Battery Tender Jr

[fishingeek]

Hi all,

I bought a Battery Tender Jr charger and maintainer for my 12v 7ah sla battery. This charger also has a selectable option to charge and maintain a 12v lithium LifePo4 battery also.

I recently bought a Marcum Brute 12v LifePo4 battery. It also came with a stock charger for it. My question is would it be better to use the Battery Tender Jr or the OEM charger? Is true that it is bad to keep a lithium battery on a maintainer on float charge for a long time?

Any info is appreciated. I am fairly new to the LifePo4 battery scene. Just trying to find the best way to extend the battery life.

[DR.SPECKLER]

The battery tender jr is a better quality charger than marcum.i just ordered one for my lithium batteries because the chargers they came with are very cheaply made and i dont trust them.

[kpd145]

Hi all,

I bought a Battery Tender Jr charger and maintainer for my 12v 7ah sla battery. This charger also has a selectable option to charge and maintain a 12v lithium LifePo4 battery also.

I recently bought a Marcum Brute 12v LifePo4 battery. It also came with a stock charger for it. My question is would it be better to use the Battery Tender Jr or the OEM charger? Is true that it is bad to keep a lithium battery on a maintainer on float charge for a long time?

Any info is appreciated. I am fairly new to the LifePo4 battery scene. Just trying to find the best way to extend the battery life.

If your charger supports a LifePo4 then use that. Its not bad to keep the lithium on the charger but its not good for its overall life. LIfePo4 work best when not fully charged and not fully discharged. I unplug mine when its fully charged. Ideally you want to charge to 90% and discharge down to 20%, I know that's not possible all the time.

I have been doing alot of reading up on LifePo4 batteries as I need a few for this coming open water season and I wanted to buy them in the winter. They are great environmentally friendly batteries that can last a long time with proper care and maintenance

[Kevin23]

6 of one half dozen of the other. Both will do the same thing, marcum is a 3A charger though so it would charge 3 times faster. Use whichever is easier for you IMO. I use a noco genius for all of my battery charging because its convenient, same concept as the battery tender jr.

[bigfoot86]

Believe the battery tender is .75 amp charge, I know mine is.  More like a trickle charge but more than enough for 7-9 amp batteries, especially with an over night charge.

[fishingeek]

Thanks for the info! I ran my Marcum brute for 2 days straight. Love it

[3300]

You can charge with lower amps, but it won't be fully charged unless your using a higher voltage charger that's made for it.

I keep mine topped for use and try to leave them at 70% for long term storage and that's the way they are delivered or supposed to be.

There's a big difference from sla and LifePo4, sla doesn't use a control board.

[Kevin23]

Edited*

. The lithium batteries have an internal BMS that controls the charging of the battery, you can charge a lithium SLA replacement with 50mah if you want.

This whole "you need OUR CHARGER" is just marketing BS to sell you a charger. As long as it has lithium mode or able to output 14.6V it will charge your battery to the same level. Dakota is the WORST about it, they will straight lie to a customer and tell them you need our charger or it wont work.

How it works is the battery takes in 13.2-13.5V from your charger until the cells within are mostly charged, when the cells are near full the voltage slowly rises to finish filling up the cells to their max capacity. This needs to rise to 14.6V for the cells to be fully charged, this is why normal SLA chargers that only output 13.5V will never fully charge a lithium. The cells will rise to 14.6V until no more absorption is detected, then the BMS cuts it off and the pack drops back to nominal voltage of around 13-13.4. If the cells then settle and are able to take in more current, the BMS kicks them back open and lets more current in until it hits 14.6 and cuts off again.

The amperage does not matter, its the voltage that matters.

[3300]

I fixed it and then read your comment.

https://ampedoutdoors.com/pages/faq

[Kevin23]

I fixed it and then read your comment.

https://ampedoutdoors.com/pages/faq

Edited mine to reflect. Trying to help people get switched over to lithium without being hosed by the battery sites adding in chargers they don't need. If you have a name brand charger made in the last 5 years, chances are it has a lithium or AGM mode that will work.

[DR.SPECKLER]

I will add the noco genius 2 is the cats a$$ for charging all types of batteries.i got the 2 bank charger and can charge lithium and sla batteries at the same time.

[Kevin23]

I will add the noco genius 2 is the cats a$$ for charging all types of batteries.i got the 2 bank charger and can charge lithium and sla batteries at the same time.

I also have switched my chargers out to noco! The genius 1 for all my SLA (does 6v, 12sla, 12agm, 12lithium), and a genius gen5 onboard on the boat for my lithium trolling motor batteries. Super pleased with both!

[3300]

I have 3 battery tender Jr's. 1 battery tender. 1 Marcum shuttle charger that uses less voltage and plugs into their shuttle directly. 1 marcum sla charger. 1 humminbird sla charger. 1 smoked cabelas sla charger. 1 noco that I use on my amped outdoors 12amp battery. 1 amped outdoors charger, their first one got sent back with their bad battery they replaced both at same time. Numerous automotive charges and minnkota charger for deep cycle.