30v battery charging

Thread Starter

brianvlad

Joined May 1, 2021
1
So I need to charge 30v battery bank (5 6v sla) I'm having a hard time finding a premade charger to accomplish this. My area of work is in the automotive electronics industry and my knowledge to build one is limited. Does anyone know if a company who may make such a thing...or possibly a how to on how to build one?
 

LowQCab

Joined Nov 6, 2012
1,082
Nobody makes one, at least not that you could reasonably afford.
If you have to ask, then you are not capable of building it yourself.

It would help if you would state what problem you are trying to solve by
using ~30-Volts in a Car in the first place.
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.
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dendad

Joined Feb 20, 2016
3,906
Why 30V?
If you go to 36V, there are many ready made SLA chargers available. Lots of scooters use them.
But make sure you get a charger suites for the chemistry of the battery. Do not use a Lithium battery charger on SLA for instance.
You may be able to modify a 36V SLA charger for 30V, but it may be better to change your target voltage if you can.
 

crutschow

Joined Mar 14, 2008
27,697
A constant-voltage power supply with adjustable current limit would work, as JMW suggested.
You would adjust the voltage to about 2.45V per cell (36.75V) @ 25°C, with a current limit of about 0.3 times the battery Ah rating.
But you would need to stop the charge within a few hours after the battery current drops to a low level, (say 10% of the limit setting), to avoid overcharging and gassing.

Note that all the batteries need to be identical type, brand, age, and initial charge status for that to work with the batteries in series.
 
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narkeleptk

Joined Mar 11, 2019
540
Then it would be logical to use a 24V battery, not a 30V battery.
I dont work on 24v stuff but I build a lot of equipment for bench testing ecus on 12v automotive stuff and I generally use running/charging voltage (14~15V) rather then the battery voltage. For 24v systems I guess that would be 28~30V.
 
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narkeleptk

Joined Mar 11, 2019
540
The TS stated he was using five 6v SLA batteries with would then have running/charging voltage of 35-37.5V.
Sorry, I'm probably not clear enough on what I mean. I'm not talking about the charging voltage needed to charge these batteries.


what problem you are trying to solve by
using ~30-Volts in a Car in the first place.
Perhaps they are working with some tool designed for 24V systems.
Then it would be logical to use a 24V battery, not a 30V battery.
I dont work on 24v stuff but I build a lot of equipment for bench testing ecus on 12v automotive stuff and I generally use running/charging voltage (14~15V) rather then the battery voltage.
I was being a bit of a smartass to the guy in the first reply because I thought his questioning of why he wants to use 30V is a bit silly. I was just giving a reason on why TS could be using 30V in an auto system. We dont even know if this is what its for, the first reply was just assuming. Then since I learn so much from great posts by you, I wanted to return the favor and explain why 24V may seem like the logical answer its really not how you would go about simulating a 24V automotive environment. You should actually be running it with 28-30V which is the running/charging voltage for 24V cars.

An example, I built a device that supply's power, ignition, ground, cam/crank signals and test lamps for various sensors and what not to an engine computer that is sitting on my desk, not in the car. I run it at 14-15V's not 12 because I want to simulate what it normally see's while its in the car and running. If I was to make this a more portable device and not dependent on a dc power supply sitting at my desk, then I would probably look for 14V+ battery.

As a side not since maybe people do not understand why someone would need something like this or understand what I'm rambling on and on about I will say, many techs that work on larg trucks that use 24v systems are mobile. Its also common to remove ecu's and tune them on the bench. A portable rig for some basic testing after its done tuning before hooking it back up in the truck is a useful tool.
 
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