Kussmaul AutoCharger 2000 Giving my Batteries 15v

[dstn2bdoa]

Hey Gentleman, as stated in the title I have a Kussmaul Auto charger 2000 in my truck. It's wired to two batteries, starting battery is a standard group 65 starting battery, the second is an Interstate group 27 marine.

The manual for the AutoCharger states that 15v is the normal charging voltage, but it seems high to me. Am I over thinking this, or am I cooking my batteries?

In case your wondering how I came across this setup, I bought a used Power Wagon from a small fire department in SD County. Most of the electronics were just torn out and the nightmare I bought was above my pay grade. So I took the rig to a local mechanic that does all the local Volunteer Fire Departments electrical work. He cleaned up the mess and did some upgrades for me. The Kussmaul is standard fire apparatus equipment. I'll do a write up on the truck soon, I'm pretty happy with it so far.

AutoCharger manual: http://www.kussmaul.com/pdfs/091-39.pdf

 

[AndrewP]

I read briefly through the manual and you may be confusing volts for amperes.

It's kind of strange, it doesn't really go into what the charge and float voltages are. It would be worth some time with your volt meter and see exactly what it is doing. For instance, there's nothing about 3 stage charging or anything else. Just charge and "battery saver". Plus it says the output is "12 volts" which has to be wrong, because the batteries need to see higher than that to charge. Strange there is no temperature compensation.

But if you ran your batteries down a bit by leaving the lights on, when you plugged in the charger, you could take a series of measurements and know pretty quick what it's actually doing. Looks like a commercial grade piece of equipment and might be a really good thing if the voltages are what you want.

 

[dstn2bdoa]

Thanks for the reply.

I also thought that the manual was quite vague. I used my volt meter and it truly was putting out 15v. Scared, I unplugged it and used my regular charger, it was only pushing 13v

I'm gonna head out and mess around with it, I'll report my findings.

 

[dstn2bdoa]

Ok, so I hooked up a battery charger/tender and it charged for two days then when to float mode. I unhooked it and plugged in the shore line to see what it would do on a battery at 14v. It immediately started charging at 15.3v, so I unplugged it again.

Any wisdom?

 

[AndrewP]

15.3 would be ok and even desirable for an equalize charge, as long as it dropped to float (around 13.5) within a short period. You may not have time to mess with it, but if you could sit with it and take voltage readings every 5 minutes for an hour and really see what it does. You could leave your battery caps off and see how much electrolysis is going on.

This looks to be a device installed in an ambulance and plugged into shore power when the ambulance is in the station-so it's always 100% charged. Why not call the 800 number they list for the company?

 

[dstn2bdoa]

I called Kussmaul this morning and the technician had a few questions I couldn't answer from work. I'm going to have to put this on hold till the end of the week when I get home from work.

The manual states that it doesn't trickle,

The charger contains two independent charge controls, one for each battery. This allows each battery to be independently charged while maintaining battery isolation. Each battery voltage is remotely sensed, electronically, eliminating the need for four sense wires. Each of the charge controls is com- pletely automatic and stops charging the battery when it is fully charged. There is no trickle charge and therefore no danger of overcharging and water boil-off.

When I get home from work later this week, I'll wine and dine the wife, take the boys skiing, then dig into it. I'll revive the thread then.

Thanks

 

[DiploStrat]

With the caveat that I don't anything more about the unit than I can learn from reading the manual, I would agree with Andrew about the intended purpose - shore power to keep ambulance/fire truck batteries charged. It seems to have a secondary circuit for flashlights, etc. (So how do you charge your batteries when driving?)

To this end a 15v charge is useful to charge quickly (see also products by CTEK and Sterling which use high voltages), especially as 15A is not a lot of charge; my shore charger is rated at 125A. Depending on your temperature, 15v is not all that high, especially for open FLA batteries and the device claims to reduce the amperage as the battery takes a charge. 15v at 0A isn't going to hurt anything.

Thus my immediate reaction is that you don't have anything to worry about, unless you are trying to run gel cells. I would:

-- Read the manual(s) for my batteries and see what they specify, and,

-- I would call the company and get them to walk you through the intended use of their product.

 

[comptiger5000]

I'd agree that 15v is no problem for an AGM or flooded battery in colder weather. Heck, I see that out of the Jeep's alternator when it's cold enough (regulator has a temp sensor on the battery tray). In warm weather or for a gel cell, 15v is probably a little high, but on a flooded cell where you can add water, it's unlikely to kill anything.

 

[jeep-N-montero]

Most alternators charge between 14.3-14.7 volts so I wouldn't be worried in the least about 15 volts.

 

[dwh]

Reading 15.3v (and the manual says it has a potential of up to 17.5v) at the terminals of the charger is actually measuring the voltage potential of a "short circuit". What matters is the battery voltage. Is it actually pushing the battery voltage up to 15v and above?

 

[rlrenz]

Based on what I see above, it sounds like the charging voltage is way too high. My IOTA charger charges at 14.1 volts, and floats at 13.5 volts. Every 7 days, it kicks into a charge cycle to equalize the batteries, then it drops back to 13.5 volts.

 

[dstn2bdoa]

Reading 15.3v (and the manual says it has a potential of up to 17.5v) at the terminals of the charger is actually measuring the voltage potential of a "short circuit". What matters is the battery voltage. Is it actually pushing the battery voltage up to 15v and above?

I measured the 15.3v at the battery terminals during charge.

The ~ 4' of snow I found in my driveway and on my vehicles took the wind out of my sails. After clearing everything off, I had little motivation to investigate in the cold. Perhaps tomorrow will be more productive.

 

[4x4junkie]

The ~ 4' of snow I found in my driveway and on my vehicles took the wind out of my sails. After clearing everything off, I had little motivation to investigate in the cold. Perhaps tomorrow will be more productive.

Sounds to me like it's working perfectly normal...

Any good temperature-compensated battery charger will vary the output voltage inversely with temperature. At 32°F it should indeed be around 15.3V for a maintenance-free (calcium grid) type battery setting, and will be higher still at colder temps.

On a 80°F day it should measure closer to 14.5V.

 

[rlrenz]

I don't think the Kussmaul charger is temperature compensated.