Dual battery charger advice

[dalcini]

Hi folks,
First boat - purchased used last fall. I'm wet-slipping at a marina this summer and feel I need to install a battery charger. I've read many great posts from folks like @FSH 210 Sport and others on batts and chargers and want to check my plan before moving ahead.

Here's my general plan for a charger install:

• Remove Solar panel (It's dead anyway and I don't know how to properly integrate with a plug-in charger - and plug-in takes priority)
• Victron IP67 charger for each battery
• DVSR switched hot mod

The two FLA batteries that came with the boat (used) still seem healthy, reading 12.5-12.7v. I maintained them over the winter on a small Noco Genius at home.

Some questions I have:

• Is it ok to go with the 7a Victrons to keep the cost down? Mininum time between boat use will be overnight so charge time is not much concern.
• Someday when I'm ready to replace my FLA batteries, I'll probably go with FLA+AGM or AGM+AGM. Does this change the plan for the Victron model at all? (my guess is no).

Any additional comments/advice welcome.

 

[FSH 210 Sport]

Go with the 25A IP67’s… they are worth the money, keep in mind you need 10-13% of the Ah rating of a lead acid battery to properly charge it. The new IP 67’s are highly adjustable from 3A to 25A, having used the 10A or 25A model I would not have any other battery charger. As a fyi, I shared several emails with Interstates tech dept and I was told in writing that their AGM batteries can be charged at 25A as long as voltage does not exceed 14.4 volts.

 

[dalcini]

Thanks @FSH 210 Sport. Another question just occurred to me... I don't see any dual bank chargers in Victron's IP67 line. If I recall correctly, you have at least 3 installed. How are you handling AC power to all of these? I was hoping to do something clean but hadn't considered the need for multiple plugs.

 

[CastawayRK]

I have 2 2 bank chargers plugged into this

 

[FSH 210 Sport]

Thanks @FSH 210 Sport. Another question just occurred to me... I don't see any dual bank chargers in Vicron's IP67 line. If I recall correctly, you have at least 3 installed. How are you handling AC power to all of these? I was hoping to do something clean but hadn't considered the need for multiple plugs.

I have 5 batteries in all, three trolling motor batteries with an IP67 charger for each one, and a minnkota two bank charger for the house lfp and starter agm batteries.

I have the two plug noco ac adapter that @CastawayRK has pictured above, in one plug I have a short three plug extension cord, and the other noco plug goes to the minnkota.. Thats a total of 11.4A on the 120 vac side and the noco adapter is rated for 15A.

 

[dalcini]

Thanks gents. I'll pick one of these up too.

 

[FSH 210 Sport]

Thanks gents. I'll pick one of these up too.

I made an assumption that you were going to be charging at 25A, but after reviewing the thread again I see that you have two FLA batteries, not sure what size they are but since they came with the boat I’ll assume group 24 and 70Ah and a 7A per battery charge rate you’ll only have 1.7A on the 120V side for both chargers.

7A charge rate X 14.7VDC=102.9W / 120VAC= .86A X 2= 1.71A @120VAC

 

[dalcini]

I made an assumption that you were going to be charging at 25A, but after reviewing the thread again I see that you have two FLA batteries, not sure what size they are but since they came with the boat I’ll assume group 24 and 70Ah and a 7A per battery charge rate you’ll only have 1.7A on the 120V side for both chargers.

7A charge rate X 14.7VDC=102.9W / 120VAC= .86A X 2= 1.71A @120VAC

@FSH 210 Sport, you are correct sir! I looked my batteries up and they're 72ah. I actually hit the "buy" button on two ip67's a few minutes before you posted this morning. Full disclosure, I went with two 17a (instead of 25a) models to keep the cost down.

Your formula looks like it's based on a single charger for both batteries. I assumed I needed one for each. Is that not required to enable individual charge profiles? I didn't think these were dual bank chargers.

 

[FSH 210 Sport]

My formula is for two individual IP67’s, its .86A per charger per battery. On their website it looks like the chargers are selectable between all amperage’s? Mine are selectable between 10A and 25A, that has come in handy on occasion when the outlets, like at marinas outlets that are slip side that would not support the 25A charge rate. What I saw on the app was that my chargers were going between 25A and 10A, so I went in put them in 10A and they became stable at 10A each..

 

[FSH 210 Sport]

Just got off the phone with Battle Born and now I understand the two different charge levels.. I should have seen that before I suppose.

The is a high and low are for each charger, the 25A model has a low charge rate of 10A, the 17A model has a low of 6A and so on..

 

[dalcini]

Interesting - thanks for all the great info guys. Believe it or not, the Noco GCP2 already showed up on my porch from this morning's order. I have a lot to do this spring!