Spare radio always on charger solution?

[MaxK98]

Hi,

I'd like to know the best way to cope with spare radios that are left on the chargers? I found 2 GP300 for our volunteer fire dept since we needed spare radios for the pager users or the ones that are almost out of battery with their issued radio. Also useful when issued radios radios runs out on a long day of firefighting.

I currently have 2 good batteries. One NiCd and One NiMh. They analyse at 92%.

My plan is to deploy them with 2 rapid chargers in the equipment truck. We currently have one VHF Vertex from the neighboring fire department that they lent us.
It is plugged in AC and is on charge 24/7. As expected the NiMH battery does not last very long. It has probably burnt out from overcharging.

I don't want to do the same thing with our new(to us) GP300. What's the best way to prevent overcharging with rapid chargers? We won't use these very often, probably once every 2-3 weeks.

Would a timer do the job? I'm pretty sure someone with more experience than me has some kind of trick up their sleeve.


On a side note, Anyone has some GP300 or anything in the ~410MHz range laying around? we could use some more spare radios

Thanks a lot

[MaxK98]

I just wanted to add that this slightly off topic note that we also need a similar idea for our Bullard T3Max thermic camera. Our captain bought a new battery one year ago and after 5 minutes it's dead. It has alwasy been left on charger when not in use

[Bill_G]

Common problem with no simple solution. The use of GP300 portables that cannot be narrowbanded aside, the only way to stay ahead of this is assigning someone to manage the batteries, and to have plenty of spares. If you leave them in the chargers for weeks at a time, the batteries slowly cook themselves to death. If you put the chargers on a timed outlet strip, the squad could walk into a bunch of dead radios when they are needed because they self discharged. If you charged the batteries, and stored them separated from the radios, they can still self discharge over time. You need chargers at the station and chargers in the apparatus along with enough spares to work several shifts. It's some work, but someone needs to manage the batteries in the chargers at least once a week to get the best life out of them.

[Satelite]

Hello:
Just for added info.
Motorola did in fact make the GP300 in 12.5 narrow band from the factory.
So if he has the correct model number he does have a narrow band GP300.
In the VHF band a narrow band model number is as shown below.
An 8ch GP300 VHF narrow band has the model number of P93YPC00D1A or P93YPC00D2A
The 16ch GP300 VHF narrow band has the model number of P93YPC00C1A or P93YPC00D2A
The 2ch GP300 VHF narrow band model has a model number of P93YPC00A1A or P93YPC00A2A
If the GP300 is a wide band version then it will have the 7th and 8th characters in the model being a 20 for wide rather than 00 which is narrow band.
Same applies for the UHF version too if anyone wanted to know.
UHF wide example =P94YPC20A2A---- UHF narrow band example =P94YPC00A2A
Motorola made both wide band and narrow band in the P110 and Gp300 portables but the radio did only one version not capable of doing both narrow and wide as the P1225 could.( They were either only narrow or only wide band not both in same radio)
Also Motorola made the M10 and M120 and the GM300 mobiles in one or the other narrow or wide band as well again did only one not both tx widths either 12.5 NB or 25 Wide .
I have customers that have the factory GP300 narrow band portables and the GM300 narrow band mobiles in use yet today.
The one draw back by using a GP300 or GM300 narrow band radio today is that they did not do the new 12.5 splinter freq spacings that were the new added freqs by going from wide to narrow band.
Unless you did the shift key entry during programming and retuned settings then they would as I recall.
I would have to try a narrow band GM300 and enter the 461.0125 freq as an example of the new added freq and tune one up and double check the above info on it doing the new splinter freqs but I think it did as I recall.
My customers had the same licensed freqs before the 12.5 narrow band ruling so it did not affect the channel spacing of the radio since it was on the 25khz split anyway and since the radio was txing at 12.5 width it was already fcc compliant.
We knew the ruling was coming many years before it happened so when a new licensee came we simply asked for the license and put him on with narrow banders at that time to eliminate the problem of telling the customer your wide banders gotta go and you need to buy new.
Also had several purchase used GM300 and GP300 in factory narrow band to replace there GM300 and GP300 wide banders.
There happy which makes me happy .
Satelite

[RFguy]

The solution is IMPRES batteries and chargers.

Look for some used HT750's or HT1250's. Buy a couple of new IMPRES batteries and use IMPRES chargers.

We have volunteer departments here where batteries sit on charge for months on end. IMPRES batteries/chargers properly manage the batteries, not cooking them and reconditioning as needed.

[Satelite]

Hello:
You asked about radios in the 410 MHz range.
Are you VHF 136 to 147 MHz range or actualy 410 MHz area ?
The Gp300 was made in the UHF with a freq range of 403 to 433 MHz too but normaly was a govt freq use if im thinkin right.
I have one but im thinkin its a 25 kHz wide band - Id have to check and it was a 16ch version.
Satelite

[RadioSouth]

Tough situation as mentioned when the radios aren't being cycled more often. Motorola saw the need for this type seldom used service and came out with alkaline packs for the idea of having a bunch on hand ready to go when that sudden need arises. Possibly getting a BMS and have someone assigned to weekly cycle the fleet might be a solution. I got handed the task of maintaing batteries for a 24/7 work group of about 120. We had been getting failures probably attributable to guys grabbing the batteries in the front of the chargers while others were left to cook. I painted the batteries 3 different colors, one for each patrticular shift so that they would rotate service. Your situation primarily calls for getting the batteries cycled in some manner.

[MaxK98]

Hello:
You asked about radios in the 410 MHz range.
Are you VHF 136 to 147 MHz range or actualy 410 MHz area ?
The Gp300 was made in the UHF with a freq range of 403 to 433 MHz too but normaly was a govt freq use if im thinkin right.
I have one but im thinkin its a 25 kHz wide band - Id have to check and it was a 16ch version.
Satelite

As mentioned in one of my previous that has not been approved yet, I am in Canada where the Narrowband laws don't apply. We are on a wideband repeater.

We are also on 410.3625/415.3625 MHz. The trend I have seen in Canada so far is 403MHz to 430Mhz is public safety/gov't agency.
Commercial is 450MHz to 470MHz

Our neighboring fire dept is on VHF. I could use some VHF radios also for mutual aid.

[Will]

There is a simple Mod for the GP300 Rapid charger so you can leave the battery on there without burning it up.

[MTS2000des]

A battery eliminator is a great way to leave your portable on 24/7. Spare batteries still need to be maintained, but at least they are not left "floating" to cook while a radio is on standby.
I bought a Jedi battery eliminator for my Jedi radios for around $20 off Ebay, an OEM one at that. Save the batteries for field use.

[MaxK98]

There is a simple Mod for the GP300 Rapid charger so you can leave the battery on there without burning it up.

Would you mind to share it with us?

[Will]

Would you mind to share it with us?

Certainly:
There is basically two types of circuit boards used in the GP300/350 P110 and Jedi series Rapid chargers.
The circuits are similar.
The older board with the four leaded 2 watt resistors near the heatsink on the left side. The top two resistors closest to the power jack sets the trickle or 'Complete' charge rate. One is 47 ohms and the other is 82 ohms, or 39 ohms and 39 ohms in some models. Change one of them to a 330 ohm 1/2 watt resistor, they are both in series so it doesn't matter. This sets the 'Complete' charging rate to 20 ma, which is safe enough to leave the battery in the charger for extended time.

For a minimum safe value the two resistors should total 160 ohms or more.

The two other resistors, the bottom one, a 1.1 ohm resistor, and a 1.5 ohm resistor sets the Rapid Rate to near 950 ma.

The newer circuit board has all surface mount components, five large surface mounted resistors, two rows of two resistors, and three in an inverted L shape. The three marked 620 set the 'Complete' rate, changing one of them to 150 1/2 watt will set the Complete rate to 20 ma enabling you to leave the battery in the Charger for extended time.

The four resistors marked 2R0 set the Rapid Rate at about 1100 ma.


For the really long time in the charger, use a higher resistance value, 470 Ohms or so.

[Satelite]

Hello:
I routinely chg the nimh batts in my rapid charger but I always remove them after fully charged and not having any batt issues myself.
But im asking if by chance I shouldn't chg with the normal rapid chgr without doing the mod ?
Would I see a better performance with the nimh batt if I did the mod ?
Remember I don't leave the nimh batt in chgr after full charge so am I going to benefit by doing the mod or is it a non issue as to my habits per the batt in chgr ?
Satelite

[Will]

Satelite,

I can not answer for you in particular, but a simple mod and you do not have to worry about leaving the battery in the charger.. NiCad or NiMh is not the problem.
Batteries just do not like to be over charged......

For the OP, a simple change in the GP300 chargers he already has will take care of the problem.

[Satelite]

Hello Will:
Ok im going to assume since I haven't had any issues with nimh batts in my rapid charger and don't leave them in im probably ok since ive done it for years with good success.
I routinely get 3 to 3.5 yrs on a batt in nimh so most likely fine as long as I don't develop the habit of storing the radio in the charger for long periods of time.
But im going to store the chgr mod info just in case later I see the need.
Thanx Will for the info.
Satelite

[wavetar]

Just get a timer, preferably one that allows variable timing on a per day basis. Depending on the model, you could either set it for coming on a single day of the week, for say two hours, or, even one that needs to come on for say an hour every day will be far better than leaving the batteries charging 24/7. If every day, the rapid charger will quickly switch to a trickle charge within a minute or two (assuming your batteries are in decent shape) and keep the batteries topped up without 'cooking' them.

[Will]

Wavetar, problem is the 'timer' has been tried and that resulted in a bunch of burned up batteries. Even Kenwood and ICOM radios and chargers.

[wavetar]

Wavetar, problem is the 'timer' has been tried and that resulted in a bunch of burned up batteries. Even Kenwood and ICOM radios and chargers.

I'm sure your mod works fine, but so does the timer method if set as described. Subtracting 23 hours a day from the trickle charge, or charging once a week after self discharging approx 20% capacity, has worked well for our customers.

[MaxK98]

Wavetar, problem is the 'timer' has been tried and that resulted in a bunch of burned up batteries. Even Kenwood and ICOM radios and chargers.

I'm sure your mod works fine, but so does the timer method if set as described. Subtracting 23 hours a day from the trickle charge, or charging once a week after self discharging approx 20% capacity, has worked well for our customers.

In our case, batteries always needs to be fully charged and ready for a quick grab in case of an emergency. We never know when we will need it.

I will try Will's mod this week. I'll leave them on charger all week long and next weekend I will carry A GP300 to see if the battery is really fully charged.