsides with Lithium batts.
1). They are heckin expen$ive. Nuff said about that.
2). This is more important. Lithium batteries have very little internal resistance. This means that if they are empty they will accept as much current as you provide them. 8 batteries will consume hundreds of amps on re-charge. The inverter probably can handle this with no problem....but the alternator cannot. The alternator will put out its maximum to recharge the batts and will eventually get hot and melt down if not robust enough. The more batteries you have the more this is a problem. BB batteries do not talk to each other so if one is empty, they will all be empty and will all pull as many amps as they can. (See State of Charge above).
A good idea if boon docking is to crank the generator to charge the batteries BEFORE you crank the engine. Just cranking the engine will cause the isolator to start sending a massive amount of current to the batts. (Potentially melting the isolator too).
I know this is a lot of random thoughts (hopefully some use to you)....but the path to lithiums is paved with dead electronics.
Cheers,
bill
Bill Johnson
Birmingham, Alabama