Battery tender noob

[Rockcrawlindude]

Good morning all.

Problem: I have an older car that does not have a very robust charging system. I’ve been through it and fixed parasitic draws that it had. I’ve replaced the alternator and the battery. Short of rewiring the car, I’ve got it working about as good as it can. It runs about 13.5v at the battery and about 12.4 at the dash on a good day. Overall, it doesn’t keep the battery charged very well. I guess it uses slightly more than it charges on a normal day with headlights and all that. I pull the battery out and charge it overnight occasionally (monthly?)

Solution? I’d like to add a battery tender to keep it topped off. I drive the car almost daily, so I’d like a permanent/ quick connect solution. The battery in this car is in a wet location, so the tender needs to be mounted somewhere else (few foot leads) or weatherproof. I also don’t know which tender I need. 800mA, 1.5A, 4A etc.

The battery in the vehicle is a 50Ah 650CCA

Duracell Ultra Gold Flooded 650CCA BCI Group 40R Car and Truck Battery - SLI40RT6M

Duracell Ultra Gold BCI group 40R replacement battery designed for low maintenance and dependable engine starting power. Perfect replacement battery for Ford, Mazda and more

www.batteriesplus.com

Any help and experience would be appreciated.

 

[flan]

I run this charger on my truck and kubota tractor. The 2nd pic is the cord that hooks permanently to the battery. I just stub it out of the grill. Quick to disconnect and go.

 

[Rockcrawlindude]

I run this charger on my truck and kubota tractor. The 2nd pic is the cord that hooks permanently to the battery. I just stub it out of the grill. Quick to disconnect and go.
View attachment 34436



View attachment 34437

Thanks. you da man!

 

[flan]

They sell extension cables to go between the truck and charger as well in case you don’t have an outlet nearby.

 

[flan]

Thanks. you da man!

No problem, there’s a ton of options but that’s what I’ve been using for the last few years they seem to hold up. They are about 55 bucks on amazon too.

 

[Rockcrawlindude]

No problem, there’s a ton of options but that’s what I’ve been using for the last few years they seem to hold up. They are about 55 bucks on amazon too.

Ordering now.

 

[H3LZSN1P3R]

1A should be plenty… one thought on the alternator assuming its an older car how tight is the alternator belt? I have seen a semi slacked off belt cause a low charge many times

 

[H3LZSN1P3R]

Ordering now.

You wont regret it they are great we use one in our back hoe that had a D8 battery also noco makes decent ones same setup…

 

[flan]

Everyone likes pics, right?

 

[Rockcrawlindude]

Do you think I should bump up to the 4A since I have a known charging issue? Are there any downsides, other than cost, of going to the larger unit? It looks like it has the same pigtails.

 

[Crusty old shellback]

Sounds like you have some serious electrical issues. Not a charging issue.
If you are daily driving it, there should be no need for a battery tender.

Everyone kept telling me I needed one for my Harley as the battery would go dead. It even came from the dealer with the pigtail already mounted for one.

My answer, apparently you are not riding enough if you need a tender.

Rode that bike, with no tender, for 8 years before the battery finally died.

If you show 13.5 at the battery when running, then you are charging. The 12.4 inside while running is an issue. You should not see that much of a voltage drop. There are some electrical gremlins in there. Partial grounds, bad fusible links, old brittle wiring, bad light bulbs.

Either that or you have a monster stereo system in there you are not telling us about.

 

[Rockcrawlindude]

Sounds like you have some serious electrical issues. Not a charging issue.
If you are daily driving it, there should be no need for a battery tender.

Everyone kept telling me I needed one for my Harley as the battery would go dead. It even came from the dealer with the pigtail already mounted for one.

My answer, apparently you are not riding enough if you need a tender.

Rode that bike, with no tender, for 8 years before the battery finally died.

If you show 13.5 at the battery when running, then you are charging. The 12.4 inside while running is an issue. You should not see that much of a voltage drop. There are some electrical gremlins in there. Partial grounds, bad fusible links, old brittle wiring, bad light bulbs.

Either that or you have a monster stereo system in there you are not telling us about.

Thanks for taking the time to respond. I am slowly repairing / restoring the car. It definitely has old and probably some bad wiring. One day I’ll run new wires through it.

A battery tender won’t be wasted money as I can always hook it up to the 94 Toyota based crawler which is probably the most reliable used vehicle I’ve ever had.

 

[Rockcrawlindude]

I went with the 3A model. Thanks for the help, y’all.

 

[Deleted member 21465]

Thanks for taking the time to respond. I am slowly repairing / restoring the car. It definitely has old and probably some bad wiring. One day I’ll run new wires through it.

Bad wiring doesn't cause parasitic draws or low voltage.

What kind of old car is this?
What amp rating is the current alternator or is this old enough it has a generator?
Have you measured the parasitic draws on the battery?
Have you checked to see what total amp draw is with everything on?

Old cars usually had very robust charging systems and the parasitic draws usually would take 30-45 days of no use before you might have a low battery. You have something wrong, if it is wiring so bad it's not allowing you to charge you can bet where ever the bad wire is you have something getting hot if the alternator is generating enough power.

 

[Rockcrawlindude]

Bad wiring doesn't cause parasitic draws or low voltage.

What kind of old car is this?
What amp rating is the current alternator or is this old enough it has a generator?
Have you measured the parasitic draws on the battery?
Have you checked to see what total amp draw is with everything on?

Old cars usually had very robust charging systems and the parasitic draws usually would take 30-45 days of no use before you might have a low battery. You have something wrong, if it is wiring so bad it's not allowing you to charge you can bet where ever the bad wire is you have something getting hot if the alternator is generating enough power.

It’s an 87 Porsche 944. They’re known to have poor charging systems.

Thank you for taking the time to respond but I’m not looking for troubleshooting help with the car itself.

 

[Crusty old shellback]

Good luck with it. Hopefully it's not overheating bad wires which could lead to a fire. hate to see that. Been there done that on my '73 K5 build.

 

[Rockcrawlindude]

Good luck with it. Hopefully it's not overheating bad wires which could lead to a fire. hate to see that. Been there done that on my '73 K5 build.

Thanks man. That sounds like it sucked bad.

 

[Deleted member 21465]

It’s an 87 Porsche 944. They’re known to have poor charging systems.

Thank you for taking the time to respond but I’m not looking for troubleshooting help with the car itself.

Understood but if memory serves me the 944 only offered two alternators that year and it was either a 90 amp or 115 amp which should keep the system charged very well. As mentioned if the wiring is that bad anytime you have voltage that wiring won't carry it causes the wires to heat, sometimes until they glow. If not that the power is going to ground or not being generated at all. They really were easy cars to work on and you are correct they had electrical issues but usually it was parasitic draws from some early electronic systems.

Good luck.