3 Battery Tender Question

[JLG]

I am looking into getting a 3 battery tender for my boat as I have 3 batteries. I have installed a single battery tender and I assumed that it would charge all 3 but now appears that only 1 battery gets charged all the way when I ohm them. I don't know a whole lot about them but am I going in the right direction to get a 3 battery tender to keep all of them charged?

Does it matter if the battery kill switch is shut off when charging as I have 2 of the batteries positives tied together anyway that run my stereo and the main start battery is on its own wired before the switch?

Are there any brands of tenders that are good and ones that I need to stay away from?

Do these tenders actually shutoff when charged or do they overheat and shorten the life of a battery if left connected majority of the time?

[trudelle]

I have four batteries and have three of them wired in parallel (+ to +) for the stereo and one battery to start. I use a 4 bank NOCO genius charger. I leave the batteries switches off when I charge and all batteries charge completely. I am not an electrical guy so I won't guess as to why your batteries won't charge. All I can do is tell you that if you get a charger/tender you could use a two or three bank as the way the stereo batteries are wired basically makes them one. I personally like to have a charger for each battery as it will speed up the charging time. I love the NOCO charger/tender and it is perfect for my application. But what I have does not allow me to manually change the charge that is delivered to the batteries (trickle, quick, normal, etc). What it does it automatically charge and maintain the battery level.

With the intelligent NOCO VosFX processor constantly monitoring the power input, attached battery and charger itself, the GEN4 charger is capable of diagnosing, recovering, charging and maintaining batteries.

[trudelle]

I meant a bank for each battery not a charger for each lol

[chpthril]

You have two battery bank, so ideally, you would want a 2 bank charger. That pair of batteries wired together are now one battery.

I would get more than just a battery tender. Go with an actual on-board multi-stage smart 2 bank charger with amp output in the range of 10% of your total battery Ah.

Yes it matters to have the battery switch off. This allows the charger to condition and recharge each bank differently. This is good because each bank is obviously used differently. Most main cranking banks do not need much charging.

[JLG]

trudelle 4 batteries?? It's hard to find space for the 3 I have. thanks for the info I will look into that brand

chpthril, I knew I should've just messaged you as you would know the answer so thanks that is kinda what my detective work has pointed me to as far as the 2 bank smart system but was leaning towards the 3 as its only a few more $$. I was thinking the switch off made a difference as I've watched the amperes on my current charger change when switching it back and forth. I currently have my tender connected to my 2 stereo batteries and was running my crank battery down if i leave the stereo on for too long.

[trudelle]

I have a few D3100's from XSPower and a basic starter battery. I have a battery and the start battery in the rear location where they originally were, one outside of that in the same rear locker with my sub box and one in the other rear locker side where my other sub box is but the battery is in the rear location like the other batteries. I need the batteries as I have oh about 5000watts in the stereo and like to play it loud and for long periods of time. like I said check out NOCO genius chargers as they are not that expensive and are very reliable. It has all my batteries charged over night and all winter long I have left the charger hooked up and no problems. good luck as I know what you are going thru... I researched and researched and researched before I finally went with the products I have.