Motorola MT351R walkie talkie

1

Bought aet if Motorola MT351r walkies and
found one nicad 950 amp was weak. Decided
to purchase a replacement but more amp hrd.
Got new one from Kestar 1300 amp hr which
they said would work. Well…when i hook up
the charger (using one that pluge into wall
socket n has two leads which plug into radios.
Here is problem/question…radio with old 950
battery - screen lights up and battery icon lights
up showing it is charging. Other lead going tp new battery … battery does not light up at all. Swapped batteries and the unit with new battery
does not light up. Is it because i have two batterieswith different amps causing this? NOTE…unit with new Kastar battery fires up, transmits, etc. Just when charging i have the issue. Hope this rembling makes sence.

e this rambling makes sence!

a

2

Does it make sense? Even google translate gave up? I think you mean you have replaced multiple ni-cad cells with ones that have different capacities? If you have two, or more cells in series, and you change the type of cells, then simple battery chargers have problems. With nicads, chargers are often a simple resistor to set a limit to the current. Two different cells means the charge isnt balanced and one cell is getting charged but the other doesnt. Its not clear why on earth you did not replace both cells in the radio with the same type? You found one cell which was weak? How? If you measured the voltage, it could have been the other cell preventing that one charging, if a unit has two cells, replace both, the other at best is nearly dead too? Replacing both with the same rating, but higher than the original will mean they last longer but take longer to charge. One old and new is not going to make any sense, its still as weak as the oldest one. Buy another the same value.

3

My Motorola MT351R walkies came with 950 mAh nicads. One was weak so replaced with 1300 mAh and ordered another one (not received yet). When put on factory charger, (ac charger with split charging wires), unit with 950, screen lights up n battery logo shows charging. Other unit - no lights n assume it is charging? 2nd battery due next week, then will tell if both units respond the same.

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OSrry - I thought you were replacing individual cells, not the pack. Don’t forget these are NOT Ni-cads, they are Ni-MH, and these need different charging current and end of charge protection. A Ni-MH charger will normally charge Ni-cads. The other way around can damage the cells - Ni-MH like controlled chargers.

5

I’m confused. Is the battery in the photo the original that came with the radio or the one you purchased to replace it? Either way, that’s a Ni-MH, not a NiCad and and it’s only 650mAh.

I know the MT350 Series very well. As a Motorola dealer, we used to sell it, along with the replacement battery packs. It was discontinued some years ago and replaced with the T Series radios. The batteries typically lasted about 3 years new on average and as thy got older, generally lost their ability to hold a charge. This is normal for batteries in general.

6

Here is pix of charger that came with Motorola’s. Can it be used to charge Ni-MH battery packs of 1650 mAh 3.6v? Seems i cant attach a pix but on charger it says . Output 5v - 650mA

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Well - it’s not a charger is it? It’s a continuous voltage power supply, and won’t know when the Ni-Mh cells are charged.It will charge them till it destroys them. Ni-cads can be trickle charged without real harm. Ni-Mh need chargers that have current control.

8

The cord from part that plugs in splits with two pins that plug into the side of each Motorola uniat. When plugged in the units vibrate and a shape of a battery shows with charge bars, when filly charged the battery image shows full. So…it IS a charger in my opinion.

9

Let’s back up just a little for some clarification so we can best help you with this.
Trust me, it’s important.

Typos can make a huge difference in the answer, especially when it comes to amps and voltages. You said 1650mAh, but I think you probably meant to type 650mAh. Is that correct?

The output listed on the label of the charger (and yes, it is a charger, we’ll get to that in a moment) is 5V 650mA. To clarify, it isn’t about the battery, it’s about what is actually coming out of the charger and into the battery. The battery is capable of producing 3.6v after it is fully charged. The charger is capable of sending 5V to charge the battery. Those are two different things. In this case, the mA is how much amperage is going to the battery. The battery mAh is how much amperage the battery discharges in one hour. Those are also two different things.

Okay, now for the charger itself. The MT350 series radios originally included an AC wall charger with a USB Y adapter that plugged directly into the radios to charge them simultaneously. These chargers were packaged with the MT350R, MT351R and MT352R radios, as well as several other Motorola Talkabout radios of that period.

The radios were sold in 2-packs (aka bubble packs) that also included a pair of 650mAh Ni-MH (aka Nickel Metal Hydride) battery packs, an example of which is shown in the photo you posted above. So far so good.

The distinction between Ni-MH and Ni-CAD (Nickel Cadmium) is important, as Paul mentioned, because the wrong type of battery in the wrong charger can be a real problem. This is why, when you mention the battery type, we need to be sure it is correct. We’re not being condescending or anything, we need to be sure we have the correct information, because it’s potentially a performance and safety issue that can affect the answers to your questions.

These Talkabout series radios were capable of operating on the provided Ni-MH rechargeable battery packs or 3 AA alkaline batteries. The average battery uptime was 10 hours with the Ni-MH batteries and 15 hrs. with the alkalines.

As I mentioned previously, I know the MT350 series radios well. Your issue can be due to several things. To troubleshoot, we need the full backstory on them, because they are old models that were discontinued over a decade ago and are no longer manufactured. I don’t think the company that originally made them for Motorola is even still in business. So, we need more information.

  1. Were these purchased new?
  2. If so, how long ago and from where?
  3. Were the original battery packs that came with the radios factory sealed with the two pack?
  4. Were the replacement battery packs purchased from a reputable dealer or from a third party or overseas seller on Amazon or eBay?
  5. Is the charger the original OEM charger or was it purchased from a third party reseller?
  6. If these are radios that you purchased new when they were in production between 12-15 years ago, did you use them before, and if so, when was the last time they did hold a charge?
  7. If they ever worked in the past, has anything changed between the last time they charged and now?

The answers to these questions can really shorten the troubleshooting time, help determine what the issue is and how it can be resolved.

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  1. Units bought 2nd hand,
  2. Charger was included.
  3. Came with Ni-MH KEBT-650, 3xAA 3.6v-650 mAh made in China enclosed in blk plastic.
  4. One battery pack went to 1/2 as shown on screen while other unit showed full battery power left. This was after leaving units on at rest for approx 4 hrs.
  5. Went o/l n bought set of higher Ni-MH from Kastar (believe i sent pix of them). They are same diam. as 650’s n fit perfect. Units accepted them, all functions worked perfect. Here is where my question came up … can i recharge them while installed in the units using the charger that csme with radios?
11

Thanks, that’s exactly what we needed.

If the Kaster batteries are higher mAh, I think the image you posted was the included battery pack, because it is the same 650mAh as the ones that were originally made for the radios. Either way, the mAh basically tells you how much of a charge it will hold and how long it it will last. All other things being equal, a higher mAh battery will generally give you more uptime than a lower one.

If the new battery is intended for use in the radios, charging them in the radio itself shouldn’t be an issue, as that’s how the original OEM batteries were designed to be charged. It is important to note, however, that Motorola specifically stated in the manual that after market batteries are not recommended. Since they no longer manufacture them and the radios are long out of warranty anyway, that may be moot, but just passing that along.

In your OP you said that the old battery charges, but the new battery doesn’t, and swapping radios confirms this. You have a couple of possibilities here.

  1. The higher the mAh rating, the longer it takes to charge the radios, especially if the battery is almost totally drained. The average charge time for the original KEBT-650 battery is about 7 hours. A 1300mAh battery would take about 14 hours, according to the manual. It could be that it’s just taking a very long time to get started on the charge cycle with the new battery.

  2. If the original battery charges in both radios, but the new battery doesn’t, it is possible that there is either a mismatch or the battery is defective. The radio already proved that it can charge a battery. In this case, you will probably need to contact the seller of the battery to resolve the issue.

These are not complicated radios, they are just old. I think the issue really comes down to the battery itself.

12

Got it!! Tnx 4 all the good info. My situatio is opposite…orig 650 batteries go down quick vs 1300 seem ok. 14 hrs of recharge!! Wow, will try higher ones after 14 hrs n see how long they last. Tnx agaib

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Happy to help. Keep us posted!

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