Thoughts on a single battery setup

[JBehrens]

So recently I have been thinking about getting rid of my duel battery setup on the 190. Currently, the boat has two group 31 AGM’s, 1 is a NorthStar X2 and the other is a Sam’s Club Duracell. Initially, this setup was installed with the recommendations from all of my boating friends and family that say to never go out without a second battery (for fear of getting stranded), and to give me more then enough power to rock the stereo for 8 hours without having to worry about the state of charge. I figured that on a normal trip I would likely be switching from bat 1 and 2 on a regular basis but I have found that I generally use bat 1 (NorthStar) 99% of the time and don’t even touch or think about bat 2.

So is it even worth it to carry around another 80ish lbs of battery and charger that take up space and don’t even get used? My only concern would be if on a 9 day Lake Powell trip the battery dies I would not have a backup but that’s all I can think of. What are your thoughts and/or experience?

Thanks

 

[LoWeLL216]

I'd keep the two personally. The space and weight you'd save are fairly minimal and the cons of only having 1 battery make it not worth it - to me anyway.

 

[FSH 210 Sport]

This quote by Benjamin Franklin popped in my head when I read your post…”The worth of the water in the well is not known until it is gone”. So I’d keep the second battery.

I used your build link thread to see what you had done battery wise on your build, looks like at some point you replaced the group 24 start battery with another group 31 battery. Also I saw another linked thread to a DVSR debate thread. What I think you could add to your battery system is a Victron smart shunt so you can accurately know how much power you are using off of a battery, anything less is just guessing. I have measured the output from the TR-1 engines in my boat and I have seen 13A’s off of each motor at 3500 and up going into my house battery for a total of 26 amps when the battery is down 20% or more, so I think your estimate of 14A coming off your single 1.8L is close. Again without a smart shunt it’s all a guess as to how much is actually being drawn out and then put back into the battery(ies).

If it was me I would install a BEP DVSR, put the smart shunt on the house battery, then use the start battery voltage tap of the smart shunt so you can have a voltmeter on the start battery and the house battery. Now when you are on a nine day LP trip you can know how much you’ll need to cruise around to keep your battery charged as the smart shunt will monitor charge current coming into the battery, and the state of charge will update while your engine is charging the batteries. I’ve been using the BEP dual battery set up that came with my boat with great success, I have modified it to the storage mode since I went to a 100Ah battle born LiFePO4 house battery and have a group 24 AGM start battery. If you want to dump half the weight of your house battery and have thrice the KWh of storage then go with the BB LiFePO4 house battery set up like I did. The LiFePO4 battery is a great marriage between the charging system our boats have and the rapid recharging rate of the LiFePO4 battery. Just make sure the DVSR is not active when the engine is off when using a LiFePO4 battery or the DVSR will stay closed due to the LiFePO4 batteries’ higher resting voltage. You could also set up the DVSR to activate using an engine run hot to activate the DVSR.

Check out this thread if you want to know more about upgrading your battery system to LiFePO4 batteries.

https://jetboaters.net/threads/conversion-to-lifepo-batteries.35834/

 

[kgower]

Two is one and one is none. We have two batteries and a jump pack on our 195s.

 

[JBehrens]

This quote by Benjamin Franklin popped in my head when I read your post…”The worth of the water in the well is not known until it is gone”. So I’d keep the second battery.

I used your build link thread to see what you had done battery wise on your build, looks like at some point you replaced the group 24 start battery with another group 31 battery. Also I saw another linked thread to a DVSR debate thread. What I think you could add to your battery system is a Victron smart shunt so you can accurately know how much power you are using off of a battery, anything less is just guessing. I have measured the output from the TR-1 engines in my boat and I have seen 13A’s off of each motor at 3500 and up going into my house battery for a total of 26 amps when the battery is down 20% or more, so I think your estimate of 14A coming off your single 1.8L is close. Again without a smart shunt it’s all a guess as to how much is actually being drawn out and then put back into the battery(ies).

If it was me I would install a BEP DVSR, put the smart shunt on the house battery, then use the start battery voltage tap of the smart shunt so you can have a voltmeter on the start battery and the house battery. Now when you are on a nine day LP trip you can know how much you’ll need to cruise around to keep your battery charged as the smart shunt will monitor charge current coming into the battery, and the state of charge will update while your engine is charging the batteries. I’ve been using the BEP dual battery set up that came with my boat with great success, I have modified it to the storage mode since I went to a 100Ah battle born LiFePO4 house battery and have a group 24 AGM start battery. If you want to dump half the weight of your house battery and have thrice the KWh of storage then go with the BB LiFePO4 house battery set up like I did. The LiFePO4 battery is a great marriage between the charging system our boats have and the rapid recharging rate of the LiFePO4 battery. Just make sure the DVSR is not active when the engine is off when using a LiFePO4 battery or the DVSR will stay closed due to the LiFePO4 batteries’ higher resting voltage. You could also set up the DVSR to activate using an engine run hot to activate the DVSR.

Check out this thread if you want to know more about upgrading your battery system to LiFePO4 batteries.

https://jetboaters.net/threads/conversion-to-lifepo-batteries.35834/

Very interesting info, I am going to read through the thread. I think my main motivation is on space and weight saving, been finding a lot of things that just hangout in the boat and never get used or only get used at Powell.

 

[FSH 210 Sport]

Very interesting info, I am going to read through the thread. I think my main motivation is on space and weight saving, been finding a lot of things that just hangout in the boat and never get used or only get used at Powell.

Well, a single 100Ah LiFePO4 battery has more kWh of storage, roughly twice, than both of the group 31 AGM batteries you have and weighs 31 pounds. You’d still need a start battery, Dakota Lithium makes a 1000 CCA LiFePO4 start battery that weighs 24 pounds I believe, so you could drop 106 pounds of weight and have roughly twice the amount of stored energy that you do now with two group 31 batteries, and still have a start battery that is isolated.

I hear you about trying to keep the boat storage area’s free of “stuff” that doesn’t get used…

 

[jimbobalu]

I'm going to try the AO Lithium 100AH LiFePO4 battery, it can do 200 amps for 10 seconds. I have measured the starting amps and it was a maximum of 150 amps that I measured. It's on sale for $250 with $20 off if you sign up for email. I don't really want to mess with 2 batteries.

https://aolithium.com/products/12v100ah-4s-lithium-lifepo4-battery?ref=h-cvbzfahsek

 

[gthorson]

https://jetboaters.net/threads/yamaha-252x-on-single-battery.42120/

This is my experience taking a small step in that direction. You might be able to make it work better.

 

[JBehrens]

https://jetboaters.net/threads/yamaha-252x-on-single-battery.42120/

This is my experience taking a small step in that direction. You might be able to make it work better.

Ya I would never go single battery on a 252 as those electrical systems are designed for two with the house/start split. The 190's are a lot simpler and just have everything on the same battery.

 

[FSH 210 Sport]

I'm going to try the AO Lithium 100AH LiFePO4 battery, it can do 200 amps for 10 seconds. I have measured the starting amps and it was a maximum of 150 amps that I measured. It's on sale for $250 with $20 off if you sign up for email. I don't really want to mess with 2 batteries.

https://aolithium.com/products/12v100ah-4s-lithium-lifepo4-battery?ref=h-cvbzfahsek

Did you see these comments?





I also question the weight of this battery at 23# where all other 100Ah LiFePO4 weigh 31#. Also, why is their warranty only 8 years? All other battery manufacturers offer 10 -11 year warranties. But the most disturbing thing is the comment from Roy T from this August.

I suggest you try calling these numbers and ask some pointed questions, like about how do I return these for warranty issues?

If you have not done so already, I humbly suggest that you read this thread: https://jetboaters.net/threads/conversion-to-lifepo-batteries.35834/ There is a lot of great info there about these batteries.

 

[jEt_jAk]

Ran a single quality AGM battery since it was owned. Kept a jump pack for emergency, never saw the need for a second.

 

[AuburnVFR]

Swap the extra 80 lb battery for a smaller powersports battery used on the same engine in waverunners.

 

[JBehrens]

Swap the extra 80 lb battery for a smaller powersports battery used on the same engine in waverunners.

Now that's an idea!

 

[Beachbummer]

2 is 1, and 1 is none, as far as the sea is concerned.